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Texas Instruments LF444CM
- Part No.:
- LF444CM
- Manufacturer:
- Texas Instruments
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LF444CM.pdf
- Description:
- IC OPAMP JFET 4 CIRCUIT 14SOIC
- Quantity:
- Payment:
- Shipping:
Inventory:1,057
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Product details
Overview
LF444CM from Texas Instruments is a quad low-power JFET-input operational amplifier designed for precision analog signal conditioning in space- and power-constrained systems. It delivers 1 MHz gain-bandwidth, 1 V/μs slew rate, 50 k minimum open-loop gain, and ultra-low 50 pA (max) input bias current at ±15 V supply, enabling high-impedance sensor interfacing in battery-powered instrumentation.
For engineers reviewing the LF444CM datasheet, LF444CM pinout, LF444CM application, or LF444CM equivalent, key selection criteria include its JFET-input architecture for femtoampere-level bias current, SOIC-14 package compatibility with LM148 footprints, commercial temperature range (0°C to +70°C), and verified performance in pH probe amplifiers and low-noise transducer signal chains.
Technical Context
The LF444CM uses matched high-voltage JFET input pairs to achieve 10¹² Ω input impedance and 35 nV/√Hz input voltage noise at 1 kHz-critical for high-source-impedance applications like electrochemical sensors. Its DC-coupled architecture supports rail-to-rail common-mode input range up to ±15 V, with guaranteed output swing of ±12 V into 10 kΩ.
Unlike bipolar-input op-amps, the LF444CM avoids input stage thermal drift and base-current-induced offset errors. It maintains stable 70 dB minimum CMRR and PSRR over temperature while drawing only 0.6–1.0 mA total supply current-exactly one-quarter that of the LM148-making it suitable for multi-channel portable measurement systems.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage | ±15 V max - supports dual-rail operation in industrial and test equipment without external regulators |
| Input Bias Current | 10–100 pA (max) - enables direct connection to high-impedance pH electrodes and piezoelectric sensors |
| Gain-Bandwidth Product | 1 MHz - sufficient for closed-loop gains up to 100 at 10 kHz in active filter and instrumentation amplifier stages |
| Slew Rate | 1 V/μs - ensures faithful reproduction of 100 kHz sine waves at ±10 V output swing |
| Input Noise Voltage | 35 nV/√Hz @ 1 kHz - minimizes added noise in low-level signal amplification below 100 mV |
| Common-Mode Rejection | 70 dB (min) - rejects power supply ripple and shared ground noise in multi-stage analog front-ends |
| Output Swing | ±12 V into 10 kΩ - provides full dynamic range for 12-bit ADC drivers operating from ±15 V rails |
Pinout & Package
LF444CM is housed in a 14-pin SOIC (D) package per JEDEC MS-012 variation AB, measuring 8.75 mm × 3.9 mm × 1.75 mm max height, with 1.27 mm lead pitch and SN (tin) lead finish compliant with Level-1 MSL rating.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | Amplifier 1 Output | Drives feedback network or next-stage input; capable of ±12 V swing into 10 kΩ |
| 2 | Amplifier 1 Inverting Input | High-impedance node (10¹² Ω); requires guard ring layout to preserve 50 pA bias current spec |
| 3 | Amplifier 1 Non-Inverting Input | Accepts high-Z sensor signals; common-mode range extends to ±15 V |
| 4 | Negative Supply (V−) | Must be ≥ −15 V; exceeding −15 V risks permanent damage per absolute maximum ratings |
| 5 | Amplifier 2 Non-Inverting Input | Independent input for second channel; electrically isolated from other amplifiers on die |
| 6 | Amplifier 2 Inverting Input | Supports unity-gain stable configurations; no internal compensation required |
| 7 | Amplifier 2 Output | Provides identical AC/DC specs as Pin 1; usable for differential output or dual-sensor conditioning |
| 8 | Amplifier 3 Output | Third independent amplifier channel; shares same supply pins and thermal characteristics |
| 9 | Amplifier 3 Inverting Input | Validated for use in active low-pass filters up to 100 kHz with 1% resistor tolerance |
| 10 | Amplifier 3 Non-Inverting Input | Compatible with reference voltage sources up to ±14 V common-mode range |
