Rainbow Electronics MAX1976 - Manual (Page 6)

MAX1963/MAX1976
Detailed Description
The MAX1963/MAX1976 are low-dropout, high-accuracy,
low-quiescent-current linear regulators designed primarily
for battery-powered applications. These devices supply
loads up to 300mA and are available with preset output
voltages from +0.75V to +3.0V. As illustrated in Figure 1,
the MAX1963/MAX1976 consist of a reference, an error
amplifier, a P-channel pass transistor, an internal feed-
back voltage-divider, and a power-good comparator.
The reference is connected to the error amplifier, which
compares this reference with the feedback voltage and
amplifies the difference. If the feedback voltage is
lower than the reference voltage, the pass-transistor
gate is pulled lower, which allows more current to pass
to the output and increases the output voltage. If the
feedback voltage is too high, the pass-transistor gate is
pulled up, allowing less current to pass to the output.
Low-Input-Voltage, 300mA LDO Regulators
with
RESET
in SOT and TDFN
6 _______________________________________________________________________________________
Pin Description
PIN
SOT23 TDFN
NAME FUNCTION
1 6 IN
Regulator Input. Supply voltage can range from +1.62V to +3.6V. Bypass IN with at least a 1µF
ceramic capacitor to GND (see the Capacitor Selection and Regulator Stability section).
2 — GND
Ground. GND also functions as a heatsink. Solder to a large pad or circuit-board ground plane to
maximize SOT23 power dissipation.
— 4 GND Ground
3 5 SHDN
Active-Low Shutdown Input. A logic low reduces supply current to below 1µA. Connect to IN or
logic high for normal operation.
4 3 RESET
Open-Drain, Active-Low Reset Output. RESET rises 3.2ms (MAX1963) or 100ms (MAX1976) after
the output has achieved regulation. RESET falls immediately if V
OUT drops below 82.5% of its
nominal voltage, or if the MAX1963/MAX1976 are shut down.
5 2 I.C. Internally Connected. Leave floating or connect to GND.
6 1 OUT Regulator Output. Sources up to 300mA. Bypass with a 4.7µF low-ESR ceramic capacitor to GND.
—
Exposed
Pad
EP
Ground. EP also functions as a heatsink. Solder EP to a large pad or circuit-board ground plane
to maximize TDFN power dissipation.
MAX1963
MAX1976
IN
GND
SHDN
SHUTDOWN
LOGIC
THERMAL
SENSOR
REF
82.5%
REF
TIMER
ERROR
AMP
MOS DRIVER
WITH I LIMIT
OUT
RESET
P
Figure 1. Functional Diagram