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Home > Products > Integrated Circuits (ICs) > Linear > Instrumentation, Op Amps, Buffer Amps

STMicroelectronics TS921IN

Name: TS921IN
Brand: STMicroelectronics
SKU: TS921IN
Price: 2.40 USD
Availability: InStock
Rating: 5 (2 reviews)

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Part No.:: TS921IN

Manufacturer:: STMicroelectronics

Category:: Instrumentation, Op Amps, Buffer Amps

Package:: 8-DIP (0.300", 7.62mm)

Datasheet:: TS921IN.pdf

Description:: IC OPAMP GP 1 CIRCUIT 8DIP

Quantity:: RFQ Add To RFQ list

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Inventory:3,176

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Product details

Overview

TS921IN from STMicroelectronics is a rail-to-rail input/output single BiCMOS operational amplifier optimized for 3 V and 5 V battery-powered audio systems. It delivers 80 mA output current into 32 Ω loads, features 9 nV/√Hz input noise at 1 kHz, 4 MHz gain-bandwidth product, 1 V/μs slew rate, and operates from 2.7 V to 12 V supply.

For engineers reviewing the TS921IN datasheet, TS921IN pinout, TS921IN application, or TS921IN equivalent, key selection criteria include rail-to-rail swing capability, low-noise performance in portable audio front-ends, high-output-current drive for piezoelectric speakers, and stability with ≥500 pF capacitive loads without external compensation.

Technical Context

The TS921IN uses a BiCMOS input stage enabling rail-to-rail common-mode input range (V_CC − 0.2 V to V_CC + 0.2 V) and rail-to-rail output swing within 100 mV of rails under 32 Ω load. Its architecture supports stable unity-gain operation with 68° phase margin at 100 pF load capacitance.

It achieves low distortion (0.005% THD+N at 1 kHz, 2 V_pk-pk, R_L = 600 Ω) and high PSRR/CMRR (≥60 dB over full temperature range), making it suitable for precision analog signal conditioning where supply rejection and noise immunity are critical.

Key Specifications

Parameter	Value and Actual Design Meaning
Supply Voltage Range	2.7 V to 12 V - enables direct use in single-cell Li-ion (3.0–3.6 V), dual-cell alkaline (3.0 V), and 5 V logic-supplied systems.
Output Current	80 mA - drives low-impedance loads including 32 Ω headphones and piezoelectric actuators without external buffers.
Input Noise Density	9 nV/√Hz at 1 kHz - preserves signal integrity in microphone preamps and audio line drivers where SNR is critical.
Gain-Bandwidth Product	4 MHz - supports bandwidth-critical applications like servo amplifiers and active filters up to ~300 kHz closed-loop.
Slew Rate	1 V/μs - ensures faithful reproduction of fast transients in audio waveforms and actuator control signals.
Input Offset Voltage	3–5 mV max - minimizes DC error in precision DC-coupled gain stages and sensor interfaces.
Capacitive Load Drive	Stable up to 500 pF - eliminates need for isolation resistors when driving long cables or ADC input capacitance.

Pinout & Package

DIP8 plastic package (16.0 mm × 6.35 mm body, 2.54 mm lead pitch) with through-hole mounting and industry-standard pin spacing.

Pin/Terminal	Circuit Role	Design Meaning
1	Inverting Input (−)	Differential input node; accepts signals referenced to ground or virtual ground; rail-to-rail common-mode range.
2	Non-inverting Input (+)	Differential input node; supports input voltages from V_CC − 0.2 V to V_CC + 0.2 V relative to ground.
3	Output	Rail-to-rail output capable of sourcing/sinking 80 mA; swings within 100 mV of V_CC and GND under 32 Ω load.
4	Negative Supply (V−)	Ground reference terminal for single-supply operation; tied to 0 V in 3 V/5 V systems.
5	Positive Supply (V+)	Primary power connection; accepts 2.7–12 V; thermal resistance junction-to-ambient is 85 °C/W in DIP8.
6–8	No Connect / Unused	Not internally bonded; left unconnected per datasheet - no routing or termination required.

