MAX1625 ,High-Speed Step-Down Controllers with Synchronous Rectification for CPU PowerApplicationsVV DDCCPentium Pro™, Pentium II™, PowerPC™, Alpha™,TO AGNDand K6™ SystemsCSHDesktop Com ..
MAX1625ESE ,High-Speed Step-Down Controllers with Synchronous Rectification for CPU Powerfeatures such as a digitally programmable out-' Current-Mode Feedbackput in 100mV increments; adjus ..
MAX1625ESE+ ,High-Speed Step-Down Controllers with Synchronous Rectification for CPU PowerApplicationsVV DDCCPentium Pro™, Pentium II™, PowerPC™, Alpha™,TO AGNDand K6™ SystemsCSHDesktop Com ..
MAX1626 ,5V/3.3V or Adjustable, 100% Duty Cycle, High-Efficiency, Step-Down DC-DC ControllersApplications• External P-Channel MOSFET Allows Output Power• Handheld Computersof > 12.5W• High-Eff ..
MAX1626ESA ,5V/3.3V or Adjustable / 100% Duty-Cycle / High-Efficiency / Step-Down DC-DC ControllersMAX1626/MAX162719-1075; Rev 0; 6/965V/3.3V or Adjustable, 100% Duty-Cycle, High-Efficiency, Step-Do ..
MAX1626ESA+ ,5V/3.3V or Adjustable, 100% Duty Cycle, High-Efficiency, Step-Down DC-DC ControllersEVALUATION KIT AVAILABLE5V/3.3V or Adjustable,MAX1626/MAX1627100% Duty-Cycle, High-Efficiency,Step- ..
MAX4365ETA+T ,1.4W and 1W, Ultra-Small, Audio Power Amplifiers with ShutdownELECTRICAL CHARACTERISTICS—5V(V = 5V, R = ∞, C = 1µF to GND, V = V , T = +25°C, unless otherwise no ..
MAX4365ETA-T ,1.4W and 1W, Ultra-Small, Audio Power Amplifiers with ShutdownApplicationsMARKMAX4364ESA+ -40°C to +85°C 8 SO —Cellular PhonesMAX4365EUA+ -40°C to +85°C 8 µMAX — ..
MAX4365EUA ,1.4W and 1W / Ultra-Small / Audio Power Amplifiers with ShutdownFeaturesThe MAX4364/MAX4365 are bridged audio power 1.4W into 8Ω Load (MAX4364)amplifiers intended ..
MAX4366EUA+ ,330mW, Ultra-Small, Audio Power Amplifiers with ShutdownApplicationsMAX4366EBL-T -40°C to +85°C 8 UCSP-8 AAKCellular PhonesMAX4366EKA-T -40°C to +85°C 8 SO ..
MAX436CPD ,Wideband Trasconductance AmplifiersFeatures
. 275MHz Bandwidth (MAX435)
. tb50Wps Slew Rate
ta
. No Feedback
. True Differentia ..
MAX436CSD ,Wideband Trasconductance AmplifiersApplications
High-Speed Instrumentation Amplifiers
High-Speed Filters
Wideband, High-Gain Bandpa ..
MAX1625
High-Speed Step-Down Controllers with Synchronous Rectification for CPU Power
_______________General DescriptionThe MAX1624/MAX1625 are ultra-high-performance,
step-down DC-DC controllers for CPU power in high-end
computer systems. Designed for demanding applications
in which output voltage precision and good transient
response are critical for proper operation, they deliver
over 35A from 1.1V to 3.5V with ±1% total accuracy from
a +5V ±10% supply. Excellent dynamic response cor-
rects output transients caused by the latest dynamically
clocked CPUs. These controllers achieve over 90% effi-
ciency by using synchronous rectification. Flying-capaci-
tor bootstrap circuitry drives inexpensive, external
N-channel MOSFETs.
The switching frequency is resistor programmable from
100kHz to 1MHz. High switching frequencies allow the
use of a small surface-mount inductor and decrease out-
put filter capacitor requirements, reducing board area
and system cost.
