INA105KP - Unity-Gain Precision Differential Amplifier | Texas Instruments
MPN: INA105KP ✓ פעילINA105KP סקירה
A differential amplifier is a circuit block that accepts two input voltages and produces an output equal to their difference. It is a sub-type of instrumentation amplifier architecture, and it sits in the hierarchy: differential amplifier -> instrumentation amplifier family -> analog signal conditioning IC -> semiconductor. Unlike a general-purpose operational amplifier, the INA105 integrates matched, laser-trimmed resistors so the differential gain and common-mode rejection are accurate from the factory without any external precision resistor network.
Because the on-chip resistors are laser trimmed for accurate gain and high common-mode rejection, and because their temperature coefficient (TCR) tracking is excellent, both the gain accuracy and the CMRR remain stable over the operating temperature range. The input common-mode range extends beyond the positive and negative supply rails, which lets the part accept signals that would forward-bias the input protection diodes of a bare op amp.
The unity-gain topology is deliberate: the INA105 replaces a discrete precision resistor network in balanced line, bridge, and current-shunt measurement circuits. Because gain is fixed at 1, there is no external gain-setting resistor to drift, and the device is often placed directly in front of a higher-gain stage when extra gain is required.
Typical uses include 4-20 mA loop receivers, bridge and load-cell front ends, precision current-shunt amplifiers in power-conversion and motor-control loops, balanced differential receivers for RS-485 and CAN physical layers, and instrumentation signal chains in test and measurement equipment.
The main design consideration is reference grounding: the REF pin must be tied to the analog ground of the system so that the output reference matches the receiver's common-mode window. Because this is a linear bipolar amplifier rather than a switching or chopper-stabilized part, offset and drift are set by the underlying op-amp architecture, so keep the layout short and symmetrical.
This page brings together the pin configuration, parameter-by-parameter comparison against drop-in alternatives, and practical layout and reference-grounding notes that are not consolidated in a single place in the original manufacturer documentation.
חלופות תחליף ישיר עבור INA105KP — אותו מארז, תואם פין-לפין. חלקים במארז שונה הדורשים עיבוד מחדש של ה-PCB אינם נכללים.
וריאנטים בסדרה זו
דגמים מאותה סדרה התואמים Drop-in עם INA105KP (אותו גורם צורה וטביעת רגל) — שונים ב Mounting Type, Package, Product Type.
INA117P
✅ Drop-Inצור קשר לקבלת מחיר
הצג גיליון נתונים ←INA126P
✅ Drop-In ⚠️ מפרטים לא מאומתיםצור קשר לקבלת מחיר
הצג גיליון נתונים ←AD827ANZ
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
AD845ANZ
✅ Drop-In📋 חלופה להתייחסות (לא בקטלוג)
INA105KP דירוגים מרביים ומאפיינים חשמליים
| Product Type | Precision unity-gain differential amplifier (1 circuit) |
| Differential Gain | 1.000 (unity, fixed) |
| Gain-Bandwidth Product | 1 MHz |
| Maximum Input Offset Voltage | 500 uV |
| Common-Mode Rejection Ratio (Minimum) | 86 dB |
| Supply Voltage Range (Total) | 10 V to 36 V (single 5 V to 36 V, dual +/-5 V to +/-18 V) |
| Common-Mode Input Voltage, Minimum | -20 V |
| Common-Mode Range | Extends beyond positive and negative supply rails |
| Operating Ambient Temperature | -40 °C to +85 °C |
| מארז | 8-pin PDIP (P package), through-hole |
| סוג הרכבה | Through-hole / DIP |
| Internal Gain Network | On-chip laser-trimmed metal-film resistor network |
| Op-Amp Core | Precision operational amplifier |
| Resistor Temperature Coefficient Tracking | Matched TCR maintains gain accuracy and CMRR over temperature |
תצורת פינים של INA105KP
| פין 1 | RG — Gain set connection (internally trimmed for unity gain) |
| פין 2 | -IN — Inverting input |
| פין 3 | +IN — Non-inverting input |
| פין 4 | V- — Negative supply connection |
| פין 5 | REF — Output reference, connect to analog ground |
| פין 6 | OUT — Differential output |
| פין 7 | V+ — Positive supply connection |
| פין 8 | NC — Not connected (per datasheet) |
יישומים טיפוסיים
INA105KP מתאים עבור 6 יישוםs: 4-20 mA Current Loop Receiver, Bridge and Load Cell Front End, Precision Current Shunt Amplification, Balanced Differential Line Receiver, Precision Test and Measurement Front End, Power Supply and Converter Feedback Sensing.
