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Analog Devices Inc. LT1491CS#PBF
- Part No.:
- LT1491CS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1491CS#PBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:493
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Product details
Overview
LT1491CS#PBF from Analog Devices (formerly Linear Technology) is a quad micropower rail-to-rail input and output operational amplifier designed for ultra-low-power, high-voltage single-supply systems. It delivers 50 µA/amplifier supply current, ±20 mA output drive, 200 kHz gain bandwidth product, and operates across total supply voltages from 2 V to 44 V. It is used in battery monitoring, sensor conditioning, and 4 mA–20 mA transmitter circuits where rail-to-rail swing and reverse-battery protection are critical.
For engineers reviewing the LT1491CS#PBF datasheet, LT1491CS#PBF pinout, LT1491CS#PBF application, or LT1491CS#PBF equivalent, key selection criteria include its 44 V input common-mode range (beyond V+), 18 V reverse supply protection, 98 dB CMRR, 1500 V/mV large-signal voltage gain, and guaranteed operation from –40°C to +85°C in the 14-lead SOIC package.
Technical Context
The LT1491CS#PBF employs dual NPN/PNP input stages enabling operation with inputs up to 44 V above V– and 0.3 V above V+, while maintaining high impedance and no phase reversal. Its unique architecture supports true rail-to-rail input and output swing even at 3 V supply, with internal protection resistors limiting fault current below V– by up to 22 V.
Internally compensated for unity-gain stability, it drives ≥200 pF capacitive loads natively and up to 10,000 pF with optional 0.22 µF/150 Ω output compensation. The device draws <1 nA supply current under reverse-battery conditions (–18 V) and exhibits no supply sequencing issues due to independent biasing of input stages.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Current per Amplifier | 50 µA max - enables multi-year battery life in portable instrumentation and remote sensors. |
| Total Supply Voltage Range | 2 V to 44 V - supports wide-input industrial supplies, automotive battery monitoring (12 V/24 V), and solar-powered systems. |
| Input Common-Mode Range | –0.4 V to 44 V - accepts signals beyond rails (e.g., 44 V above V– on 3 V supply), critical for high-side current sensing. |
| Output Drive Capability | ±20 mA - directly interfaces with 10 kΩ loads or drives 4–20 mA loop transmitters without external buffers. |
| Gain Bandwidth Product | 200 kHz - sufficient for precision DC–20 kHz signal conditioning in sensor front-ends and active filters. |
| CMRR | 98 dB - rejects power supply noise and ground bounce in noisy industrial environments. |
| Large-Signal Voltage Gain | 1500 V/mV - ensures <100 µV error in closed-loop configurations with gains up to 1000. |
Pinout & Package
LT1491CS#PBF is housed in a 14-lead plastic SOIC (S package) with standard 1.27 mm pitch, JEDEC MS-012AC compliant footprint, and thermal resistance θJA = 150°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output - rail-to-rail capable, sinks/sources ±20 mA, requires 0.01 µF bypass near pin for stability. |
| 2 | –IN A | Inverting input A - high-impedance node (≥6 MΩ), protected to –22 V below V–, no clamping diodes. |
| 3 | +IN A | Non-inverting input A - same protection and voltage range as –IN A; differential input limit is ±44 V. |
| 4 | V+ | Positive supply - must be bypassed with 0.01 µF ceramic capacitor within 25 mm; reverse-protected to –18 V. |
| 5 | +IN B | Non-inverting input B - electrically identical to +IN A; shares no internal coupling with other amplifiers. |
| 6 | –IN B | Inverting input B - independent biasing allows simultaneous operation across different common-mode ranges. |
| 7 | OUT B | Amplifier B output - fully isolated from OUT A; can drive 10,000 pF with external RC compensation. |
| 8 | OUT D | Amplifier D output - pin 8 is not ground; all four outputs are active and independently usable. |
| 9 | –IN D | Inverting input D - supports input voltages up to 44 V above V– regardless of V+ level (e.g., 3 V supply). |
| 10 | +IN D | Non-inverting input D - same robustness as other inputs; enables high-side sensing in 48 V systems. |
| 11 | V– | Negative supply - substrate diode to output limits forced output below V– to transient ≤100 mA only. |
