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Texas Instruments LMH6645MFX/NOPB
- Part No.:
- LMH6645MFX/NOPB
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- SC-74A, SOT-753
- Datasheet:
-
LMH6645MFX/NOPB.pdf
- Description:
- IC OPAMP VFB 1 CIRCUIT SOT23-5
- Quantity:
- Payment:
- Shipping:
Inventory:6,024
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Product details
Overview
LMH6645MFX/NOPB 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 LMH6645MFX/NOPB datasheet, LMH6645MFX/NOPB pinout, LMH6645MFX/NOPB application, or LMH6645MFX/NOPB equivalent, key selection criteria include its rail-to-rail I/O swing (within 20 mV of rails), 17 nV/√Hz input voltage noise at 100 kHz, shutdown capability (in LMH6647 variant), and guaranteed performance across −40°C to +85°C industrial temperature range.
Technical Context
The LMH6645MFX/NOPB employs a proprietary VIP10 dielectrically isolated bipolar process with complementary transistors achieving ∼8 GHz fT under 2.7 V operation. Its class A-B "turn-around" input stage reduces power and improves offset/noise versus conventional high-speed op-amps.
A common-emitter push-pull output stage enables rail-to-rail output swing (20 mV from rails) and ±20 mA drive capability at light loads, while maintaining stable −3 dB bandwidth (55 MHz) and slew rate (22 V/μs) across supply voltages from 2.5 V to 12 V.
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 10 VPP output at 350 kHz without slewing distortion. |
| Supply Current | 650 μA per channel at 2.7 V - allows integration into ultra-low-power systems with tight budget constraints. |
| Input Voltage Noise | 17 nV/√Hz at 100 kHz - preserves SNR in precision sensor front-ends and active filter stages. |
| Output Swing | Within 20 mV of either rail at RL = 1 kΩ - maximizes dynamic range in single-supply 3.3 V or lower systems. |
| Input Common-Mode Range | Extends 0.3 V beyond both supply rails - simplifies level-shifting and direct interfacing with CMOS logic or ADC references. |
| CMRR | 77 dB minimum at 25°C - ensures robust rejection of supply- and reference-coupled interference in noisy environments. |
Pinout & Package
SOT-23-5 package (2.90 mm × 1.60 mm body size) with exposed pad for thermal enhancement. Pin 1: OUTPUT; Pin 2: V−; Pin 3: +IN; Pin 4: −IN; Pin 5: V+.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUTPUT) | Amplifier output node | Delivers rail-to-rail voltage swing with ±20 mA sourcing/sinking capability; requires local 0.1 μF bypass capacitor. |
| 2 (V−) | Negative supply terminal | Accepts ground (single-supply) or negative rail (split-supply); connects to system ground plane for stability. |
| 3 (+IN) | Non-inverting input | High-impedance node (3 MΩ RIN) accepting signals up to 0.3 V beyond V− or V+; used for unity-gain buffer or non-inverting gain stages. |
| 4 (−IN) | Inverting input | High-impedance node with matched bias current; connects to feedback network for inverting configurations or active filters. |
| 5 (V+) | Positive supply terminal | Accepts 2.5–12 V supply; decoupling to V− is mandatory to suppress PSRR-induced ripple at high frequencies. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables full-scale signal handling in 2.7 V single-supply systems without level-shifting circuitry. |
| 55 MHz bandwidth at 650 μA | Delivers video-bandwidth performance with micro-power efficiency - 3× faster than typical 1 mA op-amps. |
| 17 nV/√Hz input voltage noise | Preserves resolution in 12–14-bit sensor signal chains where noise dominates quantization error. |
| ±20 mA linear output drive | Directly drives 50 Ω cables, SAR ADC inputs, or multiplexed analog buses without external buffers. |
| −40°C to +85°C operating range | Qualified for industrial-grade reliability in embedded control, portable test equipment, and automotive cabin modules. |
Applications
| Active Filters | Current Sense Buffer |
|---|---|
Use Scenario: Second-order Sallen-Key low-pass filter in motor phase current monitoring with 100 kHz cutoff. IC Role / Device Role / Timing Role: Configured as unity-gain buffer and gain stage to condition shunt voltage before 1 MSPS ADC sampling. Use Value: 55 MHz bandwidth ensures minimal phase shift at cutoff; rail-to-rail I/O captures full ±50 mV shunt swing across 0–3.3 V supply. | Use Scenario: Bidirectional current sensing in USB-C PD power delivery controller with 0.5 mΩ shunt. IC Role / Device Role / Timing Role: High-side differential amplifier with G = 20 to amplify 0–100 mV shunt drop to 0–2 V range. Use Value: Input common-mode range extends to 0.3 V beyond V+, allowing direct connection to 5 V bus; 17 nV/√Hz noise avoids degrading 12-bit measurement accuracy. |
| High-Speed Portable Devices | Transducer Signal Conditioning |
Use Scenario: Front-end amplifier for piezoelectric vibration sensor in handheld predictive maintenance tool. IC Role / Device Role / Timing Role: AC-coupled non-inverting amplifier (G = 10) driving 12-bit SAR ADC at 1 MSPS. Use Value: 22 V/μs slew rate prevents distortion on 5 VPP transients; 650 μA supply current extends battery life beyond 24 hours on coin cell. | Use Scenario: Signal conditioning for MEMS microphone preamplifier in Bluetooth headset with 3.3 V supply. IC Role / Device Role / Timing Role: Inverting gain stage with DC-blocking capacitor and bias network for electret mic output. Use Value: Rail-to-rail output swings 0–3.3 V to match ADC input range; 20 mV rail margin ensures headroom during RF burst interference. |
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 | Higher 200 MHz GBW but 2.3 mA supply current; no rail-to-rail input (input range limited to V− + 1.5 V). | Better for wideband closed-loop gain >10; unsuitable for direct single-supply sensor interfacing near ground. | Select when bandwidth >100 MHz is required and power budget allows ≥3× higher quiescent current. |
| ADA4891-1ARJZ-R7 | Lower 220 MHz GBW, 1.2 mA supply current, rail-to-rail I/O, but 4.5 nV/√Hz noise at 10 kHz (higher than LMH6645's 17 nV/√Hz at 100 kHz). | Better for low-noise DC-coupled applications below 100 kHz; less optimal for high-frequency active filters. | Prefer for precision DC amplification with moderate speed; avoid when 55 MHz flat bandwidth and low 100 kHz noise are critical. |
Compared with OPA355DBVR and ADA4891-1ARJZ-R7, LMH6645MFX/NOPB uniquely balances 55 MHz bandwidth, 650 μA supply current, and true rail-to-rail input operation - making it optimal for battery-powered signal chains requiring full dynamic range at minimal power.
