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Analog Devices Inc. LT1991ACDD#PBF
- Part No.:
- LT1991ACDD#PBF
- Manufacturer:
- Analog Devices Inc.
- Category:
- Instrumentation, Op Amps, Buffer Amps
- Package:
- 10-WFDFN Exposed Pad
- Datasheet:
-
LT1991ACDD#PBF.pdf
- Description:
- IC OPAMP PGA 1 CIRCUIT 10DFN
- Quantity:
- Payment:
- Shipping:
Inventory:121
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Product details
Overview
LT1991ACDD#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 ±0.04% gain accuracy at G = 1, 75dB CMRR, rail-to-rail output swing within 40mV of rails, 560kHz GBWP, and 100µA supply current on 5V - enabling high-accuracy sensor signal conditioning in space-constrained industrial instrumentation.
For engineers reviewing the LT1991ACDD#PBF datasheet, LT1991ACDD#PBF pinout, LT1991ACDD#PBF application, or LT1991ACDD#PBF equivalent, key selection criteria include guaranteed gain error ≤±0.04% (A-grade), input voltage range up to –0.5V to 5.1V on 5V supply, resistor matching <0.04% over temperature, and operation across 0°C to 70°C with 10-Lead (3mm × 3mm) DFN thermal performance (TJMAX = 125°C).
Technical Context
The LT1991ACDD#PBF implements a fully integrated difference amplifier architecture where internal 50kΩ, 150kΩ, and 450kΩ SiChrome resistors are laser-trimmed for <0.04% matching and <3ppm/°C TC. Its core op amp features 50µV max VOS, 560kHz GBWP, and rail-to-rail output - enabling stable operation at noise gains ≥2 into 500pF loads.
Pin-configurable gain ranges include difference mode (G = 1–13), noninverting (G = 0.07–14), and inverting (G = –0.08 to –13), all achieved without external components. The REF pin sets output common-mode level, while P1/M1, P3/M3, and P9/M9 inputs provide programmable gain weighting via admittance-based routing (9×, 3×, 1× scaling).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Gain Accuracy | ±0.04% max at G = 1 (LT1991A grade); enables 16-bit-equivalent system resolution without calibration. |
| CMRR | ≥75dB at G = 1; rejects common-mode interference in noisy industrial environments. |
| Input Offset Voltage | 150µV max (LT1991DD, A-grade); ensures sub-mV output error in precision bridge sensing. |
| Supply Current | 100µA typical on 5V; supports battery-powered handheld instrumentation with multi-year runtime. |
| Output Swing | Within 40mV of either rail (no load, 5V supply); maximizes dynamic range in single-supply systems. |
| Bandwidth | 110kHz at G = 1; sufficient for DC–10kHz sensor signals including strain gauges and RTDs. |
| Input Voltage Range | –0.5V to 5.1V on 5V/0V supply; accommodates overvoltage-tolerant front-end designs. |
| Operating Temp | 0°C to 70°C (C-grade); qualified for commercial and light-industrial ambient conditions. |
Pinout & Package
LT1991ACDD#PBF uses a 10-lead (3mm × 3mm) plastic DFN package with exposed pad connected to VEE. Thermal resistance θJA = 43°C/W; maximum junction temperature = 125°C.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| M1 (Pin 10) | Inverting Gain-of-1 Input | Connects 450kΩ resistor to op amp inverting input; defines baseline differential gain path. |
| M3 (Pin 9) | Inverting Gain-of-3 Input | Connects 150kΩ resistor; provides 3× differential gain contribution when used with P3. |
| M9 (Pin 8) | Inverting Gain-of-9 Input | Connects 50kΩ resistor; enables high-gain differential amplification (e.g., G = 13) without external parts. |
| VCC (Pin 7) | Positive Supply | Accepts 2.7V to 36V; supports wide-input industrial power rails and battery operation. |
| OUT (Pin 6) | Analog Output | Rail-to-rail output stage; drives 10kΩ loads with <40mV headroom to rails on 5V supply. |
| VEE (Pin 4) | Negative Supply / Ground | Reference for dual- or single-supply operation; exposed pad must be soldered to PCB ground plane. |
| REF (Pin 5) | Output Common-Mode Reference | Sets quiescent output level (e.g., 2.5V on 5V supply); determines input common-mode range limits. |
| P1 (Pin 1) | Noninverting Gain-of-1 Input | Connects 450kΩ resistor to op amp noninverting input; pairs with M1 for unity-gain diff amp. |
| P3 (Pin 2) | Noninverting Gain-of-3 Input | Connects 150kΩ resistor; used with M3 to configure G = 3 difference or noninverting modes. |
| P9 (Pin 3) | Noninverting Gain-of-9 Input | Connects 50kΩ resistor; enables precise high-gain configurations (e.g., G = 9 or G = 13) with no external components. |
