LM258PT - Dual 1.1 MHz Low-Power Op Amp | STMicroelectronics
N.º de pieza: LM258PT ✓ ActivoLM258PT Descripción general
An operational amplifier, or op amp, is a high-gain differential-input amplifier whose inverting and non-inverting inputs produce a single-ended output. Internally frequency-compensated op amps such as the LM258PT are internally stabilized for unity-gain operation without an external compensation network. This makes them suitable for amplifier, buffer, comparator, transducer, and feedback-control circuits where simplicity and low quiescent current are more important than very high bandwidth.
Key characteristics include two amplifier circuits in one package, a large DC voltage gain of 100 dB, a 1.1 MHz unity-gain bandwidth, approximately 500 uA of supply current per amplifier, and a typical input bias current of 20 nA. Because the two channels are independent, engineers can use them for cascaded gain stages, differential signal conditioning, active filtering, or separate control and monitoring functions. The internal frequency compensation eliminates the need for external dominant-pole components in most unity-gain applications.
The LM258PT is a bipolar-input general-purpose amplifier rather than a rail-to-rail CMOS op amp. Its design is appropriate when a single supply rail is available, input-referred offset is not the dominant system requirement, and operation from a non-rail-to-rail output range is acceptable. Designers must still account for the output-swing limits, common-mode input range, stability requirements, and load capability described by the manufacturer datasheet.
Typical uses include low-frequency transducer amplification, sensor signal conditioning, audio preamplification, battery-powered instrumentation, feedback amplifiers in control loops, and general dual-amplifier boards. Its 8-pin TSSOP footprint permits compact surface-mount layouts, while the low 500 uA-per-amplifier supply current helps preserve battery life in portable systems.
The main design consideration is stability around the op amp. Place input and output components close to their associated pins, verify capacitive loading against the datasheet stability limits, and avoid driving the output into hard clipping when the input signal exceeds the available output swing. Using the device as a unity-gain buffer requires particular care with capacitive loads because the internal compensation is optimized for a specified load range.
This page consolidates manufacturer and distributor information, package details, verified pricing, drop-in alternatives, application guidance, and design notes. It is intended to complement the manufacturer datasheet with selection and implementation context that is not normally presented on a distributor listing page.
Alternativas directas para LM258PT — mismo encapsulado, compatible pin a pin. Se excluyen las piezas de otro encapsulado que requieren retrabajo de la PCB.
LM358PT
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Ver hoja de datos →LM358WPT
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LM258PT Valores máximos y características eléctricas
| Amplifier Type | Dual low-power bipolar operational amplifier |
| Number of Circuits | 2 independent amplifiers |
| Large Signal Voltage Gain | 100 dB |
| Unity-Gain Bandwidth | 1.1 MHz |
| Supply Current per Amplifier | Approximately 500 uA |
| Input Bias Current | 20 nA typical |
| Frequency Compensation | Internally frequency compensated |
| Supply Configuration | Single supply |
| Input Type | Differential bipolar input |
| Tipo de salida | Single-ended |
| Encapsulado | 8-pin TSSOP |
| Tipo de montaje | Surface mount |
Configuración de pines de LM258PT
| Pin 1 | OUT1 — Amplifier 1 output |
| Pin 2 | IN1- — Amplifier 1 inverting input |
| Pin 3 | IN1+ — Amplifier 1 non-inverting input |
| Pin 4 | V- — Negative supply or ground connection in single-supply operation |
| Pin 5 | IN2+ — Amplifier 2 non-inverting input |
| Pin 6 | IN2- — Amplifier 2 inverting input |
| Pin 7 | OUT2 — Amplifier 2 output |
| Pin 8 | V+ — Positive supply input |
Aplicaciones típicas
LM258PT es adecuado para 6 aplicacións: Low-Power Sensor Signal Conditioning, Battery-Powered Instrumentation, Audio Preamplifier Stage, Active Filtering and Feedback Control, Transducer Interface and Bridge Amplifier, Compact Dual-Signal Conditioning Board.
Low-Power Sensor Signal Conditioning
The LM258PT suits low-frequency sensor conditioning because each amplifier offers 100 dB large-signal voltage gain while drawing approximately 500 uA, reducing the power burden of two-channel measurement systems. Its typical 20 nA input bias current is favorable for relatively high-impedance sources, although the exact source impedance must be checked against the datasheet limits. Use one channel for amplification and the other for filtering, buffering, or an active transducer interface. Keep the amplifier in the linear region and confirm that the sensor's output lies inside the input common-mode range. Because this is a bipolar amplifier rather than a guaranteed rail-to-rail part, biasing or level shifting may be required near the supply rails.
Recomendado
Battery-Powered Instrumentation
The LM258PT is appropriate for portable instrumentation where each active amplifier consumes approximately 500 uA, allowing two measurement channels to share a compact 8-pin TSSOP. Its 1.1 MHz unity-gain bandwidth is more than adequate for many pressure, temperature, and resistance sensors operating at low or audio-band frequencies. Place local supply bypass capacitance beside the device and minimize the length of high-impedance input traces to reduce pickup. The main trade-off is that the bipolar architecture consumes current without the rail-to-rail input behavior associated with many CMOS amplifiers, so the system power budget must include any biasing or level-shifting circuitry.
