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Texas Instruments LMH6645MF
- Part No.:
- LMH6645MF
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LMH6645MF.pdf
- Description:
- IC OPAMP VFB 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:3,754
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Product details
Overview
LMH6645MF from Texas Instruments is a single-channel, rail-to-rail input and output voltage feedback operational amplifier optimized for low-voltage, low-power, high-speed applications. 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 at 2.7 V supply - enabling precision signal conditioning in battery-powered portable instrumentation and sensor interfaces.
For engineers reviewing the LMH6645MF datasheet, LMH6645MF pinout, LMH6645MF application, or LMH6645MF equivalent, key selection criteria include its rail-to-rail I/O capability (input extends 0.3 V beyond rails, output swings within 20 mV of rails), low 17 nV/√Hz input voltage noise, shutdown-ready SOT-23-5 package, and stable performance across 2.5–12 V supply range.
Technical Context
The LMH6645MF employs a proprietary VIP10 dielectrically isolated bipolar process, enabling high fT (~8 GHz) under low supply (2.7 V) and low bias current. Its rail-to-rail input stage uses complementary bipolar transistors with extended common-mode range (−0.3 V to VS + 0.3 V), while the Class A-B "turn-around" input stage reduces offset drift and power versus conventional high-speed op-amps.
The output stage is a common-emitter push-pull configuration delivering ±20 mA into loads while maintaining rail-to-rail swing (20 mV from rails at 1 kΩ) and fast overload recovery. Bandwidth (55 MHz), slew rate (22 V/μs), and output current remain stable across 2.5–12 V supply - a result of process-enhanced biasing and supply-independent gain-stage design.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| −3 dB Bandwidth | 55 MHz at AV = +1 - supports high-fidelity amplification of signals up to ~35 MHz fundamental without significant attenuation. |
| Slew Rate | 22 V/μs - enables clean 10 VPP output at 350 kHz full-power bandwidth; critical for pulse fidelity in active filters and transducer buffers. |
| Supply Current | 650 μA/channel at 2.7 V - allows continuous operation in ultra-low-power systems (e.g., coin-cell IoT sensors) without thermal derating. |
| Input Voltage Noise | 17 nV/√Hz at 100 kHz - preserves SNR in low-level signal chains (e.g., thermopile or bridge sensor front-ends). |
| 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 supply rails - eliminates level-shifting need when interfacing with ADCs or DACs operating near supply limits. |
| CMRR | 77 dB min (−40°C to +85°C) - ensures robust rejection of supply- or ground-related interference in noisy industrial environments. |
Pinout & Package
SOT-23-5 (DBV05A) package: 2.90 mm × 1.60 mm, surface-mount, lead-free, RoHS-compliant.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 - OUTPUT | Amplifier output | Delivers rail-to-rail voltage swing; capable of ±20 mA linear sourcing/sinking; requires local 0.1 μF bypass capacitor. |
| 2 - V− | Negative supply | Ground reference in single-supply operation; accepts 0 V minimum; must be decoupled to minimize PSRR degradation. |
| 3 - +IN | Non-inverting input | High-impedance node (3 MΩ || 2 pF); supports DC-coupled inputs extending 0.3 V below V−. |
| 4 - −IN | Inverting input | Differential pair input; matched to +IN for <3 mV offset; sensitive to PCB layout symmetry for optimal CMRR. |
| 5 - V+ | Positive supply | Accepts 2.5–12 V; internal regulation ensures stable bias across supply range; bypass with 0.1 μF ceramic capacitor. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables direct interface with 3.3 V/2.5 V ADCs/DACs and sensors without external level shifters or gain-setting resistors. |
| 55 MHz bandwidth at 2.7 V | Maintains high-speed performance down to ultra-low supply voltages - rare among micro-power op-amps. |
| 17 nV/√Hz input voltage noise | Preserves signal integrity in low-amplitude, wideband sensor amplification (e.g., piezoelectric accelerometers). |
| ±20 mA linear output drive | Drives 50 Ω cables, multiple 10 kΩ inputs, or SAR ADC sample capacitors without external buffers. |
| Stable over 2.5–12 V supply | Eliminates re-characterization when migrating designs between 3.3 V, 5 V, and 10 V systems. |
Applications
| Active Filters | Current Sense Buffer |
|---|---|
Use Scenario: Second-order Sallen-Key low-pass filter for anti-aliasing before a 1 MSPS SAR ADC in a portable ECG monitor. IC Role / Device Role / Timing Role: Voltage feedback amplifier configuring unity-gain stable filter with 55 MHz GBW and 22 V/μs slew rate to preserve transient response. Use Value: Rail-to-rail I/O captures full 0–3.3 V sensor range; 650 μA quiescent current extends battery life beyond 72 hours. |
Use Scenario: Bidirectional shunt-based current measurement in a 12 V automotive body control module. IC Role / Device Role / Timing Role: Precision difference amplifier with 77 dB CMRR rejecting common-mode noise from PWM motor drivers. Use Value: Input common-mode range extends 0.3 V beyond rails, allowing direct connection to 12 V shunt without attenuators. |
| High-Speed Portable Devices | High-Speed Transducer Amp |
Use Scenario: Signal conditioning for MEMS microphone output in a Bluetooth headset with 3.0 V supply. IC Role / Device Role / Timing Role: Low-noise preamplifier (17 nV/√Hz) with rail-to-rail output driving ADC input directly. Use Value: 20 mV output swing margin ensures >99% dynamic range utilization at 3.0 V, maximizing SNR. |
Use Scenario: Charge amplifier for piezoelectric vibration sensor in predictive maintenance edge node. IC Role / Device Role / Timing Role: High-slew-rate (22 V/μs), low-input-bias-current (±0.68 μA) amplifier conditioning fast transient pulses. Use Value: 55 MHz bandwidth resolves harmonics up to 10th order of 5 kHz mechanical resonance without phase distortion. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar high-speed, low-power op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| OPA355DBVR | Lower 250 μA supply current but reduced 200 MHz GBW and no rail-to-rail input (input limited to V− + 0.5 V to V+ − 0.5 V). | Better for ultra-low-power battery monitoring; unsuitable where input must exceed rails (e.g., direct sensor-to-amp). | Select OPA355DBVR only if supply current <300 μA is mandatory and input common-mode range requirements are relaxed. |
| ADA4891-1ARJZ-R7 | Higher 1.7 mA supply current, wider 220 MHz GBW, and rail-to-rail I/O - but input voltage noise is 9 nV/√Hz (lower) and package is SOT-23-6. | Preferred for higher-bandwidth video or composite signal paths; less suitable for sub-1 mA energy-constrained designs. | Choose ADA4891-1ARJZ-R7 when bandwidth >100 MHz is required and 1.7 mA supply current is acceptable. |
Compared with OPA355DBVR and ADA4891-1ARJZ-R7, the LMH6645MF uniquely balances 55 MHz bandwidth, rail-to-rail I/O, and sub-1 mA supply current - making it optimal for portable instrumentation where dynamic range, power, and board space are simultaneously constrained.