The MAX1624 is available in a 24-pin SSOP and offers
additional features such as a digitally programmable out-
put in 100mV increments; adjustable transient response;
selectable 0.5%, 1%, or 2% AC load regulation; and gate
drive for a current-boost MOSFET. The MAX1625 is resis-
tor adjustable and comes in a 16-pin narrow SO pack-
age. Other features in both controllers include internal
digital soft-start, a power-good output, and a 3.5V ±1%
reference output. For a similar controller compatible with
the latest Intel VRM/VIDspecification, see the MAX1638*
data sheet.
________________________ApplicationsPentium Pro™, Pentium II™, PowerPC™, Alpha™,
and K6™ Systems
Desktop Computers
LAN Servers
Industrial Computers
GTL Bus Termination
____________________________FeaturesBetter than ±1% Output Accuracy Over
Line and Load90% EfficiencyExcellent Transient ResponseResistor-Programmable Fixed Switching
Frequency from 100kHz to 1MHzOver 35A Output CurrentDigitally Programmable Output from 1.1V to 3.5V
in 100mV Increments (MAX1624)Resistor-Adjustable Output down to 1.1V
(MAX1625)Remote SensingAdjustable AC Loop Gain (MAX1624)GlitchCatcher™Circuit for Fast Load-Transient
Response (MAX1624)Power-Good (PWROK) OutputCurrent-Mode FeedbackDigital Soft-StartStrong 2A Gate DriversCurrent-Limited Outputigh-Speed Step-Down Controllers with
Synchronous Rectification for CPU Power19-1227; Rev 1; 6/97
PART
MAX1624EAG
MAX1625ESE-40°C to +85°C
-40°C to +85°C
TEMP. RANGEPIN-PACKAGE24 SSOP
16 Narrow SO
______________Ordering Information
__________Typical Operating Circuit
Pin Configurations appear at end of data sheet.*Future product.
Pentium Pro and Pentium II are trademarks of Intel Corp.
PowerPC is a trademark of IBM Corp.
Alpha is a trademark of Digital Equipment Corp.
K6 is a trademark of Advanced Micro Devices.
GlitchCatcher is a trademark of Maxim Integrated Products.
EVALUATION KIT
AVAILABLEVCC
FREQ
CC2
CC1
REF
AGND
(SIMPLIFIED)PWROK
BST
CSL
CSH
TO VDD
TO AGND
PGND
OUTPUT
1.1V TO 4.5V
INPUT
+5V
VDD
MAX1625
kHz
igh-Speed Step-Down Controllers with
Synchronous Rectification for CPU Power
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= VCC = D4 = +5V, PGND = AGND = D0–D3 = 0V, RFREQ = 33.3kΩ, TA
= 0°C to +85°C, unless otherwise noted.) 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.
VDD, VCC, PWROK to AGND......................................-0.3V to 6V
PGND to AGND..................................................................±0.3V
CSH, CSL to AGND....................................-0.3V to (VCC+ 0.3V)
NDRV, PDRV, DL to PGND.........................-0.3V to (VDD+ 0.3V)
REF, CC1, CC2, LG, D0–D4, FREQ,
FB to AGND................................................-0.3V to (VCC + 0.3V)
BST to PGND............................................................-0.3V to 12V
BST to LX....................................................................-0.3V to 6V
DH to LX.............................................(LX - 0.3V) to (BST + 0.3V)
Continuous Power Dissipation (TA= ±70°C)
24 Pin SSOP (derate 8.00mW/°C above +70°C)..........640mW
16 Pin Narrow SO (derate 8.70mW/°C above 70°C).....696mW
Operating Temperature Range
MAX162_E_ _.......................................................-40°C to +85°C
Storage Temperature Range.............................-65°C to +125°C
Lead Temperature (soldering, 10sec).............................+300°C
RFREQ= 33.3kΩ
RFREQ = 20kΩ
PWROK = 5.5V
VCC= VDD= 5.5V,
FB overdrive = 200mV
ISINK= 2mA, VCC= 4.5V
Falling FB, 1% hysteresis with respect to VREF
VCCrising edge, 1% hysteresis