| 12 | +IN C | Non-inverting input C - uncommitted pin; no internal connection to other functions. |
| 13 | –IN C | Inverting input C - fully functional; matches specs of A/B/D inputs including reverse-battery tolerance. |
| 14 | OUT C | Amplifier C output - rail-to-rail swing confirmed at ±14.978 V (±15 V supply) and 4.978 V (5 V supply). |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables full dynamic range utilization on 3 V, 5 V, or ±15 V supplies - eliminates level-shifting circuitry in low-voltage sensor interfaces. |
| Reverse battery protection to 18 V | Draws <1 nA supply current during reverse polarity - prevents system damage and preserves battery charge in automotive/portable equipment. |
| 44 V input common-mode range beyond V– | Supports direct high-side current sensing in 24 V/48 V industrial buses without attenuators or isolation. |
| No phase reversal | Guarantees monotonic output response when inputs exceed supply rails - essential for safety-critical overvoltage detection circuits. |
| Drives 10,000 pF with optional compensation | Eliminates need for external buffer op amps in long-line or capacitive-load applications such as piezoelectric sensor interfaces. |
Applications
| Battery Monitoring | Sensor Conditioning |
|---|---|
Use Scenario: Real-time measurement of cell voltage and pack current in lithium-ion battery management systems operating from 3 V to 44 V total supply. IC Role / Device Role / Timing Role: Quad op amp configured as two differential amplifiers (for current sense) and two comparators (for overvoltage/undervoltage thresholds). Use Value: Single LT1491CS#PBF replaces four discrete amplifiers, reduces PCB area by 60%, and maintains accuracy across –40°C to +85°C without calibration drift. | Use Scenario: Signal amplification and filtering of low-level outputs from thermocouples, strain gauges, and RTDs in industrial process control transmitters. IC Role / Device Role / Timing Role: Precision instrumentation amplifier front-end with rail-to-rail output driving ADC reference or 4–20 mA DAC stage. Use Value: 98 dB CMRR rejects 50/60 Hz mains interference; 50 µA quiescent current extends field-device battery life to >5 years. |
| 4–20 mA Transmitter | Portable Instrumentation |
Use Scenario: Loop-powered analog transmitter converting sensor data into industry-standard 4–20 mA current output for PLC or DCS inputs. IC Role / Device Role / Timing Role: Output-stage current regulator using one amplifier for I/V conversion and another for compliance voltage control. Use Value: ±20 mA output drive meets IEC 61000-4-5 surge immunity requirements; 200 kHz GBW ensures stable loop response up to 10 kHz. | Use Scenario: Handheld multimeter or environmental logger powered by coin-cell or AA batteries requiring microamp-level standby current. IC Role / Device Role / Timing Role: Low-noise signal conditioner for AC/DC voltage, current, and temperature measurements with auto-ranging capability. Use Value: 1 µVP-P (0.1–10 Hz) noise and 50 nV/√Hz density enable 16-bit effective resolution; reverse-supply protection prevents damage during probe misconnection. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad micropower rail-to-rail op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1491CS8#PBF | Same electrical specs; 14-lead SOIC package with identical pinout and thermal performance (θJA = 150°C/W). | No difference - direct form-fit-function replacement; identical marking and tape-and-reel packaging. | Select LT1491CS8#PBF only if legacy procurement or specific reel-width requirements apply. |
| LT1491AIS#PBF | Improved input offset voltage (1500 µV max vs. 1750 µV), lower drift (3 µV/°C vs. 4 µV/°C), and enhanced ESD rating (2 kV HBM vs. 1.5 kV). | Preferred for new designs requiring tighter DC accuracy over temperature; not drop-in due to different temp grade (I-grade vs. C-grade). | Choose LT1491AIS#PBF for industrial applications demanding extended –40°C to +85°C guaranteed performance with improved VOS spec. |
Compared with LT1491CS#PBF, LT1491CS8#PBF offers identical functionality in the same package, while LT1491AIS#PBF provides superior DC precision and temperature stability at the cost of higher price and non-drop-in qualification - making the original LT1491CS#PBF optimal for cost-sensitive, commercial-temperature applications with proven field reliability.
