19-4781; Rev 1; 7/00
`
`E V A L U A T I O N K I T
`High-Speed, Digitally Adjusted
`A V A I L A B L E
`Step-Down Controllers for Notebook CPUs
`
`MAX1710/MAX1711/MAX1712
`
`Features
`
`o Ultra-High Efficiency
`o No Current-Sense Resistor (Lossless ILIMIT)
`o Quick-PWM with 100ns Load-Step Response
`o ±1% VOUT Accuracy over Line and Load
`o 4-Bit On-Board DAC (MAX1710)
`o 5-Bit On-Board DAC (MAX1711/MAX1712)
`o 0.925V to 2V Output Adjust Range
`(MAX1711/MAX1712)
`o 2V to 28V Battery Input Range
`o 200/300/400/550kHz Switching Frequency
`o Remote GND and VOUT Sensing
`o Over/Undervoltage Protection
`o 1.7ms Digital Soft-Start
`o Drive Large Synchronous-Rectifier FETs
`o 2V ±1% Reference Output
`o Power-Good Indicator
`o Small 24-Pin QSOP Package
`Ordering Information
`TEMP. RANGE
`PIN-PACKAGE
`-40°C to +85°C
`24 QSOP
`-40°C to +85°C
`24 QSOP
`
`PART
`MAX1710EEG
`MAX1711EEG
`
`Minimal Operating Circuit
`
`+5V INPUT
`
`BATTERY
`4.5V TO 28V
`
`VCC OVP*
`SHDN
`FBS
`ILIM
`GNDS
`
`MAX1710
`MAX1711
`MAX1712
`
`REF
`
`VDD
`V+
`
`BST
`DH
`
`LX
`
`DL
`
`OUTPUT
`0.925V TO 2V
`(MAX1711/MAX1712)
`
`CC
`D0
`D1
`D2
`D3
`D4**
`
`GND
`
`D/A
`INPUTS
`
` *MAX1710 ONLY
`**MAX1711/MAX1712 ONLY
`
`PGND
`
`FB
`SKIP
`
`General Description
`The MAX1710/MAX1711 step-down controllers are
`intended for core CPU DC-DC converters in notebook
`computers. They feature a triple-threat combination of
`ultra-fast transient response, high DC accuracy, and
`high efficiency needed for leading-edge CPU core
`power supplies. Maxim’s proprietary Quick-PWM™
`quick-response, constant-on-time PWM control scheme
`handles wide input/output voltage ratios with ease and
`provides 100ns “instant-on” response to load transients
`while maintaining a relatively constant switching fre-
`quency.
`High DC precision is ensured by a 2-wire remote-sens-
`ing scheme that compensates for voltage drops in both
`the ground bus and supply rail. An on-board, digital-to-
`analog converter (DAC) sets the output voltage in com-
`pliance with Mobile Pentium II® CPU specifications.
`The MAX1710 achieves high efficiency at a reduced
`cost by eliminating the current-sense resistor found in
`traditional current-mode PWMs. Efficiency is further
`enhanced by an ability to drive very large synchronous-
`rectifier MOSFETs.
`Single-stage buck conversion allows these devices to
`directly step down high-voltage batteries for the highest
`possible efficiency. Alternatively, 2-stage conversion
`(stepping down the +5V system supply instead of the
`battery) at a higher switching frequency allows the mini-
`mum possible physical size.
`The MAX1710/MAX1711 are identical except that the
`MAX1711 have 5-bit DACs and the MAX1710 has a 4-
`bit DAC. Also, the MAX1711 has a fixed overvoltage
`protection threshold at VOUT = 2.25V and undervoltage
`protection at VOUT = 0.8V whereas the MAX1710 has
`variable thresholds that track VOUT. The MAX1711 is
`intended for applications where the DAC code may
`change dynamically.
`
`Applications
`
`Notebook Computers
`Docking Stations
`CPU Core DC-DC Converters
`Single-Stage (BATT to VCORE) Converters
`Two-Stage (+5V to VCORE) Converters
`
`Quick-PWM is a trademark of Maxim Integrated Products.
`Mobile Pentium II is a registered trademark of Intel Corp.
`
`Pin Configurations appear at end of data sheet.
`
`________________________________________________________________ Maxim Integrated Products 1
`For price, delivery, and to place orders, please contact Maxim Distribution at 1-888-629-4642,
`or visit Maxim’s website at www.maxim-ic.com.
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 1 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`ABSOLUTE MAXIMUM RATINGS
`V+ to GND ..............................................................-0.3V to +30V
`DH to LX .....................................................-0.3V to (BST + 0.3V)
`VCC, VDD to GND .....................................................-0.3V to +6V
`LX to BST..................................................................-6V to +0.3V
`PGND to GND.....................................................................±0.3V
`REF Short Circuit to GND ...........................................Continuous
`SHDN, PGOOD to GND ...........................................-0.3V to +6V
`Continuous Power Dissipation (TA = +70°C)
`OVP, ILIM, FB, FBS, CC, REF, D0–D4,
`24-Pin QSOP (derate 9.5mW/°C above +70°C)..........762mW
`GNDS, TON to GND..............................-0.3V to (VCC + 0.3V)
`Operating Temperature Range ...........................-40°C to +85°C
`SKIP to GND (Note 1).................................-0.3V to (VCC + 0.3V)
`Junction Temperature......................................................+150°C
`DL to PGND................................................-0.3V to (VDD + 0.3V)
`Storage Temperature Range .............................-65°C to +165°C
`BST to GND ............................................................-0.3V to +36V
`Lead Temperature (soldering, 10s) .................................+300°C
`Note 1: SKIP may be forced below -0.3V, temporarily exceeding the absolute maximum rating, for the purpose of debugging proto-
`type breadboards using the no-fault test mode. Limit the current drawn to -5mA maximum.
`Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional
`operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to
`absolute maximum rating conditions for extended periods may affect device reliability.
`ELECTRICAL CHARACTERISTICS
`(Circuit of Figure 1, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = 0°C to +85°C, unless otherwise noted.)
`CONDITIONS
`MIN
`TYP
`PARAMETER
`2
`4.5
`-1
`
`Input Voltage Range
`
`Battery voltage, V+
`VCC, VDD
`
`VBATT = 4.5V to 28V, includes
`load regulation error
`
`DAC codes from 1.3V to 2V
`
`DAC codes from 0.925V
`to 1.275V
`
`-1.2
`
`DC Output Voltage Accuracy
`
`Load Regulation Error
`Remote-Sense Voltage Error
`Line Regulation Error
`FB Input Bias Current
`
`FB Input Resistance
`(MAX1711/MAX1712)
`
`GNDS Input Bias Current
`Soft-Start Ramp Time
`
`On-Time
`
`ILOAD = 0 to 7A
`FB - FBS or GNDS - GND = 0 to 25mV
`VCC = 4.5V to 5.5V, VBATT = 4.5V to 28V
`FB (MAX1710 only) or FBS
`
`Rising edge of SHDN to full ILIM
`TON = GND (550kHz)
`TON = REF (400kHz)
`TON = open (300kHz)
`TON = VCC (200kHz)
`
`VBATT = 24V,
`FB = 2V
`(Note 2)
`
`9
`3
`5
`
`180
`
`1.7
`160
`200
`290
`425
`400
`600
`<1
`25
`<1
`<1
`
`<1
`
`2
`
`1.6
`
`-0.2
`
`130
`
`-1
`
`140
`175
`260
`380
`
`1.98
`
`10
`
`Minimum Off-Time
`Quiescent Supply Current (VCC)
`Quiescent Supply Current (VDD)
`Quiescent Battery Supply Current
`Shutdown Supply Current (VCC)
`Shutdown Supply Current (VDD)
`Shutdown Battery Supply
`Current
`Reference Voltage
`Reference Load Regulation
`REF Sink Current
`REF Fault Lockout Voltage
`
`(Note 2)
`Measured at VCC, FB forced above the regulation point
`Measured at VDD, FB forced above the regulation point
`Measured at V+
`SHDN = 0
`SHDN = 0
`
`SHDN = 0, measured at V+ = 28V, VCC = VDD = 0 or 5V
`
`VCC = 4.5V to 5.5V, no external REF load
`IREF = 0 to 50µA
`REF in regulation
`Falling edge, hysteresis = 40mV
`
`2
`
`_______________________________________________________________________________________
`
`UNIT
`
`V
`
`MAX
`28
`5.5
`1
`
`1.2
`
`0.2
`
`240
`
`1
`
`180
`225
`320
`470
`500
`950
`5
`40
`5
`5
`
`5
`
`2.02
`0.01
`
`%
`
`mV
`mV
`mV
`µA
`
`kΩ
`
`µA
`ms
`
`ns
`
`ns
`µA
`µA
`µA
`µA
`µA
`
`µA
`
`V
`V
`µA
`V
`
`MAX1710/MAX1711/MAX1712
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 2 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`ELECTRICAL CHARACTERISTICS (continued)
`(Circuit of Figure 1, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = 0°C to +85°C, unless otherwise noted.)
`PARAMETER
`CONDITIONS
`MIN
`TYP
`With respect to unloaded output voltage (MAX1710)
`10.5
`12.5
`2.21
`2.25
`(MAX1711/MAX1712)
`
`Overvoltage Trip Threshold
`
`MAX
`14.5
`2.29
`
`UNIT
`%
`V
`
`MAX1710/MAX1711/MAX1712
`
`75
`0.84
`
`30
`
`110
`
`60
`230
`
`-80
`
`0.4
`1
`
`4.4
`
`5
`
`5
`
`µs
`
`%
`V
`
`ms
`
`mV
`
`mV
`
`mV
`
`mV
`
`µs
`V
`µA
`°C
`
`V
`
`Ω
`
`Ω
`
`Ω
`
`A
`
`A
`A
`
`ns
`
`0.5
`
`1.7
`
`1
`
`3
`1
`35
`26
`
`FB forced 2% above trip threshold
`
`With respect to unloaded output voltageWith respect to unloaded output voltage (MAX1710)
`
`(MAX1711/MAX1712)
`
`From SHDN signal going high
`
`LX to PGND, ILIM tied to VCC
`RLIM = 100kΩ
`RLIM = 400kΩ
`
`LX to PGND
`
`LX to PGND, TA = +25°C
`
`LX to PGND
`
`FB forced 2% below PGOOD trip threshold, falling edge
`ISINK = 1mA
`High state, forced to 5.5V
`Hysteresis = 10°C
`
`Rising edge, hysteresis = 20mV,
`PWM disabled below this level
`
`4.1
`
`1.5
`
`70
`0.8
`
`100
`
`50
`200
`
`65
`0.76
`
`10
`
`90
`
`40
`170
`
`-150
`
`-120
`
`3
`
`1.5
`
`150
`
`Overvoltage Fault Propagation
`Delay
`Output Undervoltage Protection
`Threshold
`Output Undervoltage Protection
`Time
`Current-Limit Threshold
`(Positive Direction, Fixed)
`
`Current-Limit Threshold
`(Positive Direction, Adjustable)
`
`Current-Limit Threshold
`(Negative Direction)
`
`Current-Limit Threshold
`(Zero Crossing)
`
`PGOOD Propagation Delay
`PGOOD Output Low Voltage
`PGOOD Leakage Current
`Thermal Shutdown Threshold
`VCC Undervoltage Lockout
`Threshold
`
`DL Gate-Driver On-Resistance
`(Pullup)
`
`DL Gate-Driver On-Resistance
`(Pulldown)
`
`DH Gate-Driver Source/Sink
`Current
`
`DL Gate-Driver Sink Current
`DL Gate-Driver Source Current
`
`Dead Time
`
`SKIP Input Current Logic
`Threshold
`
`PGOOD Trip Threshold
`
`Logic Input High Voltage
`Logic Input Low Voltage
`Logic Input Current
`Logic Input Pullup Current
`
`DH Gate-Driver On-Resistance
`
`BST-LX forced to 5V
`
`DL, high state
`
`DL, low state
`
`DH forced to 2.5V, BST-LX forced to 5V
`
`DL forced to 2.5V
`DL forced to 2.5V
`DL rising
`DH rising
`
`To enable no-fault mode, TA = +25°C
`
`Measured at FB with respect to unloaded output voltage,
`falling edge, hysteresis = 1%
`
`D0–D4, SHDN, SKIP, OVP
`D0–D4, SHDN, SKIP, OVP
`SHDN, SKIP, OVP
`D0–D4, each forced to GND
`
`-1.5
`
`-8
`
`2.4
`
`-1
`3
`
`-0.1
`
`mA
`
`-5
`
`-3
`
`0.8
`1
`10
`
`5
`
`%
`
`V
`V
`µA
`µA
`
`_______________________________________________________________________________________
`
`3
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 3 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`ELECTRICAL CHARACTERISTICS (continued)
`(Circuit of Figure 1, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = 0°C to +85°C, unless otherwise noted.)
