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Analog Devices Inc. LT1491AHS#PBF
- Part No.:
- LT1491AHS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1491AHS#PBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:547
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Product details
Overview
LT1491AHS#PBF from Analog Devices (formerly Linear Technology) is a quad rail-to-rail input/output micropower operational amplifier with Over-The-Top® input stage enabling 44V common-mode range above V–, independent of V+. It delivers 20mA output drive, 500μV max input offset voltage (–40°C to 125°C), 200kHz gain bandwidth, and operates from 2.5V to 44V total supply. It is used in battery monitoring circuits where high-side sensing across wide voltage rails is required.
For engineers reviewing the LT1491AHS#PBF datasheet, LT1491AHS#PBF pinout, LT1491AHS#PBF application, or LT1491AHS#PBF equivalent, key selection criteria include guaranteed operation at –40°C to 125°C, reverse supply protection up to 18V, rail-to-rail I/O swing into 20mA loads, and Over-The-Top® input capability for single-supply high-voltage sensor interfacing without level-shifting.
Technical Context
The LT1491AHS#PBF integrates four independent amplifiers sharing a single dual-supply or single-supply configuration. Its unique dual-input-stage architecture (NPN + PNP) enables continuous high-impedance operation across the full 0.3V to 44V input common-mode range relative to V–, with no phase reversal even when inputs exceed V+ by 44V or drop 15V below V–.
Each amplifier features internal compensation for stability with capacitive loads up to 200pF; optional 0.22μF/150Ω external network extends stable driving capability to 10,000pF. The device draws only 40–70μA per amplifier at 125°C and remains functional with supply rise times ≥1μs on high-voltage rails (≥20V).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2.5V to 44V total - supports single-supply industrial battery stacks and dual-supply precision analog front-ends. |
| Input Offset Voltage (max) | 2500μV over –40°C to 125°C - ensures low-error DC gain accuracy in temperature-critical current sensing. |
| Output Drive Current | ±20mA - directly drives 50Ω loads or 10kΩ resistive dividers without external buffers in transmitter circuits. |
| Gain Bandwidth Product | 200kHz - sufficient for 5kHz sensor signal conditioning and active filter stages in portable instrumentation. |
| Common-Mode Input Range | 0.3V to 44V above V– - enables direct high-side current sensing in 24V/48V systems without external level shifters. |
| Reverse Supply Protection | 18V - prevents damage during battery polarity reversal in automotive or field-deployed equipment. |
| Quiescent Current per Amp | 40–70μA at 125°C - enables multi-channel always-on monitoring in energy-constrained solar-powered nodes. |
Pinout & Package
LT1491AHS#PBF is housed in a 14-lead plastic SO package (S package), 8.65mm × 3.90mm × 1.75mm, with exposed pad connected to V– for thermal and electrical integrity. Junction temperature rating is 150°C; θJA = 150°C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output - rail-to-rail swing capable of sourcing/sinking 20mA into heavy loads. |
| 2 | –IN A | Inverting input of Amp A - high-impedance node protected to ±15V beyond supplies; no phase reversal. |
| 3 | +IN A | Non-inverting input of Amp A - accepts common-mode voltages up to 44V above V–, independent of V+. |
| 4 | V+ | Positive supply rail - bypass with 0.01μF capacitor within 25mm; supports reverse-battery tolerant shutdown. |
| 5 | +IN B | Non-inverting input of Amp B - identical Over-The-Top® input specification as Pin 3. |
| 6 | –IN B | Inverting input of Amp B - matched bias and ESD protection to Pin 2. |
| 7 | OUT B | Amplifier B output - electrically isolated from other outputs; shares same drive strength and swing limits. |
| 8 | OUT D | Amplifier D output - fully independent channel; pin-compatible with all other outputs for layout reuse. |
| 9 | –IN D | Inverting input of Amp D - identical performance and protection as Pins 2 and 6. |
| 10 | +IN D | Non-inverting input of Amp D - supports same 44V-over-V– operation as Pins 3 and 5. |
| 11 | V– | Negative supply rail - underside metal pad is internally connected to this pin for low-inductance grounding. |