Rising FB, 1% hysteresis with respect to VREF
VCC= VDD
MAX1624, over line
and load (Note 1)
VREF= 0V
Rising edge, 1% hysteresis
0μA < ILOAD< 100μA
VCC= VDD= 5.5V, FB overdrive = 200mV,
operating or standby mode
MAX1625, over line
and load (Note 2)
No load
CONDITIONSSwitching Frequency1PWROK Output Current High 0.4PWROK Output Voltage Low
6.589.5%-7.5-6-4.5PWROK Trip Level%
AC Load Regulation
(Note 3)
±1.5%±1FB Set Voltage
±1.5
2.5VCCSupply Current4.04.24.55.5Input Voltage Range
Input Undervoltage Lockout±1FB Accuracy0.54.0Reference Short-Circuit Current2.73.0Reference Undervoltage Lockout10Reference Load Regulation0.30.1VDDSupply Current3.4653.53.535Reference Voltage
UNITSMINTYPMAXPARAMETEROperating mode
Standby mode= +25°C to +85°C= 0°C to +85°C= +25°C to +85°C= 0°C to +85°C
CSH - CSL =
0mV to 80mV
RFREQ= 200kΩ
kHz100115
LG = REF
LG = GND
LG = VCC
MAX1624
MAX1625
LG = REFCSH - CSL =
0mV to 80mV
LG = GND
LG = VCC
MAX1624
MAX1625
0.1%
DC Load Regulation
(Note 3)
ELECTRICAL CHARACTERISTICS (continued)(VDD= VCC = D4 = +5V, PGND = AGND = D0–D3 = 0V, RFREQ = 33.3kΩ, TA
= 0°C to +85°C, unless otherwise noted.) DH = DL = 2.5V
VDD= 4.5V
BST - LX = 4.5V
LG = GND (low)
100mV overdrive
RFREQ= 20kΩ
With respect to VREF,
FB going low
Minimum
MAX1625, CSH = CSL = 1.1V
D0–D4 = 0V, 5V
D0–D4; VCC= 4.5V
LG = REF (mid)
MAX1624, CSH = CSL = 1.3V,
D0–D3 = 5V, D4 = 0V
D0–D4; VCC= 5.5V
CONDITIONSLG = VCC (high)030
FB = 1.1V
DH, DL Dead Time2DH, DL Source/Sink Current
Maximum
DH On-Resistance0.72-3-1100CC2 Source/Sink CurrentVCCV2.43.0
mmho110CC1 Output Resistance±0.1
0.28590Maximum Duty Cycle
LG Input Voltage50CSH, CSL Input Current4LG Input Current±1D0–D4 Input Current2.0Logic Input Voltage High
VCC- 0.2
0.8Logic Input Voltage Low
UNITSMINTYPMAXPARAMETERFB Input Current
CC2 Clamp Voltage
CC2 Transconductance
PDRV Trip Level
PDRV, NDRV Response TimeFB overdrive = 5%ns75
PDRV, NDRV On-ResistanceVDD= 4.5VΩ25
PDRV, NDRV Source/Sink CurrentPDRV = NDRV = 2.5VA0.5
PDRV, NDRV Minimum On-Timens100
Current-Limit Trip VoltagemV85100115
Soft-Start TimeTo full current limit1 / fOSC1536
BST Leakage CurrentBST = 12V, LX = 7V, REF = GNDμA50
igh-Speed Step-Down Controllers wit
Synchronous Rectification for CPU PowerDL On-Resistance
NDRV Trip LevelWith respect to VREF,
FB going high
1.2522.75%13= +25°C= 0°C to +85°C= +25°C= 0°C to +85°C
igh-Speed Step-Down Controllers withSynchronous Rectification for CPU PowerRFREQ= 33.3kΩ
RFREQ = 20kΩ
VCC= VDD= 5.5V,
FB overdrive = 200mV
Falling FB, 1% hysteresis with respect to VREF
VCCrising edge, 1% hysteresis
Rising FB, 1% hysteresis with respect to VREF
VCC= VDD
RFREQ= 200kΩ
Operating mode
VCC= VDD= 5.5V, FB overdrive = 200mV,
operating or standby mode
MAX1624, over line and load
No load
CONDITIONSStandby mode
Switching Frequency810
kHz100120-8-6-4PWROK Trip Level
±2.5VCCSupply Current3.94.34.55.5Input Voltage Range
Input Undervoltage Lockout±2.5FB Accuracy0.40.2VDDSupply Current3.4473.53.553Reference Voltage
UNITSMINTYPMAXPARAMETERMAX1625FB Set Voltage
BST - LX = 4.5V
RFREQ = 20kΩ
VDD= 4.5V0.7284900.7 2
Maximum Duty Cycle
DL On-Resistance
DH On-Resistance
Current-Limit Trip VoltagemV70100130
ELECTRICAL CHARACTERISTICS(VDD= VCC= D4 = +5V, PGND = AGND = D0–D3= 0V, RFREQ = 33.3kΩ, TA
= -40°C to +85°C, unless otherwise noted.) (Note 4)
Note 1:FB accuracy is 100% tested at FB = 3.5V (code 10000) with VCC= VDD= 4.5V to 5.5V and CSH - CSL = 0mV to 80mV. The
other DAC codes are tested at the major transition points with VCC= VDD= 5V and CSH - CSL = 0. FB accuracy at other
DAC codes over line and load is guaranteed by design.
