MAX1798 Datasheet, PDF (1/20 Pages) Maxim Integrated Products – CDMA Cellular/PCS System Power Supplies

19-1655; Rev 1; 2/01
EVALUAATVIOANILKAIBTLMEANUAL
CDMA Cellular/PCS System
Power Supplies
General Description
The MAX1798/MAX1798A/MAX1799/MAX1799A system
power supplies are designed specifically for CDMA cel-
lular/PCS handsets. Each device contains five low-
dropout linear regulators (LDOs), a 140ms (min) reset
timer, a serial interface, push-on/push-off control logic,
and two general-purpose open-drain outputs. Only the
serial interface is different between the MAX1798/
MAX1798A/MAX1799/MAX1799A: the MAX1798/
MAX1798A feature an SPI™-compatible serial interface,
and the MAX1799/MAX1799A feature an I²C™-compati-
ble interface. The “A” parts have a -13% reset thresh-
old, the non-A parts have a 9.5% threshold. The “A”
parts have a 175 delay on a reset-triggered shutdown,
the non-A shutdown instantly.
Each linear regulator features extremely low dropout
voltage, specified at two-thirds of the maximum output
current. LDO1 is rated for 300mA, while LDOs 2–5 are
each rated for 150mA. All LDOs are optimized for low
noise and isolation. Each LDO can be individually
enabled and disabled through the serial port, as well as
individually programmed to any of 32 voltages from
1.8V to 3.3V.
The MAX1798/MAX1798A/MAX1799/MAX1799As’ wide
2.5V to 5.5V input voltage range makes them compati-
ble with a wide range of input supplies, including a sin-
gle lithium-ion (Li+) cell battery. Both devices are
available in thermally-enhanced 20-pin TSSOP and QFN
exposed pad (EP) packages. Evaluation kits in TSSOP
(MAX1798EVKIT and MAX1799EVKIT) are available to
facilitate designs.
Typical Operating Circuit
2.5V
TO 5.5V
SPI OR I²C
0.01µF
ONO
IN4/5
OFF
IN2/3
OUT1
IN1
RSO
MAX1798
ON MAX1798A* OUT2
MAX1799
MAX1799A* ^OUT3
CS (AS)
OUT4
SCLK (SCK)
DIN (SDA)
OUT5
BP
DR1
DR2
GND PGND
IRQ
WDOUT
V_CC
RESET
TX
RX
BBA
AUDIO OR
PLL + VCO
V_IN1
VIBRATOR
Features
o One 300mA Low-Noise LDO
o Four 150mA Low-Noise LDOs
o 45µV_RMS Noise from 10Hz to 100kHz
o >60dB Crosstalk Isolation Below 10kHz
o >60dB PSRR Below 10kHz
o 125mV (max) Dropout (OUT1 at 200mA)
o 100mV (max) Dropout (OUT2–5 at 100mA)
o Programmable Output Voltages
1.8V to 3.3V in 32 Steps
o 140ms (min) Reset Timer
o SPI- or I²C-Compatible Serial Interface
o Push-On/Push-Off Control Logic
o Two 150mA General Purpose Open-Drain Outputs
o Overcurrent and Thermal Protection (all LDOs)
o 1µA Shutdown Current
o 20-Pin Thermally-Enhanced TSSOP or QFN
Packages
Applications
CDMA Cellular/PCS Handsets
PDAs, Palmtops, and Handy-Terminals
Single-Cell Li+ Systems
2- or 3-Cell NiMH, NiCd, or Alkaline Systems
Ordering Information
PA RT
TEMP
RANGE
PIN-
PA CKA GE
INTER-
FACE
MAX1798EGP
-40°C to +85°C 20 QFN
SPI
MAX1798EUP
-40°C to +85°C 20 TSSOP-EP
SPI
MAX1798AEGP -40°C to +85°C 20 QFN
SPI
MAX1798AEUP -40°C to +85°C 20 TSSOP-EP
SPI
Ordering Information continued and Pin Configurations
appear at end of data sheet.
BACKLIGHT
( ) ARE FOR MAX1799/MAX1799A.
*-13% RESET THRESHOLD AND SHUTDOWN RESET TIMER ADDED.
SPI is a trademark of Motorola, Inc.
I²C is a trademark of Philips Corp.
________________________________________________________________ Maxim Integrated Products 1
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