Texas Instruments THS4131CDGNG4

Overview

THS4131CDGNG4 from Texas Instruments is a fully differential input/output amplifier optimized for high-speed, low-noise signal conditioning in precision analog front-ends. It delivers 170 MHz small-signal bandwidth, 51 V/µs slew rate, –102 dBc THD at 250 kHz, 1.25 nV/√Hz input voltage noise, and operates from ±2.5 V to ±15 V dual supplies - enabling high-dynamic-range differential ADC driving in medical ultrasound and instrumentation.

For engineers reviewing the THS4131CDGNG4 datasheet, THS4131CDGNG4 pinout, THS4131CDGNG4 application, or THS4131CDGNG4 equivalent, key selection criteria include its fully differential architecture, VOCM-controlled output common-mode level, HVSSOP-8 thermal performance (RθJB = 30.0 °C/W), and absence of power-down functionality - distinguishing it from the THS4130 variant.

Technical Context

The THS4131CDGNG4 implements a true fully differential signal path with matched internal gain stages and a dedicated VOCM input that directly sets output common-mode voltage. Its complementary bipolar process enables rail-to-rail output swing capability (±11.2 V at ±15 V supply) and 95 dB CMRR at 800 kHz, critical for rejecting interference in single-ended-to-differential conversion.

Unlike conventional op-amps, it features symmetrical high-impedance differential inputs (RI_CM = 215 MΩ, RI_DIFF = 10 kΩ) and low-output-impedance buffers (RO = 41 Ω open-loop), supporting stable operation into 800 Ω differential loads while maintaining 108 dB SFDR at ±15 V with 2 VPP output.

Key Specifications

Pinout & Package

HVSSOP-8 (PowerPAD™) package with exposed thermal pad on underside; requires connection to large copper plane for RθJB = 30.0 °C/W thermal performance. Pin 1 = VIN+, Pin 2 = VOCM, Pin 3 = VCC−, Pin 4 = VOUT−, Pin 5 = VIN−, Pin 6 = VCC+, Pin 7 = VOUT+, Pin 8 = NC.

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS4131IDGNR, THS4131CDGNG4 offers lower cost and sufficient temperature margin for lab/test equipment; compared with THS4561IRGET, it provides higher output voltage compliance and VOCM flexibility essential for precision data converter interfacing.

Availability

THS4131CDGNG4 is available at Aetrix Electronics and suitable for medical ultrasound beamforming, high-resolution data acquisition, and industrial sensor signal conditioning requiring stable component supply across production lifecycles.

Supply support for THS4131CDGNG4 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

Texas Instruments is a global semiconductor leader specializing in analog and embedded processing technologies, with over 50 years of innovation in high-performance amplifiers and data converters.

The THS413x family was designed specifically for high-fidelity differential signal conditioning in demanding applications including medical imaging, test instrumentation, and high-speed data acquisition - emphasizing low distortion, wide bandwidth, and robust common-mode rejection.

FAQ

What is the function of the VOCM pin on the THS4131CDGNG4?

The VOCM (Voltage Output Common-Mode) pin on the THS4131CDGNG4 directly sets the DC common-mode level of the differential outputs VOUT+ and VOUT−. When driven by a low-impedance source (e.g., DAC reference or resistor divider), it overrides the internal mid-rail default (VCC+ + VCC−)/2. This allows precise alignment to an ADC's input common-mode requirement without external level-shifting circuitry - a core feature enabling seamless integration in systems like the AFE58JD18 ultrasound AFE. The THS4131CDGNG4 VOCM input exhibits low sensitivity to noise, and TI recommends bypassing it with a 0.1-µF capacitor to ground.

Does the THS4131CDGNG4 have a power-down feature?

No, the THS4131CDGNG4 does not include a power-down pin. Unlike the THS4130 variant (which has an active-low PD pin on Pin 7), the THS4131CDGNG4 omits this function entirely - Pin 7 is designated as VOUT+, and Pin 8 is NC. This simplifies system control logic and eliminates potential failure modes associated with improper power-down sequencing. As a result, the THS4131CDGNG4 draws a continuous 13 mA quiescent current at ±15 V, making it best suited for always-on or duty-cycled applications where thermal management via the HVSSOP PowerPAD™ is feasible.

What is the maximum differential output voltage swing for the THS4131CDGNG4?

The THS4131CDGNG4 delivers a guaranteed differential output voltage swing of ±11.2 V (22.4 VPP) under full-temperature-range conditions (–40°C to +85°C) when operated at ±15 V supplies into a 1 kΩ differential load. At +25°C, the typical swing extends to ±12.4 V. This high output compliance enables direct drive of 16-bit+ differential ADCs without external gain stages or level-shifting, preserving dynamic range and minimizing THD degradation. The swing is symmetric about the VOCM-set common-mode voltage, and performance is maintained across the full specified supply range (±2.5 V to ±15 V).

How does the THS4131CDGNG4 achieve high common-mode rejection?

The THS4131CDGNG4 achieves 95 dB common-mode rejection ratio (CMRR) at 800 kHz through a monolithic fully differential architecture fabricated in TI's high-voltage complementary bipolar process. Its matched internal transistor pairs and symmetrical layout minimize gain and phase mismatches between the positive and negative signal paths. CMRR remains >80 dB across the full operating temperature range (–40°C to +85°C). Critical to sustaining this performance is external resistor matching - TI specifies ≤1% tolerance for feedback networks, as mismatch directly degrades CMRR, PSRR, and second-harmonic distortion. The THS4131CDGNG4's high 215 MΩ common-mode input resistance further reduces error currents that could compromise rejection.

Which package type does the THS4131CDGNG4 use, and why is thermal design important?

The THS4131CDGNG4 uses the HVSSOP-8 (DGN) package with an exposed thermal pad on the underside. This PowerPAD™ construction achieves a junction-to-board thermal resistance (RθJB) of just 30.0 °C/W - significantly lower than SOIC-8 (69.8 °C/W) or VSSOP-8 (83.2 °C/W). Because the device draws 13 mA at ±15 V (≈390 mW dissipation), proper thermal management is essential to prevent junction temperature exceedance. TI mandates connecting the thermal pad to a large internal or external copper plane; failure to do so risks exceeding the 125°C maximum continuous junction temperature, leading to reliability degradation or parametric shift. The DGN package thus enables sustained 170 MHz operation in space-constrained layouts where SOIC would require derating.