MAX1730 Datasheet, PDF (1/8 Pages) Maxim Integrated Products – 50mA Regulated Step-Down Charge Pump for 1.8V or 1.9V Logic

19-1618; Rev 0; 4/00
50mA Regulated Step-Down Charge Pump
for 1.8V or 1.9V Logic
General Description
The MAX1730 regulated step-down charge pump gen-
erates up to 50mA at fixed output voltages of 1.8V or
1.9V from an input voltage in the 2.7V to 5.5V range.
Specifically designed to provide high-efficiency logic
supplies in applications that demand a compact
design, the MAX1730 employs fractional conversion
techniques to provide efficiency exceeding that of a lin-
ear regulator.
The MAX1730 operates at up to 2MHz, permitting the
use of small 0.22µF flying capacitors while maintaining
low 75µA quiescent supply current. Proprietary soft-
start circuitry prevents excessive current from being
drawn from the supply during startup, making the
MAX1730 compatible with higher impedance sources
such as alkaline and lithium-ion cells.
The MAX1730 is available in a space-saving 10-pin
µMAX package that is only 1.09mm high and occupies
one-half the area of an 8-pin SO.
Applications
Low-Voltage Logic Supplies
Wireless Handsets
PDAs
PC Cards
Hand-Held Instruments
Features
o > 85% Peak Efficiency
o 50mA Guaranteed Output Current
o Dual-Mode 1.8V or 1.9V Output
o ±3% Output Voltage Accuracy
o Up to 2MHz Operating Frequency
o Small 0.22µF Capacitors
o No Inductor Required
o 2.7V to 5.5V Input Voltage Range
o Output Disconnects from Input in Shutdown Mode
o Small 10-Pin µMAX Package (1.09mm max height)
PART
MAX1730EUB
Ordering Information
TEMP. RANGE
-40°C to +85°C
PIN-PACKAGE
10 µMAX
Typical Operating Circuit
INPUT
2.7V TO 5.5V
1µF
0 22µF
SHDN ^IN OUT
MAX1730
C1P
C2P
C1N
C2N
FB _GND PGND
OUTPUT
1.8V OR 1.9V, UP TO 50mA
4.7µF
0.22µF
TOP VIEW
Pin Configuration
FB 1
SHDN 2
C1P 3
C1N 4
GND 5
MAX1730
µMAX
10 IN
9 OUT
8 C2P
7 C2N
6 PGND
________________________________________________________________ Maxim Integrated Products 1
For free samples and the latest literature, visit www.maxim-ic.com or phone [phone].
For small orders, phone [phone].