MAX840ISA

Overview

The MAX840ISA is a low-noise, regulated -2V GaAsFET bias voltage regulator IC manufactured by Analog Devices Inc./Maxim Integrated. It utilizes a charge pump architecture to generate a stable negative output voltage from a positive input supply ranging from 2.5V to 10V. The device is housed in an 8-SOIC surface-mount package with a width of 3.90mm. It operates within a temperature range of -25°C to +85°C and is designed for applications requiring precise biasing of GaAsFET components.

Feature Summary

• Provides regulated -2V output specifically optimized for GaAsFET biasing
• Integrates a charge pump circuit for efficient voltage inversion
• Operates from a single positive supply input between 2.5V and 10V
• Delivers low-noise performance suitable for sensitive RF transmitter stages

Applications

• Cellular telephone transmitter bias circuits
• GaAsFET gate bias regulation
• RF power amplifier bias networks

Procurement Notes

Verify component authenticity through authorized distributors or direct manufacturer channels due to potential availability constraints. Confirm the specific suffix (e.g., ISA vs. ISAE) matches design requirements as some variants may be obsolete. Request current lifecycle status documentation to ensure long-term supply viability for production runs.

Selection Notes

Select this component when a stable, low-noise negative bias voltage is required for GaAsFET-based RF circuits. Ensure the input supply voltage remains within the 2.5V to 10V range. Consider the 8-SOIC package dimensions for PCB layout compatibility. Verify thermal dissipation capabilities if operating near maximum temperature limits.

Part Context

The MAX840 belongs to Maxim Integrated's family of specialized voltage regulators designed for cellular communication systems. It addresses the specific need for clean negative bias voltages in high-frequency analog front-ends. The ISA variant denotes a commercial grade temperature range and standard SOIC packaging, distinguishing it from industrial or extended temperature options.

Replacement Considerations

Check for MAX840ISA+T or MAX840ISAE+ as potential pin-compatible alternatives depending on packaging preference (tape/reel vs. tube). Verify functional equivalence with newer generations of GaAsFET bias controllers if the original part is discontinued.