`PARAMETER
`CONDITIONS
`MIN
`TYP
`TON logic input high level
`VCC - 0.4
`TON VCC Level
`TON logic input upper-midrange level
`3.15
`TON Float Voltage
`TON logic input lower-midrange level
`1.65
`TON Reference Level
`TON logic input low level
`TON GND Level
`TON only, forced to GND or VCC
`TON Logic Input Current
`
`-3
`
`MAX
`
`3.85
`2.35
`0.5
`3
`
`ELECTRICAL CHARACTERISTICS
`(Circuit of Figure 1, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = -40°C to +85°C, unless otherwise noted.) (Note 3)
`CONDITIONS
`MIN
`TYP
`MAX
`PARAMETER
`2
`28
`4.5
`5.5
`-1.5
`1.5
`
`Battery voltage, V+
`VCC, VDD
`
`VBATT = 4.5V to 28V, for all
`D/A codes, includes load
`regulation error
`
`DAC codes from 1.32V to 2V
`
`DAC codes from 0.925V to
`1.275V
`
`Input Voltage Range
`
`DC Output Voltage Accuracy
`
`On-Time
`
`Minimum Off-Time
`Quiescent Supply Current (VCC)
`Reference Voltage
`
`Overvoltage Trip Threshold
`
`Output Undervoltage
`Protection Threshold
`
`Current-Limit Threshold
`(Positive Direction, Fixed)
`
`Current-Limit Threshold
`(Positive Direction, Adjustable)
`
`VCC Undervoltage Lockout
`Threshold
`Logic Input High Voltage
`Logic Input Low Voltage
`Logic Input Current
`Logic Input Pullup Current
`
`VBATT = 24V,
`FB = 2V
`(Note 2)
`
`TON = GND (550kHz)
`TON = REF (400kHz)
`TON = open (300kHz)
`TON = VCC (200kHz)
`
`(Note 2)
`Measured at VCC, FB forced above the regulation point
`VCC = 4.5V to 5.5V, no external REF load
`With respect to unloaded output voltage (MAX1710)
`(MAX1711/MAX1712)
`With respect to unloaded output voltage (MAX1710)
`(MAX1711/MAX1712)
`
`LX to PGND
`
`LX to PGND, ILIM tied to VCC
`RLIM = 100kΩ
`RLIM = 400kΩ
`Rising edge, hysteresis = 20mV, PWM disabled below
`this level
`
`D0–D4, SHDN, SKIP, OVP
`D0–D4, SHDN, SKIP, OVP
`SHDN, SKIP, OVP
`D0–D4, each forced to GND
`
`-1.7
`
`140
`175
`260
`380
`
`1.98
`10
`2.20
`65
`0.75
`
`85
`
`35
`160
`
`4.1
`
`2.4
`
`-1
`3
`
`1.7
`
`180
`225
`320
`470
`500
`950
`2.02
`15
`2.30
`75
`0.85
`
`115
`
`65
`240
`
`4.4
`
`0.8
`1
`10
`
`UNIT
`V
`V
`V
`V
`µA
`
`UNIT
`
`V
`
`%
`
`%
`
`ns
`
`ns
`µA
`V
`%
`V
`%
`V
`
`mV
`
`mV
`
`V
`
`V
`V
`µA
`µA
`
`MAX1710/MAX1711/MAX1712
`
`4
`
`_______________________________________________________________________________________
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 4 of 28
`
`

`

`MAX1710/MAX1711/MAX1712
`
`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`ELECTRICAL CHARACTERISTICS (continued)
`(Circuit of Figure 1, VBATT = 15V, VCC = VDD = 5V, SKIP = GND, TA = -40°C to +85°C, unless otherwise noted.) (Note 3)
`CONDITIONS
`MIN
`TYP
`MAX
`PARAMETER
`
`PGOOD Trip Threshold
`
`PGOOD Output Low Voltage
`PGOOD Leakage Current
`
`Measured at FB with respect to unloaded output voltage,
`falling edge, hysteresis = 1%
`ISINK = 1mA
`High state, forced to 5.5V
`
`-8.5
`
`-2.5
`
`0.4
`1
`
`UNIT
`
`%
`
`V
`µA
`
`Note 2: On-Time and Off-Time specifications are measured from 50% point to 50% point at the DH pin with LX forced to 0V, BST
`forced to 5V, and a 250pF capacitor connected from DH to LX. Actual in-circuit times may differ due to MOSFET switching
`speeds.
