Texas Instruments OPA695IDG4

Overview

OPA695IDG4 from Texas Instruments is a current-feedback operational amplifier optimized for high-gain, wideband signal conditioning in precision instrumentation. It delivers 600MHz small-signal bandwidth at G = +8V/V, 5000V/μs slew rate, ±4.05V output swing, and 2nV/√Hz input voltage noise under ±5V supply. It serves as an ADC driver, IF amplifier, or video line driver in high-speed digitizers and portable test equipment.

For engineers reviewing the OPA695IDG4 datasheet, OPA695IDG4 pinout, OPA695IDG4 application, or OPA695IDG4 equivalent, key selection criteria include disable-mode power-down (160µA), harmonic distortion performance at 10MHz (–65dBc HD2 / –92dBc HD3), thermal pad–connected WSON-8 package, and current-feedback architecture requiring precise feedback resistor selection.

Technical Context

The OPA695IDG4 implements a current-feedback topology with transimpedance gain (Z_OL) of 45kΩ typical, enabling stable high-bandwidth operation across gains ≥+2V/V. Its inverting input presents low impedance (~20Ω), while noninverting input impedance is 450kΩ || 2pF - critical for matching and stability in high-frequency closed-loop configurations.

It features a dedicated DIS pin that enables full power-down mode with <1μs disable time and 25ns enable time. The internal feedback path remains isolated during shutdown, achieving 70dB off-isolation at 10MHz and limiting output capacitance to 2.5pF - essential for multiplexed or shared-bus signal paths.

Key Specifications

Pinout & Package

OPA695IDG4 uses the DSG (WSON-8) package: 2mm × 2mm body with exposed thermal pad, rated for 86.5°C/W junction-to-ambient thermal resistance. The thermal pad must be soldered to –V_S for optimal thermal performance and EMI suppression.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar current-feedback amplifier applications.

Compared with LMH6702MF/NOPB and THS3491DGNR, the OPA695IDG4 uniquely combines WSON-8 miniaturization, sub-200µA disable current, and 600MHz bandwidth at ±5V - making it the only option for space-constrained, battery-operated wideband gain stages requiring dynamic power control.

Availability

OPA695IDG4 is available at Aetrix Electronics and suitable for very wideband ADC drivers, low-cost precision IF amplifiers, and broadband video line drivers requiring stable component supply across industrial temperature ranges (–40°C to +85°C).

Supply support for OPA695IDG4 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 company specializing in analog and embedded processing technologies, with leadership in high-speed op amps, data converters, and power management ICs.

The OPA695 product line targets high-fidelity, wideband signal chain applications - specifically engineered for precision intermediate gain stages in digitizers, DAC output buffering, and cable-modem upstream line drivers where speed, noise, and power efficiency intersect.

FAQ

What is the recommended feedback resistor value for OPA695IDG4 at G = +8V/V with ±5V supply?

The OPA695IDG4 datasheet specifies R_F = 402Ω for G = +8V/V under ±5V supply conditions. This value ensures optimal bandwidth (600MHz), stability, and distortion performance. Deviating significantly from 402Ω degrades gain flatness and increases peaking - especially critical in WSON-8 layouts where parasitic capacitance is low but trace inductance must be minimized.

Does OPA695IDG4 support single-supply operation, and what are the input/output voltage limitations?

Yes, OPA695IDG4 supports single 5V operation. With V_S+ = 5V and V_S– = 0V, the common-mode input range is +1.6V to +3.4V, and output swings from +0.9V to +4.05V (no load). These limits ensure compatibility with 3.3V logic-controlled systems and unipolar DAC outputs without level-shifting circuitry.

How does the thermal pad on the OPA695IDG4 WSON-8 package affect electrical performance?

The exposed thermal pad on the OPA695IDG4 must be soldered to the –V_S net. This connection reduces θ_JA from 164°C/W (SOT-23) to 86.5°C/W, prevents thermal runaway during sustained 100mA output, and lowers ground impedance - directly improving PSRR (72dB) and reducing output noise coupling in high-frequency applications.

What is the minimum load resistance OPA695IDG4 can drive while maintaining –65dBc HD2 at 10MHz?

OPA695IDG4 maintains –65dBc HD2 at 10MHz into 100Ω loads per datasheet characterization. Driving lower impedances (e.g., 50Ω) increases distortion: HD2 degrades to –62dBc at 50Ω. For 10MHz IF applications demanding <–65dBc, maintain R_L ≥ 100Ω or add a series 25Ω isolation resistor to preserve linearity.

Can OPA695IDG4 be used in inverting configuration, and how does its performance differ from noninverting mode?

Yes, OPA695IDG4 operates in inverting mode with matched bandwidth (600MHz at G = –8V/V) and identical slew rate (5000V/μs). However, inverting configuration exhibits 3dB higher HD2 (–62dBc vs –65dBc) at 10MHz due to asymmetrical current flow in the feedback path - a known characteristic of current-feedback topologies that must be accounted for in distortion-sensitive designs.