Analog Devices Inc. ADA4255ACPZ

Overview

ADA4255ACPZ from Analog Devices is a zero-drift, high-voltage programmable gain instrumentation amplifier (PGIA) with integrated bipolar charge pump, 36 precision gains from 1/16 V/V to 176 V/V, ±14 μV max input offset voltage, and robust ±60 V input protection-designed for universal process control front ends interfacing with low-noise ADCs like AD7175-2.

For engineers reviewing the ADA4255ACPZ datasheet, ADA4255ACPZ pinout, ADA4255ACPZ application, or ADA4255ACPZ equivalent, this device delivers verified dc precision (±0.01% gain error post-calibration), SPI-controlled gain selection with CRC, integrated excitation current source for RTDs, and high-voltage isolated signal conditioning without external level-shifting circuitry.

Technical Context

The ADA4255ACPZ implements a zero-drift PGIA topology using chopper-stabilized amplifiers to self-calibrate dc errors and suppress 1/f noise across −40°C to +105°C. Its internal charge pump generates ±22 V high-voltage rails (VDDH/VSSH) from a 5 V supply, enabling 38 V typical input range while maintaining >1 GΩ input impedance.

It integrates a 2:1 input multiplexer with ±60 V fault protection, seven GPIOs supporting sequential chip select and wire-break detection, and an excitation current source (100–1500 μA) with ±3% initial tolerance-enabling direct 3-wire RTD biasing and PLC analog input channel consolidation.

Key Specifications

Pinout & Package

ADA4255ACPZ uses a compact 28-lead, 5 mm × 5 mm LFCSP package with exposed pad connected to VSSH. Pin functions are validated per Analog Devices Rev. 0 datasheet Figure 5 and Table 5.

Key Features

Applications

Equivalent & Alternatives

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

Compared with AD8429ARZ and LTC6373IMS#PBF, ADA4255ACPZ uniquely combines programmable gain, integrated high-voltage generation, excitation current, and fault-protected multiplexing - enabling full analog front-end integration in a single 5 mm × 5 mm package, whereas alternatives require ≥3 additional ICs to match functionality.

Availability

ADA4255ACPZ is available at Aetrix Electronics and suitable for universal process control front ends, high-channel data acquisition systems, and industrial test equipment requiring stable component supply, long-term lifecycle support, and guaranteed traceability.

Supply support for ADA4255ACPZ 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 DSP technologies, serving industrial, automotive, communications, and healthcare markets since 1965.

The ADA4255ACPZ belongs to Analog Devices' precision instrumentation amplifier product line, engineered specifically for industrial process control and high-accuracy data acquisition where dc precision, high-voltage tolerance, and system integration are critical.

FAQ

What is the maximum input voltage range supported by the ADA4255ACPZ?

The ADA4255ACPZ supports a guaranteed input operating voltage range of VSSH + 3 V to VDDH − 3 V. With VDDCP = 5 V, typical VDDH and VSSH are +22.3 V and −21.7 V, yielding a 38 V typical input range. Absolute maximum ratings allow ±60 V input voltage relative to VSSH and 60 V differential between any two inputs - confirmed in Table 3 of the Rev. 0 datasheet.

How does the ADA4255ACPZ achieve zero-drift performance?

The ADA4255ACPZ uses a proprietary zero-drift architecture across all internal amplifiers (A1–A9), combining chopper stabilization and auto-zero techniques to cancel input offset voltage and its drift. This achieves ±14 μV max input offset and ±0.08 μV/°C max drift over −40°C to +105°C - specified in Table 1 and validated in Figures 6–11 of the datasheet.

Can the ADA4255ACPZ drive an ADC directly without external level-shifting?

Yes. The ADA4255ACPZ includes a dedicated output amplifier stage with independent VOCM pin control, allowing precise setting of the differential output common-mode voltage to match ADC input requirements (e.g., AVDD/2). Its ±22 V internal rails and rail-to-rail output swing ensure full-scale ADC utilization without external level-shifting circuitry - detailed in the "Output Amplifier" section (p.27) and VOCM specifications (p.5).

What is the purpose of the integrated charge pump in the ADA4255ACPZ?

The integrated bipolar charge pump in the ADA4255ACPZ generates high-voltage rails (VDDH ≈ +22 V, VSSH ≈ −22 V) from a low-voltage supply (VDDCP = 2.7–5 V), enabling wide input voltage range operation while preserving high input impedance. This eliminates external isolated DC/DC converters and reduces system cost, size, and complexity - described in the General Description (p.1) and Charge Pump specifications (p.7).

Does the ADA4255ACPZ support RTD temperature sensing?

Yes. The ADA4255ACPZ integrates a programmable excitation current source (IOUT) delivering 100–1500 μA with ±3% initial tolerance and ±200 ppm/°C drift, explicitly designed for biasing 2-wire and 3-wire RTDs. Application information for 3-wire RTD with current excitation is provided on page 42 of the datasheet, confirming direct compatibility with ADA4255ACPZ.