`Note 3: Specifications from -40°C to 0°C are guaranteed but not production tested.
`
`__________________________________________Typical Operating Characteristics
`(7A CPU supply circuit of Figure 1, TA = +25°C, unless otherwise noted.)
`
`MAX1710-03
`
`10
`
`EFFICIENCY vs. LOAD CURRENT
`(VO = 1.3V, f = 300kHz)
`
`VIN = 4.5V
`
`VIN = 7V
`
`VIN = 15V
`
`VIN = 24V
`
`100
`
`90
`
`80
`
`70
`
`60
`
`50
`
`40
`
`EFFICIENCY (%)
`
`EFFICIENCY vs. LOAD CURRENT
`(VO = 1.6V, f = 300kHz)
`
`MAX1710-02
`
`VIN = 4.5V
`
`VIN = 7V
`
`VIN = 15V
`
`VIN = 24V
`
`100
`
`90
`
`80
`
`70
`
`60
`
`50
`
`40
`
`EFFICIENCY (%)
`
`EFFICIENCY vs. LOAD CURRENT
`(VO = 2.0V, f = 300kHz)
`
`MAX1710-01
`
`VIN = 7V
`
`VIN = 4.5V
`
`VIN = 15V
`
`VIN = 24V
`
`100
`
`90
`
`80
`
`70
`
`60
`
`50
`
`40
`
`EFFICIENCY (%)
`
`0.01
`
`1
`0.1
`LOAD CURRENT (A)
`
`10
`
`0.01
`
`1
`0.1
`LOAD CURRENT (A)
`
`10
`
`0.01
`
`1
`0.1
`LOAD CURRENT (A)
`
`MAX1710-06
`
`FREQUENCY vs. INPUT VOLTAGE
`(IO = 7A)
`
`VO = 2.0V
`
`VO = 1.6V
`
`TON = OPEN
`
`0
`
`5
`
`20
`15
`10
`INPUT VOLTAGE (V)
`
`25
`
`30
`
`320
`318
`316
`314
`312
`310
`308
`306
`304
`302
`300
`
`FREQUENCY (kHz)
`
`MAX1710-05
`
`FREQUENCY vs. LOAD CURRENT
`(VO = 1.6V)
`
`VIN = 15V, PWM MODE
`
`VIN = 4.5V, SKIP MODE
`
`VIN = 15V, SKIP MODE
`
`TON = OPEN
`
`0.01
`
`1
`0.1
`LOAD CURRENT (A)
`
`10
`
`350
`
`300
`
`250
`
`200
`
`150
`
`100
`
`50
`
`0
`
`FREQUENCY (kHz)
`
`EFFICIENCY vs. LOAD CURRENT
`(VO = 1.6V, f = 550kHz)
`
`MAX1710-04
`
`VIN = 4.5V
`
`VIN = 7V
`
`VIN = 15V
`
`VIN = 24V
`
`0.01
`
`1
`0.1
`LOAD CURRENT (A)
`
`10
`
`100
`
`90
`
`80
`
`70
`
`60
`
`50
`
`40
`
`EFFICIENCY (%)
`
`_______________________________________________________________________________________
`
`5
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 5 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`_____________________________Typical Operating Characteristics (continued)
`(7A CPU supply circuit of Figure 1, TA = +25°C, unless otherwise noted.)
`FREQUENCY vs. TEMPERATURE
`(VIN = 15V, VO = 2.0V)
`
`CURRENT-LIMIT TRIP POINT
`vs. TEMPERATURE
`
`MAX1710-09
`
`ILIM = 400kΩ
`
`ILIM = VCC
`
`ILIM = 100kΩ
`
`-60
`
`-40
`
`-20
`
`40
`20
`0
`TEMPERATURE (°C)
`
`60
`
`80
`
`100
`
`NO-LOAD SUPPLY CURRENTS
`vs. INPUT VOLTAGE
`(SKIP MODE, f = 300kHz)
`
`MAX1710-12
`
`ICC
`
`30
`
`25
`
`20
`
`15
`
`10
`
`05
`
`0.7
`
`0.6
`
`0.5
`
`CURRENT TRIP POINT (A)
`
`ON-TIME vs. TEMPERATURE
`
`MAX1710-08
`
`IO = 1A
`
`IO = 4A OR 7A
`
`-60
`
`-40
`
`-20
`
`40
`20
`0
`TEMPERATURE (°C)
`
`60
`
`80
`
`100
`
`INDUCTOR CURRENT PEAKS AND
`VALLEYS vs. INPUT VOLTAGE
`(AT CURRENT-LIMIT POINT)
`
`MAX1710-11
`
`IPEAK
`
`474
`
`472
`
`470
`
`468
`
`466
`
`464
`
`462
`
`460
`
`458
`
`456
`
`14.0
`
`13.5
`
`13.0
`
`12.5
`
`ON-TIME (ns)
`
`MAX1710-07
`
`IO = 7A
`
`IO = 4A
`
`TON = OPEN
`
`IO = 1A
`
`-60
`
`-40
`
`-20
`
`40
`20
`0
`TEMPERATURE (°C)
`
`60
`
`80
`
`100
`
`CONTINUOUS TO DISCONTINUOUS
`INDUCTOR CURRENT POINT
`vs. INPUT VOLTAGE
`
`MAX1710-10
`
`VO = 2.0V
`
`VO = 1.6V
`
`VO = 1.3V
`
`315
`
`310
`
`305
`
`300
`
`295
`
`290
`
`285
`
`0.9
`
`0.8
`
`0.7
`
`0.6
`
`FREQUENCY (kHz)
`
`30
`
`MAX1710-15
`
`IBATT
`
`IDD
`
`0
`
`5
`
`25
`
`20
`10
`15
`INPUT VOLTAGE (V)
`NO-LOAD SUPPLY CURRENTS
`vs. INPUT VOLTAGE
`(PWM MODE, f = 550kHz)
`
`IDD
`
`IBAT
`
`ICC
`
`0
`
`5
`
`20
`15
`10
`INPUT VOLTAGE (V)
`
`25
`
`30
`
`0.4
`
`0.3
`
`0.2
`
`0.1
`
`0
`
`20
`18
`16
`14
`12
`10
`8
`
`6 4 2
`
`0
`
`SUPPLY CURRENT (mA)
`
`SUPPLY CURRENT (mA)