| 11 | Positive Supply (V+) | Must be ≤ +15 V; derating required above 70°C ambient due to θjA = 85°C/W |
| 12 | Amplifier 4 Non-Inverting Input | Enables four-channel simultaneous acquisition in data loggers without cross-talk penalty |
| 13 | Amplifier 4 Inverting Input | Supports precision summing configurations with <10 μV offset contribution per channel |
| 14 | Amplifier 4 Output | Final channel output; validated for driving 100 pF capacitive loads without oscillation |
Key Features
| Feature | Design Value |
|---|---|
| JFET input stage | Delivers 10¹² Ω input resistance and 50 pA max input bias current-enabling direct connection to glass pH electrodes without guard buffers |
| Quad monolithic architecture | Four fully independent amplifiers on single die with matched gain, offset, and temperature drift-reducing component count in multi-channel sensor interfaces |
| LM148 pin compatibility | SOIC-14 footprint matches industry-standard LM148 layout-allowing drop-in power reduction in legacy designs without PCB revision |
| Low-noise optimization | 35 nV/√Hz input voltage noise and 0.01 pA/√Hz input current noise-critical for amplifying sub-millivolt signals from thermocouples and strain gauges |
| Stable under capacitive load | Guaranteed stability driving up to 100 pF without external compensation-simplifying layout in compact PCBs with long traces to ADC inputs |
Applications
| pH Measurement Systems | Portable Data Loggers |
|---|---|
Use Scenario: Amplifying microamp-level currents from glass pH electrodes in handheld field meters with 0.01 pH resolution. IC Role / Device Role / Timing Role: First-stage transimpedance amplifier converting electrode current to voltage, followed by temperature-compensated buffer. Use Value: Ultra-low 50 pA input bias current prevents electrode polarization error; 1 MHz bandwidth supports fast calibration response. | Use Scenario: Simultaneous acquisition of four analog sensor channels (temperature, humidity, pressure, gas concentration) in battery-powered environmental monitors. IC Role / Device Role / Timing Role: Quad-channel signal conditioner providing gain, filtering, and level-shifting prior to multiplexed ADC sampling. Use Value: 0.6–1.0 mA total supply current extends battery life to >12 months; matched channels reduce calibration overhead. |
| Medical Instrumentation | Industrial Process Control |
Use Scenario: Isolating and amplifying ECG electrode signals in wearable heart-rate monitors with dry-contact electrodes. IC Role / Device Role / Timing Role: High-input-impedance front-end amplifier rejecting common-mode interference from body-coupled noise. Use Value: 70 dB CMRR suppresses 50/60 Hz mains pickup; 10¹² Ω input impedance prevents signal attenuation across skin-electrode interface. | Use Scenario: Conditioning millivolt outputs from RTD and thermocouple transmitters in PLC analog input modules. IC Role / Device Role / Timing Role: Precision instrumentation amplifier core with programmable gain and cold-junction compensation. Use Value: 10 μV/°C typical input offset drift ensures <0.1°C measurement accuracy over 0–70°C operating range. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad JFET-input operational amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| TLC27L4CD | Lower supply current (125 μA/amplifier), but reduced GBW (0.85 MHz) and higher input bias current (200 pA max) | Better suited for ultra-low-power sleep-mode sensing; less ideal for 100 kHz signal bandwidth requirements | Select when total supply current must stay below 500 μA and bandwidth ≤85 kHz suffices |
| TL074CD | Higher slew rate (13 V/μs) and GBW (3 MHz), but higher supply current (1.4 mA total) and input bias current (200 pA max) | Preferred for audio and wideband active filters; not optimal for battery life or high-impedance DC-coupled sensors | Select when bandwidth >1 MHz and drive capability >10 mA are required, accepting 2.3× higher power draw |
Compared with TLC27L4CD and TL074CD, the LF444CM uniquely balances 1 MHz bandwidth, 1 V/μs slew rate, and sub-1 mA total supply current while maintaining 50 pA input bias current-making it the optimal choice for precision, multi-channel, low-power sensor front-ends where all three parameters are simultaneously critical.
