Texas Instruments PGA205AP

Overview

PGA205AP from Burr-Brown (now Texas Instruments) is a digitally programmable gain instrumentation amplifier with fixed gain options of 1, 2, 4, and 8 V/V, ±50 µV max input offset voltage, 0.25 µV/°C drift, and 16-pin plastic DIP package. It operates from ±4.5V to ±18V supplies and is used in precision data acquisition systems where low-noise, high-CMRR signal conditioning of sensor outputs is required.

For engineers reviewing the PGA205AP datasheet, PGA205AP pinout, PGA205AP application, or PGA205AP equivalent, key selection considerations include its 8-V/V maximum gain, 100 kHz bandwidth at G=8, ±40V input overvoltage protection, and compatibility with TTL/CMOS digital control lines A0/A1 without requiring a separate logic supply.

Technical Context

The PGA205AP integrates three op-amps (A1, A2, A3) in a classic three-op-amp instrumentation topology with digitally switched internal feedback resistors. Gain selection is performed via two unbuffered TTL/CMOS-compatible address inputs (A0, A1), directly controlling resistor networks that set the overall closed-loop gain.

It features laser-trimmed input stage offset (±50 µV max), internal overvoltage protection on both inputs (±40V survivable), and output referenced to a dedicated Ref pin-requiring low-impedance grounding for >112 dB CMRR at G=8. The device supports operation from –40°C to +85°C and draws ±5.2 mA quiescent current at ±15V.

Key Specifications

Pinout & Package

PGA205AP is housed in a 16-pin plastic dual in-line package (PDIP, package number 180), through-hole mountable, with 0.3-inch body width and standard 0.1-inch pin spacing.

Key Features

Applications

Equivalent & Alternatives

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

Compared with INA128UA and AD8253ARMZ, the PGA205AP uniquely delivers TTL/CMOS-compatible digital gain control without auxiliary logic supplies or serial interfaces-making it optimal for simple, low-cost, through-hole-based analog front-ends where moderate bandwidth and proven industrial reliability are prioritized.

Availability

PGA205AP is available at Aetrix Electronics and suitable for data acquisition systems, medical instrumentation, general-purpose analog boards, and test equipment requiring stable component supply with long-term industrial temperature support (–40°C to +85°C).

Supply support for PGA205AP 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

Burr-Brown Corporation, acquired by Texas Instruments in 2000, specialized in high-precision analog ICs including instrumentation amplifiers, data converters, and op-amps for measurement and control systems.

The PGA204/205 product line was designed specifically for cost-sensitive, high-accuracy analog signal conditioning in industrial and medical data acquisition-emphasizing digital programmability, input ruggedness, and laser-trimmed DC performance in standard packages.

FAQ

What gain settings does the PGA205AP support?

The PGA205AP supports four discrete, digitally selectable gains: 1 V/V, 2 V/V, 4 V/V, and 8 V/V. These are selected using the binary combination of logic inputs A0 and A1 (00 = 1×, 01 = 2×, 10 = 4×, 11 = 8×). Unlike the PGA204AP, the PGA205AP does not support gains of 10, 100, or 1000 V/V. This fixed low-gain range makes the PGA205AP ideal for applications requiring modest amplification with high bandwidth and low noise.

Does the PGA205AP require a separate logic supply voltage?

No, the PGA205AP does not require a separate logic supply. Its digital inputs A0 and A1 are TTL/CMOS-compatible and reference to the Digital Ground (pin 14), which can be connected anywhere between V– and (V+)–4V. The device draws only ~1 µA from each logic input when low, and nearly zero when high-enabling direct interfacing with microcontrollers or FPGAs operating at 3.3V or 5V without level-shifting circuitry. This simplifies design and reduces BOM count.

How is the output reference (Ref) pin used in the PGA205AP?

The Ref pin (pin 10) defines the output common-mode voltage level of the PGA205AP. It must be connected to a low-impedance ground (ideally <5 Ω) to achieve specified CMRR (up to 112 dB at G=8). If a series resistance >5 Ω is introduced, CMRR degrades significantly-e.g., to ~80 dB. The Ref pin may also accept an external offset voltage (e.g., from a buffered DAC) to level-shift the output, but this requires maintaining low impedance to preserve AC performance and CMRR.

What is the purpose of pins 6 and 7 (VOS Adj) on the PGA205AP?

Pins 6 and 7 are dedicated input offset voltage trim terminals for the PGA205AP's first-stage amplifiers (A1 and A2). They allow fine adjustment of input-stage offset using an external potentiometer (200kΩ–1MΩ). Because the device is laser-trimmed to ±50 µV max, external trimming is rarely needed-but when required, it should be performed at highest gain (G=8) with inputs grounded. Trimming here affects only input-stage offset and avoids degrading temperature drift, unlike output-stage adjustments.

Can the PGA205AP operate from a single supply?

No, the PGA205AP is specified only for dual-supply operation (±4.5V to ±18V). Its internal architecture-including input amplifiers A1 and A2 and output amplifier A3-requires symmetrical positive and negative rails to maintain linear input common-mode range (±12.7V) and full output swing. Attempting single-supply operation (e.g., 0V and +15V) will result in input saturation, degraded CMRR, and loss of specified performance. For single-supply applications, consider rail-to-rail alternatives like the AD8237 or INA333.