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Analog Devices Inc. LT1491IS#PBF
- Part No.:
- LT1491IS#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1491IS#PBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:189
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Product details
Overview
LT1491IS#PBF from Analog Devices (formerly Linear Technology) is a quad micropower rail-to-rail input and output operational amplifier optimized for single-supply battery-powered systems. It delivers 50 µA/amplifier quiescent current, ±20 mA output drive, 200 kHz gain bandwidth product, and operates from 2 V to 44 V total supply voltage - enabling precision signal conditioning in 3 V, 5 V, or ±15 V configurations. It is used in battery monitoring, sensor interfaces, and 4 mA–20 mA transmitters where low power and wide input/output swing are critical.
For engineers reviewing the LT1491IS#PBF datasheet, LT1491IS#PBF pinout, LT1491IS#PBF application, or LT1491IS#PBF equivalent, key selection criteria include confirmed rail-to-rail I/O performance at 3 V/5 V, reverse battery protection to 18 V, no phase reversal over ±22 V input beyond rails, 98 dB CMRR, and verified 10,000 pF capacitive load drive capability with external compensation.
Technical Context
The LT1491IS#PBF employs a dual-input-stage architecture (NPN + PNP) enabling operation with inputs up to 44 V above V– and 0.3 V above V+, while maintaining high-impedance behavior across the full common-mode range. Its unique input stage eliminates phase reversal even when inputs exceed rails by 22 V below V– or 44 V above V–.
Internally compensated for unity-gain stability, it drives ≥200 pF capacitively without external components; optional 0.22 µF + 150 Ω network extends stable operation to 10,000 pF. Output stage delivers ±20 mA into resistive loads and sustains rail-to-rail swing under 10 mA sourcing/sinking at 5 V supply.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2 V to 44 V total - supports single-supply 3 V/5 V and split ±15 V operation without level-shifting. |
| Quiescent Current | 50 µA per amplifier max - enables multi-year battery life in portable instrumentation and remote sensors. |
| Input Common-Mode Range | –0.4 V to 44 V - includes both supply rails and allows direct sensing of battery voltages up to 12 V on 3 V systems. |
| Output Swing | Rail-to-rail - delivers 0.022 V to 4.978 V at 5 V supply (no load), enabling full dynamic range utilization in ADC front-ends. |
| Gain Bandwidth Product | 200 kHz - sufficient for anti-aliasing filters, active RC filters, and slow-loop control in industrial monitoring. |
| CMRR | 98 dB - rejects supply noise and common-mode interference in noisy environments like motor drives or PLCs. |
| Reverse Battery Protection | 18 V - prevents damage during incorrect battery insertion in automotive or field-deployed equipment. |
Pinout & Package
LT1491IS#PBF is housed in a 14-lead plastic SO (Small Outline) package with standard JEDEC MS-012AC footprint (5.0 mm × 10.2 mm, 1.27 mm pitch). Thermal resistance θJA = 150 °C/W.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output - rail-to-rail capable, drives 20 mA, supports 10,000 pF with compensation. |
| 2 | –IN A | Inverting input of Amp A - high-impedance dual-stage input, no phase reversal up to ±22 V beyond rails. |
| 3 | +IN A | Non-inverting input of Amp A - same robust input structure as –IN A; accepts 44 V differential/common-mode. |
| 4 | V+ | Positive supply rail - bypass with 0.01 µF ceramic capacitor within 25 mm; reverse-protected to 18 V. |
| 5 | +IN B | Non-inverting input of Amp B - electrically identical to +IN A; shares same input stage architecture. |
| 6 | –IN B | Inverting input of Amp B - matched bias and offset characteristics to other inputs; supports rail-to-rail CM range. |
| 7 | OUT B | Amplifier B output - fully independent, same drive strength and swing as OUT A. |
| 8 | OUT D | Amplifier D output - fourth channel; identical AC/DC specs to OUT A/B/C; enables 4-channel signal processing. |
| 9 | –IN D | Inverting input of Amp D - validated for 44 V common-mode and 44 V differential operation per datasheet. |
| 10 | +IN D | Non-inverting input of Amp D - symmetric design ensures matching across all four amplifiers. |
| 11 | V– | Negative supply rail - substrate diode limits output pull-down below V–; transient currents ≤100 mA tolerated. |
| 12 | +IN C | Non-inverting input of Amp C - part of quad configuration; enables simultaneous multi-sensor conditioning. |
| 13 | –IN C | Inverting input of Amp C - supports same fault-tolerant input operation as other channels. |
| 14 | OUT C | Amplifier C output - completes quad set; usable for feedback loops, reference buffering, or parallel gain stages. |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables full-scale signal acquisition and drive in single-supply systems (e.g., 3 V microcontroller ADCs). |
| No phase reversal | Guarantees monotonic output response even when inputs exceed supply rails - critical for overvoltage-safe sensor interfaces. |
| Reverse battery protection | Draws <1 nA at –18 V supply - eliminates need for external series diodes in battery-powered equipment. |
| Capacitive load drive (10,000 pF) | Stable operation with long cables or EMI filters via optional 0.22 µF + 150 Ω compensation network. |
| High voltage gain (1500 V/mV) | Supports precision low-level signal amplification (e.g., thermocouple or shunt-based current sensing) without external gain stages. |
Applications
| Battery Monitoring | Sensor Conditioning |
|---|---|
Use Scenario: Real-time measurement of 12 V lead-acid or Li-ion battery voltage and charge/discharge current in portable medical devices. IC Role / Device Role / Timing Role: Quad op amp configured as two differential amplifiers (for voltage/current sensing) plus two buffers (for ADC input drive and reference scaling). Use Value: Rail-to-rail I/O captures full battery range (0–12.6 V) on 3.3 V MCU supply; 50 µA/quiescent current extends runtime between charges. | Use Scenario: Signal conditioning for bridge-based pressure sensors in HVAC controllers, where ambient temperature varies from –40°C to 85°C. IC Role / Device Role / Timing Role: Instrumentation amplifier front-end (using two LT1491IS#PBF amps) with gain-setting resistors and offset trimming. Use Value: 98 dB CMRR rejects common-mode noise from shared power rails; guaranteed –40°C to 85°C operation ensures reliability across environmental extremes. |
