Texas Instruments PGA870IRHDT

Overview

PGA870IRHDT from Texas Instruments is a wideband, fully differential programmable-gain amplifier (PGA) optimized as an ADC driver for 14-bit wireless base station signal chains. It delivers 650-MHz bandwidth, –11.5 dB to +20 dB gain in precise 0.5-dB steps, and –98 dBc third-order intermodulation distortion at 100 MHz with 2-V_PP output into 200 Ω.

For engineers reviewing the PGA870IRHDT datasheet, PGA870IRHDT pinout, PGA870IRHDT application, or PGA870IRHDT equivalent, this page provides verified technical context on fast gain control loop integration, differential input/output impedance matching, power-down sequencing, and QFN-28 thermal design constraints.

Technical Context

The PGA870IRHDT implements a two-stage architecture: a logarithmic R2R ladder input attenuator (controlled by B5–B3) followed by a programmable buffer stage (B2–B0), enabling precise 0.5-dB gain resolution across its full –11.5 dB to +20 dB range. Gain settling occurs within 5 ns after strobe assertion.

Its differential voltage-mode output drives 100–1000 Ω loads with <0.3 Ω series resistance and 3.8 nH inductive reactance, maintaining >45 dBm OIP3 up to 300 MHz. The PD pin enables analog circuitry shutdown while retaining active digital gain control, with 2 mA quiescent current and 60 ns turn-off delay.

Key Specifications

Pinout & Package

PGA870IRHDT is housed in a thermally enhanced QFN-28 PowerPAD™ package (RHD designation) with exposed thermal pad connected to GND. The 4-mm × 4-mm body height is 0.8 mm, requiring solder paste stencil optimization for thermal pad void control.

Key Features

Applications

Equivalent & Alternatives

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

Compared with THS4509IRGTR and THS7700IRGTR, PGA870IRHDT uniquely integrates 6-bit parallel programmability, 0.5-dB gain steps, and sub-10-ns latency-making it the only option for closed-loop IF gain control in wireless infrastructure and radar systems requiring both precision and speed.

Availability

PGA870IRHDT is available at Aetrix Electronics and suitable for wireless base station signal chains, fast automatic gain control (AGC) loops, radar/ranging systems, and digital radio receiver front-ends requiring stable component supply across extended production lifecycles.

Supply support for PGA870IRHDT 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 and embedded processing solutions, with deep expertise in high-speed data acquisition and RF signal chain components.

The PGA870IRHDT belongs to TI's high-performance programmable-gain amplifier product line, designed specifically for demanding wireless infrastructure, test equipment, and radar applications requiring wide bandwidth, exceptional linearity, and deterministic digital gain control.

FAQ

What is the maximum operating frequency supported by PGA870IRHDT before gain flatness degrades beyond 0.1 dB?

The PGA870IRHDT maintains 0.1-dB gain flatness up to 100 MHz across its full –11.5 dB to +20 dB gain range. At higher frequencies, gain roll-off begins gradually; for example, at 200 MHz, gain deviation reaches approximately –0.5 dB at +20 dB setting. This makes PGA870IRHDT optimal for IF stages below 100 MHz or wideband applications where moderate flatness tolerance is acceptable.

How does the PGA870IRHDT handle single-ended input signals, and what is the impact on performance?

The PGA870IRHDT accepts single-ended inputs directly at IN+ while referencing IN– to the internal VMID2 node. This configuration yields slightly reduced input return loss (–30 dB vs –40 dB differential) and increased noise figure (by ~1.5 dB at 100 MHz), but preserves full gain range and distortion performance. No external components are required, simplifying PCB layout in cost-sensitive SDR front-ends.

Can PGA870IRHDT be used with a 3.3-V supply, or is +5 V mandatory?

The PGA870IRHDT is specified exclusively for +4.75 V to +5.25 V operation. Operation at 3.3 V is not supported: the internal bias networks, output stage headroom, and digital interface thresholds are all calibrated for 5-V rails. Attempting 3.3-V operation results in undefined gain behavior, degraded distortion, and potential failure to meet AC specifications.

What is the recommended bypassing strategy for VMID1 and VMID2 pins on PGA870IRHDT?

Both VMID1 (pin 28) and VMID2 (pin 4) must be bypassed to GND with 0.1-μF ceramic capacitors placed within 2 mm of each pin. VMID1 is a passive resistor-divider midpoint; VMID2 is an active buffer output. Neither pin may drive external loads or receive external bias. Failure to properly bypass causes gain instability, increased noise, and degraded harmonic distortion.

Does PGA870IRHDT support simultaneous power-down and gain reconfiguration?

Yes. When the PD pin is asserted low, the analog signal path enters low-current mode (2 mA), but the 6-bit digital interface remains fully functional. Gain can be updated via B0–B5 and latched using GAIN STROBE or LATCH MODE while powered down. Upon PD deassertion, the new gain takes effect immediately with 16 ns turn-on delay - enabling zero-latency wake-up in burst-mode systems.