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MAX840 - Low-Noise / Regulated / -2V GaAsFET Bias

Description

The MAX840/MAX843/MAX844 low-noise, inverting charge-pump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers.

They operate with inputs down to 2.5V.

The MAX840 offers both a -2V preset output and a -0.5V to -9.4V adjustable output.

Features

  • o Fixed -2V or Adjustable -0.5V to -9.4V Output at 4mA (MAX840) o 2.5V to 10V Input Voltage Range o Operate with Small Capacitors (as low as 0.22µF) o 1mVp-p Output Voltage Ripple o Charge-Pump Switching Frequency: 100kHz in Normal Operation 20kHz in Shutdown Mode (MAX844) o 1µA Max Logic-Level Shutdown Over Temp. (MAX840/MAX843) o Small 8-Pin SO Package MAX840/MAX843/MAX844 ______________Ordering Information PART MAX840C/D MAX840ISA MAX840ESA MAX843C/D MAX843ISA MAX843ESA MAX844C/D MAX844ISA.

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Full PDF Text Transcription (Reference)

The following content is an automatically extracted verbatim text from the original manufacturer datasheet and is provided for reference purposes only.

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19-0388; Rev 1; 3/96 UAL IT MAN TION K A ET U E L H A S EV TA WS DA FOLLO Low-Noise, Regulated, -2V GaAsFET Bias _______________General Description The MAX840/MAX843/MAX844 low-noise, inverting charge-pump power supplies are ideal for biasing GaAsFETs in cellular telephone transmitter amplifiers. They operate with inputs down to 2.5V. The MAX840 offers both a -2V preset output and a -0.5V to -9.4V adjustable output. The MAX843/MAX844 use an external positive control voltage to set the negative output voltage. Input voltage range for all the devices is 2.5V to 10V, and output current is 4mA with VIN > 2.7V. These circuits can operate with small capacitors, as low as 0.22µF. An internal linear regulator reduces the MAX840’s output voltage ripple to 1mVp-p.
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