19-1655; Rev 2; 5/10
CDMA Cellular/PCS System
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
TQFN exposed pad (EP) packages. Evaluation kits in
TSSOP (MAX1798EVKIT and MAX1799EVKIT) are avail-
able to facilitate designs.
Typical Operating Circuit
SPI OR I2C
GND PGND EP
PLL + VCO
( ) ARE FOR MAX1799/MAX1799A.
*-13% RESET THRESHOLD AND SHUTDOWN RESET TIMER ADDED.
o One 300mA Low-Noise LDO
o Four 150mA Low-Noise LDOs
o 45µVRMS 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 TQFN
CDMA Cellular/PCS Handsets
PDAs, Palmtops, and Handy-Terminals
Single-Cell Li+ Systems
2- or 3-Cell NiMH, NiCd, or Alkaline Systems
MAX1798ETP+ -40°C to +85°C 20 TQFN
MAX1798EUP+ -40°C to +85°C 20 TSSOP-EP*
MAX1798AETP+ -40°C to +85°C 20 TQFN
MAX1798AEUP+ -40°C to +85°C 20 TSSOP-EP*
+Denotes a lead(Pb)-free/RoHS-compliant package.
*EP = Exposed pad.
Ordering Information continued and Pin Configurations
appear at end of data sheet.
SPI is a trademark of Motorola, Inc.
________________________________________________________________ Maxim Integrated Products 1
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.