Recomendado
Audio Preamplifier Stage
The LM258PT can provide modest audio gain in a single-supply preamplifier when the operating point and output swing are carefully chosen. Its 100 dB large-signal voltage gain and 1.1 MHz unity-gain bandwidth provide useful headroom for gain stages around microphones, pickups, and line-level sources. The amplifier is not rail-to-rail, so the quiescent output point must remain between its usable output limits. Add input coupling and biasing as required by the source, and verify stability with the selected feedback network. For low-noise audio channels where lower noise and rail-to-rail flexibility are more important than low supply current, an alternative such as the NE5534DR may be a better functional match.
Recomendado
Active Filtering and Feedback Control
The internally frequency-compensated LM258PT is well suited to unity-gain buffers, active filters, and feedback-control loops operating well below its 1.1 MHz unity-gain bandwidth. Two independent channels allow construction of a second-order active filter or a separate error amplifier in a control circuit. Stable resistor and capacitor values should be calculated around the closed-loop gain and the datasheet's unity-gain stability expectations. Avoid placing the amplifier directly at the output of a long cable or a heavily capacitive transducer; a series isolation resistor can reduce the risk of oscillation. The 500 uA-per-amplifier supply current also helps maintain a compact, low-power control board.
Recomendado
Transducer Interface and Bridge Amplifier
LM258PT can amplify the differential output of a resistive bridge or other low-level transducer when the source impedance is compatible with its typical 20 nA input bias current. Two channels permit differential excitation or the amplification of a bridge signal without requiring a dedicated instrumentation amplifier. The 1.1 MHz bandwidth supports many industrial measurement systems operating at low frequency, while the low supply current is beneficial in distributed sensor nodes. Designers must check common-mode range carefully because transducer signals can sit near a supply rail. Input protection, shielding, and a grounded guard region are as important as the amplifier selection when working with microvolt-level bridge signals.
Recomendado
Compact Dual-Signal Conditioning Board
The 8-pin TSSOP LM258PT lets engineers implement two independent analog channels in a compact surface-mount design. A typical board uses one amplifier for a first gain stage and the other for filtering or level shifting, reducing component count compared with two single-amplifier packages. The device operates from a single supply and does not require external frequency-compensation components in standard unity-gain use. Adequate bypass capacitance and short analog traces are essential, especially when both channels process small signals. The TSSOP footprint is compact but its fine lead pitch requires careful land patterns, solder-paste control, and adequate thermal performance during rework.
Recomendado
Resumen de productos recomendados
Datos de referencia de ingeniería para LM258PT — comparación, orientación de diseño e información de cumplimiento.
Guía de selección
Comparación con alternativas
| Parámetro | Este producto | LM358PT | LM358WPT |
|---|---|---|---|
| Package | 8-TSSOP | 8-TSSOP | 8-TSSOP |
| Brand | STMicroelectronics | STMicroelectronics | ROHM Semiconductor |
| Number of Amplifiers | 2 | 2 | 2 |
| Compensation | Internal | Internal | Internal |
| Supply Configuration | Single supply | Single supply | Single supply |
Diferenciadores clave
- Low-power focus within a dual general-purpose amplifier (frente a LM358PT)
- Two independent compensated amplifiers in an 8-pin TSSOP (frente a LM358WPT)
- Verified current distributor availability and low starting unit price (frente a LM358WPT)
Notas de diseño
Do not assume that every LM358-family orderable part is a footprint-compatible replacement for LM258PT. The verified search results include LM358PT and LM358WPT, but the same dual-amplifier families are also offered in DIP and SOIC packages. Before changing the BOM, confirm the package drawing, pin numbering, and pin names, then compare supply range, common-mode input range, output swing, offset voltage, bias current, and temperature rating. A matching package suffix is necessary but does not by itself guarantee regulatory qualification or identical AC noise behavior.
Place the supply bypass capacitor directly between the V+ and V- pins, and route the amplifier ground or negative-supply return without long loops beneath the device. Keep high-impedance input traces short, guard them where practical, and maintain spacing from switching nodes and digital clock lines. Because the LM258PT is an 8-pin TSSOP with a fine lead pitch, verify the land pattern against the manufacturer's mechanical drawing and use a paste stencil that supports reliable joint formation.
The LM258PT is internally compensated and intended primarily for unity-gain or moderate-gain closed-loop use. Avoid loading an output with a long cable, large sensor capacitance, or an ADC sampling input unless the capacitive load has been checked against the manufacturer stability guidance. When isolation is necessary, a small series resistor placed close to the op-amp output can damp the capacitive load and reduce the likelihood of oscillation. Validate the final configuration with a scope because parasitic capacitance can change the stability margin.
Información de cumplimiento
The supplied verified results identify the part, package, core performance values, distributor availability, and a starting price, but do not explicitly state RoHS, REACH, lead-free, halogen-free, or conflict-minerals status. The automotive qualification field is not applicable because the general-purpose LM258PT was not identified as an AEC-Q100-qualified automotive variant in the supplied data.
