Analog Devices Inc. AMP04FSZ

Overview

AMP04FSZ from Analog Devices is a precision single-supply instrumentation amplifier optimized for low-power, high-accuracy signal conditioning in battery-powered and industrial sensor interfaces. It delivers 150 µV max input offset voltage, 700 µA max supply current, and programmable gain from 1 to 1000 via a single external resistor - enabling direct connection to strain gages, RTDs, and thermocouples with zero-in/zero-out operation on +5 V supplies.

For engineers reviewing the AMP04FSZ datasheet, AMP04FSZ pinout, AMP04FSZ application, or AMP04FSZ equivalent, key selection criteria include its extended input common-mode range (0 V to V_S–1 V), rail-to-rail output swing capability, laser-trimmed thin-film resistor network for <0.005% gain nonlinearity, and guaranteed CMRR ≥90 dB at G ≥100 - all critical for precision data acquisition in medical instrumentation and portable test equipment.

Technical Context

The AMP04FSZ employs a proprietary three-op-amp topology with matched internal resistors and a dedicated reference input (Pin 5), enabling true zero-input/zero-output behavior in single-supply systems without requiring level-shifting circuitry. Its input stage uses low-drift, low-bias-current transistors (<5 nA IB, <8 pA/°C drift) and laser-trimmed thin-film resistors to achieve 30 ppm/°C gain tempco and 6 µV/°C max input offset drift.

Unlike conventional instrumentation amplifiers, the AMP04FSZ supports full-scale differential input signals with common-mode voltages extending to ground (0 V) and up to V_S–1 V, while maintaining >75 dB CMRR over –40°C to +85°C. Its accessible feedback node (Pin 8) allows external capacitor-based noise filtering, and its RGAIN pins (1 & 8) provide precise gain-setting with G = 100 kΩ/R_GAIN.

Key Specifications

Pinout & Package

AMP04FSZ is housed in an 8-lead narrow-body SOIC (SO-8) package with standard JEDEC MS-012AC footprint (4.9 mm × 3.9 mm × 1.75 mm height). Pin 1 is marked with a dot; pin numbering follows counterclockwise convention from top-left corner.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar instrumentation amplifier applications.

Compared with AD8221ARMZ and INA333AIDR, the AMP04FSZ uniquely combines single-supply zero-in/zero-out operation, laser-trimmed gain accuracy, and a dedicated REF pin - making it the only choice for battery-powered RTD/thermocouple systems requiring true unipolar signal chains without external level-shifting circuitry.

Availability

AMP04FSZ is available at Aetrix Electronics and suitable for precision sensor signal conditioning, portable medical instrumentation, and industrial 4–20 mA loop transmitter/receiver designs requiring stable component supply, long-lifecycle support, and traceable sourcing.

Supply support for AMP04FSZ 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

Analog Devices is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets since 1965.

The AMP04FSZ belongs to Analog Devices' precision instrumentation amplifier product line, engineered specifically for low-power, single-supply sensor interface applications where zero-referenced operation, laser-trimmed accuracy, and simplified gain configuration are critical design requirements.

FAQ

What is the maximum gain achievable with AMP04FSZ, and how is it set?

The AMP04FSZ supports a maximum gain of 1000, set precisely by a single external resistor connected between Pins 1 and 8 (RGAIN). The gain equation is G = 100 kΩ / RGAIN, so a 100 Ω resistor yields G = 1000. This configuration avoids resistor matching errors and maintains accuracy across temperature due to the device's internal laser-trimmed 100 kΩ resistor network. For AMP04FSZ, this method is validated across the full –40°C to +85°C operating range.

Can AMP04FSZ operate from a single +5 V supply while accepting input signals down to 0 V?

Yes, AMP04FSZ is explicitly designed for single-supply operation with input common-mode voltage ranging from 0 V to V_S–1 V. When powered from +5 V, it accepts differential inputs with common-mode voltages from ground up to +4 V while maintaining full accuracy and >75 dB CMRR. This eliminates the need for input biasing networks typically required by other instrumentation amplifiers - a key advantage confirmed in the "Input Common-Mode Range Includes Ground" section of the AMP04FSZ datasheet.

What is the purpose of the REF pin (Pin 5) on AMP04FSZ, and how should it be used?

The REF pin (Pin 5) on AMP04FSZ sets the output DC level relative to the differential input. When grounded in single-supply operation, it ensures 0 V output for 0 V differential input - enabling true zero-in/zero-out behavior. In dual-supply systems, it can be tied to ground or a reference voltage to shift the output baseline. The datasheet specifies that REF must be driven by a low-impedance source (<100 Ω) to preserve CMRR and gain accuracy; buffering with an op amp (e.g., OP113) is recommended for adjustable offset applications.

How does AMP04FSZ achieve low input bias current, and why is this important?

AMP04FSZ achieves input bias current <5 nA (typical) and <8 pA/°C drift through a proprietary input structure using low-leakage transistors and guarded layout techniques. This is critical for interfacing with high-impedance sensors such as thermocouples, piezoresistive elements, or floating RTD bridges, where even nanoampere-level leakage currents would generate significant offset errors across source impedances >10 kΩ. The datasheet confirms this performance is maintained over the full –40°C to +85°C temperature range.

Is AMP04FSZ suitable for driving ADC inputs directly, and what output swing can be expected?

Yes, AMP04FSZ is well-suited for direct ADC interfacing. With a +5 V supply, its output swings from <2.5 mV above ground to >4.0 V (RL = 2 kΩ), providing >4 V of usable range for 12-bit+ ADCs. At higher supplies (e.g., ±15 V), output swing extends to ±12.5 V. The datasheet guarantees this performance under load and across temperature, and the device's low output impedance (<1 Ω) ensures minimal settling time when driving ADC sample capacitors.