Key Features

Feature	Design Value
Rail-to-rail I/O	Enables full dynamic range utilization in low-voltage systems (e.g., 3 V supply yields >2.8 Vpp output swing into 600 Ω).
High Output Current	80 mA continuous drive allows direct interfacing with 32 Ω headphones and piezo elements without discrete output transistors.
Low Input Noise	9 nV/√Hz at 1 kHz supports high-fidelity audio paths where noise floor directly impacts perceived quality.
Capacitive Load Stability	Remains stable with up to 500 pF load capacitance - simplifies PCB layout for DAC output buffering or cable driving.
ESD Protection	1.5 kV HBM rating protects against handling damage during assembly and field service in consumer electronics environments.

Applications

Headphone Amplifier

Piezoelectric Speaker Driver

Use Scenario: Driving stereo 32 Ω dynamic headphones from a 3.3 V microcontroller DAC output in portable media players.

IC Role / Device Role / Timing Role: Single-supply voltage follower with gain-of-1 configuration, providing low-impedance buffered output and rail-to-rail swing.

Use Value: Delivers >2.6 Vpp output into 32 Ω while maintaining <0.005% THD+N, eliminating need for external level-shifting or boost circuitry.

Use Scenario: Driving high-impedance piezoelectric buzzer elements requiring fast voltage transitions and moderate current in alarm systems.

IC Role / Device Role / Timing Role: High-slew-rate voltage amplifier with capacitive load tolerance, configured as non-inverting gain stage.

Use Value: Achieves 1 V/μs slew rate and 500 pF stability to generate clean 2–5 kHz square-wave drive signals without ringing or overshoot.

Line Driver for Sound Cards

Servo Amplifier in Portable Instruments

Use Scenario: Buffering analog audio outputs from PC sound cards to external powered speakers over 1–2 m shielded cables.

IC Role / Device Role / Timing Role: Low-noise, unity-gain line driver with high PSRR to reject digital noise coupling from motherboard traces.

Use Value: 60 dB PSRR and 9 nV/√Hz noise ensure clean signal transmission even when sharing noisy 5 V supply with USB controllers.

Use Scenario: Closed-loop position control of small DC motors or voice coil actuators in handheld test equipment.

IC Role / Device Role / Timing Role: Precision error amplifier in PID feedback loop, operating from 5 V supply with low offset drift.

Use Value: 2 μV/°C offset drift and 3–5 mV max V_io minimize steady-state positioning error across −40 °C to +125 °C industrial temperature range.

Equivalent & Alternatives

The following parts are listed as comparable options for similar rail-to-rail audio op-amp applications.

Alternative Part	Technical Difference	Application Difference	Selection Advice
TLC27L2CP	Lower output current (10 mA), higher V_io (10 mV max), slower slew rate (0.05 V/μs)	Only suitable for high-impedance line-level outputs, not headphone or piezo drive	Select only if ultra-low quiescent current (120 μA) outweighs drive capability requirements.
MCP6001T-I/OT	Higher noise (17 nV/√Hz), lower output current (23 mA), same GBW (1 MHz)	Cannot drive 32 Ω loads; limited to 10 kΩ+ sources in audio paths	Prefer for cost-sensitive, low-power sensor signal conditioning-not audio output stages.

Compared with TLC27L2CP and MCP6001T-I/OT, the TS921IN uniquely combines 80 mA drive, 9 nV/√Hz noise, and rail-to-rail swing-making it the only option among the three qualified for direct 32 Ω headphone amplification and piezoelectric actuation in battery-powered designs.

Availability

TS921IN is available at Aetrix Electronics and suitable for portable audio systems, instrumentation front-ends, and industrial actuator interfaces requiring stable component supply across extended temperature ranges (−40 °C to +125 °C).

Supply support for TS921IN includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, MCU, power, and sensor solutions for industrial, automotive, and consumer markets.

