LT1102CH - 10/100 Gain JFET Instrumentation Amp | Analog Devices
MPN: LT1102CH ✓ ActiveLT1102CH Overview
An instrumentation amplifier is a differential-input amplifier whose internal gain is set by internal resistor networks rather than by external feedback components. It belongs to the amplifier IC hierarchy, which sits above the general-purpose operational amplifier: while an op-amp needs external resistors, matched networks and careful layout to reject common-mode noise, an instrumentation amplifier integrates the differential pair, gain network and output stage so that high common-mode rejection is achieved with essentially no user gain-setting hardware. The LT1102 family extends that concept into the fast FET-input domain, delivering precision DC accuracy together with wideband dynamic performance in a low-cost, space-saving 8-pin package.
Key features include a selectable fixed gain of 10 or 100, gain accuracy of 0.01%, non-linearity of 3 ppm, input offset voltage of 180 microvolts, and input bias plus offset currents below 10 pA. No external gain-setting resistor is required, which removes the resistor-tolerance and drift contribution that normally limits the accuracy of a discrete instrumentation front end. Slew rate, settling time, gain-bandwidth product and overdrive recovery time are all improved relative to competitive high-speed instrumentation amplifiers of the generation.
The JFET input stage gives very low input bias current and high input impedance, which is essential when the source is a resistive bridge, a thermocouple, or a high-impedance transducer whose output would otherwise be loaded by the amplifier. Internal precision matching and laser trimming of the gain network are what deliver the 0.01% gain accuracy and 3 ppm non-linearity figures, and the fixed-gain architecture removes the need for a user-supplied external network that would degrade both figures.
Typical applications include strain-gauge and load-cell bridge front ends, high-speed current shunt measurement, precision instrumentation for laboratory and test equipment, medical patient-monitoring signal chains, and industrial process-control sensor interfaces where fast settling after a large input step is required.
When designing with the LT1102CH, verify that the supply rails stay within the ±9 V to ±20 V operating window and that the input common-mode range and output swing remain valid for the chosen gain. Because the gain is fixed internally, the system designer selects the 10 or 100 gain version at ordering time rather than trimming gain in-circuit; layout should keep the input traces short, guarded and away from switching nodes to preserve the benefit of the low-noise JFET input stage.
This page brings together the manufacturer product information, the family-level precision and speed specifications, package and supply details, and engineering guidance on gain selection, layout and drop-in sourcing options that are spread across many separate documents.
Drop-in alternatives for LT1102CH — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
LT1102ACH
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
LT1101CH
✅ Drop-In ⚠️ Specs UnverifiedContact for price
View Datasheet →LT1102CH Maximum Ratings & Electrical Characteristics
| Product Type | Instrumentation Amplifier, JFET input |
| Number of Channels | 1 |
| Internal Gain Options | 10 or 100 (fixed) |
| Gain Accuracy | 0.01% |
| Non-Linearity | 3 ppm |
| Input Offset Voltage | 180 uV |
| Input Bias Current | < 10 pA |
| Input Offset Current | < 10 pA |
| Supply Voltage Range (differential) | +/-9 V to +/-20 V |
| Typical Dual Supply Rails | +/-12 V, +/-15 V, +/-18 V |
| Package | TO-5, 8-lead hermetic metal can (CH) |
| Mounting Type | Through-hole, hermetic sealed |
| External Gain-Setting Resistor Required | No |
| Input Stage Topology | FET (JFET) differential input |
LT1102CH to-5, 8-lead hermetic metal can (ch) Pin Configuration Guide
Pin configuration for LT1102CH (to-5, 8-lead hermetic metal can (ch) package). This analog component features input, output, and power supply pins. Refer to the manufacturer datasheet for offset null, compensation, and enable pin configurations. Ideal for signal conditioning and amplifier circuits.
No detailed pinout data available for LT1102CH.
Refer to the datasheet for full pin configuration.
Typical Applications
LT1102CH is suitable for 6 applications: Strain-Gauge and Load-Cell Bridge Front Ends, High-Speed Shunt and Current Sensing, Medical Patient Monitoring Signal Chains, Precision Test and Measurement Instrumentation, Industrial Process Control Sensor Interfaces, Audio and Instrumentation Signal Conditioning.