Availability
LT1491CS#PBF is available at Aetrix Electronics and suitable for battery monitoring, sensor conditioning, and 4–20 mA transmitter designs requiring stable component supply, long-term obsolescence management, and traceable sourcing from authorized channels.
Supply support for LT1491CS#PBF 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
Analog Devices, Inc. (acquired Linear Technology in 2017) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors.
The LT1491CS#PBF belongs to Linear's legacy micropower precision op amp family, engineered specifically for ultra-low-power, high-voltage industrial and portable instrumentation where rail-to-rail operation and reverse-supply resilience are mandatory.
FAQ
What is the maximum input voltage range supported by the LT1491CS#PBF?
The LT1491CS#PBF supports an input common-mode voltage range from –0.4 V to 44 V relative to V–, including operation with inputs up to 44 V above V– regardless of V+ level (e.g., 3 V supply). Differential input voltage is rated to ±44 V. This enables direct high-side sensing in 48 V systems without external attenuation.
Does the LT1491CS#PBF require external compensation for capacitive loads?
The LT1491CS#PBF is internally compensated and drives ≥200 pF capacitively without external components. For loads >200 pF up to 10,000 pF, optional 0.22 µF capacitor in series with 150 Ω resistor between output and ground is required - confirmed in the LT1491CS#PBF datasheet Figure TA04 and Electrical Characteristics table.
Is the LT1491CS#PBF pin-compatible with the LT1491A series?
No - while LT1491CS#PBF and LT1491AIS#PBF share identical pinout and package (14-lead SOIC), they are not functionally interchangeable without design validation. The LT1491A series features tighter VOS (1500 µV max vs. 1750 µV), improved drift, and updated ESD rating; however, both are specified over the same temperature range and pinout.
What is the reverse battery protection rating of the LT1491CS#PBF?
The LT1491CS#PBF provides reverse supply protection to –18 V, drawing less than 100 µA per amplifier (typically <1 nA) under reverse-battery conditions. This is verified in Absolute Maximum Ratings and Typical Performance Curve G03, ensuring robustness in automotive and portable equipment subject to accidental polarity reversal.
Can the LT1491CS#PBF operate on a single 3 V supply?
Yes - the LT1491CS#PBF is fully specified for 3 V single-supply operation (V+ = 3 V, V– = 0 V), delivering rail-to-rail input and output swing, 50 µA/amplifier supply current, and 200 kHz gain bandwidth. All key parameters (CMRR, PSRR, VOS, GBW) are tested and guaranteed at 3 V per the Electrical Characteristics table.
LT1491CS#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- LT®
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- General Purpose
- Number of Circuits:
- 4
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.07V/µs
- Gain Bandwidth Product:
- 200 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 4 nA
- Voltage - Input Offset:
- 400 µV
- Current - Supply:
- 40µA (x4 Channels)
- Current - Output / Channel:
- 25 mA
- Voltage - Supply Span (Min):
- 2 V
- Voltage - Supply Span (Max):
- 44 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
LT1491CS#PBF FAQ
1.How can I place an order for LT1491CS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491CS#PBF 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 LT1491CS#PBF reliable?
The price and inventory of LT1491CS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491CS#PBF is usually 5 days.
3.What payment methods are accepted for LT1491CS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491CS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491CS#PBF?
LT1491CS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491CS#PBF 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 LT1491CS#PBF?
For technical support, including LT1491CS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491CS#PBF requirements.
6.How does Aetrix verify that LT1491CS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1491CS#PBF 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 LT1491CS#PBF meets industry standards.
7.What is the process for return or replacement of LT1491CS#PBF?
All LT1491CS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491CS#PBF, 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 LT1491CS#PBF part is unused and in its original packaging.
Return procedure for LT1491CS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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