TLC545CFN Equivalent & Substitute Parts

Part Overview

The TLC545CFN is an 8-bit Analog to Digital Converter (ADC) manufactured by Texas Instruments, designed for data acquisition applications requiring multiplexed input sampling with integrated sample-and-hold functionality. This device features 20 single-ended inputs, a SAR (Successive Approximation Register) architecture, and SPI data interface, operating from a 5V supply across the industrial temperature range of 0°C to 70°C.

The TLC545CFN is classified as obsolete. Identifying equivalent and substitute parts is necessary to maintain design continuity, ensure supply chain reliability, and support long-term product availability for legacy systems and new designs requiring compatible functionality.

Substiute Parts

TLC545CFN

Texas InstrumentsIn Stock: 713TLC545CFN Datasheet

Current PartRFQ

ADS7961SRHBT

Texas InstrumentsIn Stock: 825ADS7961SRHBT Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the TLC545CFN is evaluated based on core functional parameters that determine electrical and mechanical compatibility:

Primary Substitution Criteria:

• Resolution: 8-bit ADC architecture maintained
• Sampling Rate: Minimum 76 kSPS to support equivalent throughput
• Input Type: Single-ended input configuration
• Data Interface: SPI protocol compatibility
• Architecture: SAR-based conversion method
• Supply Voltage Compatibility: Operation within or overlapping the 5V supply domain

Secondary Compatibility Factors:

• Number of Inputs: Functional equivalence with multiplexed input capability
• Package Type: Surface mount technology with pinout compatibility considerations
• Product Status: Active or current production status preferred for long-term availability
• Compliance: RoHS3 and REACH compliance maintained

The ADS7961SRHBT meets the core functional requirements as an 8-bit SAR ADC with SPI interface, single-ended inputs, and active product status. While it features reduced input channels (16 vs. 20) and operates at higher sampling rates (1 MSPS), it maintains electrical compatibility and provides enhanced performance characteristics suitable for legacy system replacement.

Parameter Comparison

Engineering Selection Recommendations

The ADS7961SRHBT is designated as the manufacturer-recommended substitute for the TLC545CFN based on functional equivalence and active product status. Both devices maintain ROHS3 compliance and REACH unaffected status, ensuring regulatory continuity.

Key considerations for selection:

Advantages of ADS7961SRHBT:

• Active product status ensures long-term availability and supply chain stability
• Extended operating temperature range (-40°C to 125°C) provides broader environmental compatibility
• Higher sampling rate (1 MSPS) supports increased throughput requirements
• Wider supply voltage range (2.7V to 5.25V) enables flexible power architecture implementation
• Smaller package footprint (32-VQFN 5x5 vs. 28-PLCC 11.51x11.51) reduces PCB area requirements

Design Considerations:

• Input channel reduction from 20 to 16 requires circuit-level multiplexing evaluation
• Package transition from PLCC to VQFN necessitates PCB layout redesign
• Digital supply voltage range (1.7V to 5.25V) permits lower-voltage logic interface compatibility

Frequently Asked Questions (FAQ)

Q: Can the ADS7961SRHBT directly replace the TLC545CFN without circuit modifications?

A: Direct pin-for-pin replacement is not possible due to package differences (28-PLCC vs. 32-VQFN) and pinout variations. PCB layout redesign is required. However, functional substitution is viable with circuit-level adaptation for the reduced input channel count (16 vs. 20).

Q: What is the impact of reduced input channels (16 vs. 20)?

A: The ADS7961SRHBT provides 16 multiplexed single-ended inputs compared to 20 on the TLC545CFN. Applications requiring all 20 channels must implement external multiplexing or use multiple ADS7961SRHBT devices in parallel configuration.

Q: Are the SPI interfaces compatible between these devices?

A: Both devices implement SPI data interface protocol. Timing parameters and command structures must be verified against respective datasheets to ensure software compatibility during migration.

Q: Does the ADS7961SRHBT support the same 5V supply voltage as the TLC545CFN?

A: Yes. The ADS7961SRHBT operates across 2.7V to 5.25V for analog supply and 1.7V to 5.25V for digital supply, encompassing the TLC545CFN's 5V requirement. Existing 5V power distribution can be maintained.

Q: What are the compliance and regulatory implications of this substitution?

A: Both devices maintain ROHS3 compliance and REACH unaffected status. No regulatory documentation changes are required for compliance purposes.

Q: How does the sampling rate difference affect system performance?

A: The ADS7961SRHBT operates at 1 MSPS versus the TLC545CFN's 76 kSPS. This higher sampling rate provides improved temporal resolution and supports faster data acquisition, representing a performance enhancement rather than a limitation.

Q: What packaging considerations apply to this substitution?

A: The transition from 28-PLCC surface mount to 32-VQFN surface mount requires PCB redesign. The VQFN package features a smaller footprint (5x5 mm) and exposed pad for thermal management, improving thermal performance compared to the PLCC package.