OPA655U Equivalent & Substitute Parts

Part Overview

The OPA655U is a voltage feedback amplifier manufactured by Texas Instruments, housed in an 8-SOIC surface mount package. This device is classified as obsolete, indicating discontinued production and limited availability. The OPA655U delivers a gain bandwidth product of 240 MHz with a slew rate of 295 V/µs, making it suitable for high-speed signal conditioning applications. Due to its obsolete status, identifying compatible substitute components is essential for design continuity and procurement planning.

Substiute Parts

OPA655U

Texas InstrumentsIn Stock: 1449OPA655U Datasheet

Current PartRFQ

OPA656U

Texas InstrumentsIn Stock: 3577OPA656U Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the OPA655U is determined by strict alignment of electrical and mechanical parameters within the voltage feedback amplifier category. The primary substitute identified is the OPA656U, also manufactured by Texas Instruments. Substitution validity is established through the following criteria:

Electrical Compatibility Parameters:

• Amplifier topology (voltage feedback architecture)
• Number of circuits (single circuit configuration)
• Slew rate performance (295 V/µs maintained)
• Gain bandwidth product (230 MHz minimum, acceptable for OPA655U applications)
• Input bias current specification (2 pA, superior to OPA655U)
• Input offset voltage (250 µV, superior to OPA655U)
• Output current capability (70 mA, exceeds OPA655U requirement)
• Operating temperature range (-40°C to 85°C, identical)

Mechanical Compatibility Parameters:

• Package type (8-SOIC surface mount, identical footprint)
• Package dimensions (0.154" × 3.90mm width, identical)

Supply Voltage Consideration: The OPA656U operates across 8 V to 12 V supply span, which encompasses the OPA655U supply range of 9.5 V to 10.5 V, ensuring direct compatibility in existing power distribution designs.

Parameter Comparison

Engineering Selection Recommendations

Primary Substitute: OPA656U

The OPA656U is the direct substitute for the OPA655U based on electrical and mechanical parameter alignment. Selection of the OPA656U is supported by the following factors:

1. Product Status Transition: The OPA655U is obsolete, while the OPA656U carries a Last Time Buy status, providing a defined procurement window for design migration.

2. Regulatory Compliance: The OPA656U achieves ROHS3 compliance, whereas the OPA655U is RoHS non-compliant. This distinction is significant for applications subject to environmental regulations and supply chain requirements.

3. Electrical Performance: The OPA656U demonstrates superior input characteristics (2 pA input bias current versus 5 pA, and 250 µV input offset versus 1 mV), while maintaining identical slew rate performance and comparable gain bandwidth product (230 MHz versus 240 MHz).

4. Power Efficiency: The OPA656U operates at 14 mA supply current compared to the OPA655U's 25 mA, reducing power dissipation in battery-powered or thermally constrained applications.

5. Supply Voltage Flexibility: The OPA656U's 8 V to 12 V supply range provides broader operational margin than the OPA655U's 9.5 V to 10.5 V specification.

6. Mechanical Compatibility: Identical 8-SOIC package and footprint dimensions enable direct PCB layout compatibility without redesign.

Frequently Asked Questions (FAQ)

Q1: Can the OPA656U directly replace the OPA655U in existing designs?

A: Yes. The OPA656U is electrically and mechanically compatible with the OPA655U. Both devices share identical slew rate (295 V/µs), operating temperature range (-40°C to 85°C), and 8-SOIC package footprint. The OPA656U's supply voltage range (8 V to 12 V) encompasses the OPA655U's operating range (9.5 V to 10.5 V), ensuring compatibility in existing power supply designs.

Q2: What are the key performance differences between OPA655U and OPA656U?

A: The OPA656U offers improved input characteristics with lower input bias current (2 pA versus 5 pA) and lower input offset voltage (250 µV versus 1 mV). The OPA656U also operates at reduced supply current (14 mA versus 25 mA). The gain bandwidth product is slightly lower in the OPA656U (230 MHz versus 240 MHz), which remains acceptable for most voltage feedback amplifier applications.

Q3: Are there compliance differences between these parts?

A: Yes. The OPA656U is ROHS3 compliant, while the OPA655U is RoHS non-compliant. For applications subject to environmental regulations or customer requirements mandating RoHS compliance, the OPA656U is the appropriate selection.

Q4: What is the packaging difference between OPA655U and OPA656U?

A: Both devices are supplied in 8-SOIC surface mount packages with identical physical dimensions (0.154" × 3.90mm width). The OPA655U is supplied in standard packaging, while the OPA656U is supplied in Tube packaging. This difference does not affect electrical performance or PCB compatibility.

Q5: Is the OPA656U available for new procurement?

A: The OPA656U carries a Last Time Buy status, indicating that Texas Instruments has defined a final procurement window before discontinuation. Current inventory availability is 3565 pieces. For long-term production requirements, design migration planning should begin immediately.

Q6: What supply voltage should be used when substituting OPA656U for OPA655U?

A: The OPA655U operates within 9.5 V to 10.5 V. The OPA656U accepts 8 V to 12 V. Existing power supply designs using 9.5 V to 10.5 V will operate the OPA656U within specification. No power supply modification is required for substitution.