Note 2:FB set voltage is 100% tested with VCC= VDD= 4.5V to 5.5V and CSH - CSL = 0mV to 80mV.
Note 3:AC load regulation sets the AC loop gain, to make tradeoffs between output filter capacitor size and transient response,
and has only a slight effect on DC accuracy or DC load-regulation error.
Note 4:Specifications from 0°C to -40°C are not production tested.
igh-Speed Step-Down Controllers witSynchronous Rectification for CPU Power
__________________________________________Typical Operating Characteristics(TA = +25°C, using the MAX1624 evaluation kit, unless otherwise noted.)
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE DETAIL
(WITH GLITCHCATCHER)
(1.1V) AX1624/25 TO
C01
A: PDRV, 5V/div
B: VOUT, 50mV/div, AC COUPLED
C: NDRV, 5V/div
D: LOAD CURRENT, 0A TO 10A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITH GLITCHCATCHER)
(1.1V )AX1624/25 TOC
A: VOUT, 50mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 10A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITHOUT GLITCHCATCHER)
(1.1V)X1624/25 TO
C03
A: VOUT, 50mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 10A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITHOUT GLITCHCATCHER)
(3.5V)AX1624/25 TOC
A: VOUT, 100mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 11A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITH GLITCHCATCHER)
(2.5V)X1624/25 TO
C17
A: VOUT, 50mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 10A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITHOUT GLITCHCATCHER)
(2.5V)1624/25 TO
C18
A: VOUT, 50mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 10A, tRISE = tFALL = 100ns
LG = REF
10ms/div
MAX1624
LOAD-TRANSIENT RESPONSE
(WITH GLITCHCATCHER)
(3.5V)AX1624/25 TOC
A: VOUT, 100mV/div, AC COUPLED
B: INDUCTOR CURRENT, 10A/div
C: LOAD CURRENT, 0A TO 11A, tRISE = tFALL = 100ns
LG = REFs/div
MAX1624
SWITCHING WAVEFORMSAX1624/25 TOC
VIN = 5V, VOUT = 2.5V, LOAD = 5A
A: LX, 5V/div
B: VOUT, 20mV/div, AC COUPLED
C: INDUCTOR CURRENT, 5A/div
1ms/div
MAX1624
STARTUP AND STANDBY RESPONSEAX1624/25 TOC
VIN = 5V, VOUT = 2.5V, LOAD = 13.8A
A: VOUT, 1V/div
B: INDUCTOR CURRENT, 10A/div
C: STANDBY, D0–D4
igh-Speed Step-Down Controllers with
Synchronous Rectification for CPU Power
____________________________Typical Operating Characteristics (continued)(TA = +25°C, using the MAX1624 evaluation kit, unless otherwise noted.)
MAX1624
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 1.1V)
1624/25 TO
C04
OUTPUT CURRENT (A)
(%
MAX1624
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 2.5V)
AX1624/25 TOC
OUTPUT CURRENT (A)
(%
MAX1624
EFFICIENCY vs. OUTPUT CURRENT
(VOUT = 3.5V)
1624/25 TO
C06
OUTPUT CURRENT (A)
(%
igh-Speed Step-Down Controllers witSynchronous Rectification for CPU Power
____________________________Typical Operating Characteristics (continued)(TA = +25°C, using the MAX1624 evaluation kit, unless otherwise noted.)