Strain-Gauge and Load-Cell Bridge Front Ends
The LT1102CH is built for low-level bridge excitation measurement because its JFET input stage draws less than 10 pA of bias current, so the 120-350 ohm strain-gauge legs are effectively unloaded and the excitation rail sees no meaningful droop. With 0.01% gain accuracy and 3 ppm non-linearity, scale-factor error stays well below the budget of a typical 2 mV/V bridge output, while the 180 uV input offset voltage contributes negligibly next to a millivolt-level signal. The device is placed directly across the differential bridge output with a single gain of 10 or 100 selected at ordering, avoiding the external gain-setting resistor whose tolerance would otherwise dominate the error budget. Because the internal gain network is laser-trimmed, no user calibration of gain is required, only a simple zero and scale calibration in firmware. Place the amplifier close to the bridge connector and keep the input pair away from motor and relay wiring.
Recommended
High-Speed Shunt and Current Sensing
Fast current measurement in switching converters, motor drives and battery systems needs an amplifier that settles quickly after a large input step, and the LT1102CH is described by the manufacturer as improving slew rate, settling time, gain-bandwidth product and overdrive recovery relative to competitive high-speed instrumentation amplifiers. With fixed gains of 10 and 100, the amplifier can sit directly across a milliohm shunt and present a scaled signal to the ADC without external gain components. Overdrive recovery matters when the sensed current steps abruptly, for example at PWM edges, because a slow recovery produces a false reading lasting long enough to corrupt a control loop. The low-noise JFET input also avoids adding noise directly to the measured shunt voltage. Keep the shunt and amplifier in a tight two-loop layout, and use a Kelvin connection at the shunt pads.
Recommended
Medical Patient Monitoring Signal Chains
Patient monitoring front ends work with microvolt to millivolt level bio-electrode signals where the amplifier must add as little error as possible, and the LT1102CH contributes less than 10 pA of input bias current with a 180 uV input offset voltage. That low-current input stage preserves the integrity of high-impedance skin electrodes and resistive sensor bridges without drawing signal charge from the source. The hermetic TO-5 metal can provides sealed, inert internal atmosphere and long-term stability, which suits equipment expected to remain in service for many years. The 0.01% gain accuracy keeps channel-to-channel and unit-to-unit calibration error predictable for traceable measurements. A 1.8 V to 5 V instrument amplifier front end is common in these designs, but the fast fixed-gain arrangement also suits monitor and diagnostic modules with wide bandwidth requirements.
Recommended
Precision Test and Measurement Instrumentation
Laboratory and factory test equipment often needs accurate gain without user calibration, and the LT1102CH provides fixed gains of 10 and 100 with 0.01% gain accuracy and 3 ppm non-linearity straight from the internal trimmed network. That removes the external gain-setting resistor, its tolerance contribution and its temperature coefficient from the error budget, which is exactly what limits the accuracy of many discrete instrumentation front ends. The device also saves board area by condensing the differential pair, gain network and output stage into an 8-pin hermetic package, so it suits bench instruments with dense analog sections. Because the amplifier is a single-channel part, dual-channel analysers typically pair two devices and rely on the tight gain matching of the trimmed internal networks for channel comparison. Keep the analog ground and the digital ground separated under the package to preserve measurement integrity.
Recommended
Industrial Process Control Sensor Interfaces
Plant instrumentation handles sensors such as RTDs, thermocouples, pressure transducers and strain bridges that sit far from the electronics, so the interface amplifier must combine high input impedance with accurate, stable gain. The LT1102CH input bias current below 10 pA means even kilohm-level sources are barely loaded, preserving the true value of slow and small signals. The 0.01% gain accuracy and 3 ppm non-linearity translate directly into better measurement certainty at the plant floor, while the hermetic TO-5 package is well suited to long-life field equipment with wide temperature exposure. Because the gain is fixed internally at 10 or 100, designers can order the exact gain for a given sensor output and simplify calibration procedures. For installations with long cable runs, place the amplifier close to the sensor and protect the input nodes from common-mode interference.