| 12 | +IN C | Non-inverting input of Amp C - matches input stage behavior and voltage range of other +IN pins. |
| 13 | –IN C | Inverting input of Amp C - symmetrical design ensures channel-to-channel matching within 10%. |
| 14 | OUT C | Amplifier C output - provides fourth independent output with identical rail-to-rail swing and load capability. |
Key Features
| Feature | Design Value |
|---|---|
| Over-The-Top® Input Stage | Enables 44V common-mode input range above V– regardless of V+, eliminating need for external level-shifting in high-side current sensing. |
| Rail-to-Rail Input and Output | Supports full dynamic range utilization in 3V–5V microcontroller-based systems without signal clipping or headroom loss. |
| Micropower Operation | 40–70μA per amplifier at 125°C allows four-channel continuous monitoring in battery-backed IoT edge nodes for >5 years. |
| No Phase Reversal | Guarantees stable closed-loop behavior when inputs go 15V below V– or 44V above V–, critical for fault-tolerant power system monitors. |
| Reverse Battery Protection | Draws <1nA under –18V reverse supply - preserves backup power and prevents latch-up in automotive accessory modules. |
| Capacitive Load Drive | Stable with up to 10,000pF using optional 0.22μF/150Ω compensation - supports long-line sensor interfaces and LCD biasing. |
Applications
| Battery Monitoring System | Industrial 4–20mA Transmitter |
|---|---|
|
Use Scenario: Real-time voltage and current measurement across 12V–48V lead-acid or LiFePO₄ battery banks in telecom backup systems. IC Role / Device Role / Timing Role: LT1491AHS#PBF acts as high-side current sense amplifier and differential voltage monitor, providing isolated analog signals to an ADC. Use Value: Over-The-Top® input eliminates external high-voltage op-amp or isolated amplifier, reducing BOM count and PCB area by 30%. |
Use Scenario: Converting process sensor outputs (e.g., pressure, temperature) into standardized 4–20mA loop signals for PLC interfaces. IC Role / Device Role / Timing Role: LT1491AHS#PBF serves as precision I/V converter and loop driver amplifier in two-wire transmitter designs. Use Value: 20mA output drive and rail-to-rail swing enable direct loop current control without external transistor stages, simplifying compliance with HART physical layer specs. |
| Portable Instrumentation Front-End | Micropower Active Filter |
|
Use Scenario: Signal conditioning for handheld multimeters or environmental sensors powered by coin-cell or AA batteries. IC Role / Device Role / Timing Role: LT1491AHS#PBF performs programmable-gain amplification, offset correction, and anti-alias filtering before SAR ADC sampling. Use Value: 40μA per amplifier quiescent current enables >100-hour runtime on two AA cells while maintaining 16-bit effective resolution. |
Use Scenario: Low-frequency noise suppression in vibration or acoustic monitoring nodes deployed in remote locations. IC Role / Device Role / Timing Role: LT1491AHS#PBF implements 2nd-order Sallen-Key low-pass topology with selectable cutoff (1Hz–100Hz). Use Value: Unity-gain stability and 200kHz GBW ensure accurate filter response shape without peaking, even with 1% tolerance passive components. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar quad micropower op amp applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| LT1491ACS#PBF | Same architecture but rated for 0°C to 70°C; lower max input offset (110μV typ) at room temp; higher PSRR (98dB). | Not qualified for extended temperature industrial or automotive under-hood use. | Select when operating ambient stays within commercial grade and cost sensitivity outweighs temperature margin. |
| AD8602ARZ-REEL7 | Lower input offset (60μV max), higher GBW (8MHz), but only 1.8V–5.5V supply range and no Over-The-Top® input capability. | Cannot replace LT1491AHS#PBF in high-voltage (>6V) single-supply sensing applications. | Choose for ultra-low-offset, low-noise signal chains in 3.3V embedded systems where rail voltage headroom is constrained. |
Compared with LT1491ACS#PBF, the LT1491AHS#PBF trades minor room-temperature offset degradation for guaranteed 125°C operation and robust high-voltage input tolerance; versus AD8602ARZ-REEL7, it sacrifices bandwidth and noise performance to achieve 44V Over-The-Top® operation and reverse-battery survival - making it irreplaceable in harsh-environment battery management.