MAX1624
OUTPUT VOLTAGE vs. OUTPUT CURRENT
(VOUT = 1.1V)
1624/25 TO
C07
OUTPUT CURRENT (A)
(V
LG = VCC
LG = REF
LG = AGND
R9 AND R10 = 4.7W
MAX1624
OUTPUT VOLTAGE vs. OUTPUT CURRENT
(VOUT = 2.5V)
AX1624/25 TOC
OUTPUT CURRENT (A)
(V
LG = VCC
LG = REF
LG = AGND
R9 AND R10 = 4.7W
MAX1624
OUTPUT VOLTAGE vs. OUTPUT CURRENT
(VOUT = 3.5V)
AX1624/25 TO
C09
OUTPUT CURRENT (A)
(V
LG = VCC
LG = REF
LG = AGND
R9 AND R10 = 4.7W
REFERENCE VOLTAGE
vs. OUTPUT CURRENT
AX1624/25 TOC
OUTPUT CURRENT (mA)
(V
SOURCING
CURRENT
SINKING
CURRENT
MAXIMUM DUTY CYCLE
vs. SWITCHING FREQUENCYAX1624/25 tTOC
SWITCHING FREQUENCY (kHz)
(%
MAX1624
OUTPUT ERROR vs.
DAC OUTPUT VOLTAGE SETTING
AX1624/25 TOC19
DAC OUTPUT VOLTAGE SETTING (V)
(m
igh-Speed Step-Down Controllers withSynchronous Rectification for CPU Power
MAX1625MAX1624
PINHigh-Side Main MOSFET Switch Gate-Drive Output. DH is a floating driver output that
swings from LX to BST, riding on the LX switching-node voltage. See the section BST
High-Side Gate-Driver Supply and MOSFET Drivers.1624
Switching Node. Connect LX to the high-side MOSFET source and inductor.LX1523
Power GroundPGND1422Low-Side Synchronous Rectifier Gate-Drive Output. DL swings between PGND and VDD.
See the section BST High-Side Gate-Driver Supply and MOSFET Drivers.1321
VDD5V Power Input for MOSFET Drivers. Bypass VDDto PGND within 0.2 in. (5mm) of the
VDDpin using a 0.1μF capacitor and 4.7μF capacitor connected in parallel. 1220
PDRVGlitchCatcher P-Channel MOSFET Driver Output. PDRV swings between VDDand PGND. —19
NDRVGlitchCatcher N-Channel MOSFET Driver Output. NDRV swings between VDDand
PGND. —18
D4, D3Digital Inputs for Programming the Output Voltage —16, 17
FREQFrequency-Programming Input. Attach a resistor within 0.2 in. (5mm) of FREQ to AGND to
set the switching frequency between 100kHz and 1MHz. The FREQ pin is normally 2V DC.1115
CC2Slow-Loop Compensation Capacitor Input. Connect a ceramic capacitor from CC2 to
AGND. See the section Compensating the Feedback Loop.1014
BST
Boost-Capacitor Bypass for High-Side MOSFET Gate Drive. Connect a 0.1μF capacitor
and low-leakage Schottky diode as a bootstrapped charge-pump circuit to derive a 5V
gate drive from VDDfor DH.1
NAMEFUNCTION
______________________________________________________________Pin DescriptionCC1Fast-Loop Compensation Capacitor Input. Connect a ceramic capacitor and resistor in
series from CC1 to AGND. See the section Compensating the Feedback Loop.913
Voltage-Feedback Input.
MAX1624:Connect FB to the CPU’s remote voltage-sense point. The voltage at this
input is regulated to a value determined by D0–D4.
MAX1625:Connect a feedback resistor voltage divider close to FB from the output to
AGND. FB is regulated to 1.1V.12
PWROKOpen-Drain Logic Output. PWROK is high when the voltage on FB is within +8% and -6%
of its setpoint. 22
CSLCurrent-Sense Amplifier’s Inverting Input. Place the current-sense resistor very close to
the controller IC, and use a Kelvin connection. Use an RC filter network at CSL (Figure 1).33
CSHCurrent-Sense Amplifier’s Noninverting Input. Use an RC filter network at CSH (Figure 1).44
D2, D1,
Digital Inputs for Programming the Output Voltage. D0–D4 are logic inputs that set the
output to a voltage between 1.1V and 3.5V in 100mV increments. —5, 6, 7
Loop Gain-Control Input. LG is a three-level input that is used to trade off loop gain vs.
