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Texas Instruments LMH6646MA
- Part No.:
- LMH6646MA
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 8-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LMH6646MA.pdf
- Description:
- IC VOLTAGE FEEDBACK 2 CIRC 8SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:2,187
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Product details
Overview
LMH6646MA from Texas Instruments is a dual, rail-to-rail input and output voltage feedback operational amplifier optimized for low-voltage, high-speed signal conditioning. It delivers 55 MHz −3 dB bandwidth, 22 V/μs slew rate, and ±20 mA linear output current per channel at 650 μA supply current per channel, enabling precision buffering in portable instrumentation and active filter stages.
For engineers reviewing the LMH6646MA datasheet, LMH6646MA pinout, LMH6646MA application, or LMH6646MA equivalent, key selection considerations include its rail-to-rail I/O swing (within 20 mV of rails), 17 nV/√Hz input voltage noise, −40°C to +85°C operating range, and dual-channel SOIC-8 packaging with independent shutdown control on the LMH6647 variant (not present on LMH6646).
Technical Context
The LMH6646MA employs a proprietary VIP10 dielectrically isolated bipolar process, enabling high ft (∼8 GHz) operation under low 2.7 V supply while maintaining stable gain and phase response across temperature. Its class A-B "turn-around" input stage reduces power dissipation without compromising offset or noise performance.
It features a common-emitter push-pull output stage delivering ±20 mA into loads while sustaining rail-to-rail output swing - even at 1 kΩ load tied to V+/2 - and maintains consistent −3 dB bandwidth (55 MHz) and slew rate (22 V/μs) across 2.5 V to 12 V supply range.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| −3 dB Bandwidth | 55 MHz at AV = +1: supports high-fidelity signal amplification up to video and medium-speed data acquisition frequencies. |
| Slew Rate | 22 V/μs: enables clean 1 VPP step response within 40 ns, critical for pulse conditioning and multiplexed sensor interfaces. |
| Supply Current | 650 μA per channel: allows dual-channel high-speed amplification in battery-powered systems with sub-1.3 mA total quiescent draw. |
| Input Voltage Noise | 17 nV/√Hz at 100 kHz: ensures minimal added noise in precision transducer and current-sense buffer applications. |
| Output Swing | Within 20 mV of either rail at 1 kΩ load: maximizes dynamic range in 3.3 V or lower single-supply systems. |
| Input Common-Mode Range | Extends 0.3 V beyond both rails: simplifies level-shifting and direct interfacing with ADCs or sensors operating outside supply bounds. |
| Cross-Talk Rejection | 47 dB at 5 MHz (dual-channel): preserves channel isolation in simultaneous sampling or differential pair configurations. |
Pinout & Package
LMH6646MA is housed in an SOIC-8 (D08A) package measuring 4.90 mm × 3.91 mm, rated for surface-mount assembly and JEDEC-standard reflow profiles. Thermal resistance RθJA is 190°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| OUT A (Pin 1) | Output Channel A | Amplified, rail-to-rail voltage output for first op-amp channel; drives loads up to ±20 mA with <20 mV headroom. |
| −IN A (Pin 2) | Inverting Input Channel A | Differential input node for Channel A; accepts common-mode voltages from −0.3 V to V+ + 0.3 V. |
| +IN A (Pin 3) | Non-inverting Input Channel A | Differential input node for Channel A; same CMVR and impedance as −IN A. |
| V− (Pin 4) | Negative Supply | Ground or negative rail connection; supports single-supply (0 V) or split-supply (±2.5 V) operation. |
| V+ (Pin 5) | Positive Supply | Primary power rail (2.5–12 V); supplies both channels and sets output swing limits. |
| −IN B (Pin 6) | Inverting Input Channel B | Independent input for second op-amp channel; electrically isolated from Channel A except via substrate coupling. |
| +IN B (Pin 7) | Non-inverting Input Channel B | Independent input for second op-amp channel; identical specs and bias behavior to +IN A. |
