MAX1638EAG ,High-Speed Step-Down Controller with Synchronous Rectification for CPU Powerapplications in which' Greater than 90% Efficiency Using N-Channeloutput voltage precision and good ..
MAX1638EAG+ ,High-Speed Step-Down Controller with Synchronous Rectification for CPU PowerELECTRICAL CHARACTERISTICS(V = V = D4 = +5V, PGND = AGND = D0–D3 = 0V, FREQ = REF, T = 0°C to +85°C ..
MAX1638EAG+T ,High-Speed Step-Down Controller with Synchronous Rectification for CPU Powerapplications in which♦ Greater than 90% Efficiency Using N-Channeloutput voltage precision and good ..
MAX1639ESE ,High-Speed Step-Down Controller with Synchronous Rectification for CPU PowerApplicationsLocal DC-DC Converters for CPUsINPUT+5VWorkstationsV VDDCCDesktop ComputersAGND BSTLAN ..
MAX1639ESE+ ,High-Speed Step-Down Controller with Synchronous Rectification for CPU PowerELECTRICAL CHARACTERISTICS(V = V = +5V, PGND = AGND = 0V, FREQ = REF, T = 0°C to +85°C, unless othe ..
MAX1639ESE+T ,High-Speed Step-Down Controller with Synchronous Rectification for CPU Powerapplications in which♦ Greater than 90% Efficiency Using N-Channeloutput voltage precision and good ..
MAX4383ESE ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs and DisableFeaturesThe MAX4380–MAX4384 family of op amps are unity- Low Cost and High Speed:gain-stable devic ..
MAX4383EUD ,Ultra-Small / Low-Cost / 210MHz / Single-Supply Op Amps with Rail-to-Rail Outputs and DisableELECTRICAL CHARACTERISTICS–Single Supply (V = +5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, DISABL ..
MAX4383EUD+T ,Ultra-Small, Low-Cost, 210MHz, Single-Supply Op Amps with Rail-to-Rail Outputs and DisableELECTRICAL CHARACTERISTICS–Single Supply (V = +5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, DISABL ..
MAX4385EEUK+T ,Low-Cost, 230MHz, Single/Quad Op Amps with Rail-to-Rail Outputs and ±15kV ESD ProtectionELECTRICAL CHARACTERISTICS (V = 5V, V = 0, V = V /2, V = V /2, R = ∞ to V /2, C = 2.2µF, T = T to T ..
MAX4386EESD ,Low-Cost / 230MHz / Single/Quad Op Amps with Rail-to-Rail Outputs and 15kV ESD ProtectionApplications Ultra-Small 5-Pin SOT23 and 14-Pin TSSOPSet-Top Boxes CCD Imaging PackagesSystemsSurv ..
MAX4386EEUD+T ,Low-Cost, 230MHz, Single/Quad Op Amps with Rail-to-Rail Outputs and ±15kV ESD ProtectionApplications♦ Ultra-Small 5-Pin SOT23 and 14-Pin TSSOPPackagesSet-Top Boxes CCD ImagingSystemsSurve ..
MAX1638EAG
High-Speed Step-Down Controller with Synchronous Rectification for CPU Power
_______________General DescriptionThe MAX1638 is an ultra-high-performance, step-down
DC-DC controller 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, it delivers over 35A from 1.3V
to 3.5V with ±1% total accuracy from a +5V ±10% supply.
Excellent dynamic response corrects output transients
caused by the latest dynamically clocked CPUs. This
controller achieves over 90% efficiency by using synchro-
nous rectification. Flying-capacitor bootstrap circuitry
drives inexpensive, external N-channel MOSFETs.
The switching frequency is pin-selectable for 300kHz,
600kHz, or 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 MAX1638 is available in 24-pin SSOP and QSOP
(future package) packages, and offers additional fea-
tures such as a digitally programmable output;
adjustable transient response; and selectable 0.5%, 1%,
or 2% AC load regulation. Fast recovery from load tran-
sients is ensured by a GlitchCatcher™ current-boost cir-
cuit that eliminates delays caused by the buck inductor.
