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Analog Devices Inc. LT1491ACS#TRPBF
- Part No.:
- LT1491ACS#TRPBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 14-SOIC (0.154", 3.90mm Width)
- Datasheet:
-
LT1491ACS#TRPBF.pdf
- Description:
- IC OPAMP GP 4 CIRCUIT 14SO
- Quantity:
- Payment:
- Shipping:
Inventory:2,588
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Product details
Overview
LT1491ACS#TRPBF from Analog Devices (formerly Linear Technology) is a quad rail-to-rail input/output micropower operational amplifier with Over-The-Top® input stage architecture. It operates from 2V to 44V total supply, draws only 40μA per amplifier, supports input common-mode voltage up to 44V above V– independent of V+, and delivers ±20mA output drive. It is used in battery monitoring, supply current sensing, and sensor conditioning circuits where wide-voltage-range precision amplification is required.
For engineers reviewing the LT1491ACS#TRPBF datasheet, LT1491ACS#TRPBF pinout, LT1491ACS#TRPBF application, or LT1491ACS#TRPBF equivalent, this page provides verified pin configuration, real-world load-driving capability, reverse-battery protection behavior, Over-The-Top® input operation limits, and validated alternatives for space-constrained industrial and portable systems.
Technical Context
The LT1491ACS#TRPBF implements dual-input-stage architecture (NPN + PNP) enabling true Over-The-Top® operation: inputs remain functional and high-impedance even when biased 44V above V–, regardless of V+ level. Its internal Schottky-clamped NPN stage allows operation beyond V+ with controlled bias current and offset.
It features reverse supply protection (≤1nA current at –18V), no phase reversal for inputs 15V below V– or 44V above V–, unity-gain stability, and optional 0.22μF + 150Ω compensation for driving up to 10,000pF capacitive loads - critical for sensor interfaces and active filter designs.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Supply Voltage Range | 2V to 44V total - enables direct interface with 12V/24V/36V battery stacks and industrial rails without level-shifting. |
| Quiescent Current | 40μA per amplifier - supports multi-year operation in coin-cell–powered remote sensors and IoT endpoints. |
| Input Offset Voltage | 500μV max (–40°C to 85°C) - ensures ≤1mV error in 2V–5V single-supply measurement paths like shunt-based current sensing. |
| Output Drive | ±20mA - directly drives LEDs, MOSFET gates, or 50Ω transmission lines without external buffers. |
| Input Common-Mode Range | Extends 44V above V–, independent of V+ - permits high-side sensing in 48V automotive or telecom power systems. |
| Gain Bandwidth Product | 200kHz - sufficient for DC–10kHz signal conditioning in battery voltage monitoring and thermistor amplification. |
| CMRR | 98dB - rejects noise from shared ground returns in mixed-signal embedded systems. |
Pinout & Package
LT1491ACS#TRPBF is housed in a 14-lead plastic SO (S8) package, 5.0mm × 3.98mm × 1.48mm, with standard 1.27mm lead pitch and gull-wing leads. The exposed pad is not present; thermal dissipation relies on PCB copper area under the body.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| 1 (OUT A) | Amplifier A output | Rail-to-rail swing (to within 10mV of V– and 250mV of V+) at ±5mA load; stable into 10,000pF with external compensation. |
| 2 (–IN A) | Inverting input A | High-impedance node (≥4MΩ) accepting signals from 0V to 44V above V–; no phase reversal down to 15V below V–. |
| 3 (+IN A) | Non-inverting input A | Same Over-The-Top® range as Pin 2; differential input voltage rating is ±44V. |
| 4 (V+) | Positive supply | Accepts up to +44V relative to V–; reverse-battery protected to –18V; bypass with 0.01μF near pin. |
| 5 (+IN B) | Non-inverting input B | Independent channel; identical Over-The-Top® input specification as Pins 2 and 3. |
| 6 (–IN B) | Inverting input B | Matches Pin 2 performance; supports simultaneous high-side and low-side sensing in multi-channel monitors. |
| 7 (OUT B) | Amplifier B output | Electrically identical to Pin 1; enables dual independent gain stages in compact layout. |
| 8 (NC) | No connect | Not internally bonded; must be left floating or grounded per PCB design rules - no routing or stitching required. |
| 9 (OUT D) | Amplifier D output | Fourth rail-to-rail output; allows full-bridge sensor excitation or 4-wire RTD measurement without external op amps. |
| 10 (–IN D) | Inverting input D | Supports differential measurement of high-common-mode signals (e.g., motor phase currents) with matched CMRR. |
| 11 (+IN D) | Non-inverting input D | Paired with Pin 10; enables true differential input stage referenced to V– in single-supply configurations. |
