LT1167IS8 - Precision InAmp, Single-Resistor Gain, SOIC-8 | Analog Devices
Teilenummer: LT1167IS8 ✓ Aktiv| Menge | Stückpreis | Gesamt |
|---|---|---|
| 1 | $8.5 | $8,50 |
| 10 | $7.65 | $76,50 |
| 100 | $6.8 | $680,00 |
| 500 | $6.05 | $3.025,00 |
| 1.000 | $5.4 | $5.400,00 |
LT1167IS8 Übersicht
An instrumentation amplifier is a specialized differential amplifier topology designed to extract a small differential signal riding on a large common-mode voltage. The internal three-op-amp architecture provides high common-mode rejection ratio (CMRR), high input impedance on both inputs, and a single external gain-setting resistor (RG), dramatically simplifying precision signal-chain design compared to discrete implementations. The LT1167 belongs to the analog-front-end / signal-conditioning IC category, sitting between sensors and ADCs in measurement systems where low noise and high CMRR are paramount.
The single-resistor gain programmability eliminates the matched-resistor pairs required by classic InAmp topologies - any gain from G=1 (RG open) to G=10,000 (RG=60.4Ω) is set by one standard-value resistor, which simplifies calibration and reduces bill-of-material cost. The LT1167 also passes the IEC 1000-4-2 level 4 ESD specification on the inputs when used with two 5 kΩ protection resistors, making it robust for industrial sensor interfaces.
Typical applications include weigh scales and load-cell bridges, ECG and biomedical front-ends, thermocouple amplifiers, industrial process-control transducer conditioning, and precision data-acquisition systems. The wide ±2.3V to ±18V supply range and 8-pin SO footprint make it a drop-in upgrade path for legacy AD620, INA128 and similar 3-op-amp InAmp sockets.
When designing with the LT1167, place the gain-setting resistor close to the RG pins to minimize parasitic capacitance, and provide an output-referred filter capacitor if driving long cables to prevent capacitive loading instability. The reference pin (REF) should be driven by a low-impedance source or decoupled with 0.1 µF to ground for optimal CMRR.
This page synthesizes verified distributor pricing, parametric drop-in alternatives (same-package and pin-compatible), and practical design notes that go beyond the Analog Devices datasheet table alone.
Drop-in-Alternativen für LT1167IS8 – gleiches Gehäuse, Pin-kompatibel. Bauteile mit anderem Gehäuse, die eine PCB-Überarbeitung erfordern, sind ausgeschlossen.
Schnellvergleichstool – Wählen Sie Alternativbauteile für den Direktvergleich:
LT1167AIS8
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1167IS8-1
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1167IS8#PBF
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1167ACS8#TRPBF
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1167AIS8-1
✅ Drop-In📋 Referenzalternative (nicht im Katalog)
LT1167IS8 Grenzwerte & elektrische Eigenschaften
| Amplifier Type | Instrumentation Amplifier |
| Number of Channels | 1 |
| Gain Range | 1 to 10,000 (single external resistor) |
| Input Voltage Noise Density | 7.5 nV/√Hz at 1 kHz |
| Maximum Offset Voltage | 60 µV |
| Slew Rate | 1.2 V/µs |
| Gain-Bandwidth Product | 1 MHz |
| Supply Current (typical) | 0.9 mA |
| Supply Voltage Range | ±2.3 V to ±18 V |
| Betriebstemperatur | -40 °C to +85 °C (industrial) |
| Gehäuse | 8-pin SOIC (SO-8) |
| ESD Protection (with 5 kΩ resistors) | IEC 1000-4-2 level 4 compliant |
| RoHS-Status | Compliant (PBF suffix) |
| Montageart | Surface Mount |
LT1167IS8 Pin-Konfiguration
| Pin 1 | RG — Gain-setting resistor (tie to pin 8) |
| Pin 2 | -IN — Inverting input |
| Pin 3 | +IN — Non-inverting input |
| Pin 4 | V- — Negative supply |
| Pin 5 | REF — Reference voltage (output baseline) |
| Pin 6 | OUT — Amplifier output |
| Pin 7 | V+ — Positive supply |
| Pin 8 | RG/SENSE — Gain-setting resistor (tie to pin 1) |
Typische Anwendungen
LT1167IS8 ist geeignet für 6 Anwendungs: Weigh Scale / Load Cell Bridge Amplifier, Thermocouple / Precision Sensor Front-End, ECG / Biomedical Signal Conditioning, Industrial Process-Control Transducer Conditioning, Precision Data-Acquisition System Front-End, Strain-Gauge / Pressure Sensor Amplifier.
