Texas Instruments LMH6647MA

Overview

LMH6647MA from Texas Instruments is a single-channel, rail-to-rail input and output voltage feedback amplifier with shutdown control, operating from 2.5 V to 12 V supply. It delivers 55 MHz −3 dB bandwidth, 22 V/μs slew rate, and ±20 mA linear output current while consuming only 650 μA per channel in active mode and <50 μA in shutdown - enabling high-speed signal conditioning in battery-powered portable instrumentation and multiplexed sensor interfaces.

For engineers reviewing the LMH6647MA datasheet, LMH6647MA pinout, LMH6647MA application, or LMH6647MA equivalent, key selection criteria include its shutdown threshold (2.30 V typ at 2.7 V supply), rail-to-rail input beyond rails by 0.3 V, 20 mV output swing from rails, 17 nV/√Hz input voltage noise, and SOT-23-6 package compatibility with space-constrained PCB layouts.

Technical Context

The LMH6647MA uses a proprietary VIP10 dielectrically isolated bipolar process to sustain high ft (~8 GHz) under low-voltage (2.7 V) and low-current bias conditions. Its input stage supports common-mode voltage beyond both supply rails by 0.3 V, and its class A-B "turn-around" input stage reduces power dissipation versus comparable-speed amplifiers.

The output employs a common-emitter push-pull stage delivering ±20 mA into loads while maintaining rail-to-rail swing (20 mV from rails at 1 kΩ) and stable performance across 2.5–12 V supply range - with −3 dB bandwidth, slew rate, and output current varying less than ±15% over that range.

Key Specifications

Pinout & Package

SOT-23-6 package (2.92 mm × 1.60 mm body), thermally enhanced for compact, low-power analog signal paths.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar high-speed, low-power operational amplifier applications.

Compared with LMH6645MA, LMH6647MA adds shutdown control and an extra pin for power management - essential for portable and multiplexed applications - while matching bandwidth, noise, and output swing. Versus OPA355UA, LMH6647MA trades bandwidth for rail-to-rail input flexibility and integrated power gating, making it superior for low-voltage sensor interfaces.

Availability

LMH6647MA is available at Aetrix Electronics and suitable for active filters, portable instrumentation front-ends, multiplexed sensor interfaces, current sense buffers, and high-speed transducer amplification requiring stable component supply across industrial, medical, and test equipment programs.

Supply support for LMH6647MA 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-performance op-amps, data converters, and power management ICs.

The LMH664x product line was designed for low-voltage, high-speed signal conditioning in portable and space-constrained systems - combining rail-to-rail I/O, micro-power shutdown, and stable AC performance across 2.5–12 V supplies.

FAQ

What is the shutdown threshold voltage for LMH6647MA at 2.7 V supply?

The LMH6647MA shutdown threshold voltage is 2.30 V (typical) when operated at 2.7 V supply, with guaranteed range of 1.95 V to 2.30 V. This allows reliable activation using standard 1.8 V or 3.3 V logic levels via a simple resistive divider. The shutdown pin draws only −20 μA, minimizing control circuit loading. LMH6647MA enters ultra-low-power state (<50 μA total supply current) once threshold is exceeded.

Can LMH6647MA operate from a single 2.7 V supply with ground-referenced input signals?

Yes, LMH6647MA supports true single-supply operation: its input common-mode voltage range extends 0.3 V below V− (i.e., to −0.3 V when V− = 0 V), allowing direct connection of ground-referenced sensors or transducers. Output swings to within 20 mV of 0 V and 2.7 V rails at 1 kΩ load. This eliminates level-shifting components in 2.7 V systems - a key advantage confirmed in TI's SNOS970D datasheet Section 7.5.

What is the typical slew rate and −3 dB bandwidth of LMH6647MA?

The LMH6647MA delivers a typical slew rate of 22 V/μs and −3 dB bandwidth of 55 MHz under AV = +1, RL = 1 kΩ, and 2.7 V supply conditions. These values remain stable across 2.5–12 V supply range and −40°C to +85°C temperature range, with <±15% variation. This combination enables faithful reproduction of fast edges and wideband signals in active filters and ADC driver applications.

How does LMH6647MA compare to LMH6645MA in pin compatibility and functionality?

LMH6647MA (SOT-23-6) and LMH6645MA (SOT-23-5) share identical signal pins (OUTPUT, IN−, IN+, V−, V+) in same physical locations, but LMH6647MA adds Pin 5 (SD) for shutdown control. They are not pin-compatible due to the extra terminal; PCB layout must allocate space for the sixth pin and SD routing. Functionally, LMH6647MA adds power-gating capability absent in LMH6645MA - critical for battery life in portable designs.

What is the input voltage noise density of LMH6647MA and at what frequency is it specified?

The LMH6647MA has a typical input voltage noise density of 17 nV/√Hz at 100 kHz, and 25 nV/√Hz at 1 kHz, as specified in TI's SNOS970D datasheet Section 7.5. This low noise floor - combined with 650 μA supply current - makes LMH6647MA especially effective in low-level signal amplification, such as thermocouple or bridge sensor interfaces, where preserving signal-to-noise ratio is critical without increasing power consumption.