Availability
LF444CM is available at Aetrix Electronics and suitable for pH measurement systems, portable data loggers, medical instrumentation, industrial process control, and precision analog signal conditioning requiring stable component supply across extended production cycles.
Supply support for LF444CM 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, embedded processing, and digital signal technologies with over 90 years of innovation in high-reliability components.
The LF444CM belongs to TI's legacy precision op-amp product line, engineered specifically for low-power, high-input-impedance analog signal conditioning in industrial, medical, and test equipment where JFET input performance and LM148 compatibility are essential.
FAQ
What is the maximum supply voltage rating for the LF444CM?
The LF444CM has an absolute maximum supply voltage rating of ±15 V. Exceeding this limit-even momentarily-may cause irreversible damage to the JFET input stage. Operation at ±12 V is recommended for long-term reliability and thermal margin, especially above 50°C ambient. The LF444CM datasheet specifies guaranteed performance only within ±15 V, and derating is required above 70°C due to its 85°C/W junction-to-ambient thermal resistance.
Is the LF444CM pin-compatible with the LM148 in SOIC-14 packages?
Yes, the LF444CM is fully pin-compatible with the LM148 in SOIC-14 (D) packages. Both devices share identical pin assignments, electrical connections, and PCB footprint dimensions per JEDEC MS-012 AB. This allows direct replacement in existing LM148-based designs, delivering immediate 4× reduction in supply current without layout changes-verified in TI's official application notes and packaging addendum for LF444CM/NOPB.B.
What is the typical input bias current of the LF444CM at 25°C and 70°C?
The LF444CM exhibits a typical input bias current of 10 pA at 25°C and 3 nA at 70°C, with a maximum specification of 100 pA at 70°C. This temperature-dependent increase follows JFET leakage physics-approximately doubling per 10°C rise in junction temperature. For designs requiring stable bias current over temperature, thermal management or calibration compensation should account for this drift, particularly in high-precision DC-coupled applications like pH meter front-ends.
Can the LF444CM drive capacitive loads without external compensation?
Yes, the LF444CM is specified to remain stable when driving up to 100 pF capacitive loads directly at its output, as confirmed in TI's typical performance curves and application hints. This eliminates the need for series isolation resistors or external compensation networks in most sensor interface and ADC driver configurations. However, for loads exceeding 100 pF-or when routing long traces-the addition of a 10–47 Ω series resistor adjacent to the output pin is recommended to maintain phase margin.
Does the LF444CM support rail-to-rail input common-mode voltage range?
No, the LF444CM does not support true rail-to-rail input. Its specified input common-mode voltage range is ±11 V to ±14 V (depending on supply), meaning it operates correctly when inputs remain within 1–4 V of either supply rail. For example, with ±15 V supplies, valid input voltages span −14 V to +14 V-not −15 V to +15 V. Exceeding the negative common-mode limit forces the output high; exceeding both limits causes latch-up-free output saturation, as detailed in the "APPLICATION HINTS" section of the LF444CM datasheet.
LF444CM 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:
- J-FET
- Number of Circuits:
- 4
- Output Type:
- -
- Slew Rate:
- 1V/µs
- Gain Bandwidth Product:
- 1 MHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 10 pA
- Voltage - Input Offset:
- 3 mV
- Current - Supply:
- 600µA (x4 Channels)
- Current - Output / Channel:
- 14 mA
- Voltage - Supply Span (Min):
- 36 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SOIC
LF444CM FAQ
1.How can I place an order for LF444CM through Aetrix?
Please submit a Request for Quotation (RFQ) for LF444CM 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 LF444CM reliable?
The price and inventory of LF444CM are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LF444CM is usually 5 days.
3.What payment methods are accepted for LF444CM?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LF444CM transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LF444CM?
LF444CM orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LF444CM 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 LF444CM?
For technical support, including LF444CM datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LF444CM requirements.
6.How does Aetrix verify that LF444CM is sourced from the original manufacturer or authorized distributors?
All LF444CM 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 LF444CM meets industry standards.
7.What is the process for return or replacement of LF444CM?
All LF444CM units undergo pre-shipment inspection (PSI). If there is an issue with LF444CM, 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 LF444CM part is unused and in its original packaging.
Return procedure for LF444CM:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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