AC load-regulation and load-transient response. Connect LG to VCC, REF, or AGND for
2%, 1%, or 0.5% AC load-regulation errors, respectively. 8
VCCAnalog Supply Input, 5V. Use an RC filter network, as shown in Figure 1. 59
REFReference Output, 3.5V. Bypass REF to AGND with 0.1μF (min). Sources up to 100μA for
external loads. Force REF below 2V to turn off the controller. 610
AGNDAnalog Ground711
igh-Speed Step-Down Controllers witSynchronous Rectification for CPU PowerC2D1
(OPTIONAL)
(OPTIONAL)
R10
(OPTIONAL)
39W
C12
4.7nF
C11
4.7nFVCCVDD
CSH
PWROKCSL
BST
PGND
PDRV
NDRV
AGND
REF
CC1
CC2
CC2
CC1RC1
AGND
C6, 1.0mF
CERAMIC
R4, 40.1k
FOR 500kHz
100k
0.1mF
4.7mF
100W
TO VDD
FREQREF
0.1mF
4.7mF
CMPSH-3
0.1mF
VIN = 5V
39W
LOCAL
BYPASSING
MAX1624
R11
VOUT = 1.1V
TO 3.5VLOAD
Figure 1. MAX1624 Standard Application Circuit
igh-Speed Step-Down Controllers withSynchronous Rectification for CPU PowerLOCAL
BYPASSINGC2
R3
100kW
200kW
C10
(OPTIONAL)
(OPTIONAL)
(OPTIONAL)
R10
(OPTIONAL)
C12
4.7nF
C11
4.7nF
VCCVDD
CSH
PWROK
CSL
BST
PGND
AGND
REF
CC1
CC2
CC2
CC1RC1
AGND
C6, 1.0mF
CERAMIC
R4, 40.1kW
FOR 500kHz
100kW
0.1mF
4.7mF
100W
TO VDD
FREQ
0.1mF
4.7mF
CMPSH-3
0.1mF
VIN = 5V
39W
39W
LOAD
VOUTMAX1625
Figure 2. MAX1625 Standard Application Circuit
igh-Speed Step-Down Controllers witSynchronous Rectification for CPU Power
Table 1. Component List for Standard 3.3V Applications by Load Current*
(Output Voltage = 3.3V, Frequency = 500kHz)*MAX1624:LG = REF, D4–D0 = 10010.
C10 Capacitor
CC1 Capacitor
D2 Rectifier
L1 Inductor
R2 Resistor
R3 Resistor
Application Equipment
R11 Resistor (MAX1624)
C1 Input Capacitor100μF, 10V Sanyo
OS-CON 10SL100M
Optional (see text)
680pF ceramic
1.5μH, 8A Coiltronics UP2-1R5
200kΩ, 1% resistor
100kΩ, 1% resistor
Power PC/Pentium/GTL
bus termination
3 x 100μF, 10V Sanyo
OS-CON 10SL100M
1000pF ceramic
0.5μH, 17A Coilcraft
DO5022P-501HC
N/A
N/A
Pentium Pro
500mΩDale WSL-2512-R500
C2 Output Capacitor2 x 220μF, 4V Sanyo
OS-CON 4SP220M
3 x 220μF, 4V Sanyo
OS-CON 4SP220M
0.056μF ceramic 0.056μF ceramic CC2 Capacitor
Optional Schottky,
Nihon
NSQ03A02
Optional Schottky,
Nihon
NSQ03A02
D1 Rectifier
1kΩ, 5% resistor1kΩ, 5% resistorRC1 Resistor
International Rectifier IRF7413International Rectifier
IRL3103S, D2PAKN1 High-Side MOSFET
International Rectifier IRF7413International Rectifier
IRL3103S, D2PAK
International Rectifier IRF7107N3/P1 (MAX1624)
N2 Low-Side MOSFET
12mΩDale WSL-2512-R012-F2 x 12mΩin parallel,
Dale WSL-2512-R012-FR1 Resistor
12ACOMPONENT3 x 2700μF, 6.3V
aluminum electrolytic,
Sanyo 6MV2700GX
1000pF ceramic
Central Semiconductor
CMPSH-3
0.5μH Coiltronics UP4-R47,
Coilcraft DO5022P-501HC
N/A
N/A
Pentium Pro
N/A
DESCRIPTION BY LOAD CURRENT4 x 2700μF, 6.3V
aluminum electrolytic,
Sanyo 6MV2700GX
0.056μF ceramic
Optional Schottky,
Nihon
NSQ03A02
11A
(LOW-COST VRM)1kΩ, 5% resistor
International Rectifier IRF7413
x 2
International Rectifier IRF7413
x 2
2 x 12mΩin parallel
Dale WSL-2512-R012-F
Central Semiconductor
CMPSH-3
Central Semiconductor
CMPSH-3
igh-Speed Step-Down Controllers withSynchronous Rectification for CPU PowerAVX(803) 946-0690(803) 626-3123
Coilcraft(847) 639-6400(847) 639-1469