| OUT B (Pin 8) | Output Channel B | Amplified, rail-to-rail voltage output for second op-amp channel; fully symmetric to OUT A. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables full utilization of supply voltage in low-voltage systems (e.g., 3.3 V or 2.7 V), eliminating level-shifting components. |
| 55 MHz bandwidth at 650 μA/channel | Delivers video-grade speed with micro-power efficiency-unusual combination for general-purpose op-amps. |
| 17 nV/√Hz input voltage noise | Preserves SNR in low-level signal paths such as strain gauge or thermopile amplifiers without requiring external filtering. |
| 47 dB crosstalk rejection at 5 MHz | Ensures channel independence in dual-channel active filters or simultaneous-sampling front-ends. |
| Stable performance from 2.5 V to 12 V supply | Eliminates recalibration or redesign when migrating between 3.3 V embedded systems and 5 V industrial controllers. |
Applications
| Portable Instrumentation | Active Filter Stages |
|---|---|
Use Scenario: Battery-powered handheld multimeters and oscilloscope probes requiring low-noise, rail-to-rail buffering of mV-level sensor outputs. IC Role / Device Role / Timing Role: Precision voltage follower and gain stage for analog front-end signal conditioning prior to ADC sampling. Use Value: 17 nV/√Hz noise floor and 20 mV rail headroom preserve resolution in 12-bit+ conversions at 3.3 V supply. |
Use Scenario: Second-order Sallen-Key and MFB filters in medical ECG monitors and audio preamps needing precise frequency shaping. IC Role / Device Role / Timing Role: Unity-gain stable voltage feedback amplifier implementing filter transfer functions with minimal phase distortion. Use Value: 55 MHz GBW and 22 V/μs slew rate support filter cutoffs up to 5 MHz with <0.1% THD at 1 VPP output. |
| Current Sense Buffering | Multiplexed Sensor Interfaces |
Use Scenario: Isolation-free shunt-based current monitoring in motor drives and power supplies where ground-referenced sensing is required. IC Role / Device Role / Timing Role: Low-offset, high-CMRR difference amplifier stage converting mV shunt voltage to system-level logic-compatible signal. Use Value: 77 dB CMRR at DC and 56 dB at 1 MHz ensure accurate measurement despite high dv/dt noise on power rails. |
Use Scenario: Signal conditioning for 8-channel thermistor or RTD arrays in HVAC controllers, where one dual op-amp handles two sensor channels. IC Role / Device Role / Timing Role: Dual-channel buffer/gain block driving multiplexer inputs with matched gain and timing characteristics. Use Value: 47 dB inter-channel crosstalk at 5 MHz prevents signal bleed between adjacent channels during fast switching. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar dual high-speed rail-to-rail op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA2350UA | Lower 38 MHz bandwidth, higher 5.5 mA supply current per channel, 7 nV/√Hz noise. | Better for ultra-low-noise DC-coupled applications; unsuitable for >3 MHz signal paths due to bandwidth limit. | Select OPA2350UA only when noise dominates over speed and power; LMH6646MA preferred for bandwidth/power trade-off. |
| ADA4891-2ARZ | Higher 225 MHz bandwidth but 3.2 mA supply current per channel; rail-to-rail output only (not input). | Requires external level-shifting for below-rail inputs; better for high-frequency AC-coupled video or comms signals. | Choose ADA4891-2ARZ when >100 MHz small-signal response is mandatory; LMH6646MA fits wider supply range (2.5–12 V) and true RRO+RRIO. |
Compared with OPA2350UA and ADA4891-2ARZ, LMH6646MA uniquely balances 55 MHz bandwidth, 650 μA/channel quiescent current, and full rail-to-rail input/output-making it optimal for portable, multi-supply, and precision analog front-ends where power, speed, and dynamic range intersect.
Availability
LMH6646MA is available at Aetrix Electronics and suitable for portable instrumentation, active filter stages, current sense buffering, and multiplexed sensor interfaces requiring stable component supply across industrial and medical design cycles.
