Rainbow Electronics MAX1643 - Manual

_______________General Description
The MAX1642/MAX1643 are high-efficiency, low-voltage,
step-up DC-DC converters intended for devices pow-
ered by a single alkaline cell. They feature low quies-
cent supply currents and are supplied in the ultra-small
µMAX package, which is only 1.1mm high. The guaran-
teed start-up voltage is 0.88V.
Each device consists of an internal 1
Ω
, N-channel
MOSFET power switch; a built-in synchronous rectifier
that acts as the catch diode; an oscillator; a reference;
and pulse-frequency-modulation (PFM) control circuitry.
Both devices feature an independent undervoltage
comparator (PFI/PFO). The MAX1642 also includes a
2µA logic-controlled shutdown mode. The MAX1643
offers a dedicated low-battery detector (BATTLO) in
lieu of shutdown.
The output voltage for each device is preset to 3.3V
±4%, or can be adjusted from +2V to +5.2V using only
two resistors.
________________________Applications
Pagers
Remote Controls
Pointing Devices
Personal Medical Monitors
Single-Cell Battery-Powered Devices
____________________________Features
♦ Built-In Synchronous Rectifier
♦ 0.88V Guaranteed Start-Up
♦ Ultra-Small µMAX Package: 1.1mm High
♦ 83% Efficiency
♦ 4µA Quiescent Supply Current into BATT Pin
♦ 2µA Logic-Controlled Shutdown (MAX1642)
♦ Two Undervoltage Detectors (MAX1643)
♦ 2V to 5.2V Output Range
♦ 20mA Output Current at 1.2V Input
♦ Reverse Battery Protection
MAX1642/MAX1643
High-Efficiency, Step-Up
DC-DC Converters for 1V Inputs
________________________________________________________________ Maxim Integrated Products 1
GND PFO
FB SHDN
1
2
8
7
OUT
LX PFI
BATT
MAX1642
µ
MAX
TOP VIEW
3
4
6
5
GND BATTLO
FB PFO
1
2
8
7
OUT
LX PFI
BATT
MAX1643
µ
MAX
3
4
6
5
_________________Pin Configurations
OUT
OUTPUT
3.3V
INPUT
0.88V TO 1.65V
100 µ H
22 µ F
22 µ F
ON
LOW-BATTERY
DETECTOR INPUT
LOW-BATTERY
DETECTOR OUTPUT
OFF
PFO
BATT
LX
MAX1642
SHDN
PFI
GND FB
__________Typical Operating Circuit
______________Ordering Information
PART
MAX1642 C/D
MAX1642EUA
MAX1643 C/D 0°C to +70°C
-40°C to +85°C
0°C to +70°C
TEMP. RANGE PIN-PACKAGE
Dice*
8 µMAX
Dice*
MAX1643EUA -40°C to +85°C 8 µMAX
EVALUATION KIT MANUAL
FOLLOWS DATA SHEET
19-1183; Rev 0; 6/97
* Dice are tested at T A = +25°C.
Note: To order these devices shipped in tape and reel, add a -T
to the part number.
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.