MAX1637 Datasheet, PDF (9/20 Pages) Maxim Integrated Products – Miniature, Low-Voltage, Precision Step-Down Controller

Miniature, Low-Voltage,
Precision Step-Down Controller
3.15V TO 5.5V
V_BIAS
V_CC
SYNC
SKIP
V_BATT
+
IC
POWER
MAX1637
V_GG
BST
200kHz
TO
300kHz
DH
OSC
PWM
LX
LOGIC
V_OUT
DL
+
REF
1.1V
REF.
PGND
SHDN
SHUTDOWN
CONTROL
OFF
REF
CSH
-
CSL
UNDER-
VOLTAGE
FAULT
SLOPE
ERROR
COMPENSATION _INTEGRATOR
CC
OVERVOLTAGE
gm-
- FAULT
REF
V_REF -30%
V_REF +7%
60kHz
FB
LP FILTER
GND
Figure 2. Functional Diagram
The pulse-width-modulation (PWM) controller consists
of a multi-input PWM comparator, high-side and low-
side gate drivers, and logic. It uses a 200kHz/300kHz
synchronizable oscillator. The MAX1637 contains fault-
protection circuits that monitor the PWM output for
undervoltage and overvoltage. It includes a 1.100V pre-
cision reference. The circuit blocks are powered from
an internal IC power rail that receives power from V_CC.
V_GG provides direct power to the synchronous-switch
gate driver, but provides indirect power to the high-
side-switch gate driver via an external diode-capacitor
boost circuit.
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