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Analog Devices Inc. LT1491CN#PBF
- Part No.:
- LT1491CN#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-DIP (0.300", 7.62mm)
- Datasheet:
-
LT1491CN#PBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14DIP
- Quantity:
- Payment:
- Shipping:
Inventory:4,707
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Product details
Overview
LT1491CN#PBF from Analog Devices (formerly Linear Technology) is a quad micropower rail-to-rail input and output operational amplifier in a 14-lead PDIP package. It operates from total supply voltages of 2V to 44V, draws only 50µA per amplifier, delivers ±20mA output current, supports rail-to-rail input common-mode range up to 44V beyond V–, and maintains no phase reversal across its full input range - enabling precision signal conditioning in battery-powered sensor monitoring systems.
For engineers reviewing the LT1491CN#PBF datasheet, LT1491CN#PBF pinout, LT1491CN#PBF application, or LT1491CN#PBF equivalent, this page provides verified pin functions, confirmed rail-to-rail I/O behavior, validated 200kHz gain-bandwidth product, documented reverse-battery protection to 18V, and real-world use cases in 4–20mA transmitters and supply current sensing circuits.
Technical Context
The LT1491CN#PBF employs a dual-input-stage architecture (NPN and PNP) that enables operation with inputs extending 44V above V– and 0.3V above V+, while maintaining high-impedance behavior across its full common-mode range. Its unique input stage eliminates phase reversal for inputs 22V below V– or 44V above V–, independent of V+ level.
This quad op amp features internal compensation for stable unity-gain operation and drives capacitive loads up to 10,000pF using optional external 0.22µF/150Ω compensation. It achieves 98dB CMRR and 1500V/mV large-signal voltage gain at 3V/5V supplies, with guaranteed performance over –40°C to 85°C for industrial-grade operation.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 44V total supply - supports single-supply 3V/5V and split-supply ±15V operation without sequencing constraints |
| Quiescent Current | 50µA per amplifier max - enables multi-year battery life in portable instrumentation and remote sensors |
| Input Common-Mode Range | –0.4V to 44V relative to V– - accepts signals beyond rails, including 44V differential and common-mode inputs on 3V supply |
| Output Drive Capability | ±20mA output current - directly interfaces with 10kΩ loads and 4–20mA transmitter circuits without external buffers |
| Gain Bandwidth Product | 200kHz - sufficient for DC-coupled sensor amplification, active filtering, and low-speed control loops |
| CMRR | 98dB - rejects power supply noise and ground bounce in noisy industrial environments |
| Reverse Supply Protection | 18V - prevents damage during battery insertion errors or polarity reversal in field-deployed equipment |
Pinout & Package
LT1491CN#PBF is housed in a 14-lead plastic DIP (PDIP) package, designated N package per Linear Technology documentation. Pin spacing is 0.300", body width 0.325", and lead count matches standard quad op amp layout.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 | OUT A | Amplifier A output - rail-to-rail swing, capable of sourcing/sinking 20mA into resistive or compensated capacitive loads |
| 2 | –IN A | Inverting input A - high-impedance node supporting 44V common-mode range and no phase reversal |
| 3 | +IN A | Non-inverting input A - same voltage range and protection as –IN A; used for precision reference buffering |
| 4 | V+ | Positive supply rail - bypass with 0.01µF capacitor within 1 inch; reverse-battery protected up to 18V |
| 5 | +IN B | Non-inverting input B - electrically identical to +IN A; enables independent channel configuration |
| 6 | –IN B | Inverting input B - matched offset and bias characteristics to other inputs; supports differential sensing |
| 7 | OUT B | Amplifier B output - fully independent channel; shares same drive strength and rail-to-rail capability as OUT A |
| 8 | OUT D | Amplifier D output - fourth channel output; identical AC/DC specs to OUT A/B/C |
| 9 | –IN D | Inverting input D - supports wide common-mode input; no clamping diodes to supply rails |
| 10 | +IN D | Non-inverting input D - usable across full –0.4V to 44V range; immune to phase reversal |
| 11 | V– | Negative supply rail - substrate diode requires current limiting if output forced below V– |
| 12 | +IN C | Non-inverting input C - third channel input; compatible with high-side current sense configurations |
| 13 | –IN C | Inverting input C - supports bidirectional current sensing when paired with external sense resistor |
| 14 | OUT C | Amplifier C output - completes quad functionality; drives 10,000pF with external compensation |
Key Features
| Feature | Design Value |
|---|---|
| Rail-to-rail input and output | Enables full dynamic range utilization on low-voltage 3V/5V supplies and simplifies level-shifting in mixed-supply systems |
| No phase reversal over full input range | Eliminates output glitches during overvoltage transients or sensor saturation, critical for closed-loop stability |
| Reverse battery protection to 18V | Removes need for external series diodes or MOSFETs in portable/battery-backed designs, reducing BOM cost and voltage drop |
| Drives 10,000pF with optional compensation | Supports direct connection to long cables, LCD bias networks, or ADC input filters without added buffer stages |
| Specified on 3V, 5V and ±15V supplies | Guarantees parametric performance across common industrial, automotive, and legacy test equipment supply rails |
Applications
| Battery Monitoring | 4–20mA Transmitter |
|---|---|
Use Scenario: Real-time measurement of cell voltage and pack current in 12V lead-acid or Li-ion battery systems with microcontroller-based supervision. IC Role / Device Role / Timing Role: Quad amplifier configured as two differential amplifiers for voltage/current sensing and two comparators for charge/discharge state logic. Use Value: Rail-to-rail input captures full 0–14.4V cell range on 5V supply; 50µA quiescent current extends standby time between measurements. | Use Scenario: Converting sensor outputs (e.g., pressure, temperature) into standardized 4–20mA loop signals for industrial PLC interfaces. IC Role / Device Role / Timing Role: Precision current source amplifier with rail-to-rail output driving the loop transistor base; one channel used for VREF buffering. Use Value: 20mA output drive eliminates need for external transistor; reverse-battery protection avoids field-repair failures due to wiring errors. |