Supply support for LMH6646MA 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 decades of innovation in high-performance op-amps and precision signal chain solutions.
The LMH6646MA belongs to TI's LMH664x family of rail-to-rail I/O amplifiers designed specifically for low-voltage, high-speed applications including portable test equipment, medical sensors, and industrial signal conditioning where power efficiency and accuracy are co-constrained.
FAQ
What is the maximum supply voltage range supported by the LMH6646MA?
The LMH6646MA operates across a supply voltage range of 2.5 V to 12 V (V+ − V−), validated per TI's SNOS970D datasheet. This includes single-supply (e.g., 3.3 V or 5 V with V− = 0 V) and split-supply (e.g., ±5 V) configurations. Absolute maximum rating is 12.6 V, but guaranteed specifications apply only within the 2.5–12 V operating range.
Does the LMH6646MA include a shutdown pin?
No, the LMH6646MA does not feature a shutdown pin. Shutdown functionality is exclusive to the LMH6647 (single-channel) variant, which includes SD pin (Pin 5 in SOT-23-6 or Pin 8 in SOIC-8). The LMH6646MA is a dual-channel amplifier with no enable/disable control - both channels operate continuously when powered.
What is the typical input offset voltage drift of the LMH6646MA over temperature?
The LMH6646MA has a typical input offset voltage drift of ±5 μV/°C, as specified in the Electrical Characteristics tables for all supply conditions (2.7 V, 5 V, ±5 V) across −40°C to +85°C. This low drift supports stable DC-coupled gain accuracy in temperature-varying environments like industrial enclosures or automotive cabins.
Can the LMH6646MA drive a 50 Ω load directly?
The LMH6646MA is not optimized for continuous 50 Ω driving: its specified linear output current is ±20 mA at 0.5 V from rails, corresponding to ~25 Ω minimum resistive load for full swing. For 50 Ω applications, use series termination or buffer with a dedicated line driver; the LMH6646MA is best suited for ≥1 kΩ loads or capacitive loads ≤13 pF per datasheet Figure 17.
Is the LMH6646MA unity-gain stable?
Yes, the LMH6646MA is unity-gain stable, as confirmed by closed-loop frequency response plots (Figure 1 and Figure 2 in SNOS970D) showing flat gain and controlled phase margin down to AV = +1. No external compensation is required for stable operation at gains ≥1, making it suitable for voltage followers and active filters without added components.
LMH6646MA Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 8-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- Voltage Feedback
- Number of Circuits:
- 2
- Output Type:
- Push-Pull, Rail-to-Rail
- Slew Rate:
- 22V/µs
- Gain Bandwidth Product:
- -
- -3db Bandwidth:
- 55 MHz
- Current - Input Bias:
- 650 nA
- Voltage - Input Offset:
- 1 mV
- Current - Supply:
- 725µA (x2 Channels)
- Current - Output / Channel:
- 20 mA
- Voltage - Supply Span (Min):
- 2.5 V
- Voltage - Supply Span (Max):
- 12 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 8-SOIC
LMH6646MA FAQ
1.How can I place an order for LMH6646MA through Aetrix?
Please submit a Request for Quotation (RFQ) for LMH6646MA on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for LMH6646MA reliable?
The price and inventory of LMH6646MA are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMH6646MA is usually 5 days.
3.What payment methods are accepted for LMH6646MA?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMH6646MA transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMH6646MA?
LMH6646MA orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMH6646MA order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for LMH6646MA?
For technical support, including LMH6646MA datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMH6646MA requirements.
6.How does Aetrix verify that LMH6646MA is sourced from the original manufacturer or authorized distributors?
All LMH6646MA products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that LMH6646MA meets industry standards.
7.What is the process for return or replacement of LMH6646MA?
All LMH6646MA units undergo pre-shipment inspection (PSI). If there is an issue with LMH6646MA, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The LMH6646MA part is unused and in its original packaging.
Return procedure for LMH6646MA:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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