Availability
LMH6645MF is available at Aetrix Electronics and suitable for active filters, current sense buffers, high-speed portable devices, and high-speed transducer amplifiers requiring stable component supply, long-term lifecycle support, and traceable sourcing.
Supply support for LMH6645MF 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 expertise in high-performance op-amps and precision signal-chain solutions.
The LMH6645MF belongs to TI's LMH664x family of rail-to-rail I/O amplifiers designed specifically for low-voltage, high-speed signal conditioning in portable, industrial, and medical instrumentation where power efficiency and dynamic range are critical.
FAQ
What is the maximum supply voltage for the LMH6645MF?
The LMH6645MF supports a recommended operating supply voltage range of 2.5 V to 12 V (V+ – V−). Absolute maximum rating is 12.6 V. Exceeding this may cause permanent damage. At 12 V operation, supply current rises to ~1.6 mA per channel, but bandwidth and slew rate remain stable at 55 MHz and 22 V/μs - confirming its robustness across the full range.
Does the LMH6645MF have a shutdown pin?
No, the LMH6645MF does not include a shutdown pin. Shutdown functionality is exclusive to the LMH6647 variant (SOT-23-6 and SOIC-8 packages). The LMH6645MF is a single-channel amplifier in SOT-23-5 format with fixed operation - five pins dedicated to V+, −IN, +IN, V−, and OUTPUT. For power-gated applications, external enable circuitry or system-level sleep control is required.
What is the input common-mode voltage range of the LMH6645MF?
The LMH6645MF features rail-to-rail input with an input common-mode voltage range extending 0.3 V beyond both supply rails - i.e., from (V− − 0.3 V) to (V+ + 0.3 V) at 25°C. This is confirmed in datasheet Section 7.5 (CMVR = −0.3 V to 3.0 V at VS = 2.7 V). At temperature extremes (−40°C to +85°C), the range tightens slightly to −0.1 V to 2.8 V, still exceeding rails by ≥0.1 V.
Can the LMH6645MF drive a 50 Ω load?
Yes, the LMH6645MF can drive a 50 Ω load, but with trade-offs. Its ±20 mA linear output current supports 1 VPP into 50 Ω (requiring 20 mA peak), though output swing will compress to ~1.5 VPP due to voltage drop across internal resistance. For sustained 50 Ω driving, thermal considerations and output stage headroom require careful PCB layout and local decoupling; for full 2 VPP+ signals, a buffer stage is recommended.
What is the typical input offset voltage drift of the LMH6645MF?
The LMH6645MF has a typical input offset voltage drift of ±5 μV/°C over −40°C to +85°C, as specified in Section 7.5 (TC VOS). This low drift ensures stable DC accuracy in temperature-varying environments - for example, maintaining <0.5 mV total offset shift across a 60°C ambient change, critical in precision current sensing and medical front-ends where calibration intervals are infrequent.
LMH6645MF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- VIP10™
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Obsolete
- Amplifier Type:
- Voltage Feedback
- Number of Circuits:
- 1
- 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
- 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:
- SOT-23-5
LMH6645MF FAQ
1.How can I place an order for LMH6645MF through Aetrix?
Please submit a Request for Quotation (RFQ) for LMH6645MF 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 LMH6645MF reliable?
The price and inventory of LMH6645MF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMH6645MF is usually 5 days.
3.What payment methods are accepted for LMH6645MF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMH6645MF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMH6645MF?
LMH6645MF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMH6645MF 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 LMH6645MF?
For technical support, including LMH6645MF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMH6645MF requirements.
6.How does Aetrix verify that LMH6645MF is sourced from the original manufacturer or authorized distributors?
All LMH6645MF 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 LMH6645MF meets industry standards.
7.What is the process for return or replacement of LMH6645MF?
All LMH6645MF units undergo pre-shipment inspection (PSI). If there is an issue with LMH6645MF, 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 LMH6645MF part is unused and in its original packaging.
Return procedure for LMH6645MF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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