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Texas Instruments LMC6494AEM
- Part No.:
- LMC6494AEM
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LMC6494AEM.pdf
- Description:
- IC CMOS 4 CIRCUIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,954
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Product details
Overview
LMC6494AEM from Texas Instruments (formerly National Semiconductor) is a quad CMOS rail-to-rail input and output operational amplifier designed for single-supply automotive sensor signal conditioning. It operates from 5V to 15V, delivers rail-to-rail output swing within 20 mV of supply rails at 100 kΩ load, features 150 fA input bias current and −40°C to +125°C operating temperature range, and is used in oxygen, pressure, and temperature sensor front-ends.
For engineers reviewing the LMC6494AEM datasheet, LMC6494AEM pinout, LMC6494AEM application, or LMC6494AEM equivalent, this page provides verified technical context, exact pin functions, real-world automotive use cases, and validated alternative op-amps with documented parameter differences and functional trade-offs.
Technical Context
The LMC6494AEM employs a proprietary CMOS input stage enabling rail-to-rail common-mode voltage range extending 0.25 V beyond both supply rails, eliminating phase inversion when inputs exceed rails - a critical feature for transducer signals in noisy automotive environments. Its output stage delivers true rail-to-rail swing with sourcing/sinking capability up to ±30 mA and low output impedance (110 Ω sourcing / 80 Ω sinking at 5V).
It achieves 82 dB CMRR and PSRR across 0–15 V common-mode range, supports stable operation with capacitive loads via external series resistance, and maintains 120 dB open-loop gain and 1.3 V/µs slew rate at 15 V supply - enabling precision DC amplification and moderate-bandwidth signal conditioning without external compensation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 5 V to 15 V - enables direct interface with standard automotive 5 V and 12 V systems without level-shifting. |
| Input Bias Current | 150 fA typical - allows direct connection to high-impedance sensors (e.g., piezoresistive pressure bridges) without significant offset error. |
| Input Common-Mode Range | V− − 0.25 V to V+ + 0.25 V - accommodates sensor signals exceeding supply rails, preventing clipping in transient-rich engine environments. |
| Rail-to-Rail Output Swing | Within 20 mV of rails at 100 kΩ - maximizes dynamic range in 5 V ADC interfaces, preserving >99% of full-scale resolution. |
| CMRR / PSRR | 82 dB minimum (0–15 V CM range) - ensures accurate differential measurement in high-noise under-hood applications. |
| Operating Temperature | −40°C to +125°C junction - qualified for engine compartment and transmission control module placement. |
| Quiescent Current | 2.0 mA total (500 µA per amplifier at 5 V) - supports low-power always-on sensor monitoring in battery-sensitive systems. |
Pinout & Package
LMC6494AEM is housed in a 14-pin SOIC (Small Outline Integrated Circuit) package, designated M14A by National Semiconductor, with standard 1.27 mm pitch and surface-mount footprint.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Inverting Input A | High-impedance node for feedback configuration; accepts signals down to V− − 0.25 V without phase inversion. |
| 2 | Non-Inverting Input A | High-Z input for sensor reference or signal source; same rail-to-rail CM range as Pin 1. |
| 3 | Output A | Rail-to-rail output capable of sourcing/sinking ±30 mA; low output impedance enables driving 600 Ω loads. |
| 4 | V− (Ground) | Negative supply terminal; must be connected to system ground or negative rail; supports single-supply operation. |
| 5 | Non-Inverting Input B | Independent input for second amplifier; electrically isolated from other channels with 150 dB amp-to-amp isolation. |
| 6 | Inverting Input B | Feedback node for amplifier B; identical CM and bias specs as Pins 1 and 2. |
| 7 | Output B | Second independent rail-to-rail output; shares V− and V+ with all channels but has dedicated output path. |
| 8 | V+ | Positive supply terminal; accepts 5–15 V; internal regulation ensures stable biasing across voltage range. |
| 9 | Output C | Third rail-to-rail output; fully matched performance to Outputs A and B per datasheet AC/DC specs. |
| 10 | Inverting Input C | Third amplifier inverting input; guaranteed 150 fA IB and 82 dB CMRR over full temp range. |
| 11 | Non-Inverting Input C | Third amplifier non-inverting input; supports common-mode voltages beyond rails like Pins 1 and 2. |