Recommended
Audio and Instrumentation Signal Conditioning
Precision audio and measurement signal chains need an amplifier that adds minimal noise and distortion while still handling fast transients, and the LT1102CH combines the low-noise JFET input stage with fixed gains of 10 and 100 for conditioning balanced or differential sources. Gain accuracy of 0.01% and non-linearity of 3 ppm keep level calibration stable across the input range, so a fixed trim in the equipment calibration table remains valid over time. The fast slew rate and improved settling behaviour described for the family help the amplifier recover cleanly from large signal steps, which matters in studio monitoring and instrumentation trigger paths. Because the gain is fixed internally, matching between channels is governed by the trimmed internal network rather than by user resistor selection. Follow the manufacturer layout guidance to keep the differential input loop small and away from digital return currents.
Recommended
Recommended Products Summary
Engineering reference data for LT1102CH — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | LT1102ACH | LT1101CH |
|---|---|---|---|
| Brand | Analog Devices (Linear Technology) | Analog Devices (Linear Technology) | Analog Devices (Linear Technology) |
| Package | TO-5, 8-lead hermetic metal can | TO-5, 8-lead hermetic metal can - same | TO-5, 8-lead hermetic metal can - same |
| Internal Gain Options | 10 or 100 (fixed) | 10 or 100 (fixed) - same | 1, 10 or 100 - one additional decade |
| Gain Accuracy | 0.01% | 0.01% | 0.01% (same family network) |
| Input Bias / Offset Current | < 10 pA | < 10 pA | < 10 pA (JFET input, same family) |
| Supply Voltage Range | +/-9 V to +/-20 V | +/-9 V to +/-20 V | +/-9 V to +/-20 V (same family) |
| External Gain-Setting Resistor Required | No | No | No |
| Qualification | Industrial/standard grade | Automotive grade | Industrial/standard grade |
Key Differentiators
- Fixed internal gain removes external gain-setting resistors from the error budget (vs LT1101CH)
- Automotive-qualified ordering option available in the identical hermetic TO-5 footprint (vs LT1102ACH)
- Very low input bias and offset currents protect high-impedance sources (vs LT1101CH)
Design Notes
Because the LT1102CH input bias current is below 10 pA, the input stage is essentially unloaded by the amplifier, so any leakage in the surrounding board dominates error. Keep the two input traces short, route them as a close differential pair, guard them if they run next to high-impedance sources, and remove flux residue and conformal-coating solvents from the board after assembly. In a hermetic TO-5 package, the internal atmosphere is inert and sealed, so keep moisture and cleaning solvents out of the can during soldering.
The fixed internal gain removes the external gain-setting resistor, which is the main advantage for precision bridge work, but it also means the input range must be planned before ordering the part. Compute the maximum expected source level at the chosen gain of 10 or 100 and confirm the amplifier input common-mode range and output swing for that configuration. A design that needs gain 1 or in-circuit gain switching should use the family member offering a 1/10/100 gain set rather than operating the fixed-gain device out of its intended range.
Estimated: at +/-15 V supplies the total quiescent current consumption of the pair of rails is set by the device supply current specification, which is not published on the product page. Budget the supply rails for the quiescent current plus load current at the amplifier output and plus any shunt or reference current in the bias network. Keep the +/-9 V to +/-20 V differential supply window in mind and add local decoupling close to the supply pins, because supply noise on a fast instrumentation amplifier modulates the gain node and shows up as output noise.
Do not substitute a surface-mount or dual-in-line suffix of the same family for the hermetic TO-5 LT1102CH without a board change; the lead frame, body diameter and pin spacing differ, so a footprint-compatible claim is invalid. Equally, do not assume a competitor's instrumentation amplifier is interchangeable simply because the gain matches: check the input common-mode range, output swing, overdrive recovery and bias current, since those are the parameters that determine whether a bridge or shunt measurement stays accurate during large signal steps.
Compliance Information
No RoHS, REACH, AEC-Q100 or lead-free statements appear on the manufacturer product page or the datasheet excerpts for this part. An automotive-grade ordering option exists in the same family, but qualification status for the specific LT1102CH ordering code should be confirmed with the manufacturer before it is used in an AEC-Q100 design.
