Texas Instruments THS4508RGTT

Overview

THS4508RGTT from Texas Instruments is a wideband, fully differential amplifier optimized for 5-V single-supply data acquisition systems. It delivers 2 GHz small-signal bandwidth, 6400 V/µs slew rate, and –72 dBc HD2 / –79 dBc HD3 at 100 MHz while driving ADCs like the ADS5500 at 125 MSPS in high-linearity signal chains.

For engineers reviewing the THS4508RGTT datasheet, THS4508RGTT pinout, THS4508RGTT application, or THS4508RGTT equivalent, key selection criteria include output common-mode control accuracy (±5 mV), power-down current (0.65 mA), differential output swing (4.4–5.2 V), noise figure (19.2 dB), and QFN-16 thermal pad layout requirements.

Technical Context

The THS4508RGTT employs a fully differential architecture with internal mid-supply common-mode set point (2.5 V) and external CM input capability (1.25–3.75 V). Its output common-mode control loop maintains <5-mV offset from the CM input voltage across temperature and load.

It features a minimum stable gain of 2 V/V (6 dB), but is optimized for G = 10 dB (10×) operation with 1.5 GHz large-signal bandwidth and 2 ns 1% settling time-enabling pulsed, high-speed sampling applications without gain-dependent performance degradation.

Key Specifications

Pinout & Package

The THS4508RGTT is housed in a thermally enhanced 16-pin QFN package (RGT) with exposed thermal pad requiring PCB connection to ground or thermal plane per TI SLMA002/SLMA004 guidelines.

Key Features

Applications

Equivalent & Alternatives

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

Compared with LMH5401RTVT and ADA4940-1ACPZ-R7, the THS4508RGTT uniquely balances 2-GHz bandwidth, integrated output common-mode control, and 0.65-mA power-down - making it the optimal choice for 5-V, high-MSPS ADC driver applications requiring both speed and DC-coupled simplicity.

Availability

THS4508RGTT is available at Aetrix Electronics and suitable for high-speed data acquisition, wireless infrastructure, medical imaging, and test and measurement applications requiring stable component supply, full industrial temperature range (–40°C to +85°C), and QFN-16 thermal reliability.

Supply support for THS4508RGTT 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 delivering analog, embedded processing, and connectivity solutions for industrial, automotive, and communications markets.

The THS4508RGTT belongs to TI's high-speed differential amplifier product line, engineered specifically for single-supply, DC-coupled ADC driver applications demanding wide bandwidth, ultra-low distortion, and precise output common-mode control.

FAQ

What is the recommended power supply configuration for THS4508RGTT?

The THS4508RGTT is specified for 5-V single-supply operation (VS+ = 5 V, VS– = 0 V). It supports supply voltages from 3.75 V to 5.25 V. Local decoupling with 0.1-µF ceramic and 10-µF bulk capacitors on VS+ pins (5–8) and proper grounding of VS– pins (13–16) is mandatory. The exposed thermal pad must be soldered to a PCB thermal plane per TI SLMA002 guidelines to maintain junction temperature below 125°C under continuous 39.2-mA operation.

How does the THS4508RGTT achieve DC coupling to ADCs?

The THS4508RGTT achieves DC coupling via its integrated output common-mode control circuit, which maintains the average of VOUT+ and VOUT– within ±5 mV of the voltage applied to the CM pins (4, 9). When CM pins are left open, internal circuitry defaults to 2.5 V - matching the mid-supply reference of most 5-V ADCs. This eliminates AC-coupling capacitors and associated low-frequency phase shift or settling errors in precision data acquisition systems.

What is the minimum stable gain for THS4508RGTT, and why is G = 10 dB recommended?

The THS4508RGTT has a minimum stable gain of 2 V/V (6 dB), but TI characterizes and optimizes performance at G = 10 dB (10×). At this gain, it delivers 1.5 GHz large-signal bandwidth, 2 ns 1% settling time, and –79 dBc HD3 at 100 MHz - all critical for driving high-speed ADCs like the ADS5500. Lower gains reduce stability margin and increase distortion; higher gains degrade bandwidth and settling behavior per the datasheet's gain-vs-bandwidth trade-off curves.

Can THS4508RGTT drive heavy loads such as 50-Ω terminated ADC inputs?

Yes, the THS4508RGTT can drive 50-Ω differential loads (i.e., 25 Ω per leg) with full performance. Its differential output current drive is rated at 96 mA, and typical output impedance is 0.3 Ω at 1 MHz. For 50-Ω double-terminated systems, TI's evaluation circuits use 25-Ω series resistors (RO) and 6-dB attenuators to match impedance while preserving SFDR. Layout must minimize trace inductance and maintain symmetry to preserve balance error <–43 dB.

What thermal considerations apply to THS4508RGTT in continuous operation?

The THS4508RGTT incorporates an exposed thermal pad (pin 17, underside) that must be soldered to a solid copper thermal plane connected to ground or dedicated thermal layer. Without this, θJA rises to ~100°C/W, risking junction temperatures >125°C at 39.2 mA and 85°C ambient. With proper pad connection, θJA is 39.5°C/W, enabling reliable continuous operation across the full –40°C to +85°C range. TI technical briefs SLMA002 and SLMA004 provide PCB layout rules for thermal pad implementation.