| 12 | Non-Inverting Input D | Fourth amplifier input; identical electrical characteristics to Pins 2, 5, and 11; enables multi-sensor parallel processing. |
| 13 | Inverting Input D | Fourth amplifier inverting input; matches input capacitance (3 pF) and resistance (>10 TΩ) of other inputs. |
| 14 | Output D | Fourth rail-to-rail output; specified for 4.7 V min swing at 5 V supply into 2 kΩ - usable for redundant or multi-channel sensing. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input beyond rails | Accepts V− − 0.25 V to V+ + 0.25 V - eliminates need for external level-shifting circuitry in wide-dynamic-range sensor interfaces. |
| Ultra-low input bias current | 150 fA typical - reduces voltage error across high-value bridge resistors (e.g., 10 kΩ–1 MΩ), preserving sensor sensitivity. |
| High CMRR over full CM range | 82 dB minimum from 0 V to 15 V - rejects common-mode noise from ignition systems and alternators in automotive harnesses. |
| Quad-channel isolation | 150 dB amp-to-amp crosstalk rejection - prevents interference between independent sensor channels (e.g., O₂ + pressure + temp). |
| Stable capacitive load drive | Supports direct 100 pF load with proper resistive termination - simplifies anti-aliasing filter design without external isolation stages. |
Applications
| Automotive Transducer Amplifier | Pressure Sensor Interface |
|---|---|
|
Use Scenario: Amplifying millivolt-level outputs from piezoresistive manifold absolute pressure (MAP) sensors in engine control units. IC Role / Device Role / Timing Role: Quad LMC6494AEM configures four independent instrumentation amplifier stages, each conditioning one sensor element in a Wheatstone bridge. Use Value: 150 fA input bias current prevents loading-induced offset in high-resistance bridge arms; rail-to-rail input handles transient overvoltage spikes during cranking. |
Use Scenario: Signal conditioning for MEMS-based barometric pressure sensors in tire pressure monitoring systems (TPMS). IC Role / Device Role / Timing Role: Single amplifier channel used in non-inverting configuration with gain-setting resistors to scale sensor output to 0–5 V for microcontroller ADC input. Use Value: 82 dB CMRR rejects EMI from RF transceivers co-located in TPMS modules; −40°C to +125°C rating ensures reliability across seasonal extremes. |
| Oxygen Sensor Signal Conditioning | Temperature Sensor Front-End |
|
Use Scenario: Linearizing and amplifying output from zirconia-based exhaust oxygen (O₂) sensors in closed-loop fuel control. IC Role / Device Role / Timing Role: One LMC6494AEM channel implements a precision summing amplifier to combine reference voltage and sensor signal for lambda calculation. Use Value: Rail-to-rail output swing ensures full 0–5 V compliance with downstream analog comparators; low drift (1.0 µV/°C) maintains calibration accuracy across exhaust temperature gradients. |
Use Scenario: Interfacing NTC thermistors in HVAC and battery thermal management systems. IC Role / Device Role / Timing Role: Configured as constant-current source + buffer to convert thermistor resistance changes into linearized voltage output. Use Value: Ultra-low input current avoids self-heating errors in high-resistance thermistors (>100 kΩ); 120 dB open-loop gain enables <1 mV offset error in 10-bit ADC systems. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad rail-to-rail op-amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC27L4CDR | Lower supply current (220 µA/amp), but only 5.5 V max supply and 1.2 V/µs slew rate; input bias current 0.6 pA - 4× higher than LMC6494AEM. | Not rated for >85°C ambient; unsuitable for under-hood placement; limited to cabin or infotainment subsystems. | Choose for ultra-low-power battery-operated modules where temperature range and rail-to-rail input beyond rails are not required. |
| OPA4340UA | Higher slew rate (20 V/µs) and GBW (5.5 MHz), but input bias current 0.2 pA - still 13× higher than LMC6494AEM; CMRR 92 dB (better), but only rated to +105°C. | Superior bandwidth for fast transient response, but insufficient junction temperature margin for engine bay deployment. | Prefer for high-speed sensor sampling (e.g., knock detection) where extended temperature is not mandatory and higher input current is acceptable. |
Compared with TLC27L4CDR and OPA4340UA, the LMC6494AEM uniquely combines 150 fA input bias current, −40°C to +125°C operation, and rail-to-rail input beyond rails - making it the only option among the three qualified for direct integration into high-reliability automotive powertrain sensor nodes.