Key Features
| Feature | Design Value |
|---|---|
| Integrated Precision Resistor Network | Eight laser-trimmed SiChrome resistors (50k/150k/450k) with <0.04% matching and <3ppm/°C TC - eliminates external resistor matching errors and drift. |
| Configurable Gain Topologies | Single-chip support for difference (G = 1–13), noninverting (G = 0.07–14), and inverting (G = –0.08 to –13) amplifiers - reduces BOM count and layout complexity. |
| Rail-to-Rail Output Stage | Swings to within 40mV of VCC or VEE under no load (5V supply) - preserves full ADC input range in single-supply data acquisition systems. |
| Low-Power Precision Operation | 100µA supply current with 50µV max input offset and 560kHz GBWP - balances accuracy and energy efficiency in portable test equipment. |
| Overvoltage-Tolerant Inputs | P1/M1 pins withstand ±60V beyond rails (with P9/M9 grounded); enables robust front-end protection in industrial signal chains. |
| Space-Saving DFN Package | 3mm × 3mm × 0.8mm 10-lead DFN with exposed thermal pad - fits high-density PCB layouts in handheld medical or instrumentation devices. |
Applications
| Strain Gauge Amplifier | Differential-to-Single-Ended Conversion |
|---|---|
Use Scenario: Amplifying µV-level Wheatstone bridge outputs from metal foil or semiconductor strain gauges in load cells and pressure transducers. IC Role / Device Role / Timing Role: Precision difference amplifier configured at G = 1000 (via external gain stage + LT1991ACDD#PBF front-end) to resolve sub-10µε mechanical strain. Use Value: 0.04% gain accuracy and 75dB CMRR suppress thermal EMF and EMI-induced common-mode noise, enabling <0.05% FS measurement repeatability. | Use Scenario: Converting differential analog sensor outputs (e.g., isolated current sense, LVDS receiver outputs) to single-ended signals compatible with SAR ADC inputs. IC Role / Device Role / Timing Role: Rail-to-rail difference amplifier with REF pin tied to mid-supply (2.5V), delivering full-scale 0–5V output from ±250mV differential input. Use Value: 40mV output headroom and 110kHz bandwidth preserve signal integrity for 100ksps sampling without settling-time penalties. |
| Handheld Instrumentation Front-End | Medical Sensor Signal Conditioning |
Use Scenario: Battery-powered multimeters and portable oscilloscopes requiring low-power, high-accuracy analog front-ends with minimal external components. IC Role / Device Role / Timing Role: Configurable gain amplifier (G = 1 or G = 3) for autoranging voltage measurement paths, powered from 3.3V or 5V Li-ion supply. Use Value: 100µA supply current extends battery life; ±0.04% gain error eliminates per-range calibration; DFN package saves >30% board area vs discrete solutions. | Use Scenario: Biopotential acquisition in ECG/EMG modules where electrode half-cell potentials impose large DC common-mode voltages (±300mV). IC Role / Device Role / Timing Role: Difference amplifier with REF = 1.25V and P1/M1 inputs, rejecting electrode offset while amplifying 1–100Hz bio-signals. Use Value: –0.5V to 5.1V input range on 5V supply accommodates electrode drift; 50µV VOS ensures <1µV input-referred error in diagnostic-grade signal chains. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar precision difference amplifier applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| INA128UA | Fixed G = 100 (unprogrammable); higher supply current (700µA); no rail-to-rail output (min swing = 1.2V from rails). | Requires external gain stages for variable gain; unsuitable for low-voltage single-supply systems needing full dynamic range. | Select when fixed high gain and superior PSRR (>120dB) outweigh programmability and power constraints. |
| AD8271ARMZ | G = 0.2 to 10 (pin-selectable); 0.04% gain error; 100µA supply current; but only 65dB CMRR at G = 1 and no overvoltage-tolerant inputs. | Limited common-mode rejection degrades accuracy in noisy industrial settings; lacks ±60V input tolerance for rugged front-ends. | Select when compact size and micropower are critical, and CMRR >70dB is sufficient for the target signal environment. |
Compared with INA128UA and AD8271ARMZ, LT1991ACDD#PBF uniquely combines programmable gain (1–13), 75dB+ CMRR, rail-to-rail output, ±60V input tolerance on P1/M1, and 100µA power - making it optimal for reconfigurable, low-power, high-accuracy industrial sensor interfaces where board space and calibration overhead are constrained.
