STMicroelectronics TSX634IQ4T

Overview

TSX634IQ4T from STMicroelectronics is a quad micropower rail-to-rail input/output CMOS operational amplifier optimized for high-impedance sensor interfaces and automotive signal conditioning. It delivers 200 kHz gain bandwidth, 45 µA supply current per amplifier at 16 V, ±500 µV max offset voltage (A-version), 1 pA typical input bias current, and operates from 3.3 V to 16 V across –40 °C to +125 °C.

For engineers reviewing the TSX634IQ4T datasheet, TSX634IQ4T pinout, TSX634IQ4T application, or TSX634IQ4T equivalent, key selection criteria include ultra-low quiescent current, rail-to-rail I/O swing in wide-supply industrial/automotive environments, low-offset stability over temperature, and compatibility with high-impedance transducers in battery-constrained or thermally demanding systems.

Technical Context

The TSX634IQ4T implements a CMOS input stage enabling 1 pA typical input bias current and 1 TΩ input resistance, supporting direct interfacing with piezoelectric, pH, and photodiode sensors. Its rail-to-rail input common-mode range extends from V_CC– – 0.1 V to V_CC+ + 0.1 V, and output swing reaches within 70 mV of both rails under 10 kΩ load at 25 °C.

It features a 200 kHz gain-bandwidth product with 55° phase margin and 9 dB gain margin, ensuring stable unity-gain follower operation. The device achieves 65–85 dB common-mode rejection (CMR) and 73–87 dB supply voltage rejection (SVR) across its full operating temperature and supply range.

Key Specifications

Pinout & Package

TSSOP14 package: 4.4 mm × 5.0 mm body, 0.65 mm pitch, 14-lead thin shrink small outline package with exposed thermal pad (not electrically connected). Pin 1 marked by dot; pin count increases counter-clockwise.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar quad micropower rail-to-rail op-amp applications.

Compared with TSX634IQ4T, TSX634AIDT offers tighter offset specification at identical footprint and temperature capability, while MCP6004-E/ST trades automotive robustness and ultra-low power for higher speed and lower cost in benign environments.

Availability

TSX634IQ4T is available at Aetrix Electronics and suitable for automotive cabin control, industrial process monitoring, portable medical instrumentation, and high-impedance sensor interface designs requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TSX634IQ4T 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

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing microcontrollers, power management ICs, analog components, and MEMS sensors for industrial, automotive, and consumer markets.

The TSX63x series belongs to ST's precision analog portfolio, engineered specifically for ultra-low-power, high-accuracy signal conditioning in harsh-environment applications where supply constraints and thermal stress limit conventional op-amp choices.

FAQ

What is the maximum capacitive load the TSX634IQ4T can drive without instability?

The TSX634IQ4T remains stable with ≤100 pF capacitive load when driving 100 kΩ resistive loads, as verified in Figure 16 of the datasheet. For loads exceeding 100 pF, a series isolation resistor (R_iso) ≥10 Ω is required - Figure 17 specifies R_iso = 100 Ω for 470 pF. Layout parasitics must be minimized, and local 100 nF ceramic decoupling is mandatory at Pin 11.

Does TSX634IQ4T support true rail-to-rail input when V_CC = 3.3 V?

Yes - the input common-mode range extends from V_CC– – 0.1 V to V_CC+ + 0.1 V across all supply voltages (3.3 V to 16 V), confirmed in Table 3. At 3.3 V, this means –0.1 V to +3.4 V, enabling direct interface with grounded sensors and reference voltages without level-shifting circuitry.

How does the input offset voltage drift behave over temperature?

ΔV_os/ΔT is specified at 1–8 µV/°C over –40 °C to +125 °C (Table 4–7). The typical distribution peaks near 2 µV/°C (Figure 6), resulting in <1 mV total drift across the full range for most units. This is significantly lower than standard bipolar-input op-amps, making it suitable for uncalibrated industrial sensors.

Can TSX634IQ4T operate from a single 3.3 V supply while driving a 10 kΩ load to 0 V?

Yes - VOL is specified at 70 mV max (25 °C) and 100 mV max (–40 °C to +125 °C) with 10 kΩ load (Table 4–7), meaning it sinks to within 100 mV of ground. For true 0 V output, add an external pull-down or select a part with complementary output stage; however, 100 mV is compatible with most 3.3 V ADCs' input low threshold.