LM340AS-5.0/NOPB Equivalent & Substitute Parts

Part Overview

The LM340AS-5.0/NOPB is a linear voltage regulator IC manufactured by Texas Instruments, designed to provide a fixed 5V positive output with 1A current capacity in a TO-263 (DDPAK-3) surface mount package. This part is classified as obsolete, making equivalent and substitute parts necessary for new designs and ongoing production requirements. The device operates across an input voltage range up to 35V with integrated over-current and short-circuit protection, suitable for power management applications requiring stable 5V regulation.

Key Parameters

Parameter	Value
Manufacturer Part Number	LM340AS-5.0/NOPB
Manufacturer	Texas Instruments
Category	Power Management (PMIC)
Output Voltage (Fixed)	5V
Output Current	1A
Input Voltage (Max)	35V
Voltage Dropout (Max)	2V @ 1A
Package / Case	TO-263-4, D2PAK (3 Leads + Tab)
Mounting Type	Surface Mount
Operating Temperature	0°C ~ 125°C
Product Status	Obsolete
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitute parts for the LM340AS-5.0/NOPB are selected based on the following critical parameters that determine functional compatibility:

Primary Substitution Criteria:

Fixed output voltage of 5V
Surface mount TO-263 (DDPAK-3) package configuration
Positive output configuration
Operating temperature range of 0°C ~ 125°C
ROHS3 compliance

Secondary Compatibility Factors:

Output current capacity (minimum 1A required; higher ratings acceptable)
Input voltage rating (minimum 25V acceptable; higher ratings acceptable)
Voltage dropout specification (2V @ 1A baseline)
Protection features (over-current and short-circuit protection required)

Substitute parts are grouped into two categories: direct Texas Instruments alternatives within the LM340 and TL780 series, and cross-manufacturer alternatives from Rohm Semiconductor. All listed substitutes maintain the same package footprint and electrical output specifications required for direct board-level replacement.

Parameter Comparison

Part Number	Manufacturer	Output Current	Input Voltage (Max)	Voltage Dropout (Max)	PSRR (120Hz)	Product Status	Packaging
LM340AS-5.0/NOPB	Texas Instruments	1A	35V	2V @ 1A	70dB	Obsolete	—
LM340S-5.0/NOPB	Texas Instruments	1.5A	35V	2V @ 1A	80dB	Active	Tube
TL780-05CKTTR	Texas Instruments	1.5A	25V	2V @ 1A	85dB	Obsolete	—
TL780-05CKTTRG3	Texas Instruments	1.5A	25V	2V @ 1A	85dB	Obsolete	Tape & Reel (TR)
UA7805CKTTR	Texas Instruments	1.5A	25V	2V @ 1A	78dB ~ 68dB	Last Time Buy	Cut Tape (CT) & Digi-Reel®
UA7805CKTTRG3	Texas Instruments	1.5A	25V	2V @ 1A	78dB ~ 68dB	Last Time Buy	Cut Tape (CT)
BD50C0AFP2-CE2	Rohm Semiconductor	1A	26.5V	0.5V @ 500mA	55dB	Active	Tape & Reel (TR)

Engineering Selection Recommendations

Recommended Primary Substitute: LM340S-5.0/NOPB

The LM340S-5.0/NOPB is the preferred direct substitute for the LM340AS-5.0/NOPB. Both parts share the same base product number (LM340) and are manufactured by Texas Instruments. The LM340S-5.0/NOPB is currently in active production status, ensuring long-term availability and supply chain stability. It provides enhanced output current capacity (1.5A versus 1A) and improved PSRR performance (80dB versus 70dB), making it a superior alternative for new designs. The part maintains identical input voltage rating (35V), voltage dropout specification (2V @ 1A), and operating temperature range (0°C ~ 125°C). ROHS3 compliance is maintained.

