THS3111ID Current Feedback Amplifier Equivalent & Substitute Parts

Part Overview

The THS3111ID is an active linear amplifier integrated circuit manufactured by Texas Instruments, classified as a current feedback operational amplifier with a single circuit configuration. The device is packaged in an 8-SOIC surface mount package and is currently in active production status with ROHS3 compliance. This part is used in high-speed signal conditioning and amplification applications requiring controlled slew rate and bandwidth characteristics. Substitute parts are identified when original inventory is unavailable, when alternative packaging formats are required, or when design specifications permit operation within the electrical and mechanical tolerances of equivalent devices.

Substiute Parts

THS3111ID

Texas InstrumentsIn Stock: 1125THS3111ID Datasheet

Current PartRFQ

LT1228CS8#PBF

Analog Devices Inc.In Stock: 1406LT1228CS8#PBF Datasheet

MFR RecommendedRFQ

LT1228CS8#TRPBF

Analog Devices Inc.In Stock: 1501LT1228CS8#TRPBF Datasheet

MFR RecommendedRFQ

LT1228IS8#PBF

Analog Devices Inc.In Stock: 27895LT1228IS8#PBF Datasheet

MFR RecommendedRFQ

LT1252CS8#PBF

Analog Devices Inc.In Stock: 1196LT1252CS8#PBF Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the THS3111ID is determined by electrical and mechanical compatibility within the following criteria:

Primary Substitution Parameters:

• Amplifier Type: Current Feedback (required match)
• Number of Circuits: 1 (required match)
• Package / Case: 8-SOIC form factor (required match)
• Mounting Type: Surface Mount (required match)
• Operating Temperature Range: Must encompass or match the application requirement
• Voltage Supply Span: Must accommodate the system supply voltage range
• Slew Rate: Application-dependent; higher values provide additional performance margin
• Bandwidth (-3dB): Application-dependent; higher values provide additional performance margin

Acceptable Variation Parameters:

• Current - Input Bias: Variation acceptable if circuit design compensates for input impedance differences
• Voltage - Input Offset: Variation acceptable if circuit design includes offset nulling or if application tolerance permits
• Current - Supply: Variation acceptable if power supply design accommodates increased or decreased current draw
• Current - Output / Channel: Variation acceptable if load impedance and current requirements are within device capability

The substitute parts listed below maintain the core functional classification (current feedback amplifier, single circuit, 8-SOIC package) while offering alternative electrical performance characteristics and operating temperature ranges suitable for different application requirements.

Parameter Comparison

Engineering Selection Recommendations

LT1228IS8#PBF (Recommended Primary Substitute)

The LT1228IS8#PBF is the preferred substitute when direct replacement of the THS3111ID is required. This device maintains identical operating temperature range (-40°C to 85°C), matching the thermal specifications of the original part. The 8-SOIC package, surface mount configuration, and tube packaging format provide mechanical and logistical compatibility. The LT1228IS8#PBF offers enhanced slew rate performance (3500 V/µs versus 1300 V/µs), providing additional performance margin in high-speed applications. Supply voltage range (4 V to 36 V) encompasses the THS3111ID requirement (10 V to 30 V). Both devices are active production status with ROHS3 compliance and REACH unaffected designation. Input offset voltage specification (3 mV) is identical. The increased input bias current (10 µA versus 1.5 µA) and supply current (6 mA versus 4.8 mA) must be evaluated within the context of circuit design and power budget constraints.

LT1228CS8#PBF (Alternative Substitute - Commercial Temperature Range)

The LT1228CS8#PBF provides equivalent electrical performance to the LT1228IS8#PBF with identical slew rate (3500 V/µs) and bandwidth (100 MHz). Operating temperature range is restricted to 0°C to 70°C, limiting applicability to commercial-grade applications. This device is suitable for substitution only when the application environment does not require extended temperature operation below 0°C or above 70°C. Packaging format (tube) and 8-SOIC configuration match the original part. All compliance certifications (ROHS3, REACH unaffected) are maintained.

LT1228CS8#TRPBF (Alternative Substitute - Tape & Reel Packaging)

The LT1228CS8#TRPBF is electrically identical to LT1228CS8#PBF with the exception of packaging format (Tape & Reel versus Tube). This variant is selected when high-volume automated assembly processes require tape and reel delivery format. Operating temperature range (0°C to 70°C) and all electrical specifications remain unchanged. Current output per channel specification (125 mA) is provided for this variant, whereas the tube-packaged LT1228CS8#PBF does not specify this parameter.