| 4 mA–20 mA Transmitter | Portable Instrumentation |
Use Scenario: Loop-powered industrial transmitter converting temperature sensor output to standardized 4–20 mA current signal over 1 km cable runs. IC Role / Device Role / Timing Role: One amplifier as sensor interface, one as voltage-to-current converter (Howland/V-I), one as loop driver, one as diagnostic comparator. Use Value: 20 mA output drive directly sources loop current; 10,000 pF capacitive load tolerance accommodates cable capacitance without oscillation. | Use Scenario: Handheld multimeter or data logger acquiring DC voltage, current, and resistance with auto-ranging and low-power sleep modes. IC Role / Device Role / Timing Role: Quad configuration used for autoranging attenuators, precision references, ADC buffer, and display driver interface. Use Value: Micropower operation (200 µA total for all four amps) minimizes impact on battery life; rail-to-rail output ensures accurate DAC interfacing. |
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 |
|---|---|---|---|
| LT1491IS8#PBF | Same electrical specs; 14-lead SO package replaced with space-saving 14-lead PDIP (N package) - larger footprint, higher θJA (250 °C/W). | Preferred for through-hole prototyping or legacy board compatibility; not suitable for fine-pitch SMT assembly. | Select when manual soldering or socket-based testing is required; avoid for high-density PCBs. |
| LT1491AIS#PBF | Improved version: 500 µV max input offset voltage (vs. 1450 µV for LT1491IS#PBF), tighter drift spec, and enhanced PSRR. | Better suited for precision DC-coupled applications (e.g., strain gauge bridges) where offset error dominates accuracy budget. | Choose for new designs requiring higher DC accuracy; LT1491IS#PBF remains valid for cost-sensitive or legacy-replacement use cases. |
Compared with LT1491IS8#PBF, LT1491IS#PBF offers superior thermal performance and smaller PCB area; compared with LT1491AIS#PBF, it trades lower offset for broader availability and lower cost in established production programs.
Availability
LT1491IS#PBF is available at Aetrix Electronics and suitable for battery monitoring, sensor signal conditioning, and 4 mA–20 mA transmitter designs requiring stable component supply, long-term manufacturability, and guaranteed industrial temperature range (–40°C to 85°C) operation.
Supply support for LT1491IS#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, datasheets, and application engineering for legacy Linear parts including the LT1491IS#PBF.
The LT1491IS#PBF belongs to Linear's micropower precision op amp family, designed specifically for ultra-low-power, wide-supply, rail-to-rail signal conditioning in portable, industrial, and automotive subsystems.
FAQ
What is the maximum supply voltage for LT1491IS#PBF?
The LT1491IS#PBF supports a total supply voltage (V+ to V–) of up to 44 V. This allows operation on single supplies from 2 V to 44 V or split supplies such as ±15 V. Exceeding 44 V risks permanent damage, and rapid supply ramp rates (>1 µs rise time) above 30 V require series damping resistance to prevent oscillation.
Does LT1491IS#PBF support rail-to-rail input and output simultaneously?
Yes, the LT1491IS#PBF provides true rail-to-rail input and output operation. Its input common-mode range extends from –0.4 V to 44 V relative to V–, and its output swings within 22 mV of either rail at 5 V supply with no load. This enables full dynamic range utilization in single-supply systems without external level-shifting circuitry.
Can LT1491IS#PBF drive large capacitive loads without oscillation?
Yes - the LT1491IS#PBF is internally compensated for stability with ≥200 pF. For loads up to 10,000 pF (e.g., long cables or EMI filters), add an external 0.22 µF capacitor in series with a 150 Ω resistor from output to ground. This compensation network ensures unity-gain stability across all output current levels and temperatures.
What is the input offset voltage specification for LT1491IS#PBF?
The LT1491IS#PBF has a maximum input offset voltage of 1450 µV over the full –40°C to 85°C operating temperature range (guaranteed for I-grade parts). At 25°C, typical VOS is 350 µV, and the drift is 2–4 µV/°C. For applications demanding tighter DC accuracy, the pin-compatible LT1491AIS#PBF offers 500 µV max VOS.
Is LT1491IS#PBF protected against reverse battery connection?
Yes - the LT1491IS#PBF includes built-in reverse supply protection rated to –18 V. Under reverse-battery conditions, supply current drops below 100 nA per amplifier, preventing damage and eliminating the need for external blocking diodes in battery-powered equipment.
LT1491IS#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:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
LT1491IS#PBF FAQ
1.How can I place an order for LT1491IS#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491IS#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 LT1491IS#PBF reliable?
The price and inventory of LT1491IS#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491IS#PBF is usually 5 days.
3.What payment methods are accepted for LT1491IS#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491IS#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491IS#PBF?
LT1491IS#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491IS#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 LT1491IS#PBF?
For technical support, including LT1491IS#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491IS#PBF requirements.
6.How does Aetrix verify that LT1491IS#PBF is sourced from the original manufacturer or authorized distributors?
All LT1491IS#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 LT1491IS#PBF meets industry standards.
7.What is the process for return or replacement of LT1491IS#PBF?
All LT1491IS#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491IS#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 LT1491IS#PBF part is unused and in its original packaging.
Return procedure for LT1491IS#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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