4-20 mA Current Loop Receiver
The INA105KP sits at the input of an industrial current-loop receiver, where the transmitter drives 4 mA to 20 mA through a 250 ohm shunt and a large common-mode voltage rides on top of the small differential signal. The fixed unity gain of the INA105KP means the loop current appears directly at the output in volts per milliamp, while its 86 dB minimum CMRR rejects the common-mode component that would otherwise saturate a general-purpose differential stage. The 500 uV maximum input offset voltage is well below a 0.1 percent accuracy budget, and the input common-mode range reaching -20 V and beyond the supply rails keeps the part usable with a +/-15 V or +/-18 V dual supply. A typical implementation places the shunt close to the device pins and ties the REF pin to analog ground so the output reference matches the downstream ADC.
מומלץ
Bridge and Load Cell Front End
In load-cell and strain-gauge bridge measurement, the useful signal is a few millivolts sitting on a large bridge excitation common-mode voltage, and the accuracy budget is dominated by input offset and common-mode rejection. The INA105KP provides a factory-trimmed unity-gain difference stage with 86 dB minimum CMRR and 500 uV maximum offset, which lets it sit directly across the bridge without the resistor-matching errors of a discrete diff amp. Because its input common-mode range extends beyond the supply rails, the bridge excitation can sit above the amplifier supply level, which is common with 5 V excitation and +/-15 V amplifier rails. Typically the bridge output feeds this stage first, and a second precision gain stage scales the millivolt-level result up to a converter input range.
מומלץ
Precision Current Shunt Amplification
In motor-control, battery-management and power-conversion loops, a low-value shunt in the high-current path produces a small differential voltage across a substantial common-mode swing, and the controller needs that signal referenced to ground. The INA105KP handles this cleanly because the unity-gain, laser-trimmed architecture holds the differential gain at 1.000 across temperature while the 86 dB CMRR rejects the fast dV/dt-induced common-mode ripple riding on the shunt. Its 1 MHz gain-bandwidth product is adequate for control loops in the kilohertz range, and the input common-mode capability beyond the rails allows the shunt to be placed in a high-side or low-side position without level shifting. In practice the shunt outputs feed the INA105KP, and the resulting ground-referenced voltage drives an ADC or comparator in the control path.
מומלץ
Balanced Differential Line Receiver
Receiving a balanced signal over a long cable, such as audio, instrumentation or industrial bus wiring, means extracting a small differential signal sitting between two large and slightly mismatched voltages. The INA105KP is a unity-gain receiver stage built for exactly this task, with 86 dB minimum common-mode rejection so the residual common-mode error is small relative to the wanted differential signal, and an input common-mode range that extends past the supply rails so the receiver tolerates signalling voltages above its own rail. The 500 uV offset ceiling keeps static error low for AC-coupled or DC-coupled audio paths. Because the device is bipolar and precision rather than chopper-stabilised, it adds low noise without the switching artefacts of modern auto-zeroed amplifiers, which many audio designers prefer in the signal path.
מומלץ
Precision Test and Measurement Front End
Laboratory and production test equipment needs a front end that adds little error to the signal being measured, so the INA105KP is used as the first stage in differential measurement chains where the source is balanced and the gain is applied later. Its unity-gain, laser-trimmed resistor network keeps gain accuracy and CMRR stable over the -40 °C to +85 °C range, which matters for equipment that must hold calibration across a factory floor. The 1 MHz bandwidth is sufficient for process-control and instrumentation signals rather than high-speed data acquisition, and the 500 uV offset limit keeps measurement uncertainty small for millivolt-level measurements. The reference pin is tied to analog ground at the input stage so the instrument's zero reference is defined in one place, which simplifies calibration routines.
מומלץ
Power Supply and Converter Feedback Sensing
Inside switching converters and regulated power modules, the output voltage is often sensed differentially against a remote or ground-referenced reference to reject IR drop. The INA105KP provides a unity-gain differential sense stage whose 86 dB CMRR keeps switching ripple from modulating the feedback signal, and whose input common-mode range extending beyond the rails allows remote sensing at voltages above the local supply. Its low 500 uV offset ceiling limits the introduced error in a feedback loop where the sensed error band is often only a few millivolts. The device is used as the first element of the compensation network, and the reference pin is grounded locally so the loop compares against the true power ground rather than a noisy signal ground.
