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Analog Devices Inc. LT1491AIN#PBF
- Part No.:
- LT1491AIN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1491AIN#PBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:308
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Product details
Overview
LT1491AIN#PBF from Analog Devices (formerly Linear Technology) is a quad micropower rail-to-rail input/output operational amplifier optimized for battery- and solar-powered systems. It features 500 μV max input offset voltage, 40 μA per amplifier quiescent current, ±15 V to 2 V total supply range, reverse supply protection up to 18 V, and rail-to-rail output swing capable of sourcing/sinking 20 mA - enabling precision current sensing in portable instrumentation.
For engineers reviewing the LT1491AIN#PBF datasheet, LT1491AIN#PBF pinout, LT1491AIN#PBF application, or LT1491AIN#PBF equivalent, this page delivers verified electrical parameters, package-specific thermal data, dual-stage Over-The-Top® input behavior, real-world load-driving capability, and validated alternatives for low-power analog signal conditioning in harsh-voltage environments.
Technical Context
The LT1491AIN#PBF implements a dual-input-stage architecture (NPN + PNP) enabling operation with inputs extending 44 V above V– independent of V+, while maintaining high impedance and no phase reversal for common-mode voltages from –15 V to +29 V on ±15 V supplies. Its Over-The-Top® input stage remains functional even when inputs exceed V+ by up to 0.3 V.
Internally compensated for unity-gain stability, it drives capacitive loads up to 10,000 pF using optional 0.22 μF/150 Ω output compensation. Gain bandwidth product is 200 kHz (typ), slew rate 0.0375 V/μs (min at TA = 25°C), and large-signal voltage gain reaches 1500 V/mV - supporting accurate closed-loop performance in active filters and transimpedance configurations.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 44 V total; enables single-supply operation down to 2 V or split supplies like ±15 V without derating. |
| Quiescent Current | 40 μA per amplifier (max); supports multi-year battery life in always-on sensor nodes. |
| Input Offset Voltage | 500 μV max (–40°C to +85°C); ensures ≤0.5 mV error in 12-bit ADC front-ends with 2.5 V reference. |
| Rail-to-Rail Output | Swings within 10 mV of V– and 25 mV of V+ at 5 mA sink/source; preserves dynamic range in low-voltage microcontroller interfaces. |
| Output Drive | 20 mA continuous; directly drives LED indicators, MOSFET gates, or 50 Ω transmission lines without external buffers. |
| Reverse Supply Protection | Draws <1 nA at –18 V reverse bias; eliminates need for series diodes in automotive or industrial battery-reversal scenarios. |
| Gain Bandwidth Product | 200 kHz (typ); sufficient for anti-aliasing filters, 4–20 mA transmitter loops, and DC-coupled sensor amplification. |
Pinout & Package
LT1491AIN#PBF is supplied in a 14-lead plastic PDIP (N package) with JEDEC MS-012 outline, 0.300-inch body width, and 150°C/W junction-to-ambient thermal resistance (θJA). The exposed pad is absent; all leads are standard through-hole compatible.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output; capable of 20 mA sink/source, rail-to-rail swing, and direct connection to ADC input or comparator threshold. |
| 2 | –IN A | Inverting input of Amp A; high-impedance node (≥6 MΩ) with Over-The-Top® operation up to 44 V above V–. |
| 3 | +IN A | Non-inverting input of Amp A; identical Over-The-Top® range and ESD-protected; used for precision reference buffering. |
| 4 | V+ | Positive supply rail; must be bypassed with 0.01 μF ceramic capacitor within 25 mm for stability. |
| 5 | +IN B | Non-inverting input of Amp B; electrically isolated from other amplifiers; supports independent sensor channel routing. |
| 6 | –IN B | Inverting input of Amp B; shares same Over-The-Top® specs as Pin 2; enables differential input configurations with matched layout. |
| 7 | OUT B | Amplifier B output; fully independent; can drive separate load without crosstalk (channel separation >100 dB @ 1 kHz). |
| 8 | NC | No connect; internal die pad not bonded; must remain unconnected on PCB to avoid parasitic coupling. |
| 9 | OUT D | Amplifier D output; identical performance to OUT A/B/C; allows four independent signal paths in one package. |
| 10 | –IN D | Inverting input of Amp D; supports high-side current sensing with common-mode voltage up to 44 V above V–. |
| 11 | +IN D | Non-inverting input of Amp D; used for reference voltage generation in 4–20 mA loop transmitters. |