Weigh Scale / Load Cell Bridge Amplifier
The LT1167IS8 is well suited for weigh-scale and load-cell bridge front-ends. Its 7.5 nV/√Hz input voltage noise density and 1.2 V/µs slew rate let it resolve microvolt-level bridge signals from a 350Ω strain gauge at gains up to 10,000 with a single external gain resistor RG per the Analog Devices datasheet. Placed between the bridge and a 24-bit sigma-delta ADC, the single-resistor gain programmability eliminates matched resistor pairs, while the ±2.3V to ±18V supply range accepts both ±5V and ±15V instrumentation racks. Compared to the AD620, the LT1167 requires only two 5kΩ resistors to meet IEC 1000-4-2 level 4 ESD on the bridge inputs.
Empfohlen
Thermocouple / Precision Sensor Front-End
The LT1167IS8 provides a low-noise, high-CMRR front-end for thermocouple and precision sensor amplification. Its 7.5 nV/√Hz noise floor is well below the typical K-type thermocouple Seebeck voltage of 40 µV/°C, so the amplifier does not become the dominant noise contributor at gains of 100-1000, and the 1 MHz gain-bandwidth product is more than sufficient for slow thermal signals. With a single RG resistor the cold-junction compensation voltage can be applied to the REF pin while the differential thermocouple signal is amplified by the same stage, simplifying the BOM. Recommended adjacent parts: a precision CJC sensor and a 16- to 24-bit ADC for digitization.
Empfohlen
ECG / Biomedical Signal Conditioning
The LT1167IS8 is a candidate front-end for ECG and low-frequency biomedical signal chains. Its high CMRR rejects the 50/60 Hz mains common-mode pickup that dominates ECG environments, while the 7.5 nV/√Hz input noise keeps the amplifier noise contribution well below the electrode thermal noise floor per the Analog Devices datasheet. Single-resistor gain programmability supports the typical ECG gain of 1000 (RG = 49.4 Ω), and the 1.2 V/µs slew rate is sufficient for the QRS complex without slew-induced distortion. The IEC 1000-4-2 level 4 ESD rating (with 5 kΩ input resistors) protects patient-connected leads from defibrillator-like discharge events.
Empfohlen
Industrial Process-Control Transducer Conditioning
The LT1167IS8 conditions 4-20 mA loop-powered and bridge-based industrial transducers. Its ±2.3V to ±18V supply range accepts ±15V PLC analog rails directly, and the 0.9 mA typical supply current keeps the InAmp well below the 3.5 mA budget of a true 4-20 mA current loop when configured with a stack-derived supply. The wide industrial temperature range (-40 °C to +85 °C) lets it operate inside unheated control cabinets, and the IEC 1000-4-2 ESD robustness (level 4 with 5 kΩ resistors) protects against installer-induced cable discharge. Pair with an ADC and an isolated digital isolator for a complete PLC analog input module.
Empfohlen
Precision Data-Acquisition System Front-End
The LT1167IS8 serves as the analog front-end in precision multi-channel data-acquisition systems. Its single-resistor gain programmability allows per-channel gain selection from 1 to 10,000 without matched resistor arrays, dramatically simplifying calibration of mixed-range inputs (e.g., ±10 V and ±100 mV on the same board). The 1 MHz GBW comfortably drives successive-approximation ADCs at full throughput, while the 60 µV maximum offset voltage contributes negligible error versus 16-18-bit ADC LSBs. The REF pin accepts a DAC-driven offset for software-calibrated system zero, an architecture commonly seen in PXI and LXI instrumentation.
Empfohlen
Strain-Gauge / Pressure Sensor Amplifier
The LT1167IS8 amplifies low-level differential signals from strain-gauge and piezoresistive pressure sensors. With a 350 Ω bridge and a 5 V excitation, full-scale outputs of 10-30 mV are common; the LT1167's 7.5 nV/√Hz input noise density and 60 µV maximum offset let it resolve 16-bit dynamic range at a gain of 100, per the Analog Devices datasheet. The single-resistor gain setting (RG between pins 1 and 8) lets the same PCB accommodate 100, 250, and 500 psi sensors by swapping one component. The 1.2 V/µs slew rate also covers pressure-transient events in hydraulic systems without slew limiting.
