MAX8594 Datasheet, PDF (1/22 Pages) Maxim Integrated Products – 5-Output PMICs with DC-DC Core Supply for Low-Cost PDAs

19-3349; Rev 2; 4/05
5-Output PMICs with DC-DC Core Supply for
Low-Cost PDAs
General Description
The MAX8594/MAX8594A complete power-manage-
ment chips for low-cost personal digital assistants
(PDAs) operates from a 1-cell lithium-ion (Li+) or 3-cell
NiMH battery. They include all regulators, outputs, and
voltage monitors necessary for small portable devices
while requiring a bare minimum of external compo-
nents. Featured are three linear regulators, a boost DC-
DC converter for LCD bias, an efficient 4MHz buck
DC-DC converter for core power, a microprocessor
(µP) reset output, and low-battery shutdown in a 0.8mm
high thin QFN package.
The COR1 buck DC-DC converter supplies a pin-selec-
table output at 400mA. All linear regulators feature
PMOS pass elements for efficient low-dropout opera-
tion. A MAIN LDO supplies 3.3V at 500mA. A secure-
digital (SD) card slot output supplies 3.3V at 500mA,
and a COR2 LDO supplies 1.8V at 50mA. Each output
has its own logic-controlled enable. For other output
voltage combinations, contact Maxim.
An LCD bias boost DC-DC converter features an on-
board MOSFET and True Shutdown™ when off. This
means that during shutdown, input power is disconnect-
ed from the inductor so the boost output falls to 0V rather
than remaining one diode drop below the input voltage.
A µP reset output clears 20ms (typ) after the COR1 out-
put achieves regulation to ensure an orderly start. In
addition, the COR1 regulator is not started until the 3.3V
main output is in regulation. Also included are a 1%
accurate reference and low-battery monitor. Thermal
shutdown protects the die from overheating.
The MAX8594/MAX8594A operate from a 3.1V to a 5.5V
supply voltage and consume 46µA no-load supply cur-
rent. They are packaged in a tiny, 4mm x 4mm, 24-pin
thin QFN capable of dissipating 1.67W. The devices
are specified for operation from -40°C to +85°C.
Applications
PDAs
Organizers
Cellular and Cordless Phones
MP3 Players
Handheld Devices
Ordering Information
PART
TEMP RANGE PIN-PACKAGE
MAX8594ETG
-40°C to +85°C
24 Thin QFN-EP* 4mm x 4mm
(T2444-4)
Features
♦ Minimum External Components
♦ Efficient Step-Down DC-DC Powers CPU Core
♦ 1V/1.3V Selectable Core Voltage, 400mA
(MAX8594)
♦ 1.3V/1.8V Selectable Core Voltage, 400mA
(MAX8594A)
♦ Main LDO 3.3V, 500mA
♦ SD Card Output 3.3V, 500mA
♦ Second Core LDO 1.8V, 50mA
♦ High-Efficiency LCD Boost
♦ LCD 0V True Shutdown when Off
♦ 46µA Quiescent Current
Typical Operating Circuit
VIN
MAIN
ON
OFF
SDIG
ON
OFF
COR2 _ON
OFF
COR1 _ON
OFF
1.8V/1.3V
1.3V/1V
LCD _ON
OFF
TO MAIN
TO MAIN
TO MAIN
MAX8594
MAX8594A
MAIN
IN
LBI
SDIG
DBI
COR2
ENM
ENSD
PV
ENC2
ENC1
CV
ENL
RS
LBO
LXC
PGND
COR1
SW
LXL
LFB
GND
REF
DBO
3.3V, 500mA
MAIN
3.3V, 500mA
SD CARD SLOT
1.8V, 50mA
COR2
TO IN
1.3V OR 1.8V (MAX8594A)
1V OR 1.3V (MAX8594)
400mA
COR1
LCD
15V
MAX8594AETG
-40°C to +85°C
24 Thin QFN-EP* 4mm x 4mm
(T2444-4)
*EP = Exposed pad.
Pin Configuration appears at end of the data sheet.
True Shutdown is a trademark of Maxim Integrated Products, Inc.
________________________________________________________________ Maxim Integrated Products 1
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.