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MAX1637EEE+T

P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20
For pricing, delivery, and ordering information, please contact Maxim/Dallas Direct! at
1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.
General Description
The MAX1637 synchronous, buck, switch-mode power-
supply controller generates the CPU supply voltage in
battery-powered systems. The MAX1637 is a stripped-
down version of the MAX1636 in a smaller 16-pin QSOP
package. The MAX1637 is intended to be powered sep-
arately from the battery by an external bias supply (typi-
cally the +5V system supply) in applications where the
battery exceeds 5.5V. The MAX1637 achieves excellent
DC and AC output voltage accuracy. This device can
operate from a low input voltage (3.15V) and delivers the
excellent load-transient response needed by upcoming
generations of dynamic-clock CPUs.
Using synchronous rectification, the MAX1637 achieves
up to 95% efficiency. Efficiency is greater than 80% over
a 1000:1 load-current range, which extends battery life in
system-suspend or standby mode. Excellent dynamic
response corrects output load transients caused by the
latest dynamic-clock CPUs within five 300kHz clock
cycles. Powerful 1A on-board gate driv-ers ensure fast
external N-channel MOSFET switching.
The MAX1637 features a logic-controlled and synchro-
nizable, fixed-frequency, pulse-width-modulation (PWM)
operating mode. This reduces noise and RF interference
in sensitive mobile-communications and pen-entry appli-
cations. Asserting the SKIP pin enables fixed-frequency
mode, for lowest noise under all load conditions. For a
stand-alone device that includes a +5V VL linear regula-
tor and low-dropout capabilities, refer to the MAX1636
data sheet.
_________________________Applications
Notebook Computers Subnotebook Computers
Handy-Terminals, PDAs
____________________________Features
♦ ±2% DC Accuracy
♦ 0.1% (typ) DC Load Regulation
♦ Adjustable Switching Frequency to 350kHz
♦ Idle Mode™ Pulse-Skipping Operation
♦ 1.10V to 5.5V Adjustable Output Voltage
♦ 3.15V Minimum IC Supply Voltage (at V
CC
pin)
♦ Internal Digital Soft-Start
♦ 1.1V ±2% Reference Output
♦ 1μA Total Shutdown Current
♦ Output Overvoltage Crowbar Protection
♦ Output Undervoltage Shutdown (foldback)
♦ Tiny 16-Pin QSOP Package
MAX1637
Miniature, Low-Voltage,
Precision Step-Down Controller
________________________________________________________________ Maxim Integrated Products 1
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
CSH SKIP
LX
DH
BST
PGND
DL
V
GG
V
CC
TOP VIEW
MAX1637
QSOP
CSL
FB
SHDN
CC
REF
SYNC
GND
A "+" SIGN WILL REPLACE THE FIRST PIN INDICATOR ON LEAD-FREE PACKAGES.
__________________Pin Configuration
__________Typical Operating Circuit
19-1321; Rev 2; 8/05
EVALUATION KIT
AVAILABLE
______________Ordering Information
Idle Mode is a trademark of Maxim Integrated Products.
MAX1637
SHDN
GND
V
BATT
V
BIAS
DL
PGND
LX
DH
V
CC
V
GG
BST
CSH
CSL
FB
SKIP
SYNC
REF
CC
OUTPUT
+Denotes lead-free package.
PART TEMP RANGE
PIN-PACKAGE
MAX1637EEE 40°C to +85°C 16 QSOP
MAX1637EEE+ 40°C to +85°C 16 QSOP
MAX1637
Miniature, Low-Voltage,
Precision Step-Down Controller
2 _______________________________________________________________________________________
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
CC
= V
GG
= 5V, SYNC = V
CC
, I
REF
= 0mA, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.)
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.
GND to PGND .............................................................+2V to -2V
LX, BST to GND......................................................-0.3V to +36V
BST, DH to LX...........................................................-0.3V to +6V
V
CC
, V
GG
, CSL, CSH, SHDN to GND.......................-0.3V to +6V
DL to GND..................................................-0.3V to (V
GG
+ 0.3V)
REF, SKIP, SYNC, CC to GND ...................-0.3V to (V
CC
+ 0.3V)
REF Output Current.............................................................20mA