Empfohlen
Zusammenfassung der empfohlenen Produkte
Technische Referenzdaten für LT1167IS8 – Vergleich, Designhinweise und Compliance-Informationen.
Auswahlhilfe
Vergleich mit Alternativen
| Parameter | Dieses Produkt | LT1167AIS8 | LT1167IS8-1 | LT1167IS8#PBF | LT1167ACS8#TRPBF | LT1167AIS8-1 |
|---|---|---|---|---|---|---|
| Brand | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices | Analog Devices |
| Package | SOIC-8 (8-pin SO) | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same | SOIC-8 - same |
| Input Voltage Noise (nV/√Hz at 1 kHz) | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 | 7.5 |
| Maximum Offset Voltage | 60 µV | Tighter ('A' grade) | 60 µV | 60 µV | Tighter ('A' grade) | Tighter ('A' grade) |
| -1 High-CM Input Bias Optimization | No | No | Yes | No | No | Yes |
| Operating Temperature | -40 °C to +85 °C (industrial) | -40 °C to +85 °C | -40 °C to +85 °C | -40 °C to +85 °C | 0 °C to +70 °C (commercial) | -40 °C to +85 °C |
| Lead-Free / RoHS | No (original) / Yes with #PBF suffix | Yes with #PBF suffix | Yes with #PBF suffix | Yes (lead-free) | Yes (lead-free, T&R) | Yes with #PBF suffix |
| Supply Voltage Range | ±2.3 V to ±18 V | ±2.3 V to ±18 V | ±2.3 V to ±18 V | ±2.3 V to ±18 V | ±2.3 V to ±18 V | ±2.3 V to ±18 V |
| Typical Unit Price (USD, qty-1) | 8.50 | Higher (A grade premium) | Comparable | 8.50 | Lower (commercial temp) | Higher (A+ grade premium) |
Wichtigste Unterscheidungsmerkmale
- Single-resistor gain programmability from 1 to 10,000 (vs. AD620)
- IEC 1000-4-2 level 4 ESD protection with 5 kΩ input resistors (vs. LT1167IS8-1)
- Industrial temperature range (-40 °C to +85 °C) (vs. LT1167ACS8#TRPBF)
Designhinweise
Place the gain-setting resistor RG directly between pins 1 and 8 with the shortest possible trace length - any stray capacitance in parallel with RG introduces a pole that reduces phase margin at high gain. Estimated: even 5 pF of parasitic capacitance forms a pole at f = 1/(2π·RG·Cp); with RG = 60.4 Ω and Cp = 5 pF this pole is at ~530 MHz, but with RG = 5 kΩ (gain 10) it falls to 6.4 MHz and starts to interact with the 1 MHz GBW. Keep RG within 3 mm of the SO-8 pins and use a grounded guard ring if the board stack-up allows.
Decouple both supply rails (V+ pin 7 and V- pin 4) with 0.1 µF ceramic capacitors placed within 2 mm of the package pins, plus a 10 µF bulk tantalum or ceramic on each rail at the chip. The REF pin (5) should be tied to mid-supply through a low-impedance buffer, or driven by a clean reference source; bypass REF with 0.1 µF to ground if it is left floating at mid-rail. The combination of high CMRR and the REF pin's role as the output baseline means any noise on REF couples directly into the differential measurement.
Do not assume the LT1167IS8 is pin-compatible with the AD620 or INA128 - all three use 8-pin SOIC but the pin assignments for RG and REF differ. Cross-reference data shows the LT1167 places RG on pins 1+8 and REF on pin 5, while the AD620 places RG on pins 1+8 but uses a different REF pinout. Substituting one for the other without checking the pinout will short the gain-setting resistor to the wrong node and likely damage the part. Always consult the manufacturer's SO-8 mechanical drawing before PCB layout.
Estimated: the LT1167IS8 has an input bias current of roughly 0.3 nA per the typical data sheet curve; with a 10 kΩ source imbalance this introduces a 3 µV error, comparable to the 60 µV maximum offset voltage. For high-impedance sources (>10 kΩ) the LT1167IS8-1 variant's optimized input bias current characteristic at high common-mode voltage is the better choice. Source impedances should be balanced within 1% to preserve CMRR at high gains (G > 100).
Compliance-Informationen
RoHS/REACH compliance for the LT1167IS8#PBF variant; the original non-PBF suffix is not lead-free. Not AEC-Q100 qualified - for automotive choose a Q-graded variant or different InAmp.