`
`12.0
`
`11.5
`
`11.0
`
`10.5
`
`10.0
`
`0
`
`20
`18
`16
`14
`12
`10
`8
`
`6 4 2
`
`0
`
`IVALLEY
`
`30
`
`MAX1710-14
`
`5
`
`25
`
`20
`15
`10
`INPUT VOLTAGE (V)
`NO-LOAD SUPPLY CURRENTS
`vs. INPUT VOLTAGE
`(PWM MODE, f = 300kHz)
`
`IDD
`
`IBAT
`
`ICC
`
`0
`
`5
`
`20
`15
`10
`INPUT VOLTAGE (V)
`
`25
`
`30
`
`INDUCTOR CURRENT (A)
`
`SUPPLY CURRENT (mA)
`
`30
`
`MAX1710-13
`
`0
`
`5
`
`25
`
`20
`15
`10
`INPUT VOLTAGE (V)
`NO-LOAD SUPPLY CURRENTS
`vs. INPUT VOLTAGE
`(SKIP MODE, f = 550kHz)
`
`ICC
`
`IBATT
`
`IDD
`
`0
`
`5
`
`15
`20
`10
`INPUT VOLTAGE (V)
`
`25
`
`30
`
`MAX1710/MAX1711/MAX1712
`
`0.5
`
`0.4
`
`0.3
`
`0.2
`
`0.1
`
`0
`
`0.7
`
`0.6
`
`0.5
`
`0.4
`
`0.3
`
`0.2
`
`0.1
`
`0
`
`LOAD CURRENT (A)
`
`SUPPLY CURRENT (mA)
`
`6
`
`_______________________________________________________________________________________
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 6 of 28
`
`

`

`MAX1710/MAX1711/MAX1712
`
`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`_____________________________Typical Operating Characteristics (continued)
`(7A CPU supply circuit of Figure 1, TA = +25°C, unless otherwise noted.)
`
`LOAD-TRANSIENT RESPONSE
`(WITH INTEGRATOR)
`
`LOAD-TRANSIENT RESPONSE
`(WITH INTEGRATOR)
`
`LOAD-TRANSIENT RESPONSE
`(WITHOUT INTEGRATOR)
`
`MAX1710-18
`
`MAX1710-21
`
`10µs/div
`VIN = 15V, VO = 1.6V, IO = 30mA TO 7A
`A = VOUT, AC-COUPLED, 50mV/div
`B = INDUCTOR CURRENT, 5A/div
`
`STARTUP WAVEFORM
`
`A
`
`B
`
`A
`
`B
`
`C
`
`MAX1710-17
`
`MAX1710-20
`
`10µs/div
`VIN = 15V, VO = 1.6V, IO = 30mA TO 7A
`A = VOUT, AC-COUPLED, 50mV/div
`B = INDUCTOR CURRENT, 5A/div
`
`LOAD-TRANSIENT RESPONSE
`(WITH INTEGRATOR)
`
`A
`
`B
`
`A
`
`B C
`
`MAX1710-16
`
`MAX1710-19
`
`10µs/div
`VIN = 15V, VO = 1.6V, IO = 0A TO 7A
`A = VOUT, AC-COUPLED, 50mV/div
`B = INDUCTOR CURRENT, 5A/div
`
`LOAD-TRANSIENT RESPONSE
`(WITH INTEGRATOR)
`
`A
`
`B
`
`A
`
`B C
`
`20µs/div
`VIN = 4.5V, VO = 2V, IO = 30mA TO 7A
`A = VOUT, AC-COUPLED, 50mV/div
`B = INDUCTOR CURRENT, 5A/div
`C = DL, 10V/div
`
`20µs/div
`VIN = 4.5V, VO = 1.3V, IO = 30mA TO 7A
`A = VOUT, AC-COUPLED, 50mV/div
`B = INDUCTOR CURRENT, 5A/div
`C = DL, 10V/div
`
`500µs/div
`
`A = SHDN
`B = VOUT, 0.5V/div
`C = INDUCTOR CURRENT, 5A/div
`
`_______________________________________________________________________________________ 7
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 7 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`_____________________________Typical Operating Characteristics (continued)
`(7A CPU supply circuit of Figure 1, TA = +25°C, unless otherwise noted.)
`
`OUTPUT OVERLOAD WAVEFORM
`
`LOAD-TRANSIENT RESPONSE
`
`SHUTDOWN WAVEFORM
`
`MAX1710-24
`
`A B C
`
`D
`
`MAX1710-23
`
`CERAMIC COUT
`
`MAX1710-22
`
`A
`
`B C
`
`A B
`
`C
`
`50µs/div
`
`VOUT = 1.6V
`A = VIN, AC-COUPLED, 2V/div
`B = VOUT, 0.5V/div
`C = INDUCTOR CURRENT, 5A/div
`
`5µs/div
`L = 0.7µH, VOUT = 1.6V, VIN = 15V, COUT = 47µF (x4), f = 550kHz
`A = VOUT, AC-COUPLED, 100mV/div
`B = INDUCTOR CURRENT, 5A/div
`C = DL, 5V/div
`
`5µs/div
`VIN = 15V, V0 = 1.6V, I0 = 7A
`A = VOUT, 0.5V/div
`B = INDUCTOR CURRENT, 5A/div
`C = SHDN, 2V/div
`D = DL, 5V/div
`
`Pin Description
`
`PIN
`
`NAME
`
`FUNCTION
`
`1
`
`2
`
`3
`
`4
`
`5
`
`6
`
`7
`
`8
`
`9
`
`V+
`
`SHDN
`
`FB
`
`FBS
`
`CC
`
`ILIM
`
`VCC
`
`TON
`
`REF
`
`Battery Voltage Sense Connection. V+ is used only for PWM one-shot timing. DH on-time is inversely propor-
`tional to V+ input voltage over a range of 2V to 28V.