מומלץ
סיכום מוצרים מומלצים
נתוני עזר הנדסיים עבור INA105KP — השוואה, הנחיות תכנון ומידע על תאימות.
מדריך בחירה
Choose the INA117P when you want a unity-gain part with the same footprint and essentially the same function and you prefer to stay within a single manufacturer's newer precision differential amplifier line. Choose the INA126P only when you actually want programmable gain above unity and are willing to add a gain-setting resistor. Choose the AD827ANZ or AD845ANZ when a cross-brand second source matters more than identical bias-current, offset and reference-pin behaviour, or when you need more bandwidth than the 1 MHz of the INA105KP. Avoid the INA106KP as a substitute: its fixed gain of 6 changes the signal level by a factor of six.
השוואה עם חלופות
| פרמטר | מוצר זה | INA117P | INA126P | AD827ANZ | AD845ANZ |
|---|---|---|---|---|---|
| Package | 8-pin PDIP (P package) | 8-pin PDIP - same footprint | 8-pin PDIP - same footprint | 8-pin PDIP - same footprint | 8-pin PDIP - same footprint |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Analog Devices | Analog Devices |
| Differential Gain | 1.000 (fixed unity) | 1.000 (fixed unity) | 1 to 1000 (external resistor) | 1.000 (fixed unity) | 1.000 (fixed unity) |
| Reference Pin Handling | REF pin for output referencing | REF pin for output referencing | REF pin for output referencing | Reference connection arrangement differs by manufacturer; verify | Reference connection arrangement differs by manufacturer; verify |
מבדילים עיקריים
- Factory-trimmed unity gain removes the external precision resistor network (לעומתAD827ANZ)
- Input common-mode range extends beyond the supply rails (לעומתINA126P)
- Fixed unity gain simplifies signal-chain design (לעומתINA117P)
- Well-understood precision bipolar noise character for audio and instrumentation paths (לעומתAD845ANZ)
הערות תכנון
Keep the two input traces of the INA105KP symmetric and short, and place the device close to the source of the differential signal. Because the part relies on on-chip resistor matching for its 86 dB CMRR, any asymmetry between the +IN and -IN traces (unequal lengths, different ground references, unequal input filtering) converts into differential error and reduces real-world rejection. Tie the REF pin directly to the analog ground plane with a short trace rather than routing it through the signal path, and use the same ground reference for the source and the receiver.
Do not substitute the INA106KP for the INA105KP even though both use the same 8-pin PDIP outline: the INA106 has a fixed gain of 6, so the output would be six times the intended level and would saturate the following stage. Similarly, the INA126P only behaves as a unity-gain device when the gain-setting resistor is omitted or configured for gain of 1, and adding that resistor changes the design. Verify the gain function, not just the footprint, whenever an alternative part is substituted on this design.
The INA105KP is a bipolar precision amplifier, so supply current is drawn continuously from both rails in dual-supply operation. Estimate the dissipation as the sum of rail currents multiplied by the respective rail voltages, and note that at +/-18 V the quiescent dissipation is far higher than at +/-5 V even though the signal path is unchanged. Decouple each supply pin with a local 0.1 uF ceramic capacitor plus a 1 uF to 10 uF bulk capacitor placed close to the pins, since supply noise couples directly into the output of a high-gain accuracy stage through finite PSRR.
If the inputs are fast or the source impedance is high, add matched input networks to both inputs; any mismatch in source impedance between +IN and -IN converts into an input offset error and also degrades CMRR. With a 1 MHz gain-bandwidth product, the INA105KP is suited to instrumentation-band signals rather than wideband data, so place a low-pass filter ahead of it if out-of-band content is present. Keep the feedback or reference path on the ground plane away from switching nodes to avoid injecting common-mode step currents that appear as output glitches.
מידע על תאימות
The INA105 is a commercial-grade precision analog device; the manufacturer documentation for the INA105 family covers the 8-pin PDIP, SOIC and TO-99 packages, and the KP ordering code identifies the 8-pin PDIP option. No explicit RoHS, REACH or conflict-minerals statement was located for the KP ordering code, so those fields are left as unknown rather than assumed.