LT1252CS8#PBF (Alternative Substitute - Video Amplifier Application)

The LT1252CS8#PBF is a current feedback amplifier optimized for video and wideband signal applications, offering significantly higher bandwidth (282 MHz versus 100 MHz) at the cost of reduced slew rate (125 V/µs versus 1300 V/µs). This device is suitable for substitution only when application requirements prioritize bandwidth performance over slew rate. Supply voltage range (4 V to 28 V single supply, ±2 V to ±14 V dual supply) encompasses the THS3111ID requirement. Increased supply current (8.5 mA versus 4.8 mA) and reduced output current capability (55 mA versus 260 mA) must be evaluated against circuit requirements. Operating temperature range is not specified in the provided data. ROHS3 compliance and REACH unaffected status are maintained.

Frequently Asked Questions (FAQ)

Q: Can the LT1228IS8#PBF directly replace the THS3111ID in all applications?

A: The LT1228IS8#PBF is mechanically and functionally compatible with the THS3111ID in terms of package type (8-SOIC), circuit count (1), and amplifier classification (current feedback). Both devices operate across the temperature range -40°C to 85°C. However, electrical parameter differences must be evaluated: the LT1228IS8#PBF has higher input bias current (10 µA versus 1.5 µA), higher supply current (6 mA versus 4.8 mA), and higher slew rate (3500 V/µs versus 1300 V/µs). Circuit designs that depend on low input bias current or low power consumption may require modification. Applications that benefit from higher slew rate performance will operate within improved specifications.

Q: What is the difference between LT1228CS8#PBF and LT1228CS8#TRPBF?

A: These devices are electrically identical. The primary difference is packaging format: LT1228CS8#PBF is supplied in tube packaging, while LT1228CS8#TRPBF is supplied in tape and reel format. Tape and reel packaging is used for high-volume automated assembly processes, while tube packaging is used for lower-volume or manual assembly operations. Both variants have restricted operating temperature range (0°C to 70°C) compared to the THS3111ID (-40°C to 85°C).

Q: When should the LT1252CS8#PBF be selected as a substitute?

A: The LT1252CS8#PBF is selected when the application requires bandwidth performance significantly higher than 100 MHz. This device offers 282 MHz bandwidth, making it suitable for video amplification and wideband signal conditioning applications. However, the slew rate is substantially lower (125 V/µs versus 1300 V/µs), which may limit performance in applications requiring rapid signal transitions. Output current capability is also reduced (55 mA versus 260 mA). Selection of this device requires confirmation that bandwidth requirements take priority over slew rate and output current specifications.

Q: Are all substitute parts ROHS3 compliant?

A: Yes. All substitute parts listed (LT1228CS8#PBF, LT1228CS8#TRPBF, LT1228IS8#PBF, and LT1252CS8#PBF) are ROHS3 compliant and REACH unaffected, matching the compliance status of the THS3111ID. All devices are in active production status.

Q: What is the impact of increased input bias current in the LT1228 series?

A: The LT1228 series devices specify 10 µA input bias current compared to 1.5 µA for the THS3111ID. Input bias current flows into the amplifier input terminals and can affect circuit performance in high-impedance applications. Circuits designed with the THS3111ID may require input impedance compensation or offset nulling adjustments when substituted with LT1228 devices. Low-impedance signal sources (below 1 kΩ) are generally unaffected by this parameter difference.

Q: Can the THS3111ID be substituted with LT1228 devices in applications requiring -40°C operation?

A: The LT1228CS8#PBF and LT1228CS8#TRPBF are rated only to 0°C minimum operating temperature and cannot be used in applications requiring -40°C operation. The LT1228IS8#PBF is rated to -40°C and is the only LT1228 variant suitable for extended low-temperature applications. Verification of all electrical parameters within the -40°C to 85°C operating range is required before final design approval.

Q: What supply voltage range is acceptable for each substitute part?

A: THS3111ID requires 10 V to 30 V supply span. LT1228CS8#PBF, LT1228CS8#TRPBF, and LT1228IS8#PBF accept 4 V to 36 V supply span, providing broader compatibility with different power supply designs. LT1252CS8#PBF accepts 4 V to 28 V single supply or ±2 V to ±14 V dual supply. All substitute parts can operate within the THS3111ID supply voltage range, but designs utilizing supply voltages below 10 V or above 30 V require selection of appropriate substitute devices.