`
`Shutdown Control Input, active low. SHDN cannot withstand the battery voltage. In shutdown mode, DL is
`forced to VDD in order to enforce overvoltage protection, even when powered down (unless OVP is high).
`Fast Feedback Input, normally connected to VOUT. FB is connected to the bulk output filter capacitors local-
`ly at the power supply. An external resistor-divider can optionally set the output voltage.
`
`Feedback Remote-Sense Input, normally connected to VOUT directly at the load. FBS internally connects to
`the integrator that fine tunes the DC output voltage. Tie FBS to VCC to disable all three integrator amplifiers.
`Tie FBS to FB (or disable the integrators) when externally adjusting the output voltage with a resistor-divider.
`
`Integrator Capacitor Connection. Connect a 100pF to 1000pF (470pF typical) capacitor to GND to set the
`integration time constant.
`Current-Limit Threshold Adjustment. Connects to an external resistor to GND. The LX-PGND current-limit
`threshold defaults to +100mV if ILIM is tied to VCC. The current-limit threshold is 1/10 of the voltage forced at
`ILIM. In adjustable mode, the threshold is VTH = RLIM ✕ 5µA/10.
`Analog Supply Voltage Input for PWM Core, 4.5V to 5.5V. Bypass VCC to GND with a 0.1µF minimum
`capacitor.
`
`On-Time Selection Control Input. This is a four-level input that sets the K factor to determine DH on-time.
`GND = 550kHz, REF = 400kHz, open = 300kHz, VCC = 200kHz.
`2.0V Reference Output. Bypass REF to GND with a 0.22µF minimum capacitor. REF can source 50µA for
`external loads. Loading REF degrades FB accuracy according to the REF load-regulation error
`(see Electrical Characteristics).
`
`8
`
`_______________________________________________________________________________________
`
`MAX1710/MAX1711/MAX1712
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 8 of 28
`
`

`

`MAX1710/MAX1711/MAX1712
`
`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`Pin Description (continued)
`
`PIN
`10
`
`11
`
`12
`13
`14
`15
`
`16
`(MAX1710)
`
`16
`(MAX1711/
`MAX1712)
`
`17
`18
`19
`20
`
`21
`
`22
`
`23
`
`24
`
`NAME
`GND
`
`GNDS
`
`PGOOD
`DL
`PGND
`VDD
`
`OVP
`
`D4
`
`D3
`D2
`D1
`D0
`
`SKIP
`
`BST
`
`LX
`
`DH
`
`Analog Ground
`
`FUNCTION
`
`Ground Remote-Sense Input, normally connected to ground directly at the load. GNDS internally con-
`nects to the integrator that fine tunes the ground offset voltage.
`
`Open-Drain Power-Good Output
`Low-Side Gate-Driver Output, swings 0 to VDD
`Power Ground. Also used as the inverting input for the current-limit comparator.
`Supply Voltage Input for the DL Gate Driver, 4.5V to 5.5V
`
`Overvoltage-Protection Disable Control Input (Table 4). GND = normal operation and overvoltage
`protection active, VCC = overvoltage protection disabled.
`
`DAC Code Input, MSB. 5µA internal pullup to VCC (Tables 1, 2, and 3).
`
`DAC Code Input. 5µA internal pullup to VCC.
`DAC Code Input. 5µA internal pullup.
`DAC Code Input. 5µA internal pullup.
`DAC Code Input LSB. 5µA internal pullup.
`
`Low-Noise-Mode Selection Control Input. Low-noise forced-PWM mode causes inductor current
`recirculation at light loads and suppresses pulse-skipping operation. Normal operation prevents
`current recirculation. SKIP can also be used to disable both overvoltage and undervoltage protection
`circuits and clear the fault latch (Figure 6). GND = normal operation, VCC = low-noise mode. Do not
`leave SKIP floating.
`
`Boost Flying-Capacitor Connection. An optional resistor in series with BST allows the DH pullup
`current to be adjusted (Figure 5). This technique of slowing the LX rise time can be used to prevent
`accidental turn-on of the low-side MOSFET due to excessive gate-drain capacitance.
`Inductor Connection. LX serves as the lower supply rail for the DH high-side gate driver. Also used
`for the noninverting input to the current-limit comparator, as well as the skip-mode zero-crossing com-
`parator.
`High-Side Gate-Driver Output. Swings LX to BST.
`
`Standard Application Circuit
`The standard application circuit (Figure 1) generates a
`low-voltage, high-power rail for supplying up to 7A to the
`core CPU VCC in a notebook computer. This DC-DC
`converter steps down a battery or AC adapter voltage to
`sub-2V levels with high efficiency and accuracy, and
`represents a good compromise between size, efficiency,
`and cost.
`See the MAX1710 EV kit manual for a list of components
`and suppliers.
