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Analog Devices Inc. LT1991IDD#PBF
- Part No.:
- LT1991IDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT1991IDD#PBF.pdf
- Description:
- IC OPAMP PGA 1 CIRCUIT 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:3,859
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Product details
Overview
LT1991IDD#PBF from Analog Devices (formerly Linear Technology) is a precision, gain-selectable difference amplifier IC integrating eight matched thin-film resistors and a low-offset op amp in a single 10-lead DFN package. It delivers ±0.08% gain error at G = 1, 560kHz gain bandwidth product, rail-to-rail output swing within 40mV of either rail, and operates from 2.7V to 36V supply with only 100µA quiescent current. It is used in medical instrumentation for high-CMRR strain gauge signal conditioning.
For engineers reviewing the LT1991IDD#PBF datasheet, LT1991IDD#PBF pinout, LT1991IDD#PBF application, or LT1991IDD#PBF equivalent, key selection criteria include guaranteed –40°C to +85°C operation, 75dB CMRR at G = 1, input offset voltage ≤150µV, resistor matching ≤0.04%, and configurable gain ranges from –13 to +14 without external components.
Technical Context
The LT1991IDD#PBF implements a fully integrated difference amplifier architecture where internal 450kΩ, 150kΩ, and 50kΩ SiChrome resistors enable precise gain settings (G = ±1, ±3, ±9, ±13) via pin-strapping. Its op amp core features 50µV max input offset voltage and 0.3µV/°C drift, referenced to the internal amplifier node.
Resistor matching is guaranteed at 0.04% over temperature for 450kΩ elements, yielding ≥75dB common-mode rejection ratio (CMRR) at G = 1 and <10ppm gain nonlinearity. The device supports differential-to-single-ended conversion with VREF pin biasing and maintains stability into 100pF capacitive loads at noise gains <2.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Error | ±0.08% at G = 1 ensures accurate scaling in precision sensor interfaces without calibration. |
| CMRR | ≥75dB at G = 1 enables reliable rejection of EMI and power-supply noise in noisy industrial environments. |
| Supply Current | 100µA at 5V enables battery-powered handheld instrumentation with multi-year runtime. |
| Output Swing | Within 40mV of rails at no load maximizes dynamic range in low-voltage 3.3V or 5V systems. |
| Input Offset Voltage | ≤150µV over –40°C to +85°C guarantees stable DC accuracy in medical-grade analog front-ends. |
| Gain Bandwidth | 560kHz GBWP supports fast settling (42µs to 0.01%) for multiplexed sensor data acquisition. |
| Operating Temp | –40°C to +85°C rated performance meets industrial and automotive under-hood requirements. |
Pinout & Package
LT1991IDD#PBF uses a 10-lead (3mm × 3mm) plastic DFN package with exposed pad connected to VEE. Pin 1 is P1 (noninverting gain-of-1 input), Pin 10 is M1 (inverting gain-of-1 input), and Pin 5 is REF (reference input). All pins are surface-mount compatible with standard reflow profiles.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| P1 (Pin 1) | Noninverting Gain-of-1 Input | Connects internal 450kΩ resistor to op amp noninverting input; enables unity-gain difference amplification. |
| M1 (Pin 10) | Inverting Gain-of-1 Input | Connects internal 450kΩ resistor to op amp inverting input; forms matched pair with P1 for CMRR optimization. |
| P3 (Pin 2), M3 (Pin 9) | Noninverting/Inverting Gain-of-3 Inputs | 150kΩ resistors allow configurable G = ±3; used in medium-gain differential sensing. |
| P9 (Pin 3), M9 (Pin 8) | Noninverting/Inverting Gain-of-9 Inputs | 50kΩ resistors support high-gain configurations (G = ±9, ±13); suitable for low-level transducer outputs. |
| REF (Pin 5) | Reference Input | Sets output DC level when differential input is zero; connects to internal 450kΩ resistor and op amp noninverting input. |