The TS921IN belongs to ST's precision rail-to-rail op-amp product line, engineered specifically for low-voltage, high-fidelity audio and sensor signal conditioning where output drive strength and noise performance are primary design constraints.

FAQ

What is the maximum capacitive load the TS921IN can drive without oscillation?

The TS921IN remains stable with capacitive loads up to 500 pF when configured in unity-gain buffer mode, as verified by phase margin measurements (68°) and gain margin (12 dB) in the official datasheet. This eliminates the need for series isolation resistors when driving ADC inputs, long cables, or piezoelectric elements with inherent capacitance.

Does the TS921IN support true single-supply operation down to 2.7 V?

Yes - the TS921IN is fully specified for operation from 2.7 V to 12 V with rail-to-rail input and output swing. At 2.7 V supply, it maintains 80 mA output current capability, 4 MHz GBW, and 1 V/μs slew rate, enabling direct integration into single-cell Li-ion and two-cell alkaline battery systems without voltage boosting.

How does the TS921IN's 9 nV/√Hz noise compare to standard bipolar op-amps?

At 1 kHz, the TS921IN's 9 nV/√Hz input voltage noise is comparable to precision bipolar op-amps like the NE5532 (5 nV/√Hz) but significantly lower than general-purpose CMOS devices (e.g., MCP6001 at 17 nV/√Hz). This enables high-SNR audio paths in portable gear where battery voltage limits headroom and noise directly impacts audible performance.

Can the TS921IN be used in inverting amplifier configurations with gain greater than 1?

Yes - the TS921IN supports stable inverting configurations with gains ≥1, provided the feedback network maintains adequate phase margin. The datasheet confirms stability with 100 pF load and 600 Ω load; for higher gains, keep total input capacitance below 10 pF and avoid excessive parasitic capacitance at the inverting node to preserve bandwidth and transient response.

TS921IN Specifications

Product attributes: Attribute value

Manufacturer:: STMicroelectronics

Series:: -

Package/Case:: 8-DIP (0.300", 7.62mm)

Packaging:: Tube

Product Status:: Obsolete

Amplifier Type:: General Purpose

Number of Circuits:: 1

Output Type:: Rail-to-Rail

Slew Rate:: 1.3V/µs

Gain Bandwidth Product:: 4 MHz

-3db Bandwidth:: -

Current - Input Bias:: 15 nA

Voltage - Input Offset:: 3 mV

Current - Supply:: 1mA

Current - Output / Channel:: 80 mA

Voltage - Supply Span (Min):: 2.7 V

Voltage - Supply Span (Max):: 12 V

Operating Temperature:: -40°C ~ 125°C

Grade:: -

Qualification:: -

Mounting Type:: Through Hole

Supplier Device Package:: 8-DIP

TS921IN FAQ

1.How can I place an order for TS921IN through Aetrix?

Please submit a Request for Quotation (RFQ) for TS921IN on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.

2.Are the price and stock information for TS921IN reliable?

The price and inventory of TS921IN are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for TS921IN is usually 5 days.

3.What payment methods are accepted for TS921IN?

We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for TS921IN transactions.

Note: Certain payment methods may incur a processing fee.

4.How is shipping managed for TS921IN?

TS921IN orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.

Once your TS921IN order is processed, you will receive an email with the shipment details and tracking number.

Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.

5.How can I obtain technical support or documentation for TS921IN?

For technical support, including TS921IN datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your TS921IN requirements.

6.How does Aetrix verify that TS921IN is sourced from the original manufacturer or authorized distributors?

All TS921IN products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that TS921IN meets industry standards.

7.What is the process for return or replacement of TS921IN?

All TS921IN units undergo pre-shipment inspection (PSI). If there is an issue with TS921IN, returns or replacements are accepted under the following conditions:

1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.

2.The issue is reported within 90 days of delivery.

3.The TS921IN part is unused and in its original packaging.

Return procedure for TS921IN:

1.Submit a request within 90 days.

2.Obtain a Return Material Authorization (RMA) from Aetrix.

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