Dale Inductors(605) 668-4131(605) 665-1627
Coiltronics(561) 241-7876(561) 241-9339
International
Rectifier(310) 322-3331(310) 322-3332
Central
Semiconductor(516) 435-1110(516) 435-1824
IRC(512) 992-7900(512) 992-3377
Matsuo(714) 969-2491(714) 960-6492
Motorola (602) 303-5454(602) 994-6430
Murata-Erie(814) 237-1431(814) 238-0490
Nichicon(847) 843-7500(847) 843-2798
NIEC(805) 867-2555*[81] 3-3494-7414
Sanyo (619) 661-6835[81] 7-2070-1174
Siliconix(408) 988-8000(408) 970-3950
SUPPLIERUSA PHONEFACTORY FAXSprague(603) 224-1961(603) 224-1430
Sumida(847) 956-0666[81] 3-3607-5144
*Distributor
†See Table 4 for a complete listing.
D2D00110——11000001——1100——1011
OUTPUT
VOLTAGE
(V)Decreases
in 100mV
increments
No CPU (OFF)
Decreases
in 100mV
increments
No CPU (OFF)
COMPATIBILITYIntel-compatible
codes
Non-Intel
compatible codes
Table 2. Component SuppliersTable 3. MAX1624 Output Voltage
Adjustment Settings (Abbreviated†
)
_____Standard Application CircuitsThe predesigned MAX1624/MAX1625 circuits shown in
Figures 1 and 2 meet a wide range of applications with
output currents up to 12A and higher. Use Table 1 to
select components appropriate for the desired output
current range, and adapt the evaluation kit PC board
layout as necessary. Table 2 lists suggested vendors.
These circuits represent a good set of trade-offs
between cost, size, and efficiency while staying within
the worst-case specification limits for stress-related
parameters, such as capacitor ripple current.
These MAX1624/MAX1625 circuits were designed for
the specified frequencies. Do not change the switching
frequency without first recalculating component val-
ues—particularly the inductance, output filter capaci-
tance, and RC1 resistance values. Recalculate the
voltage-feedback resistor and compensation-capacitor
values (CC1 and CC2) as necessary to reconfigure
them for different output voltages. Table 3 lists voltage
adjustment DAC codes for the MAX1624.
_______________Detailed DescriptionThe MAX1624/MAX1625 are BiCMOS switch-mode,
power-supply controllers designed for buck-topology
regulators. They are optimized for powering the latest
high-performance CPUs—demanding applications
where output voltage precision, good transient
response, and high efficiency are critical for proper
operation. With appropriate external components, the
MAX1624/MAX1625 deliver over 15A between 1.1V and
3.5V with ±1% accuracy. The MAX1625 offers 1% typi-
cal transient-load regulation from a +5V supply, while the
MAX1624 offers a selectable transient-load regulation of
0.5%, 1%, or 2%. Remote output sensing ensures volt-
age precision by eliminating errors caused by PC board
trace impedance. These controllers achieve 90% effi-
ciency by using synchronous rectification.
A typical application circuit consists of two N-channel
MOSFETs, a rectifier, and an LC output filter (Figure 1).
At each of the internal oscillator’s rising edges, the
high-side MOSFET switch (N1) is turned on and allows
current to ramp up through the inductor to the output
filter capacitor and load, storing energy in a magnetic
field. The current is monitored by reading the voltage