Secondary Substitutes: TL780-05CKTTR and TL780-05CKTTRG3

The TL780 series represents an alternative Texas Instruments product line with equivalent functionality. Both TL780-05CKTTR and TL780-05CKTTRG3 deliver 1.5A output current and superior PSRR performance (85dB). However, both parts are classified as obsolete, limiting their suitability for new production. The input voltage rating is reduced to 25V, which may be a constraint in applications requiring the full 35V input capability of the original part.

Tertiary Substitutes: UA7805CKTTR and UA7805CKTTRG3

The UA7805 series provides 1.5A output current with PSRR performance of 78dB ~ 68dB. Both parts carry Last Time Buy status, indicating limited remaining inventory and no future production. Input voltage rating is 25V. These parts are suitable only for applications where existing inventory must be consumed or where supply chain constraints necessitate their use.

Cross-Manufacturer Alternative: BD50C0AFP2-CE2

The BD50C0AFP2-CE2 from Rohm Semiconductor is an active production part with automotive-grade qualification (AEC-Q100). It maintains 1A output current matching the original part specification and includes an enable control feature not present in the LM340AS-5.0/NOPB. The input voltage rating is 26.5V, and voltage dropout is significantly lower (0.5V @ 500mA). This part is suitable for applications requiring automotive-grade components or where superior dropout performance is beneficial. Quiescent current is lower (2.5mA versus 6mA), providing efficiency advantages in low-power standby scenarios.

Frequently Asked Questions (FAQ)

Q: Can LM340S-5.0/NOPB directly replace LM340AS-5.0/NOPB on existing PCBs?

A: Yes. Both parts use identical TO-263 (DDPAK-3) package footprints and pinouts. The LM340S-5.0/NOPB is a direct pin-for-pin replacement. The higher output current rating (1.5A versus 1A) and improved PSRR (80dB versus 70dB) make it functionally superior for the same application.

Q: What is the difference between TL780-05CKTTR and TL780-05CKTTRG3?

A: Both parts are electrically identical with 1.5A output current and 85dB PSRR. The primary difference is packaging: TL780-05CKTTR is supplied in bulk form, while TL780-05CKTTRG3 is supplied in Tape & Reel (TR) format for automated assembly. Both are obsolete products.

Q: Why does BD50C0AFP2-CE2 have lower voltage dropout than other substitutes?

A: The BD50C0AFP2-CE2 is a more recent design from Rohm Semiconductor with improved internal architecture. The 0.5V dropout @ 500mA specification reflects modern regulator design practices. This characteristic makes it advantageous for applications with tight input-to-output voltage margins.

Q: Can I use UA7805CKTTR for new production designs?

A: The UA7805CKTTR carries Last Time Buy status, indicating no future production. It is not recommended for new designs. Use LM340S-5.0/NOPB or BD50C0AFP2-CE2 instead, both of which are in active production.

Q: What is the significance of the input voltage difference between LM340AS-5.0/NOPB (35V max) and TL780-05CKTTR (25V max)?

A: The LM340AS-5.0/NOPB accepts input voltages up to 35V, while TL780-05CKTTR is rated to 25V maximum. If your application requires input voltages between 25V and 35V, the TL780 series is not suitable. The LM340S-5.0/NOPB or BD50C0AFP2-CE2 (26.5V max) must be evaluated based on your specific input voltage requirements.

Q: Is the BD50C0AFP2-CE2 suitable for non-automotive applications?

A: Yes. Automotive-grade qualification (AEC-Q100) indicates enhanced reliability and testing standards. Parts meeting automotive specifications are fully functional in commercial and industrial applications and often provide superior performance due to stricter manufacturing controls.

Q: What does ROHS3 compliance mean for these parts?

A: ROHS3 compliance indicates the part meets Restriction of Hazardous Substances Directive requirements, restricting lead, cadmium, mercury, and other hazardous materials. All listed substitute parts maintain ROHS3 compliance, ensuring compatibility with environmental regulations and procurement standards.

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