| Portable Instrumentation | Supply Current Sensing |
Use Scenario: Low-power handheld multimeter or environmental data logger requiring µA-level sleep current and accurate analog front-end gain. IC Role / Device Role / Timing Role: Signal conditioning for thermistor, RTD, or bridge sensor inputs; one channel used for auto-zero calibration. Use Value: 44V input range allows direct connection to unregulated battery rails; 98dB CMRR rejects switching regulator noise in compact PCB layouts. | Use Scenario: Measuring load current in embedded systems (e.g., motor drivers, LED arrays) where shunt voltage must be amplified without disturbing ground integrity. IC Role / Device Role / Timing Role: High-side current sense amplifier with matched input resistors; rail-to-rail output interfaces directly to ADC reference. Use Value: Input common-mode range includes V+ - enables true high-side sensing on 5V or 12V rails without level-shifting circuitry. |
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 |
|---|---|---|---|
| LT1491CS#PBF | Same electrical specs, but in 14-lead SOIC package - smaller footprint, higher thermal resistance (θJA = 150°C/W vs 110°C/W) | Preferred for space-constrained PCBs; less suitable for high-temperature ambient or high-power dissipation scenarios | Select LT1491CS#PBF when board area is limited and thermal management is assured via copper pour or airflow. |
| LT1491IN#PBF | Identical pinout and function, but specified over –40°C to 85°C with full QA testing - wider guaranteed temp range than LT1491CN#PBF (0°C to 70°C) | Required for automotive under-hood, outdoor industrial, or extended-temperature deployments | Choose LT1491IN#PBF for applications demanding guaranteed performance across full industrial temperature range. |
Compared with LT1491CS#PBF and LT1491IN#PBF, the LT1491CN#PBF offers lowest-cost through-hole assembly and best thermal dissipation in PDIP form, making it ideal for prototyping, low-volume industrial controls, and applications where manual soldering or socketing is preferred.
Availability
LT1491CN#PBF is available at Aetrix Electronics and suitable for battery monitoring, 4–20mA transmitters, and portable instrumentation requiring stable component supply with long-term industrial availability.
Supply support for LT1491CN#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 technical and manufacturing continuity for legacy Linear op amp families.
The LT1491CN#PBF belongs to Linear's micropower precision op amp product line, designed specifically for ultra-low-power signal conditioning in battery-operated and energy-harvesting systems where supply headroom and quiescent current are critical constraints.
FAQ
What is the maximum supply voltage for LT1491CN#PBF?
The LT1491CN#PBF supports a total supply voltage (V+ to V–) of up to 44V. This allows operation on single supplies such as 5V, 12V, or 24V, as well as split supplies like ±15V. Absolute maximum ratings specify 44V; exceeding this may cause permanent damage. The device also withstands reverse supply voltages up to 18V without drawing significant current.
Does LT1491CN#PBF support rail-to-rail input on a 3V supply?
Yes, the LT1491CN#PBF supports rail-to-rail input common-mode range down to –0.4V and up to 44V relative to V–, even when operating on a 3V single supply. This means both inputs can accept signals from ground (0V) to 3V (V+) and beyond - enabling direct interface with sensors or references that operate near supply rails without level shifting.
Can LT1491CN#PBF drive a 10,000pF capacitive load?
Yes, the LT1491CN#PBF can drive up to 10,000pF when externally compensated with a 0.22µF capacitor in series with a 150Ω resistor connected between output and ground. Without this network, the device is stable for ≤200pF. This capability supports direct driving of long cables, LCD bias networks, or ADC input filters without additional buffer stages.
What is the guaranteed operating temperature range for LT1491CN#PBF?
The LT1491CN#PBF is guaranteed to meet all specified electrical performance parameters over 0°C to 70°C (commercial temperature range). While characterized and expected to function from –40°C to 85°C, only the LT1491IN#PBF variant is fully tested and guaranteed across the extended industrial range.
Is LT1491CN#PBF pin-compatible with LT1491CS#PBF?
Yes, the LT1491CN#PBF and LT1491CS#PBF share identical pinout and electrical specifications - differing only in package type (PDIP vs SOIC). Both use the same 14-pin configuration with matching terminal assignments. No PCB redesign is required when migrating between these variants, though thermal and mechanical layout considerations differ.
LT1491CN#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:
- 0.07V/µs
- Gain Bandwidth Product:
- 200 kHz
- -3db Bandwidth:
- -
- Current - Input Bias:
- 4 nA
- Voltage - Input Offset:
- 350 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:
- Through Hole
- Supplier Device Package:
- 14-PDIP
LT1491CN#PBF FAQ
1.How can I place an order for LT1491CN#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491CN#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 LT1491CN#PBF reliable?
The price and inventory of LT1491CN#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491CN#PBF is usually 5 days.
3.What payment methods are accepted for LT1491CN#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491CN#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491CN#PBF?
LT1491CN#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491CN#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 LT1491CN#PBF?
For technical support, including LT1491CN#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491CN#PBF requirements.
6.How does Aetrix verify that LT1491CN#PBF is sourced from the original manufacturer or authorized distributors?
All LT1491CN#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 LT1491CN#PBF meets industry standards.
7.What is the process for return or replacement of LT1491CN#PBF?
All LT1491CN#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491CN#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 LT1491CN#PBF part is unused and in its original packaging.
Return procedure for LT1491CN#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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