INA133U - 1.5MHz Precision Difference Amplifier | TI
MPN: INA133U ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.8407 | $3.84 |
| 10 | $3.8407 | $38.41 |
| 100 | $3.8407 | $384.07 |
| 500 | $3.8407 | $1,920.35 |
| 1,000 | $3.8407 | $3,840.70 |
INA133U Overview
A difference amplifier is a specialized analog amplifier that amplifies the voltage difference between two inputs while rejecting signals common to both inputs. This function is useful when a sensor, transducer, or measurement node is exposed to large common-mode voltages and the desired information exists only as a small differential signal. In the broader hierarchy, the INA133U belongs to instrumentation and difference amplifiers, within operational amplifiers and analog signal-conditioning ICs.
The INA133U combines 1.5 MHz bandwidth with low offset voltage and low power consumption. Its high-speed behavior makes it suitable for current-shunt monitoring, bridge excitation, differential sensing, and industrial signal-conditioning systems. The on-chip laser-trimmed resistors are designed to improve gain accuracy and common-mode rejection, while their temperature-coefficient tracking helps preserve performance across temperature changes.
The precision architecture is important because it combines amplifier bandwidth with accurate differential gain. A difference amplifier can reject shared interference, but its usefulness still depends on common-mode voltage staying within the device operating limits and on the surrounding circuit presenting suitable impedance and filtering. Designers should verify the complete input, output, supply, and common-mode conditions from the manufacturer datasheet.
Typical applications include high-side current measurement, differential voltage sensing, bridge-based sensor interfaces, amplifier-input protection networks, and industrial control systems. In a shunt monitor, the INA133U can amplify the voltage across a low-ohm resistor while reducing the effect of supply or ground disturbances. In bridge sensing, it helps convert a small differential sensor output while rejecting common-mode excitation voltage.
The principal design trade-off is bandwidth versus precision and power. The 1.5 MHz bandwidth supports faster signal changes than a purely low-bandwidth precision amplifier, while the 0.95 mA power figure favors low-power systems. PCB layout should keep input traces short, use a solid ground reference, and provide stable supply bypassing. This page synthesizes the verified manufacturer and distributor information, practical design considerations, and carefully limited replacement guidance.
Drop-in alternatives for INA133U — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
INA133U/2K5
✅ Drop-In📋 Reference alternative (not in catalog)
INA133UA
✅ Drop-In📋 Reference alternative (not in catalog)
INA133UE4
✅ Drop-In📋 Reference alternative (not in catalog)
INA133U Maximum Ratings & Electrical Characteristics
| Product Type | Precision difference amplifier |
| Amplifier Configuration | Single amplifier |
| Gain | Unity gain |
| Bandwidth | 1.5 MHz |
| Offset Voltage | 450 µV maximum |
| Offset Voltage Drift | 5 µV/°C maximum |
| Supply Current | 0.95 mA typical |
| Operating Temperature Range | -40 °C to +85 °C |
| Package | 8-pin SOIC |
| Mounting Type | Surface mount |
| Resistor Network | Laser-trimmed on-chip precision resistor network |
| Common-Mode Rejection Mechanism | Matched resistor-network tracking |
| RoHS Status | unknown |
| REACH Status | unknown |
INA133U 8-pin soic Pin Configuration Guide
Pin configuration for INA133U (8-pin soic 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 INA133U.
Refer to the datasheet for full pin configuration.
Typical Applications
INA133U is suitable for 6 applications: High-Side Current Shunt Monitoring, Bridge Sensor Interface, Industrial Differential Voltage Sensing, Battery and Power-System Monitoring, Precision Analog Signal Conditioning, High-Speed Differential Acquisition.
High-Side Current Shunt Monitoring
The INA133U fits high-side current sensing because it amplifies the small voltage generated across a shunt while rejecting the supply common-mode voltage. Its verified 1.5 MHz bandwidth handles faster current transients better than a very slow precision-only amplifier, while the 450 µV maximum offset establishes the initial dc-error scale to consider against the shunt voltage. Place the amplifier across the shunt, keep the input loop compact, and verify that the common-mode voltage and output swing remain within the datasheet limits. The main trade-off is that a wide bandwidth can increase sensitivity to fast transients and layout noise, so input filtering should be selected according to the measured current bandwidth rather than copied blindly.
Recommended
Bridge Sensor Interface
For strain, pressure, or resistive bridge sensors, the INA133U can amplify the small differential bridge output while rejecting much of the excitation voltage appearing equally on both inputs. The 1.5 MHz bandwidth provides response capability beyond static dc measurement, and the laser-trimmed resistor network supports accurate differential gain. Place the amplifier close to the bridge return, keep both input traces similarly routed, and use a quiet ground plane to reduce excitation-to-output leakage. Because the verified material does not provide the complete input common-mode range or output swing, the bridge excitation must be selected only after checking the current TI datasheet and the sensor's full-scale output.
