Rainbow Electronics MAX8621Z - Manual

General Description
The MAX8621Y/MAX8621Z power-management inte-
grated circuits (PMICs) are designed for a variety of
portable devices including cellular handsets. These
PMICs include two high-efficiency step-down DC-DC
converters, four low-dropout linear regulators (LDOs)
with pin-programmable capability, one open-drain dri-
ver, a 60ms (typ) reset timer, and power-on/off control
logic. These devices offer high efficiency with a no-load
supply current of 160µA, and their small thin QFN 4mm
x 4mm package makes them ideal for portable devices.
The step-down DC-DC converters utilize a proprietary
4MHz hysteretic-PWM control scheme that allows for
ultra-small external components. Internal synchronous
rectification improves efficiency and eliminates the
external Schottky diode that is required in conventional
step-down converters. The output voltage is adjustable
from 0.6V to 3.3V. The output current is guaranteed up
to 500mA.
The four LDOs offer low 45µV
RMS
output noise and low
dropout of only 100mV at 100mA. OUT1 and OUT2
deliver 300mA (min) of continuous output current.
OUT3 and OUT4 deliver 150mA (min) of continuous
output current. The output voltages are pin selectable
by SEL1 and SEL2 for flexibility. The MAX8621Y/
MAX8621Z offer different sets of LDO output voltages.
A microprocessor reset output (RESET) monitors OUT1
and warns the system of impending power loss, allow-
ing safe shutdown. RESET asserts during power-up,
power-down, shutdown, and fault conditions where
V
OUT1 is below its regulation voltage.
A 200mA driver output is provided to control LED back-
lighting or provide an open-drain connection for resis-
tors such as in feedback networks.
Applications
Cellular Handsets
Smart Phones, PDAs
Digital Cameras
MP3 Players
Wireless LAN
Features
♦ Two 500mA Step-Down Converters
Up to 4MHz Switching Frequency
Adjustable Output from 0.6V to 3.3V
♦ Four Low-Noise LDOs with Pin-Programmable
Output Voltages
♦ One Open-Drain Driver
♦ 60ms (typ) Reset Timer
♦ Power-On/Off Control Logic and Sequencing
♦ 4mm x 4mm x 0.8mm 24-Pin Thin QFN
MAX8621Y/MAX8621Z
Dual Step-Down DC-DC Power-Management ICs
for Portable Devices
________________________________________________________________ Maxim Integrated Products 1
PART TEMP RANGE PIN-PACKAGE
MAX8621YETG -40°C to +85°C
24 Thin QFN
4mm x 4mm (T2444-4)
MAX8621ZETG -40°C to +85°C
24 Thin QFN
4mm x 4mm (T2444-4)
Ordering Information
MAX8621Y
MAX8621Z
IN1
IN2
IN3
PWRON
EN3
EN4
SEL2
ENDR
REFBP
GND
OUT1
OUT2
OUT3
OUT4
DR
LX1
FB1
PGND1
LX2
FB2
PGND2
RESET
SEL1
EN2
INPUT
2.6V TO 5.5V
INPUT
OUT4
3V, 150mA
OUT3
1.8V, 150mA
OUT2
2.6V, 300mA
OUT1
2.6V, 300mA
BUCK1
1.375V, 500mA
BUCK2
1.8V, 500mA
RESET
Typical Operating Circuit
19-3539; Rev 0; 1/05
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.
Pin Configuration appears at end of data sheet.
EVALUATION KIT AVAILABLE