Analog Devices Inc./Maxim Integrated MAX881REUB-TG074

Overview

MAX881REUB-TG074 from Maxim Integrated is a low-noise, inverting charge-pump power supply with integrated negative linear regulator, designed specifically to bias GaAsFET power amplifiers in portable wireless transceivers. It accepts 2.5V–5.5V input, delivers up to 4mA at preset −2.0V or adjustable −0.5V to (−VIN + 0.6V), and achieves 1mV_p-p output ripple/noise. Its POK output enables controlled GaAsFET drain switching in cellular handsets.

For engineers reviewing the MAX881REUB-TG074 datasheet, MAX881REUB-TG074 pinout, MAX881REUB-TG074 application, or MAX881REUB-TG074 equivalent, key selection criteria include guaranteed startup time (≤1ms), logic-controlled shutdown (0.05µA), output load regulation (2–6mV/mA), and µMAX-10 package compatibility for space-constrained RF front-end designs.

Technical Context

The MAX881REUB-TG074 integrates a capacitive charge pump followed by an N-channel pass transistor-based linear regulator to generate stable, low-noise negative bias. Its dual-mode feedback (FB) pin supports fixed −2V operation (FB = GND) or adjustable output via external resistor divider, with FB voltage precisely regulated at −0.500V ±15mV.

Power-OK (POK) is an active-low open-drain signal asserting when OUT reaches ≥92.5% of its setpoint, enabling safe sequencing of GaAsFET drain power. Shutdown (SHDN) disables both charge pump and regulator, sinking OUT/NEGOUT to GND while drawing ≤1µA total supply current over temperature.

Key Specifications

Pinout & Package

MAX881REUB-TG074 is housed in a 10-pin µMAX package (3.0mm × 3.0mm × 0.8mm, 0.5mm pitch), optimized for high-density RF front-end placement near GaAsFETs.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar negative bias supply applications.

Compared with MAX882REUB+ and LT3467EDD#TRPBF, MAX881REUB-TG074 uniquely combines guaranteed 1mV_p-p noise, hardware POK sequencing, and adjustable bias in a 10-pin µMAX - making it the optimal choice for GaAsFET bias in space- and noise-constrained portable RF systems.

Availability

MAX881REUB-TG074 is available at Aetrix Electronics and suitable for cellular handsets, wireless modems, and two-way pagers requiring stable component supply, low-noise RF bias generation, and hardware-enforced power sequencing.

Supply support for MAX881REUB-TG074 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) is a U.S.-based semiconductor company specializing in high-performance analog, mixed-signal, and power management ICs for industrial, communications, and consumer applications.

The MAX881R product line was engineered specifically for GaAsFET PA bias in portable wireless devices, emphasizing ultra-low noise, integrated sequencing, and minimal external component count in sub-3mm packages.

FAQ

What is the guaranteed startup time for MAX881REUB-TG074, and how does it impact TDMA-based wireless systems?

The MAX881REUB-TG074 guarantees startup time ≤1ms from SHDN deassertion to POK assertion. This ensures the GaAsFET bias is fully established before the first TDMA transmit slot begins - preventing RF carrier distortion and meeting GSM/PCS frame timing budgets. The specification is tested across −40°C to +85°C and applies to both fixed −2V and adjustable output configurations of MAX881REUB-TG074.

Can MAX881REUB-TG074 be used to generate −1.8V output, and what resistor values are required?

Yes, MAX881REUB-TG074 supports −1.8V output via FB pin configuration. With V_FB = −0.500V, use R1 = 200kΩ and R2 = 260kΩ (1% tolerance) in a divider from OUT to GND. This satisfies R2 = R1(2 × |V_OUT| − 1) and maintains regulation accuracy across temperature. The −1.8V output remains stable up to 4mA load and retains 1mV_p-p noise performance in MAX881REUB-TG074.

How does the POK output of MAX881REUB-TG074 interface with external MOSFETs for GaAsFET drain control?

The POK output of MAX881REUB-TG074 is an active-low open-drain signal that sinks current when OUT reaches ≥92.5% of its setpoint. To drive a P-MOSFET gate, connect POK to the MOSFET gate through a 50kΩ pull-up to V_CC; when POK goes low, the MOSFET turns on and applies drain voltage to the GaAsFET. This hardware interlock ensures MAX881REUB-TG074 bias is verified before PA activation - a core safety feature of MAX881REUB-TG074.

What capacitor types and values are mandatory for achieving 1mV_p-p noise with MAX881REUB-TG074?

To achieve 1mV_p-p output noise, MAX881REUB-TG074 requires C1–C3 = 0.22µF ceramic capacitors with ESR <0.4Ω, and C4 = 4.7µF ceramic or chip tantalum with ESR <0.1Ω. These values are validated in Figure 3b of the datasheet. Using larger capacitors (e.g., 1µF/10µF) further reduces noise but increases board area - the specified values represent the minimum set delivering full MAX881REUB-TG074 performance.

Does MAX881REUB-TG074 require external compensation, and how is stability ensured across input voltage variations?

No, MAX881REUB-TG074 is internally compensated and requires no external compensation components. Stability is maintained across 2.5V–5.5V input via fixed-gain error amplifier design and optimized pole-zero placement in the linear regulator loop. Load regulation remains within 2–6mV/mA and startup time stays ≤1ms regardless of VIN - confirmed across all operating conditions in the MAX881REUB-TG074 datasheet.