Output overvoltage protection is enforced by a crowbar
circuit that turns on the low-side MOSFET with 100%
duty factor when the output is 200mV above the normal
regulation point. Other features include internal digital
soft-start, a power-good output, and a 3.5V ±1% refer-
ence output.
________________________ApplicationsPentium Pro™, Pentium II™, PowerPC™, Alpha™,
and K6™ Systems
Workstations
Desktop Computers
LAN Servers
GTL Bus Termination
____________________________FeaturesBetter than ±1% Output Accuracy Over
Line and LoadGreater than 90% Efficiency Using N-Channel
MOSFETsPin-Selected High Switching Frequency (300kHz,
600kHz, or 1MHz)Over 35A Output CurrentDigitally Programmable Output from 1.3V to 3.5VCurrent-Mode Control for Fast Transient
Response and Cycle-by-Cycle Current-Limit
ProtectionShort-Circuit Protection with Foldback Current
LimitingGlitch-Catcher Circuit for Fast Load-Transient
ResponseCrowbar Overvoltage ProtectionPower-Good (PWROK) OutputDigital Soft-StartHigh-Current (2A) Drive OutputsComplies with Intel VRM 8.2 Specification
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
Pin Configuration appears at end of data sheet.*Future product—contact factory for package availability.
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.
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS(VDD= VCC = D4 = +5V, PGND = AGND = D0–D3 = 0V, FREQ = REF, 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)
QSOP (derate 8.70mW/°C above +70°C).....................696mW
QSOP θJC..................................................................40°C/W
SSOP (derate 8.00mW/°C above +70°C).....................640mW
SSOP θJC..................................................................45°C/W
Operating Temperature Range...........................-40°C to +85°C
Storage Temperature Range.............................-65°C to +160°C
Lead Temperature (soldering, 10sec).............................+300°C
ELECTRICAL CHARACTERISTICS (continued)(VDD= VCC = D4 = +5V, PGND = AGND = D0–D3 = 0V, FREQ = REF, TA
= 0°C to +85°C, unless otherwise noted.)
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
ELECTRICAL CHARACTERISTICS(VDD= VCC= D4 = +5V, PGND = AGND = D0–D3= 0V, FREQ = REF, TA
= -40°C to +85°C, unless otherwise noted.) (Note 3)
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 with VCC= VDD= 5V and CSH - CSL = 0.
Note 2: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 3:Specifications from 0°C to -40°C are guaranteed by design, not production tested.
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
__________________________________________Typical Operating Characteristics(TA = +25°C, using the MAX1638 evaluation kit, unless otherwise noted.)
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU Power
______________________________________________________________Pin Description
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU PowerFigure 1. Standard Application Circuit
_____Standard Application CircuitsThe predesigned MAX1638 circuit shown in Figure 1
meets a wide range of applications with output currents
up to 19A and higher. Use Table 1 to select compo-
nents appropriate for the desired output current range,
and adapt the evaluation kit PC board layout as neces-
sary. This circuit 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.
The MAX1638 circuit was designed for the specified
frequency. Do not change the switching frequency
without first recalculating component values—particu-
larly the inductance, output filter capacitance, and RC1
resistance values. Table 2 lists the voltage adjustment
DAC codes.
_______________Detailed DescriptionThe MAX1638 is a BiCMOS power-supply controller
designed for use in switch-mode, step-down (buck)
topology DC-DC converters. Synchronous rectification
provides high efficiency. It is intended to provide the
high precision, low noise, excellent transient response,
and high efficiency required in today’s most demand-
ing applications.
MAX1638
High-Speed Step-Down Controller with
Synchronous Rectification for CPU PowerFigure 2. Simplified Block Diagram