Recommended
Industrial Differential Voltage Sensing
The INA133U is suitable for industrial measurement boards that must distinguish a small voltage difference in the presence of a larger shared process voltage. Its difference-amplifier architecture helps reject common-mode disturbances that affect both sensor nodes equally, while the 0.95 mA power figure supports lower-power acquisition systems. Use short differential routing, solid grounding, and local bypass capacitance so switching regulators and motor-return currents do not enter the input loop. Verify the operating common-mode voltage, output headroom, and temperature range from the manufacturer datasheet; the verified -40 °C to +85 °C source specification does not by itself establish suitability for extended industrial temperature grades.
Recommended
Battery and Power-System Monitoring
The INA133U can monitor differential voltage in battery-management and power-system circuitry when the measurement requires high-side sensing and common-mode rejection. The 1.5 MHz bandwidth permits measurement of dynamic events, while the low reported power consumption of approximately 0.95 mA helps when the sensing path must remain efficient. The circuit should be placed near the monitored nodes, with the shunt or divider return isolated from noisy power-switching currents. Confirm that the monitored common-mode voltage does not exceed the datasheet limits and that the output can swing far enough to represent the required measurement range. The obsolete lifecycle status makes a qualified replacement review especially important for new production designs.
Recommended
Precision Analog Signal Conditioning
The INA133U is useful as a precision difference-amplifier stage when a downstream converter or ADC needs a small differential signal amplified without adding a second, separate common-mode amplifier. Its unity-gain architecture simplifies feedback-free system design, and the 450 µV maximum offset plus 5 µV/°C maximum drift define important dc-error considerations. Place input components near the amplifier, maintain matched routing, and use filtering to limit out-of-band noise without sacrificing the intended measurement bandwidth. The verified data does not specify the exact common-mode-rejection curve or output-noise density, so those values must be obtained from the official TI datasheet before setting the analog front-end gain and filter corner.
Recommended
High-Speed Differential Acquisition
The INA133U can serve as the first analog stage in a high-speed differential acquisition path where the sensor or source produces a bipolar signal riding on a larger common-mode level. Its 1.5 MHz bandwidth is the primary verified speed metric, allowing the amplifier to preserve signal transitions substantially above dc. The layout must minimize input-loop area, provide a low-impedance return, and account for parasitic capacitance introduced by long traces and protection components. Do not assume unity gain implies zero bandwidth or zero settling requirements; verify slew rate, settling behavior, output swing, and common-mode range in the manufacturer datasheet before specifying the acquisition bandwidth.
Recommended
Recommended Products Summary
Engineering reference data for INA133U — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | INA133U/2K5 | INA133UA | INA133UE4 |
|---|---|---|---|---|
| Product Type | Precision unity-gain difference amplifier | Precision difference amplifier replacement candidate | INA133 family device | INA133 family device |
| Brand | Texas Instruments | Texas Instruments | Texas Instruments | Texas Instruments |
| Package | SOIC-8 | SOIC-8 | SOIC-8 | SOIC-8 |
Key Differentiators
- Difference-amplifier integration (vs AD623ANZ)
- Verified replacement path (vs INA133U/2K5)
- Bandwidth and power balance (vs INA133UA)
Design Notes
Keep the two INA133U input paths short, symmetric, and close to the source being measured. For a shunt monitor, route directly across the shunt terminals and avoid sharing input-return copper with switching or motor-return currents. The amplifier's common-mode rejection can be impaired by unequal routing, parasitic impedance, and unequal input filtering. Confirm the official pin assignment before placing protection components because the supplied excerpts do not provide the complete numbered pinout.
Place supply-bypass capacitance close to the power pins and use a quiet ground reference for the differential measurement loop. The verified product listing reports approximately 0.95 mA power consumption, but actual dissipation depends on supply voltage and operating current. Estimated: dissipation equals supply voltage times measured supply current; for example, 5 V times 0.95 mA is approximately 4.75 mW. This is an estimate based on the verified current figure, not a datasheet power specification.
Do not assume the INA133U can replace every INA133 orderable part without qualification. The verified TI support result states that INA133U/2K5 is the recommended replacement for discontinued INA133U, but also highlights a temperature-rating concern for a -54 °C system. Check the exact ordering code, temperature range, offset, bandwidth, supply limits, and lifecycle documentation before releasing a replacement to production.
Compliance Information
The supplied verified data does not state RoHS, REACH, lead-free, halogen-free, conflict-minerals, or automotive qualification status. The INA133U is not identified as AEC-Q100 qualified in the supplied material.