MAX844

Obsolete

Low-Noise, Regulated, -2V GaAsFET Bias

Operates with Small Capacitors, as Low as 0.22 µF

Data Sheet (Rev. 1) Product Selection Table

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Part Details

Fixed -2V or Adjustable -0.5V to -9.4V Output at 4mA (MAX840)
2.5V to 10V Input Voltage Range
Operate with Small Capacitors (as low as 0.22µF)
1mVp-p Output Voltage Ripple
Charge-Pump Switching Frequency:
- 100kHz in Normal Operation
- 20kHz in Shutdown Mode (MAX844)
1µA Max Logic-Level Shutdown Over Temp. (MAX840/MAX843)
Small 8-Pin SO Package

Documentation

Data Sheet 1

MAX840-MAX844: Low-Noise, Regulated, -2V GaAsFET Bias Data Sheet (Rev.1) 03/01/1996

Technical Articles 1

The Basics of USB Battery Charging 12/09/2010

This is the most up-to-date revision of the Data Sheet.

Evaluation Kits

Evaluation Kit for the MAX840, MAX843, MAX844

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Features and Benefits

1mVp-p Output Voltage Ripple
2.5V to 10V Input Range
Uses 0.22µF Capacitors
-2V Regulated Output (or Adjustable)
4mA Output Current
Surface-Mount Technology

Product Details

The MAX840/MAX843/MAX844 ICs are inverting, charge-pump DC-DC converters with low-noise, regulated outputs. Their low output ripple voltage makes these devices ideal for biasing the GaAsFETs commonly found in cellular telephone transmitters.

The MAX840 evaluation kit (EV kit) is a fully assembled and tested surface-mount board. The board is shipped with a MAX840 mounted, but it can be replaced by the MAX843 or MAX844. Provisions are made for mounting two additional resistors, which are required for output voltages other than -2V. A special scope-probe socket is also mounted on the board, so output noise can be observed on an oscilloscope.

Applications