Availability
LMH6645MFX/NOPB is available at Aetrix Electronics and suitable for active filters, current sense buffers, high-speed portable devices, and transducer signal conditioning requiring stable component supply across industrial temperature ranges and long production lifecycles.
Supply support for LMH6645MFX/NOPB 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 solutions, 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 industrial systems - emphasizing rail-to-rail operation, micro-power efficiency, and consistent AC performance across supply voltages.
FAQ
What is the maximum supply voltage rating for LMH6645MFX/NOPB?
The absolute maximum supply voltage (V+ − V−) for LMH6645MFX/NOPB is 12.6 V, with recommended operating range from 2.5 V to 12 V. Operation above 12 V risks permanent damage; sustained operation at 12 V is permissible but requires thermal derating per RθJA = 265°C/W (SOT-23-5). The LMH6645MFX/NOPB datasheet specifies electrical characteristics up to 12 V, including 55 MHz bandwidth and 22 V/μs slew rate.
Does LMH6645MFX/NOPB support true rail-to-rail input operation?
Yes, LMH6645MFX/NOPB supports true rail-to-rail input: the input common-mode voltage range extends 0.3 V beyond both V− and V+ rails (e.g., −0.3 V to 3.0 V on a 2.7 V single supply). This is confirmed in the datasheet's Electrical Characteristics table (CMVR = −0.3 V to 3.0 V at 25°C) and Functional Description section, enabling direct interface with sensors or logic outputs operating at supply extremes. LMH6645MFX/NOPB achieves this via proprietary VIP10 bipolar input stage design.
What is the typical output voltage swing for LMH6645MFX/NOPB at 3.3 V supply?
At V+ = 3.3 V and V− = 0 V, LMH6645MFX/NOPB delivers typical output swing of 20 mV from each rail - i.e., 0.02 V to 3.28 V with RL = 1 kΩ to V+/2. This rail-to-rail output performance is specified across −40°C to +85°C and is enabled by its common-emitter push-pull output stage. The LMH6645MFX/NOPB maintains this swing even at 20 mA load, ensuring full dynamic range in low-voltage systems.
Is LMH6645MFX/NOPB pin-compatible with other devices in the LMH664x family?
No, LMH6645MFX/NOPB (SOT-23-5) is not pin-compatible with LMH6646 (SOIC-8/VSSOP-8 dual) or LMH6647 (SOT-23-6 with shutdown). The LMH6645MFX/NOPB has five pins: OUTPUT, V−, +IN, −IN, V+. LMH6647 adds SD (shutdown) on Pin 5 and moves V+ to Pin 6, while LMH6646 uses 8-pin packages with dual-channel routing. Board layout must be specific to LMH6645MFX/NOPB's SOT-23-5 footprint.
What is the input voltage noise density of LMH6645MFX/NOPB at 1 kHz?
The input voltage noise density of LMH6645MFX/NOPB is 25 nV/√Hz at 1 kHz, as specified in Section 7.5 (Electrical Characteristics at 2.7 V) of the official datasheet. At 100 kHz, it drops to 17 nV/√Hz - a key advantage for high-frequency active filters and RF envelope detection. This value is measured with V+ = 2.7 V, V− = 0 V, and RL = 1 kΩ to V+/2, and applies directly to LMH6645MFX/NOPB across its full operating temperature range.
LMH6645MFX/NOPB Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- VIP10™
- Package/Case:
- SC-74A, SOT-753
- Packaging:
- Tape & Reel (TR)
- Product Status:
- Active
- 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
LMH6645MFX/NOPB FAQ
1.How can I place an order for LMH6645MFX/NOPB through Aetrix?
Please submit a Request for Quotation (RFQ) for LMH6645MFX/NOPB 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 LMH6645MFX/NOPB reliable?
The price and inventory of LMH6645MFX/NOPB are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMH6645MFX/NOPB is usually 5 days.
3.What payment methods are accepted for LMH6645MFX/NOPB?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMH6645MFX/NOPB transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMH6645MFX/NOPB?
LMH6645MFX/NOPB orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMH6645MFX/NOPB 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 LMH6645MFX/NOPB?
For technical support, including LMH6645MFX/NOPB datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMH6645MFX/NOPB requirements.
6.How does Aetrix verify that LMH6645MFX/NOPB is sourced from the original manufacturer or authorized distributors?
All LMH6645MFX/NOPB 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 LMH6645MFX/NOPB meets industry standards.
7.What is the process for return or replacement of LMH6645MFX/NOPB?
All LMH6645MFX/NOPB units undergo pre-shipment inspection (PSI). If there is an issue with LMH6645MFX/NOPB, 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 LMH6645MFX/NOPB part is unused and in its original packaging.
Return procedure for LMH6645MFX/NOPB:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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