Analog Devices Inc./Maxim Integrated MAX852ESA+

Overview

MAX852ESA+ from Maxim Integrated is a low-noise, inverting, regulated charge-pump DC/DC converter optimized for GaAsFET biasing in cellular transmitter amplifiers. It delivers a fixed -4.1V or adjustable -0.5V to -9.0V output at up to 5mA, operates from 4.5V to 10V input, features external clock synchronization (80–120kHz), and achieves 2mV_p-p output ripple with internal linear regulation.

For engineers reviewing the MAX852ESA+ datasheet, MAX852ESA+ pinout, MAX852ESA+ application, or MAX852ESA+ equivalent, this device is selected for precision negative bias generation where low noise, shutdown control, and EMI-sensitive RF front-end integration are critical - especially in handheld wireless transmitters requiring stable V_GG for GaAsFET power amplifiers.

Technical Context

The MAX852ESA+ integrates a capacitive charge pump followed by an N-channel pass transistor-based linear regulator to suppress switching ripple. Its OSC pin accepts an external 80–120kHz square-wave clock (40–60% duty cycle), enabling frequency coordination with system timing to avoid heterodyne interference in RF bands.

Unlike the MAX850/MAX851, the MAX852ESA+ replaces the SHDN pin with OSC for synchronous operation; FB remains grounded for fixed -4.1V output or connected to a resistor divider for adjustable output. Shutdown is achieved by gating the OSC signal low, reducing supply current to ≤1µA over temperature.

Key Specifications

Pinout & Package

MAX852ESA+ is housed in an 8-pin plastic Small-Outline (SO) package, 150mil body width, with standard gull-wing leads and RoHS-compliant finish. Pin 1 is marked by a beveled corner or dot.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative charge-pump regulator applications.

Compared with MAX850ESA+ and MAX853ESA+, the MAX852ESA+ uniquely provides external clock synchronization without sacrificing fixed-output simplicity or low-noise performance - making it optimal for RF systems where deterministic switching timing is essential but programmable output is not required.

Availability

MAX852ESA+ is available at Aetrix Electronics and suitable for cellular transmitter amplifiers, GaAsFET bias supplies, and LCD contrast control circuits requiring stable component supply, long-term lifecycle support, and consistent parametric performance across production batches.

Supply support for MAX852ESA+ includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

Maxim Integrated (now part of Analog Devices) designs precision analog, mixed-signal, and power-management ICs for demanding industrial, communications, and consumer applications.

The MAX850–MAX853 family was engineered specifically for low-noise, regulated negative bias generation in GaAsFET-based RF power amplifiers - prioritizing ripple suppression, shutdown efficiency, and EMI-controllable switching.

FAQ

What is the primary function of the MAX852ESA+ in RF power amplifier circuits?

The MAX852ESA+ serves as a low-noise, regulated negative voltage generator for GaAsFET gate bias (V_GG) in cellular transmitter amplifiers. It delivers a stable -4.1V output with only 2mV_p-p ripple, minimizing AM-to-AM distortion. Its OSC pin enables external clock synchronization - a key feature that prevents spectral interference in sensitive RF front-ends. The MAX852ESA+ integrates both charge-pump inversion and linear post-regulation in a single 8-pin SO package.

Can the MAX852ESA+ be used for adjustable output voltages, or is it fixed at -4.1V?

The MAX852ESA+ supports both configurations: grounding the FB pin yields a fixed -4.1V output, while connecting FB to a resistor divider between OUT and GND enables adjustable output from -0.5V to -9.0V. The output follows V_OUT = –1.28V × (1 + R2/R1). This dual-mode flexibility allows one MAX852ESA+ design to serve multiple GaAsFET bias points without changing the IC - unlike the MAX853ESA+, which requires a positive control voltage (CONT) instead of FB.

How does the OSC pin on the MAX852ESA+ differ from the SHDN pin on the MAX850ESA+?

The OSC pin on the MAX852ESA+ replaces the SHDN pin found on the MAX850ESA+ and accepts an external 80–120kHz square-wave clock for synchronous switching. Shutdown is achieved by pulling OSC low, reducing supply current to ≤1µA. In contrast, the MAX850ESA+ uses an active-low SHDN pin for enable/disable control but lacks clock synchronization. This makes the MAX852ESA+ preferable in EMI-sensitive RF systems where deterministic switching timing is required - a capability absent in the MAX850ESA+.

What capacitor types and values are recommended for stable operation of the MAX852ESA+?

For reliable MAX852ESA+ operation, use low-ESR surface-mount capacitors: C1 and C2 (flying caps) should be 1µF ceramic or tantalum with ≤0.8Ω ESR; C3 (input cap) is 1µF with same ESR spec; C4 (output filter) must be 10µF with ≤0.2Ω ESR. These values minimize dropout voltage and ensure regulation under load. Avoid electrolytic or high-ESR ceramics - they degrade ripple suppression and can cause instability. Layout best practices include short traces, ground plane use, and direct probing across C4 for accurate ripple measurement.

Is the MAX852ESA+ pin-compatible with other members of the MAX850–MAX853 family?

No - the MAX852ESA+ is not pin-compatible with MAX850ESA+, MAX851ESA+, or MAX853ESA+. While all share the same 8-pin SO package, pin functions differ: MAX852ESA+ uses Pin 4 for OSC, whereas MAX850ESA+/MAX851ESA+ use Pin 4 for SHDN (active-low or active-high), and MAX853ESA+ uses Pin 4 for CONT. Substituting without board revision will result in nonfunctional behavior. Each variant requires its own PCB layout - the MAX852ESA+ is purpose-built for synchronized clock operation, not drop-in replacement.