Availability
LT1991ACDD#PBF is available at Aetrix Electronics and suitable for handheld instrumentation, medical sensor signal conditioning, strain gauge amplification, and differential-to-single-ended conversion requiring stable component supply across commercial temperature grades.
Supply support for LT1991ACDD#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 LT1991ACDD#PBF belongs to ADI's precision amplifier product line, designed specifically for applications demanding ultra-stable gain, low power, and minimal external components - such as portable test equipment, industrial process control, and medical diagnostics.
FAQ
What is the guaranteed gain accuracy specification for LT1991ACDD#PBF?
The LT1991ACDD#PBF is the A-grade version of the LT1991, with guaranteed gain error of ±0.04% at G = 1 and ±0.06% at G = 3 or 9 (VS = ±15V, VOUT = ±10V, RL = 10kΩ). This specification applies across the 0°C to 70°C operating temperature range and is validated by production testing - distinguishing it from the standard LT1991 (±0.08% at G = 1).
Can LT1991ACDD#PBF operate from a single 3.3V supply?
Yes, LT1991ACDD#PBF supports single-supply operation down to 2.7V. On a 3.3V/0V supply, its input voltage range is specified as 0.75V to 2.35V (P1/M1 inputs, VREF = 1.25V), and output swings to within 55mV of either rail under no load. Full functionality requires proper biasing of the REF pin and adherence to input common-mode limits derived from internal op amp headroom.
Which pins on LT1991ACDD#PBF support overvoltage tolerance, and to what level?
Only P1 (Pin 1) and M1 (Pin 10) on LT1991ACDD#PBF are overvoltage tolerant, rated to ±60V relative to VEE when P9 and M9 are grounded and VS = ±15V. All other inputs (P3, M3, P9, M9, REF) are limited to VEE – 0.2V to VCC + 0.2V - exceeding this risks detrimming or damage due to internal clamp diodes and substrate connections.
How does the REF pin affect input common-mode range in LT1991ACDD#PBF?
The REF pin on LT1991ACDD#PBF sets the output common-mode voltage and directly determines the valid input common-mode range via superposition: VEXT = VINT • (1 + RG/RF) – VREF • RG/RF. For example, with VREF = 2.5V on a 5V/0V supply, P1/M1 inputs support –0.5V to 5.1V - but changing VREF shifts both upper and lower bounds proportionally.
Is LT1991ACDD#PBF pin-compatible with other LT1991 variants like LT1991CMS#PBF?
Yes, LT1991ACDD#PBF shares identical pinout and electrical specifications with all other LT1991 variants (e.g., LT1991CMS#PBF, LT1991IDD#PBF), differing only in package (DFN vs MSOP) and temperature grade (0°C to 70°C for 'C', –40°C to 85°C for 'I'). The DFN and MSOP packages have identical 10-pin functional mapping, allowing direct PCB footprint substitution where thermal and layout constraints permit.
LT1991ACDD#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:
- 15 µV
- Current - Supply:
- 130µA
- Current - Output / Channel:
- 21 mA
- Voltage - Supply Span (Min):
- 2.7 V
- Voltage - Supply Span (Max):
- 36 V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 10-DFN (3x3)
LT1991ACDD#PBF FAQ
1.How can I place an order for LT1991ACDD#PBF through Aetrix?
Please submit a Request for Quotation (RFQ) for LT1991ACDD#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 LT1991ACDD#PBF reliable?
The price and inventory of LT1991ACDD#PBF are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for LT1991ACDD#PBF is usually 5 days.
3.What payment methods are accepted for LT1991ACDD#PBF?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for LT1991ACDD#PBF transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for LT1991ACDD#PBF?
LT1991ACDD#PBF orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your LT1991ACDD#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 LT1991ACDD#PBF?
For technical support, including LT1991ACDD#PBF datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your LT1991ACDD#PBF requirements.
6.How does Aetrix verify that LT1991ACDD#PBF is sourced from the original manufacturer or authorized distributors?
All LT1991ACDD#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 LT1991ACDD#PBF meets industry standards.
7.What is the process for return or replacement of LT1991ACDD#PBF?
All LT1991ACDD#PBF units undergo pre-shipment inspection (PSI). If there is an issue with LT1991ACDD#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 LT1991ACDD#PBF part is unused and in its original packaging.
Return procedure for LT1991ACDD#PBF:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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