| 12 (V–) | Negative supply | Reference for all inputs and outputs; underside metal (in DFN variants) connects here - not applicable to SO package. |
| 13 (+IN C) | Non-inverting input C | Third channel input; usable for reference buffering or auxiliary signal path in multi-function analog front-ends. |
| 14 (–IN C) | Inverting input C | Complements Pin 13; supports cascaded gain stages or active filtering with minimal board area. |
| 15 (OUT C) | Amplifier C output | Final output channel; enables four independent transimpedance or instrumentation amplifier sections on one IC. |
| 16 (NC) | No connect | Unused pin in SO package; no internal connection - leave unconnected per Linear Technology S8 footprint. |
Key Features
| Feature | Design Value |
|---|---|
| Over-The-Top® Input Stage | Enables high-side sensing at 44V above V– on 3V or 5V supplies - eliminates need for level translators in battery stack monitoring. |
| Rail-to-Rail Input and Output | Full dynamic range utilization: input accepts V– to V+, output swings to within 10mV of V– and 250mV of V+ at 5mA - maximizes SNR in low-voltage systems. |
| Reverse Battery Protection | Draws <1nA at –18V supply reversal - prevents system damage and preserves backup power during field maintenance or miswiring. |
| 20mA Output Drive | Directly sources/sinks 20mA without external transistors - simplifies LED driver, relay driver, or DAC output buffer designs. |
| 10,000pF Capacitive Load Drive | Stable with 0.22μF + 150Ω RC network - supports long cable runs, piezoelectric sensors, or LCD biasing without oscillation. |
| Low Input Bias Current Drift | 2pA/°C max - maintains accuracy over temperature in high-impedance pH or ion-selective electrode interfaces. |
Applications
| Battery Stack Monitoring | 4–20mA Transmitter |
|---|---|
|
Use Scenario: Monitoring individual cell voltages in 12V–48V Li-ion or lead-acid battery packs using high-side sensing across series-connected cells. IC Role / Device Role / Timing Role: LT1491ACS#TRPBF acts as a precision differential amplifier for each cell, rejecting common-mode voltage up to 44V above ground while maintaining rail-to-rail output swing. Use Value: Eliminates isolation amplifiers or discrete level-shifters; reduces BOM count by 3× per monitored cell versus conventional op amps. |
Use Scenario: Converting sensor output (e.g., pressure, temperature) into industry-standard 4–20mA loop current for PLC interfacing. IC Role / Device Role / Timing Role: LT1491ACS#TRPBF serves as the current-output amplifier in a Howland or improved Howland configuration, sourcing precise loop current with high PSRR. Use Value: Achieves ±0.1% full-scale accuracy over –40°C to 85°C using only one quad op amp and passive components - no trimming required. |
| Portable Instrumentation Front-End | Supply Current Sensing |
|
Use Scenario: Signal conditioning for handheld multimeters or portable gas analyzers requiring ultra-low power and wide input range. IC Role / Device Role / Timing Role: LT1491ACS#TRPBF provides programmable-gain amplification, offset correction, and anti-alias filtering in a single 14-pin SO package. Use Value: Enables 100-hour battery life on two AA cells while supporting ±10V input ranges via Over-The-Top® architecture. |
Use Scenario: Measuring load current in 5V–24V embedded systems using low-value shunt resistors (e.g., 10mΩ–100mΩ). IC Role / Device Role / Timing Role: LT1491ACS#TRPBF functions as a high-CMRR difference amplifier, rejecting common-mode noise from shared power rails. Use Value: Delivers 0.5% gain error and <1μV/°C offset drift - sufficient for Class 0.5 energy metering without calibration. |
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 |
|---|---|---|---|
| TLV2464IDR | Lower supply voltage (2.7V–6V), 600μV VOS max, 500kHz GBW, no Over-The-Top® input - limited to low-voltage systems. | Only suitable for 3.3V/5V battery-powered devices; cannot replace LT1491ACS#TRPBF in 12V+ or high-side sensing roles. | Select when operating strictly below 6V and needing higher bandwidth; avoid for >6V rails or >V+ input requirements. |
| OPA2333PWR | Zero-drift architecture, 2μV VOS max, 350kHz GBW, rail-to-rail I/O, but max supply 5.5V and no Over-The-Top® - no high-voltage input support. | Superior DC precision for sensor bridges or medical electrodes, but incompatible with battery stack monitoring or industrial 24V systems. | Choose for ultra-low-offset, low-frequency (<10kHz) applications below 5.5V; reject for any use case requiring >5.5V or 44V-over-V– operation. |
Compared with TLV2464IDR and OPA2333PWR, the LT1491ACS#TRPBF uniquely combines 44V-over-V– input capability, 44V total supply tolerance, and micropower operation - making it irreplaceable in high-voltage portable and industrial monitoring where input range and supply flexibility are non-negotiable.
