10-Channel Power Management Units for 3G Applications
XX1188
PIN #
12
NAME
DESCRIPTION
EN4
Enable Input for Linear Regulator 4. Drive high to enable.
Crystal input pin. Tiethe crystal between this pin and XTALO and a 22pF capacitor to GND.
Crystal output pin. Tie the crystal between this pin and XTALI and a 22pF capacitor to GND.
Clock output. Buffered output of the crystal oscillator.
13
XTALI
XTALO
CLKOUT
FB
14
15
16
Feedback pin for BUCK. Connect to midpoint of the resistor ladder to set BUCK output
voltage.
17
18
19
20
21
22
23
24
25
26
27
28
PGND
LX
Power Ground. Connect to GND
Inductor connection for BUCK. Connect an inductor between this pin to OUT of BUCK.
Power input for BUCK, LDO7 and system control circuit.
IN1
EN7
EN9
Enable Input for Linear Regulator 7. Drive high to enable.
Enable Input for Linear Regulator 9. Drive high to enable.
PWR_ON Power on pin. Pull this pin high to turn on the IC.
REF
Low noise 1.25V reference. Bypass this pin with a 10nF cap to GND.
LDO7 Output. Delivers up to 50mA. Connect a 2.2μF ceramic capacitor from OUT7 to GND.
Ground
LDO7
GND
LDO9
EN8
LDO9 Output. Delivers up to 150mA.Connect a 2.2μF ceramic capacitor from OUT9 to GND.
Enable Input for Linear Regulator 8. Drive high to enable.
nRESET
Reset output, 65ms. Active low.. nRESET is low in shutdown.
FUNCTIONAL DESCRIPTION
The XX1188 power-management IC (PMIC) is an
complete, efficient, compact devices suitable for 3G
cellular applications such as wireless data cards,
handsets and PDAs,. It integrates a 2MHz synchronous
buck regulator, nine low-dropout linear regulators (LDOs),
a RESET generator, and an 32KHZ crystal driver and
buffer.
and for OUT4, OUT7and OUT8 they are 50mA. OUT1,
OUT2, OUT3 are enabled after the DC-DC reaches
regulation. The rest of the LDOs have enable control pins.
Output of LDO8 can also be either 3.3V or 1.8V, depends
on the voltage at SEL pin.
Crystal Driver
The XX1188 also provides a 32Khz crystal driver and a
clock buffer that can be used for the system real time
clock.
DC-DC Step-Down Converter
The XX1188 consists of a 2Mhz DC-DC step-down
converter that is capable of delivering 600mA output
current. It uses a hysteretic control scheme that provides
fast switching, low output ripple, high efficiency, and fast
transient response with simple setup of external
components. The internal synchronous rectifier eliminates
the use of external Schottky.
Reset
The XX1188 integrates a 60ms power-on reset generator,
reducing system size and cost. nRESET is an open-drain
output; connect a 10kΩ or greater pull-up resistor from
nRESET to an appropriate voltage supply. nRESET
asserts low upon startup and remains low until the 60ms
reset timeout period expires, at which point nRESET goes
high-Z.
Linear Regulators
The XX1188 contains nine low-dropout, low quiescent
current, low-operating voltage linear regulators. The
maximum output currents for OUT1, OUT2, OUT3, and
OUT5 are 300mA, for OUT6 and OUT6, they are 150mA,
Page 4
V1.1