`
`Detailed Description
`The MAX1710/MAX1711/MAX1712 buck controllers are
`targeted for low-voltage, high-current CPU power sup-
`plies for notebook computers. CPU cores typically exhib-
`it 0A to 10A or greater load steps when the clock is
`throttled. The proprietary Quick-PWM pulse-width modu-
`lator in the MAX1710/MAX1711/MAX1712 is specifically
`designed for handling these fast load steps while main-
`taining a relatively constant operating frequency and
`inductor operating point over a wide range of input volt-
`ages. The Quick-PWM architecture circumvents the poor
`load-transient timing problems of fixed-frequency cur-
`
`_______________________________________________________________________________________ 9
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 9 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`C6
`1µF
`
`D2
`CMPSH-3
`
`C7
`0.1µF
`
`C1 3 x 10µF/30V
`
`Q1
`
`PANASONIC
`ETQP6F2R0HFA
`L1
`2µH
`
`Q2
`
`D1
`
`C2
`3 x 470µF
`KEMET T510
`
`VOUT
`1.25V TO 2V AT 7A (MAX1710)
`0.925V TO 2V AT 7A (MAX1711)
`1.1V TO 1.85V AT 7A (MAX1712)
`D3
`(OPTIONAL OVP
`REVERSE-POLARITY
`CLAMP)
`
`+5V
`
`R2
`100k
`
`R4
`1k
`
`POWER-GOOD
`INDICATOR
`
`Q1 = IRF7807
`Q2 = IRF7805
`D1, D3 = MBRS130T3 (OPTIONAL)
`C1 = SANYO OS-CON (30SC10M)
`
`VBATT
`4.5V TO 28V
`+5V
`BIAS SUPPLY
`
`C5
`1µF
`
`R1
`20Ω
`
`22
`
`24
`
`23
`
`13
`
`14
`
`3 4 1
`
`1
`
`12
`
`15
`
`VDD
`
`BST
`
`DH
`
`MAX1710
`MAX1711
`MAX1712
`
`LX
`
`DL
`
`PGND
`
`FB
`FBS
`GNDS
`
`7
`VCC
`
`V+
`
`SHDN
`
`SKIP
`
`D0
`
`D1
`
`D2
`
`1 2
`
`21
`
`20
`
`19
`
`18
`
`17
`
`D3
`16 D4**
`
`TON
`
`REF
`
`CC
`
`8 9 5
`
`10
`
`GND
`
`PGOOD
`
`ILIM OVP*
`16
`6
`
`R3
`(OPTIONAL)
`
`ON/OFF
`CONTROL
`
`LOW-NOISE
`CONTROL
`
`DAC
`INPUTS
`
`C4
`1µF
`C3
`470pF
`
`TO VCC
`
`*MAX1710 ONLY
`**MAX1711/MAX1712 ONLY
`
`MAX1710/MAX1711/MAX1712
`
`Figure 1. Standard Application Circuit
`
`rent-mode PWMs while also avoiding the problems
`caused by widely varying switching frequencies in con-
`ventional constant-on-time and constant-off-time PWM
`schemes.
`
`+5V Bias Supply (VCC and VDD)
`The MAX1710/MAX1711/MAX1712 require an external
`+5V bias supply in addition to the battery. Typically, this
`+5V bias supply is the notebook’s 95% efficient 5V sys-
`tem supply. Keeping the bias supply external to the IC
`improves efficiency and eliminates the cost associated
`with the +5V linear regulator that would otherwise be
`
`needed to supply the PWM circuit and gate drivers. If
`stand-alone capability is needed, the +5V supply can be
`generated with an external linear regulator such as the
`MAX1615.
`The battery and +5V bias inputs can be tied together if
`the input source is a fixed 4.5V to 5.5V supply. If the +5V
`bias supply is powered up prior to the battery supply, the
`enable signal (SHDN) must be delayed until the battery
`voltage is present in order to ensure startup. The +5V
`bias supply must provide VCC and gate-drive power, so
`the maximum current drawn is:
`
`10
`
`______________________________________________________________________________________
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 10 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`VBATT 2V TO 28V
`
`RLIM
`
`V+
`
`ILIM
`
`TOFF
`1-SHOT
`TRIG
`
`Q
`
`VCC
`
`5µA
`
`CURRENT
`LIMIT
`
`Σ
`
`Q
`
`S R
`
`TON
`
`ON-TIME
`COMPUTE
`
`FROM
`D/A
`
`TON
`TON
`
`TRIG
`
`Q
`
`1-SHOT
`
`Q
`
`S R
`
`REF
`
`70k
`
`ERROR
`AMP
`10k
`
`REF
`
`gm
`
`gm
`
`gm
`
`OVP
`
`SKIP
`
`SHDN
`
`CC
`
`GNDS
`FBS
`
`REF
`-5%
`
`PGOOD
`
`MAX1710/MAX1711/MAX1712
`
`OUTPUT
`
`MAX1710
`
`+5V
`
`BST
`
`DH
`
`LX
`
`ZERO CROSSING
`VDD
`
`+5V
`
`DL
`
`PGND
`
`FB
`
`FB
`
`REF
`+12%
`
`REF
`-30%
`
`S1
`
`Q
`
`S2
`
`TIMER
`
`OVP/UVLO
`LATCH
`
`CHIP SUPPLY
`
`VCC
`
`+5V
`
`R-2R
`D/A CONVERTER
`
`D0
`
`D1
`
`D2
`
`D3
`
`REF
`
`2V
`REF
`
`GND
`
`Figure 2. MAX1710 Functional Diagram
`
`IBIAS = ICC + f ✕ (QG1 + QG2) = 15mA to 30mA (typ)
`where ICC is 600µA (typ), f is the switching frequency,
`and QG1 and QG2 are the MOSFET data sheet total
`gate-charge specification limits at VGS = 5V.