| VCC (Pin 7), VEE (Pin 4) | Positive/Negative Supply | Supports single (2.7V–36V) or split supplies; VEE may be ground or negative rail. |
| OUT (Pin 6) | Amplifier Output | Rail-to-rail output stage drives 10kΩ loads; settles to 0.01% in 42µs at G = 1. |
Key Features
| Feature | Design Value |
|---|---|
| Pin-configurable gain | Supports difference, inverting, and noninverting topologies (G = –13 to +14) using only internal resistors-no external components required. |
| Matched resistor network | 0.04% matching on 450kΩ resistors ensures ≥75dB CMRR and eliminates need for manual trimming in production. |
| Rail-to-rail output | Swings to within 40mV of VCC or VEE at no load, preserving full-scale resolution in low-voltage ADC interfacing. |
| Micropower operation | 100µA supply current at 5V enables integration into portable diagnostic devices with strict power budgets. |
| Wide supply range | Operates from 2.7V single supply to ±18V split supply, simplifying design across battery, industrial, and lab equipment platforms. |
Applications
| Strain Gauge Amplification | Differential-to-SE Conversion |
|---|---|
Use Scenario: Amplifying µV-level Wheatstone bridge outputs from load cells in industrial weighing systems. IC Role / Device Role / Timing Role: Precision difference amplifier with G = 13 configuration, rejecting common-mode noise from long cable runs. Use Value: 75dB CMRR and 0.08% gain error eliminate need for post-amplifier calibration, reducing BOM and test time. | Use Scenario: Converting differential LVDS or RS-422 signals to single-ended logic levels for microcontroller ADC sampling. IC Role / Device Role / Timing Role: Rail-to-rail output driver with 560kHz GBWP ensuring fidelity up to 100kHz signal bandwidth. Use Value: 42µs settling to 0.01% enables accurate sampling of fast transient events without aperture uncertainty. |
| Handheld Medical Instrumentation | High-Voltage CM Monitoring |
Use Scenario: Front-end amplification of ECG electrode signals in portable patient monitors. IC Role / Device Role / Timing Role: Low-noise (180nV/√Hz), low-offset (≤150µV), micropower (100µA) difference amplifier. Use Value: Enables >8-hour battery life while maintaining clinical-grade baseline stability and SNR. | Use Scenario: Monitoring common-mode voltage on isolated DC bus lines in motor drives with ±60V input tolerance on P1/M1 pins. IC Role / Device Role / Timing Role: High-voltage-tolerant difference amplifier configured as G = 1 with REF tied to mid-rail. Use Value: ±60V absolute maximum rating on P1/M1 allows direct connection to 48V or 60V buses without attenuators or protection networks. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar difference amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA128UA | Fixed G = 500; higher 125µV max VOS; requires external gain-setting resistor; no rail-to-rail output. | Best suited for fixed high-gain, low-bandwidth (<10kHz) instrumentation where output swing is not constrained. | Select INA128UA only if fixed gain suffices and system can tolerate 150mV output headroom loss vs. LT1991IDD#PBF. |
| AD8271ARMZ | G = 0.2 to 10; 35µV max VOS; 10MHz GBWP; 10-lead MSOP; no ±60V input tolerance on inputs. | Preferred for high-speed, moderate-gain applications (e.g., current sensing at switching frequencies >100kHz). | Choose AD8271ARMZ when bandwidth >1MHz is required and input overvoltage protection is handled externally. |
Compared with INA128UA and AD8271ARMZ, the LT1991IDD#PBF uniquely combines programmable gain (–13 to +14), ultra-low power (100µA), ±60V input tolerance on P1/M1, and rail-to-rail output - making it optimal for space-constrained, battery-powered, high-CMRR sensor interfaces requiring flexibility and robustness.
Availability
LT1991IDD#PBF is available at Aetrix Electronics and suitable for medical instrumentation, industrial sensor signal conditioning, and handheld test equipment requiring stable component supply across extended temperature ranges.
