TLC556MD Equivalent & Substitute Parts

Part Overview

The TLC556MD is a dual timer/oscillator integrated circuit manufactured by Texas Instruments, classified as a 555-type timing device. This component operates at a maximum frequency of 2.1MHz and is housed in a 14-SOIC surface mount package. The TLC556MD is currently in Last Time Buy status, indicating that Texas Instruments has discontinued or will discontinue production. This status necessitates identification of equivalent and substitute components to ensure design continuity and procurement availability for applications requiring dual timer functionality.

Substiute Parts

TLC556MD

Texas InstrumentsIn Stock: 2027TLC556MD Datasheet

Current PartRFQ

ICM7556ISD+

Analog Devices Inc./Maxim IntegratedIn Stock: 2740ICM7556ISD+ Datasheet

MFR RecommendedRFQ

ICM7556ISD+T

Analog Devices Inc./Maxim IntegratedIn Stock: 1428ICM7556ISD+T Datasheet

MFR RecommendedRFQ

TLC556MDG4

Texas InstrumentsIn Stock: 1000TLC556MDG4 Datasheet

Parametric EquivalentRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the TLC556MD is determined by the following critical parameters:

Functional Compatibility: All substitute parts must be 555-type dual timer/oscillator integrated circuits with identical functional architecture to ensure pin-level and behavioral compatibility.

Package Compatibility: All substitute parts must use the 14-SOIC surface mount package with identical physical dimensions (0.154", 3.90mm Width) to ensure PCB layout compatibility without redesign.

Electrical Operating Range: Substitute parts must support the voltage supply range and operating temperature range of the application. The TLC556MD operates from 5V to 15V and -55°C to 125°C.

Supply Current: The TLC556MD draws 720 µA at nominal operating conditions. Substitute parts with lower supply current may be used in applications where power consumption is not a constraint.

Frequency Rating: The TLC556MD is rated for 2.1MHz maximum frequency. Substitute parts with equal or higher frequency ratings are acceptable for direct replacement.

The identified substitute parts are grouped into two categories:

Parametric Equivalent (TLC556MDG4): Identical electrical specifications and frequency rating to the TLC556MD, differing only in packaging format (Tube vs. alternative designation).

Manufacturer Recommended Substitutes (ICM7556ISD+, ICM7556ISD+T): Functionally compatible 555-type dual timer devices with identical package geometry but different electrical specifications, including lower maximum frequency (500kHz) and different supply current characteristics (60 µA).

Parameter Comparison

Engineering Selection Recommendations

For Direct Replacement (No Application Modification Required):

TLC556MDG4 is the primary equivalent for the TLC556MD. Both components are manufactured by Texas Instruments with identical electrical specifications, frequency rating, and operating temperature range. Both are ROHS3 compliant and carry MSL 1 rating. The TLC556MDG4 maintains the same 2.1MHz frequency capability and 720 µA supply current, ensuring functional equivalence in all timing-critical applications. Both components are in Last Time Buy status, indicating limited future availability.

For Applications with Relaxed Frequency Requirements:

ICM7556ISD+ and ICM7556ISD+T are functionally compatible substitutes manufactured by Analog Devices Inc./Maxim Integrated. These components are currently in Active product status, ensuring long-term availability. Both variants use the identical 14-SOIC package and are ROHS3 compliant with MSL 1 rating. The primary electrical differences are: maximum frequency of 500kHz (versus 2.1MHz), supply current of 60 µA (versus 720 µA), and operating temperature range of -20°C to 85°C (versus -55°C to 125°C). These substitutes are suitable for applications where the timing frequency does not exceed 500kHz and the operating temperature range is within -20°C to 85°C.

Packaging Consideration:

ICM7556ISD+ is supplied in Tube packaging, while ICM7556ISD+T is supplied in Tape & Reel format. Selection between these variants depends on procurement and assembly requirements rather than electrical performance.

Frequently Asked Questions (FAQ)

Q: Can TLC556MDG4 be used as a direct replacement for TLC556MD?

A: Yes. TLC556MDG4 is a parametric equivalent with identical electrical specifications, frequency rating, operating temperature range, and package geometry. No circuit modifications are required for substitution.

Q: What is the primary limitation of ICM7556ISD+ and ICM7556ISD+T as substitutes?

A: The maximum frequency rating is 500kHz, compared to 2.1MHz for the TLC556MD. These substitutes are suitable only for applications where the required timing frequency does not exceed 500kHz. Additionally, the operating temperature range is limited to -20°C to 85°C, which may not be acceptable for applications requiring the full -55°C to 125°C range of the TLC556MD.

Q: Are all substitute parts RoHS compliant?

A: Yes. TLC556MDG4, ICM7556ISD+, and ICM7556ISD+T are all ROHS3 compliant with MSL 1 rating, matching the compliance status of the TLC556MD.

Q: What is the difference between ICM7556ISD+ and ICM7556ISD+T?

A: Both components are electrically identical. The difference is packaging format: ICM7556ISD+ is supplied in Tube packaging, while ICM7556ISD+T is supplied in Tape & Reel format. Selection depends on procurement volume and assembly line requirements.

Q: Why is the TLC556MD in Last Time Buy status?

A: Last Time Buy status indicates that Texas Instruments has announced the discontinuation of this product. Customers are advised to place final orders within a specified timeframe. After this period, the component will no longer be available from the manufacturer.

Q: Can I use ICM7556ISD+ in a high-temperature application requiring -55°C operation?

A: No. ICM7556ISD+ is rated for -20°C to 85°C operating temperature. For applications requiring -55°C operation, TLC556MDG4 or TLC556MD must be used, as both support the full -55°C to 125°C range.

Q: Is the 14-SOIC package identical across all substitute parts?

A: Yes. All substitute parts use the 14-SOIC package with identical physical dimensions (0.154", 3.90mm Width). No PCB layout modifications are required for package compatibility.