MAX8868 MAXIM [Maxim Integrated Products], MAX8868 Datasheet - Page 6

• Manufacturer Part Number: MAX8868
• Description: Low-Noise, Low-Dropout, 150mA Linear Regulators in SOT23
• Manufacturer: MAXIM [Maxim Integrated Products]

Low-Noise, Low-Dropout,
150mA Linear Regulators in SOT23
Figure 1. Functional Diagram
The MAX8867/MAX8868 are low-noise, low-dropout,
low-quiescent-current linear regulators designed pri-
marily for battery-powered applications. The parts are
available with preset output voltages varying from 2.5V
to 5.0V in 100mV increments. These devices can sup-
ply loads up to 150mA. As illustrated in Figure 1, the
MAX8867/MAX8868 consist of a 1.25V reference, error
amplifier, P-channel pass transistor, and internal feed-
back voltage divider.
6
______________________________________________________________Pin Description
_______________Detailed Description
PIN
_______________________________________________________________________________________
1
2
3
4
5
* AUTO-DISCHARGE, MAX8868 ONLY
SHDN
GND
NAME
SHDN
MAX8868
MAX8867
GND
OUT
IN
BP
IN
PROTECTION
REVERSE
BATTERY
Active-Low Shutdown Input. A logic low reduces the supply current to 10nA. On the MAX8868, a logic low
also causes the output voltage to discharge to GND. Connect to IN for normal operation.
Ground. This pin also functions as a heatsink. Solder to a large pad or the circuit-board ground plane to
maximize power dissipation.
Regulator Input. Supply voltage can range from 2.5V to 6.5V. Bypass with a 1µF capacitor to GND (see
Capacitor Selection and Regulator Stability section).
Regulator Output. Sources up to 150mA. Bypass with a 1µF (<0.2Ω typical ESR) capacitor to GND.
Reference-Noise Bypass. Bypass with a low-leakage, 0.01µF ceramic capacitor for reduced noise at the
output.
AND POWER-ON
SHUTDOWN
THERMAL
SENSOR
CONTROL
1.25V
REF
The 1.25V bandgap reference is connected to the error
amplifier’s inverting input. The error amplifier 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 volt-
age is too high, the pass-transistor gate is pulled up,
allowing less current to pass to the output. The output
voltage is fed back through an internal resistor voltage
divider connected to the OUT pin.
FUNCTION
ERROR
AMP
MOS DRIVER
WITH I
LIMIT
*
N
P
OUT
BP