Supply support for LT1991IDD#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, Inc. (ADI) is a global leader in high-performance analog, mixed-signal, and digital signal processing semiconductors, serving industrial, automotive, communications, and healthcare markets.
The LT1991 family was designed by Linear Technology (acquired by ADI in 2017) to simplify precision analog signal conditioning by integrating matched resistors and op amps - targeting applications demanding high CMRR, low power, and flexible gain without external components.
FAQ
What is the operating temperature range specified for the LT1991IDD#PBF?
The LT1991IDD#PBF is specified for operation from –40°C to +85°C. This I-grade temperature rating is guaranteed across all electrical parameters in the datasheet, including gain error, CMRR, and input offset voltage, making it suitable for industrial and automotive under-hood applications where ambient temperatures exceed commercial grade limits.
Can the LT1991IDD#PBF be used with a single 3.3V supply?
Yes, the LT1991IDD#PBF operates from a single 2.7V to 36V supply. With a 3.3V supply, its output swings to within 40mV of both rails (i.e., 40mV to 3.26V), and input common-mode range extends from –0.5V to 2.35V when VREF = 1.25V - enabling direct interfacing with 3.3V microcontrollers and low-voltage sensors without level-shifting circuitry.
How does the LT1991IDD#PBF achieve 75dB CMRR without external trimming?
The LT1991IDD#PBF achieves ≥75dB CMRR through factory-laser-trimmed 450kΩ resistor matching (0.04% over temperature) between the P1/M1 and P3/M3 networks. This matching is guaranteed by design and verified via gain error testing - eliminating the need for manual resistor selection or post-assembly calibration in production.
What is the maximum input voltage allowed on the P1 and M1 pins of the LT1991IDD#PBF?
The P1 and M1 pins of the LT1991IDD#PBF tolerate voltages up to ±60V relative to VEE, independent of supply rails. This is enabled by substrate-isolated 450kΩ resistors and absence of clamp diodes - allowing direct connection to high-voltage transducers or bus monitoring circuits without external attenuation or protection components.
Does the LT1991IDD#PBF require external compensation capacitors for stability?
No, the LT1991IDD#PBF is internally compensated and stable without external capacitors. At noise gains ≥2, it remains stable into capacitive loads up to 500pF; at noise gains <2 (e.g., G = 1 difference mode), stability is maintained up to 100pF. This eliminates layout complexity and component count in compact PCB designs.
LT1991IDD#PBF Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc.
- Series:
- -
- Package/Case:
- 10-WFDFN Exposed Pad
- Packaging:
- Tube
- Product Status:
- Active
- Amplifier Type:
- Programmable Gain
- Number of Circuits:
- 1
- Output Type:
- Rail-to-Rail
- Slew Rate:
- 0.12V/µs
- Gain Bandwidth Product:
- 560 kHz
- -3db Bandwidth:
- 110 kHz
- Current - Input Bias:
- 2.5 nA
- Voltage - Input Offset:
- 25 µV
- Current - Supply:
- 130µA
- Current - Output / Channel:
- 21 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT1991IDD#PBF FAQ
1.How can I place an order for LT1991IDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1991IDD#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 LT1991IDD#PBF reliable?
The price and inventory of LT1991IDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1991IDD#PBF is usually 5 days.
3.What payment methods are accepted for LT1991IDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1991IDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1991IDD#PBF?
LT1991IDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1991IDD#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 LT1991IDD#PBF?
For technical support, including LT1991IDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1991IDD#PBF requirements.
6.How does Aetrix verify that LT1991IDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT1991IDD#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 LT1991IDD#PBF meets industry standards.
7.What is the process for return or replacement of LT1991IDD#PBF?
All LT1991IDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1991IDD#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 LT1991IDD#PBF part is unused and in its original packaging.
Return procedure for LT1991IDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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