MAX1643

BATT to GND ...........................................................-0.3V to 6.0V
BATT Forward Current ..........................................................0.5A
OUT to GND.............................................................-0.3V to 6.0V
OUT, LX Current.......................................................................1A
LX to GND................................................................-0.3V to 6.0V
SHDN, FB, BATTLO, PFO to GND...............................-0.3V to 6.0V
PFI to GND ...........................................................-0.3V to V_BATT
Reverse Battery Current (T_A = +25°C) (Note 1) ...............220mA
Continuous Power Dissipation
MAX (derate 4.1mW/°C above 70°C).............................330mW
Operating Temperature Range
MAX1642EUA/MAX1643EUA ...............................-40°C to +85°C
Junction Temperature......................................................+150°C
Storage Temperature Range ............................-65°C to +165°C
Lead Temperature (soldering, 10sec) .............................+300°C

Note 1: The reverse battery current is measured from the Typical Operating Circuit's input terminal to GND when the battery is connected backward. A reverse current of 220mA will not exceed package dissipation limits but, if left for an extended time (more than 10 minutes), may degrade performance.

Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

The MAX1642/MAX1643 are high-efficiency, low-voltage, step-up DC-DC converters intended for devices powered by a single alkaline cell. They feature low quiescent supply currents and are supplied in the ultra-small MAX package, which is only 1.1mm high. The guaranteed start-up voltage is 0.88V.

Each device consists of an internal 1½, 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 2A 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.