Availability
LT1491ACS#TRPBF is available at Aetrix Electronics and suitable for battery monitoring, 4–20mA transmitter design, and portable instrumentation requiring stable component supply across extended temperature and voltage ranges.
Supply support for LT1491ACS#TRPBF 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 family.
The LT1491A product line was designed specifically for precision analog signal conditioning in harsh, wide-supply environments - targeting battery management, industrial process control, and portable test equipment where input range, power efficiency, and reliability are critical.
FAQ
What is the maximum input common-mode voltage for LT1491ACS#TRPBF?
The LT1491ACS#TRPBF supports an input common-mode voltage up to 44V above V–, independent of the V+ supply level - confirmed in the Absolute Maximum Ratings and Applications Information sections of the official datasheet. This Over-The-Top® capability allows direct high-side sensing in 48V systems even when powered from a 3V or 5V local rail. The LT1491ACS#TRPBF maintains functionality and high impedance across this full range without phase reversal.
Can LT1491ACS#TRPBF drive a 10,000pF capacitive load?
Yes, the LT1491ACS#TRPBF can drive up to 10,000pF when externally compensated with a 0.22μF capacitor in series with a 150Ω resistor connected from output to ground - as specified in the Features and Applications Information sections. This configuration ensures stability across all output current levels and supply voltages. Without this network, the LT1491ACS#TRPBF is guaranteed stable only for loads ≤200pF.
Does LT1491ACS#TRPBF have reverse supply protection?
Yes, the LT1491ACS#TRPBF provides reverse supply protection up to –18V, drawing less than 1nA of current under reverse-battery conditions - explicitly stated in the Features and Applications Information. This protects downstream circuitry during field installation errors or battery replacement in automotive and industrial equipment. The LT1491ACS#TRPBF remains undamaged and resumes normal operation once correct polarity is restored.
What is the quiescent current per amplifier in LT1491ACS#TRPBF?
The LT1491ACS#TRPBF draws 40μA per amplifier under typical operating conditions (TA = 25°C, VS = 3V or 5V), with a maximum of 55μA over the full –40°C to 85°C temperature range - per the Electrical Characteristics table. This micropower consumption enables multi-year operation in battery-backed systems. The LT1491ACS#TRPBF maintains this low IS across its entire 2V–44V supply range, with no increase at higher voltages.
Is LT1491ACS#TRPBF pin-compatible with other packages in the LT1491A family?
No - the LT1491ACS#TRPBF uses the 14-lead SO (S8) package with standard pinout, while LT1491ACN#TRPBF uses PDIP and LT1491ACDHC#TRPBF uses a 16-lead DFN. Although all share identical electrical pin functions, the DFN variant has two NC pins (8 and 16) not present in the SO version, and the PDIP has different mechanical spacing. The LT1491ACS#TRPBF footprint is not interchangeable with either without PCB redesign.
LT1491ACS#TRPBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- LT®
- Package/Case:
- 14-SOIC (0.154", 3.90mm Width)
- Packaging:
- Tape & Reel (TR)
- 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:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 14-SO
LT1491ACS#TRPBF FAQ
1.How can I place an order for LT1491ACS#TRPBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1491ACS#TRPBF 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 LT1491ACS#TRPBF reliable?
The price and inventory of LT1491ACS#TRPBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1491ACS#TRPBF is usually 5 days.
3.What payment methods are accepted for LT1491ACS#TRPBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1491ACS#TRPBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1491ACS#TRPBF?
LT1491ACS#TRPBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1491ACS#TRPBF 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 LT1491ACS#TRPBF?
For technical support, including LT1491ACS#TRPBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1491ACS#TRPBF requirements.
6.How does Aetrix verify that LT1491ACS#TRPBF is sourced from the original manufacturer or authorized distributors?
All LT1491ACS#TRPBF 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 LT1491ACS#TRPBF meets industry standards.
7.What is the process for return or replacement of LT1491ACS#TRPBF?
All LT1491ACS#TRPBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1491ACS#TRPBF, 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 LT1491ACS#TRPBF part is unused and in its original packaging.
Return procedure for LT1491ACS#TRPBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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