Document
19-1600; Rev 0; 1/00
Buck/Boost Regulating Charge Pump in µMAX
General Description
The MAX1759 is a buck/boost regulating charge pump that generates a regulated output voltage from a single lithium-ion (Li+) cell, or two or three NiMH or alkaline cells for small hand-held portable equipment. The MAX1759 operates over a wide +1.6V to +5.5V input voltage range and generates a fixed 3.3V or adjustable (2.5V to 5.5V) output (Dual Mode™). Maxim’s unique charge-pump architecture allows the input voltage to be higher or lower than the regulated output voltage. Despite its high 1.5MHz operating frequency, the MAX1759 maintains low 50µA quiescent supply current. Designed to be an extremely compact buck/boost converter, this device requires only three small ceramic capacitors to build a complete DC-DC converter capable of generating a guaranteed 100mA (min) output current from a +2.5V input. For added flexibility, the MAX1759 also includes an open-drain power-OK (POK) output that signals when the output voltage is in regulation. The MAX1759 is available in a space-saving 10-pin µMAX package that is 1.09mm high and half the size of an 8-pin SO.
Features
o Regulated Output Voltage (Fixed 3.3V or Adjustable 2.5V to 5.5V) o 100mA Guaranteed Output Current o +1.6V to +5.5V Input Voltage Range o Low 50µA Quiescent Supply Current o 1µA Shutdown Mode o Load Disconnected from Input in Shutdown o High 1.5MHz Operating Frequency o Uses Small Ceramic Capacitors o Short-Circuit Protection and Thermal Shutdown o Small 10-Pin µMAX Package
MAX1759
Ordering Information Applications
Li+ Battery-Powered Applications Miniature Equipment Backup Battery Boost Converters Translators
PART MAX1759EUB TEMP. RANGE -40°C to +85°C PIN-PACKAGE 10 µMAX
Typical Operating Circuit
CX IN +1.6V TO +5.5V CIN OUT 3.3V AT 100mA COUT
Pin Configuration
TOP VIEW
CXN IN
CXP OUT
POK 1 SHDN IN IN 2 3 4 5
10 FB 9 OUT CXP CXN PGND
MAX1759
MAX1759
ON OFF SHDN FB GND PGND POK POWER OK
8 7 6
GND
µMAX
Dual Mode is a trademark of Maxim Integrated Products. ________________________________________________________________ Maxim Integrated Products 1
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Buck/Boost Regulating Charge Pump in µMAX MAX1759
ABSOLUTE MAXIMUM RATINGS
IN, OUT, FB, POK, SHDN to GND............................-0.3V to +6V PGND to GND.....................................................................±0.3V CXN to GND ................................................-0.3V to (VIN + 0.3V) CXP to GND..............................................-0.3V to (VOUT + 0.3V) OUT Short to GND .........................................................Indefinite Continuous Power Dissipation (TA = +70°C) 10-Pin µMAX (derate 5.6mW/°C above +70°C) .........444mW Operating Temperature Range .......................... -40°C to +85°C Junction Temperature ......................................................+150°C.