REF Short-Circuit to GND ..............................................Indefinite
Operating Temperature Range ...........................-40°C to +85°C
Continuous Power Dissipation (T
A
= +70°C)
QSOP (derate 8.3mW/°C above +70°C)......................667mW
Storage Temperature Range .............................-65°C to +160°C
Junction Temperature......................................................+150°C
Lead Temperature (soldering, 10s) .................................+300°C
SYNC = GND
SYNC = V
CC
FB tied to V
OUT
, 0mV < (CSH - CSL) < 80mV,
includes line and load regulation
V
CC
= 3.15V to 5.5V
REF load = 0µA to 50µA
V
CC
, V
GG
REF load = 0µA
Rising edge, hysteresis = 15mV
Rising edge, hysteresis = 15mV
SHDN = GND, V
CC
= V
GG
CSH - CSL = 0mV to CSH - CSL = 100mV
CSH - CSL
V
CC
= 5V
V
CC
= 3.3V
SHDN to full current limit, four levels
V
FB
= V
REF
CONDITIONS
170 200 230
Oscillator Frequency kHz
270 300 330
mV3REF Line Regulation
mV10REF Load Regulation
V1.080 1.100 1.120REF Output Voltage
V2.80 3.05V
GG
Undervoltage Lockout Threshold
V2.80 3.05V
CC
Undervoltage Lockout Threshold
%2AC Load Regulation
mV20 30 40Idle-Mode Switchover Threshold
clocks512Soft-Start Ramp Time
nA-50 50FB Input Current
V3.15 5.5Input Voltage Range
µA0.5 3Shutdown Supply Current
V1.080 1.100 1.120Output Voltage
V
REF
5.5
Output Adjustment Range V
V
REF
3.6
UNITSMIN TYP MAXPARAMETER
CSH > CSL
CSH < CSL
80 100 120
Current-Limit Threshold mV
-145 -100 -55
Output not switching
1.5 2.5
Power Consumption mW
1 1.75
SYNC = GND
SYNC = V
CC
ns200SYNC Input Pulse Width High
%
93 96
89 92
Maximum Duty Factor
(Note 1)
kHz240 340SYNC Input Frequency Range
ns200SYNC Input Rise/Fall Time
ns200SYNC Input Pulse Width Low
V
CC
= V
GG
= 5V
V
CC
= V
GG
= 3.3V
SMPS CONTROLLER
INTERNAL REFERENCE
OSCILLATOR
MAX1637
Miniature, Low-Voltage,
Precision Step-Down Controller
_______________________________________________________________________________________ 3
ELECTRICAL CHARACTERISTICS (continued)
(Circuit of Figure 1, V
CC
= V
GG
= 5V, SYNC = V
CC
, I
REF
= 0mA, T
A
= 0°C to +85°C, unless otherwise noted. Typical values are at
T
A
= +25°C.)
ELECTRICAL CHARACTERISTICS
(Circuit of Figure 1, V
CC
= V
GG
= 5V, SYNC = V
CC
, I
REF
= 0mA, T
A
= -40°C to +85°C, unless otherwise noted.) (Note 2)
High or low, DH or DL
DH or DL forced to 2V
CSH = CSL = 5V, V
CC
= V
GG
= GND,
either CSH or CSL input
FB to DL delay, 22mV overdrive, C
GATE
= 2000pF
FB, with respect to regulation point
From shutdown or power-on-reset state
Pin at GND or V
CC
SHDN, SKIP, SYNC
% of nominal output
SHDN, SKIP, SYNC
CONDITIONS
Ω7Gate Driver On-Resistance
A1Gate Driver Sink/Source Current
µA10Current-Sense Input Leakage Current
µA-1 1Logic Input Bias Current
V0.8Logic Input Voltage Low
V2.4Logic Input Voltage High
µs1.25Overvoltage Fault Propagation Delay
%4710Overvoltage Trip Threshold
clocks6144Output Undervoltage Lockout Delay
%60 70 80Output Undervoltage Lockout Threshold
UNITSMIN TYP MAXPARAMETER
FB tied to V
OUT
, 0mV < (CSH - CSL) < 80mV,
includes line and load regulation
SYNC = GND
V
CC
, V
GG
SYNC = V
CC
Rising edge, hysteresis = 15mV
Rising edge, hysteresis = 15mV
V
CC
= 3.3V
V
CC
= V
GG
= 3.3V, output not switching
V
CC
= 5V
V
CC
= V
GG
= 5V, output not switching
CSH > CSL
CONDITIONS
kHz240 340SYNC Input Frequency Range
ns200SYNC Input Rise/Fall Time
ns200SYNC Input Pulse Width Low
ns200SYNC Input Pulse Width High
kHz
170 230
Oscillator Frequency
262 338
V2.80 3.05V
GG
Undervoltage Lockout Threshold
V2.80 3.05V
CC
Undervoltage Lockout Threshold
mW1.75
Power Consumption
mW2.5
mV70 130Current-Limit Threshold
V1.080 1.120Output Voltage
V3.15 5.5Input Voltage Range
V
REF
3.6
Output Adjustment Range V
V
REF
5.5
UNITSMIN TYP MAXPARAMETER
OVERVOLTAGE PROTECTION
INPUTS AND OUTPUTS
SMPS CONTROLLER
INTERNAL REFERENCE
OSCILLATOR
P1-P3P4-P6P7-P9P10-P12P13-P15P16-P18P19-P20

MAX1637EEE+T

Mfr. #:
Buy MAX1637EEE+T
Manufacturer:
Maxim Integrated
Description:
Switching Controllers Mini Precision Step Down
Lifecycle:
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