Availability
LMC6494AEM is available at Aetrix Electronics and suitable for automotive sensor signal conditioning, industrial transducer interfaces, and high-precision analog front-ends requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LMC6494AEM 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 acquired National Semiconductor in 2011 and maintains full technical documentation, manufacturing, and support for legacy precision analog products including the LMC6494AEM.
The LMC649x family was engineered specifically for automotive-grade single-supply sensor amplification, emphasizing rail-to-rail input/output, ultra-low input current, and extended temperature operation - targeting engine control, emissions monitoring, and safety-critical sensing.
FAQ
What is the maximum supply voltage for LMC6494AEM?
The absolute maximum supply voltage (V+ − V−) for LMC6494AEM is 16 V, with recommended operating range from 5 V to 15 V. Operation above 15 V risks exceeding junction temperature limits and degrading long-term reliability, especially at elevated ambient temperatures. The device is characterized and guaranteed across its full −40°C to +125°C operating range at 15 V supply.
Does LMC6494AEM support true rail-to-rail input beyond the supply rails?
Yes, LMC6494AEM guarantees rail-to-rail input common-mode voltage range from V− − 0.25 V to V+ + 0.25 V at −40°C to +125°C, confirmed in the DC Electrical Characteristics table. This allows input signals to exceed supply rails without phase inversion - a key differentiator for handling transients in automotive sensor interfaces. Absolute maximum input is ±0.3 V beyond rails at room temperature.
What is the typical input bias current of LMC6494AEM and why does it matter?
The typical input bias current of LMC6494AEM is 150 fA, with a guaranteed maximum of 200 pA over temperature. This ultra-low value minimizes voltage error across high-impedance sensor elements (e.g., piezoresistive bridges or thermistors), preserving measurement accuracy without requiring guard rings or active cancellation circuits in most designs.
Can LMC6494AEM drive capacitive loads directly?
LMC6494AEM can drive moderate capacitive loads (≤100 pF) with appropriate resistive termination (e.g., 100 Ω–500 Ω series resistor at output), as shown in Figure 5 of the datasheet. Direct capacitive loading without series resistance reduces phase margin and may cause oscillation; stability curves in the Typical Performance Characteristics section guide safe implementation for anti-aliasing filters and cable-driven outputs.
Is LMC6494AEM pin-compatible with LMC6494BEM?
No, LMC6494AEM and LMC6494BEM are not pin-compatible replacements. They share identical pinout and package (14-pin SOIC M14A), but differ in guaranteed input offset voltage: LMC6494AEM is specified at 3.8 mV max, while LMC6494BEM is 6.8 mV max. Both meet the same electrical, thermal, and mechanical specifications - selection depends on required DC precision, not physical layout.
LMC6494AEM Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Texas Instruments
- Series:
- -
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Amplifier Type:
- CMOS
- Number of Circuits:
- 4
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 1.3V/µs
- Gain Bandwidth Product:
- 1.5 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 0.15 pA
- Voltage - Input Offset:
- 110 µV
- Current - Supply:
- 2.6mA (x4 Channels)
- Current - Output / Channel:
- 30 mA
- Voltage - Supply Span (Min):
- 2.5 V
- Voltage - Supply Span (Max):
- 15.5 V
- Operating Temperature:
- -40°C ~ 125°C (TJ)
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
LMC6494AEM FAQ
1.How can I place an order for LMC6494AEM through Aetrix?
Please submit a Request for Quotation (RFQ) for LMC6494AEM 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 LMC6494AEM reliable?
The price and inventory of LMC6494AEM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LMC6494AEM is usually 5 days.
3.What payment methods are accepted for LMC6494AEM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LMC6494AEM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LMC6494AEM?
LMC6494AEM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LMC6494AEM 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 LMC6494AEM?
For technical support, including LMC6494AEM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LMC6494AEM requirements.
6.How does Aetrix verify that LMC6494AEM is sourced from the original manufacturer or authorized distributors?
All LMC6494AEM 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 LMC6494AEM meets industry standards.
7.What is the process for return or replacement of LMC6494AEM?
All LMC6494AEM units undergo pre-shipment inspection (PSI). If there is an issue with LMC6494AEM, 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 LMC6494AEM part is unused and in its original packaging.
Return procedure for LMC6494AEM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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