`Free-Running, Constant-On-Time PWM
`Controller with Input Feed-Forward
`The Quick-PWM control architecture is an almost fixed-
`frequency, constant-on-time current-mode type with volt-
`
`age feed-forward (Figure 2). This architecture relies on
`the filter capacitor’s ESR to act as the current-sense
`resistor, so the output ripple voltage provides the PWM
`ramp signal. The control algorithm is simple: the high-
`side switch on-time is determined solely by a one-shot
`whose period is inversely proportional to input voltage
`and directly proportional to output voltage. Another one-
`shot sets a minimum off-time (400ns typ). The on-time
`one-shot is triggered if the error comparator is low, the
`
`______________________________________________________________________________________ 11
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 11 of 28
`
`

`

`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`Table 1. MAX1710 FB Output Voltage
`DAC Codes
`
`Table 2. MAX1711 FB Output Voltage
`DAC Codes
`
`OUTPUT
`VOLTAGE (V)
`2.00
`1.95
`1.90
`1.85
`1.80
`1.75
`1.70
`1.65
`1.60
`1.55
`1.50
`1.45
`1.40
`1.35
`1.30
`Shutdown3*
`1.275
`1.250
`1.225
`1.200
`1.175
`1.150
`1.125
`1.100
`1.075
`1.050
`1.025
`1.000
`0.975
`0.950
`0.925
`Shutdown3*
`
`D4
`
`D3
`
`D2
`
`D1
`
`D0
`
`0 1 0 1 0 1 0 1 1 0 1 0 1 0 1
`
`0
`
`0 1 0 1 0 1 0 1 1 0 1 0 1 0 1
`
`0
`
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`*See Table 4.
`
`settings due to fixed propagation delays and is approxi-
`mately ±12.5% at 550kHz and 400kHz, and ±10% at the
`two slower settings. This translates to reduced switch-
`ing-frequency accuracy at higher frequencies (Table 5).
`Switching frequency increases as a function of load cur-
`rent due to the increasing drop across the low-side
`
`D3
`
`D2
`
`D1
`
`D0
`
`0
`0
`0
`0
`0
`0
`0
`0
`1
`1
`1
`1
`1
`1
`1
`1
`
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`
`OUTPUT
`VOLTAGE (V)
`2.00
`1.95
`1.90
`1.85
`1.80
`1.75
`1.70
`1.65
`1.60
`1.55
`1.50
`1.45
`1.40
`1.35
`1.30
`1.25
`
`low-side switch current is below the current-limit thresh-
`old, and the minimum off-time one-shot has timed out.
`On-Time One-Shot (TON)
`The heart of the PWM core is the one-shot that sets the
`high-side switch on-time. This fast, low-jitter, adjustable
`one-shot includes circuitry that varies the on-time in
`response to battery and output voltage. The high-side
`switch on-time is inversely proportional to the battery
`voltage as measured by the V+ input, and directly pro-
`portional to the output voltage as set by the DAC code.
`This algorithm results in a nearly constant switching fre-
`quency despite the lack of a fixed-frequency clock gen-
`erator. The benefits of a constant switching frequency
`are twofold: first, the frequency can be selected to avoid
`noise-sensitive regions such as the 455kHz IF band;
`second, the inductor ripple-current operating point
`remains relatively constant, resulting in easy design
`methodology and predictable output voltage ripple:
`
`On-Time = K (VOUT + 0.075V) / VIN
`where K is set by the TON pin-strap connection and
`0.075V is an approximation to accommodate for the
`expected drop across the low-side MOSFET switch.
`One-shot timing error increases for the shorter on-time
`
`12
`
`______________________________________________________________________________________
`
`MAX1710/MAX1711/MAX1712
`
`MICROCHIP TECHNOLOGY INC. EXHIBIT 1045
`Page 12 of 28
`
`

`

`MAX1710/MAX1711/MAX1712
`
`High-Speed, Digitally Adjusted
`Step-Down Controllers for Notebook CPUs
`
`Table 3. MAX1712 FB Output Voltage
`DAC Codes (VRM 9.0)
`
`D4
`
`D3
`
`D2
`
`D1
`
`D0
`
`OUTPUT
`VOLTAGE (V)
`
`1.850
`1.825
`1.800
`1.775
`1.750
`1.725
`1.700
`1.675
`1.650
`1.625
`1.600
`1.575
`1.550
`1.525
`1.500
`1.475
`1.450
`1.425
`1.400
`1.375
`1.350
`1.325
`1.300
`1.275
`1.250
`1.225
`1.200
`1.175
`1.150
`1.125
`1.100
`Shutdown3*
`
`101010110101010
`
`0
`
`101010110101010
`
`0
`
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`0
`0
`0
`0
`1
`1
`1
`1
`
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`0
`0
`1
`1
`
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`0
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`1
`*See Table 4.
`
`MOSFET, which causes a faster inductor-current dis-
`charge ramp. The on-times guaranteed in the Electrical
`Characteristics are influenced by switching delays in the
`external high-side power MOSFET. The exact switching
`frequency will depend on gate charge, internal gate
`
`where VDROP1 is the sum of the parasitic voltage drops
`in the inductor discharge path, including synchronous
`rectifier, inductor, and PC board resistances; VDROP2
`is the sum of the resistances in the charging path,
`and tON is the on-time calculated by the MAX1710/
`MAX1711/MAX1712.
`
`Integrator Amplifiers (CC)
`There are three integrator amplifiers that provide a fine
`adjustment to the output regulation point. One amplifier
`monitors the difference between GNDS and GND, while
`another monitors the difference between FBS and FB.
`The third amplifier integrates the difference between
`REF and the DAC output. These three transconductance
`amplifiers’ outputs are directly summed inside the chip,
`so the integration time constant can be set easily with a
`capacitor. The gm of each amplifier is 160µmho (typ).
`The integrator block has an ability to move and correct
`the output voltage by about -2%, +4%. For each amplifi-
`er, the differential input voltage range is about ±50mV
`total, including DC offset and AC ripple. The voltage
`gain of each integrator is about 80V/V.
`The FBS amplifier corrects for DC voltage drops in PC
`board traces and con