Availability
LT1491AHS#PBF is available at Aetrix Electronics and suitable for battery monitoring systems, industrial 4–20mA transmitters, and portable instrumentation requiring stable component supply across extended temperature ranges and high-reliability field deployment.
Supply support for LT1491AHS#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 acquired Linear Technology in 2017 and maintains full product support, datasheet documentation, and long-term manufacturing commitment for legacy Linear parts including the LT1491A series.
The LT1491A belongs to Linear's Over-The-Top® op amp family, designed specifically for high-voltage, single-supply industrial sensing applications where conventional rail-to-rail amplifiers fail due to input voltage limitations.
FAQ
What is the maximum common-mode input voltage for LT1491AHS#PBF?
The LT1491AHS#PBF supports a common-mode input voltage range of 0.3V to 44V above V–, independent of the V+ supply voltage. This Over-The-Top® capability allows direct connection to high-side shunt resistors in 48V battery systems without attenuation or level-shifting networks, and is guaranteed over the full –40°C to 125°C operating range.
Does LT1491AHS#PBF require external compensation for driving capacitive loads?
LT1491AHS#PBF is internally compensated for stable operation with up to 200pF of capacitive load. For loads exceeding 200pF - such as long cables or LCD bias networks - a 0.22μF capacitor in series with a 150Ω resistor must be placed between the output and ground. This external network extends stable operation to 10,000pF, as verified in the datasheet's Typical Performance Characteristics.
Can LT1491AHS#PBF operate with a single 3.3V supply?
Yes, LT1491AHS#PBF operates down to a minimum total supply voltage of 2.5V, making it fully compatible with 3.3V single-supply systems. At 3.3V, it delivers rail-to-rail input and output swing, 20mA output drive, and maintains 500μV max input offset voltage across –40°C to 125°C - enabling precision analog functions in space-constrained portable devices.
What is the reverse supply protection rating of LT1491AHS#PBF?
LT1491AHS#PBF provides reverse supply protection up to 18V, drawing less than 1nA supply current under reverse-battery conditions. This feature protects downstream circuitry in automotive accessories, marine electronics, and field-serviceable equipment where accidental polarity reversal is a known risk - and is fully specified in the Absolute Maximum Ratings table.
How does the Over-The-Top® input stage affect input bias current in LT1491AHS#PBF?
The Over-The-Top® input stage uses dual NPN/PNP architectures that shift conduction based on input voltage relative to V+. When inputs are near V+, bias current rises to ~3μA; when below V+ by >0.8V, it drops to ~1nA. This behavior is documented in the Input Bias Current vs Common Mode Voltage curve and must be accounted for in high-impedance sensor interfaces - but does not cause phase reversal or instability.
LT1491AHS#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:
- 0.06V/µs
- Gain Bandwidth Product:
- 200 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 1 nA
- Voltage - Input Offset:
- 250 µV
- Current - Supply:
- 50µA (x4 Channels)
- Current - Output / Channel:
- 25 mA
- Voltage - Supply Span (Min):
- 2 V
- Voltage - Supply Span (Max):
- 44 V
- Operating Temperature:
- -40°C ~ 125°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
LT1491AHS#PBF FAQ
1.How can I place an order for LT1491AHS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491AHS#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 LT1491AHS#PBF reliable?
The price and inventory of LT1491AHS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491AHS#PBF is usually 5 days.
3.What payment methods are accepted for LT1491AHS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491AHS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491AHS#PBF?
LT1491AHS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491AHS#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 LT1491AHS#PBF?
For technical support, including LT1491AHS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491AHS#PBF requirements.
6.How does Aetrix verify that LT1491AHS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1491AHS#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 LT1491AHS#PBF meets industry standards.
7.What is the process for return or replacement of LT1491AHS#PBF?
All LT1491AHS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491AHS#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 LT1491AHS#PBF part is unused and in its original packaging.
Return procedure for LT1491AHS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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