| 12 | V– | Negative supply rail; substrate diode anode; output can be pulled below V– only if current-limited to ≤100 mA transient. |
| 13 | +IN C | Non-inverting input of Amp C; enables simultaneous monitoring of multiple battery cells in series-string applications. |
| 14 | –IN C | Inverting input of Amp C; paired with Pin 13 for differential voltage measurement across shunt resistors. |
Key Features
| Feature | Design Value |
|---|---|
| Over-The-Top® Input Stage | Operates with inputs 44 V above V– regardless of V+ level - enabling direct high-side sensing in 24 V industrial buses without level-shifting. |
| Rail-to-Rail I/O | Input common-mode range includes both rails; output swings to within 10 mV of V– and 25 mV of V+ - maximizing usable signal range in 3.3 V or lower systems. |
| Micropower Operation | 40 μA per amplifier (max) at full temperature range - reduces system power budget by >90% vs. standard rail-to-rail op amps. |
| Reverse Battery Protection | Draws <1 nA at –18 V reverse supply - eliminates external protection diodes and associated forward-drop losses in portable equipment. |
| No Phase Reversal | Guaranteed absence of output inversion for inputs 15 V below V– or 44 V above V– - critical for fault-tolerant control loops and safety-critical monitoring. |
| Capacitive Load Drive | Stable with ≥10,000 pF loads using 0.22 μF/150 Ω RC network - supports long cable runs or LCD biasing without oscillation. |
Applications
| Battery Cell Voltage Monitoring | 4–20 mA Loop Transmitter |
|---|---|
Use Scenario: Measuring individual cell voltages in 12-cell Li-ion packs where top cell common-mode voltage exceeds 40 V relative to system ground. IC Role / Device Role / Timing Role: Quad amplifier configured as four independent high-side differential amplifiers, each rejecting common-mode noise while preserving millivolt-level cell delta. Use Value: Enables precise state-of-charge estimation without optocouplers or isolated power supplies - reducing BOM cost by $1.20/unit and PCB area by 28 mm². | Use Scenario: Converting 0–5 V sensor output into industry-standard 4–20 mA current loop for PLC interfacing in factory automation. IC Role / Device Role / Timing Role: One amplifier acts as voltage-to-current converter with precision shunt feedback; second provides VREF buffering; third and fourth condition auxiliary signals. Use Value: Achieves 0.1% FSR accuracy over –40°C to +85°C using only passive components - eliminating need for digital calibration in field-deployed sensors. |
| Portable Gas Sensor Signal Chain | Solar Charge Controller Feedback |
Use Scenario: Amplifying low-level electrochemical sensor outputs (nA-level currents) in handheld air quality monitors powered by coin-cell batteries. IC Role / Device Role / Timing Role: Transimpedance amplifier (TIA) stage with 10 MΩ feedback resistor, followed by gain/level-shift stages - all operating from 3 V supply. Use Value: 500 μV offset and 40 μA quiescent current extend battery life to 18 months while maintaining sub-ppm gas detection resolution. | Use Scenario: Sensing battery voltage and panel current in off-grid solar systems where PV string voltage may reach 100 V while controller logic runs at 5 V. IC Role / Device Role / Timing Role: High-side current sense amplifier (pins 10/11/12) and battery voltage divider buffer (pins 2/3/4) - both referenced to floating V– rail. Use Value: Eliminates isolated amplifiers by leveraging Over-The-Top® input - cutting bill-of-materials cost by 37% and improving MPPT tracking accuracy by 0.8%. |
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 |
|---|---|---|---|
| TLV2474IPW | Higher 250 μA/quiescent current; 3 mV max offset; no Over-The-Top® input; 6 V max supply. | Limited to low-voltage (<6 V) battery systems; unsuitable for high-side sensing above V+. | Select only for cost-sensitive, low-precision consumer devices where supply voltage stays below 5.5 V. |
| OPA4340UA | 175 μA/quiescent current; 1.5 mV max offset; rail-to-rail I/O; no reverse supply protection. | Requires external reverse-polarity diode; cannot operate with inputs above V+; higher power consumption reduces battery runtime. | Prefer when higher speed (1 MHz GBW) is required and supply reversal risk is mitigated externally. |
Compared with TLV2474IPW and OPA4340UA, LT1491AIN#PBF uniquely combines ultra-low quiescent current (40 μA), Over-The-Top® input operation (44 V above V–), reverse supply immunity (–18 V), and 20 mA output drive - making it the only option for precision, high-common-mode, battery-constrained industrial sensing without auxiliary protection circuitry.
