19-1376; Rev 1; 12/98
3V to 5V Regulating
Charge Pumps for SIM Cards
General Description
The MAX1686 provides power for dual-voltage sub-
scriber ID module (SIM) cards in portable applications
such as GSM cellular phones. Designed to reside in the
portable unit (cellular phone handset), the 1MHz charge
pump converts a 2.7V to 4.2V input to regulated 5V out-
put. The MAX1686H has a nominal output voltage of
5.0V, while the MAX1686 is set to 4.75V to reduce SIM-
card current drain. The charge pump has only 45µA qui-
escent supply current, which reduces to 3µA when a
3V-capable SIM card is being powered and the charge
pump is disabled. An internal input/output shorting
switch provides power for 3V SIM cards.
The MAX1686/MAX1686H require only three external
capacitors around their space-saving, thin (1mm) 8-pin
µMAX packages.
o
2.7V to 4.2V Input Range
o
12mA min Charge-Pump Output Current
o
45µA Quiescent Supply Current
o
0.1µA Supply Current in Shutdown Mode
o
5.0V Regulated Charge-Pump Output (MAX1686H)
4.75V Regulated Charge-Pump Output (MAX1686)
o
Input-Output Shorting Switch for 3V Cards
o
Small External Components
(Uses a 0.047µF, 0.1µF, and a 2.2µF Capacitor)
o
Output Driven to Ground in Shutdown Mode
o
Super-Small 8-Pin µMAX Package
o
Soft-Start and Short-Circuit Protection
Features
MAX1686/MAX1686H
Applications
GSM Cellular Phones
PCS Phones
Portable POS Terminals
Personal Communicators
PART
MAX1686EUA
MAX1686HEUA
Ordering Information
TEMP. RANGE
-40°C to +85°C
-40°C to +85°C
PIN-PACKAGE
8 µMAX
8 µMAX
Typical Operating Circuit
C
X
Pin Configuration
TOP VIEW
INPUT
2.7V TO 4.2V
IN
C
IN
CXN
CXP
OUT
OUTPUT
V
IN
OR 5V/20mA
C
OUT
3/5
SHDN
IN
GND
1
2
3
4
8
OUT
CXP
CXN
PGND
MAX1686
MAX1686H
SHDN
3/5
GND
PGND
MAX1686
MAX1686H
µMAX
7
6
5
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Maxim Integrated Products
1
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