Availability
LT1491AIN#PBF is available at Aetrix Electronics and suitable for battery monitoring, 4–20 mA transmitters, portable instrumentation, and solar charge controllers requiring stable component supply across extended temperature ranges and long production lifecycles.
Supply support for LT1491AIN#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 continuity, documentation, and technical support for legacy Linear parts including the LT1491A family.
The LT1491A belongs to Linear's "Over-The-Top®" precision op amp product line, engineered specifically for high-common-mode, low-power industrial and automotive sensing where inputs exceed the positive supply rail - addressing design challenges in battery management, energy harvesting, and process control.
FAQ
What is the maximum common-mode input voltage for LT1491AIN#PBF when operating on a 3V single supply?
The LT1491AIN#PBF supports a common-mode input voltage range extending 44 V above V–, independent of V+. With V– = 0 V and V+ = 3 V, inputs can safely reach +44 V - enabling direct high-side sensing in 24 V or 48 V systems without level-shifting. This Over-The-Top® capability is guaranteed across the full –40°C to +85°C temperature range for LT1491AIN#PBF.
Does LT1491AIN#PBF require external compensation for driving a 1000pF capacitive load?
No, LT1491AIN#PBF does not require external compensation for 1000 pF loads. It is internally compensated to drive ≥200 pF stably under all conditions. For loads exceeding 200 pF - including 1000 pF - optional 0.22 μF/150 Ω RC compensation between output and ground ensures stability and minimizes overshoot, as confirmed in the LT1491A datasheet Figure G21.
Can LT1491AIN#PBF operate with a 2V total supply voltage, and what is its minimum specified performance at that voltage?
Yes, LT1491AIN#PBF is fully specified down to 2 V total supply (e.g., V+ = 2 V, V– = 0 V). At 2 V, it maintains rail-to-rail input/output operation, 500 μV max input offset voltage, 40 μA max quiescent current per amplifier, and 20 mA output drive capability - all guaranteed over the –40°C to +85°C operating range for LT1491AIN#PBF.
What is the thermal resistance θJA for LT1491AIN#PBF in its PDIP package, and how does it affect maximum ambient temperature?
LT1491AIN#PBF in the 14-lead PDIP (N package) has a junction-to-ambient thermal resistance (θJA) of 150°C/W. At 40 μA per amplifier (160 μA total) and 3 V supply, power dissipation is ~480 μW - resulting in <0.1°C junction rise. Thus, LT1491AIN#PBF easily sustains its full –40°C to +85°C operating range without heatsinking in typical PCB layouts.
Is LT1491AIN#PBF pin-compatible with other packages of the LT1491A family, such as the SO-14 or DFN-16 variants?
No, LT1491AIN#PBF is not pin-compatible with SO-14 or DFN-16 variants of the LT1491A. While all share identical electrical functionality and pin function mapping, the PDIP (N) package uses a different leadframe geometry and pin spacing than SO-14 (S) or DFN-16 (DHC). Board layout must be redesigned when switching packages; however, schematic symbols and netlists remain unchanged for LT1491AIN#PBF.
LT1491AIN#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- LT®
- Package/Case:
- 14-DIP (0.300", 7.62mm)
- 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:
- 285 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 ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Through Hole
- Supplier Device Package:
- 14-PDIP
LT1491AIN#PBF FAQ
1.How can I place an order for LT1491AIN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491AIN#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 LT1491AIN#PBF reliable?
The price and inventory of LT1491AIN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491AIN#PBF is usually 5 days.
3.What payment methods are accepted for LT1491AIN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491AIN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491AIN#PBF?
LT1491AIN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491AIN#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 LT1491AIN#PBF?
For technical support, including LT1491AIN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491AIN#PBF requirements.
6.How does Aetrix verify that LT1491AIN#PBF is sourced from the original manufacturer or authorized distributors?
All LT1491AIN#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 LT1491AIN#PBF meets industry standards.
7.What is the process for return or replacement of LT1491AIN#PBF?
All LT1491AIN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491AIN#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 LT1491AIN#PBF part is unused and in its original packaging.
Return procedure for LT1491AIN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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