AP1117D18L-U Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The AP1117D18L-U is a linear voltage regulator IC manufactured by Diodes Incorporated, designed to provide a fixed 1.8V output at 1A maximum current in a TO-252-3 (DPAK) surface mount package. This device is classified as obsolete, making equivalent and substitute parts necessary for ongoing production and maintenance applications. The AP1117D18L-U serves as a positive fixed output voltage regulator with integrated over-current and over-temperature protection, suitable for power management applications requiring stable 1.8V regulation from input sources up to 18V.

Key Parameters

Parameter	Value
Output Voltage (Fixed)	1.8V
Maximum Output Current	1A
Maximum Input Voltage	18V
Maximum Dropout Voltage	1.4V @ 1A
Quiescent Current	10 mA
Package Type	TO-252-3 (DPAK)
Operating Temperature Range	0°C to 125°C
Protection Features	Over Current, Over Temperature
RoHS Status	ROHS3 Compliant

Substitute Part Grouping Explanation

Substitution of the AP1117D18L-U is determined by the following critical parameters:

Fixed output voltage of 1.8V
Output current capability (1A or 800mA minimum)
Maximum input voltage rating (15V or higher)
TO-252-3 (DPAK) package compatibility
Surface mount mounting type
Operating temperature range (0°C to 125°C minimum)
Protection features (over-current and over-temperature)
RoHS3 compliance

Substitute parts are grouped into two categories based on output current rating: full 1A output capability and 800mA output capability. Parts with 800mA output are suitable for applications where the original 1A specification is not required. All substitute parts maintain the same package footprint and pinout, ensuring direct PCB compatibility.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Output Current	Max Input Voltage	Max Dropout @ Rated Current	Quiescent Current	Operating Temp Range	Product Status	Package
AP1117D18L-U	Diodes Incorporated	1A	18V	1.4V @ 1A	10 mA	0°C to 125°C	Obsolete	TO-252-3
LD1117ADT18TR	STMicroelectronics	1A	15V	1.3V @ 1A	10 mA	0°C to 125°C	Active	TO-252-3
LD1117DT18CTR	STMicroelectronics	800mA	15V	1.3V @ 800mA	10 mA	-40°C to 125°C	Active	TO-252-3
LD1117DT18TR	STMicroelectronics	800mA	15V	1.2V @ 800mA	10 mA	0°C to 125°C	Active	TO-252-3
LM1117DT-1.8/NOPB	Texas Instruments	800mA	15V	1.2V @ 800mA	5 mA	0°C to 125°C	Active	TO-252-3
LM1117DTX-1.8/NOPB	National Semiconductor	800mA	15V	1.2V @ 800mA	5 mA	0°C to 125°C	Active	TO-252-3
NCP1117DT18G	onsemi	1A	20V	1.2V @ 800mA	10 mA	0°C to 125°C	Obsolete	TO-252-3
NCP1117DT18RKG	onsemi	1A	20V	1.2V @ 800mA	10 mA	0°C to 125°C	Active	TO-252-3
NCV1117DT18RKG	onsemi	1A	20V	1.2V @ 800mA	10 mA	-40°C to 125°C	Active	TO-252-3
NCV1117DT18T5G	onsemi	1A	20V	1.2V @ 800mA	10 mA	-40°C to 125°C	Active	TO-252-3

Engineering Selection Recommendations

Primary Substitutes (Full 1A Output Capability):

LD1117ADT18TR (STMicroelectronics) is the recommended primary substitute. It maintains 1A output current capability, operates within the required 0°C to 125°C temperature range, and holds active product status with full availability. The 15V maximum input voltage is sufficient for most applications using the original 18V-rated part.

NCP1117DT18RKG and NCV1117DT18RKG (onsemi) provide 1A output capability with extended input voltage rating to 20V. NCV1117DT18RKG and NCV1117DT18T5G include automotive-grade qualification (AEC-Q100) and extended temperature range (-40°C to 125°C), suitable for automotive and industrial applications requiring enhanced reliability.

Secondary Substitutes (800mA Output Capability):

LD1117DT18TR, LM1117DT-1.8/NOPB, and LM1117DTX-1.8/NOPB are suitable for applications where 800mA output current is sufficient. These parts reduce quiescent current (LM1117 variants at 5 mA) and maintain active product status. LD1117DT18CTR extends the operating temperature range to -40°C to 125°C for enhanced environmental performance.

All substitute parts maintain RoHS3 compliance and TO-252-3 package compatibility, ensuring direct PCB replacement without layout modifications.

Frequently Asked Questions (FAQ)

Q: Can I use an 800mA-rated substitute in place of the 1A-rated AP1117D18L-U?

A: Yes, if your application draws maximum current of 800mA or less. The 800mA-rated substitutes (LD1117DT18TR, LM1117DT-1.8/NOPB, LM1117DTX-1.8/NOPB) are electrically and mechanically compatible. If your circuit requires the full 1A capability, use LD1117ADT18TR, NCP1117DT18RKG, NCV1117DT18RKG, or NCV1117DT18T5G.

Q: Are all substitute parts pin-compatible with the AP1117D18L-U?

A: Yes. All listed substitutes use the TO-252-3 (DPAK) package with identical pinout: Input, Ground, and Output. Direct PCB replacement is possible without modification.

Q: What is the difference between NCP1117DT18RKG and NCV1117DT18RKG?

A: NCV1117DT18RKG includes automotive-grade qualification (AEC-Q100) and extended operating temperature range (-40°C to 125°C). NCP1117DT18RKG operates at 0°C to 125°C. Both provide 1A output and 20V maximum input voltage. Select NCV1117DT18RKG for automotive or harsh environment applications.

Q: Does the 15V maximum input rating of STMicroelectronics parts limit compatibility?

A: The AP1117D18L-U is rated to 18V input, while LD1117 series parts are rated to 15V. For applications using input voltages between 15V and 18V, use NCP1117DT18RKG, NCV1117DT18RKG, or NCV1117DT18T5G (all rated to 20V input).

Q: Which substitute offers the lowest quiescent current?

A: LM1117DT-1.8/NOPB and LM1117DTX-1.8/NOPB both specify 5 mA quiescent current, compared to 10 mA for other substitutes. These are beneficial for battery-powered or low-power standby applications.

Q: Are there packaging differences between substitutes?

A: All substitutes use TO-252-3 (DPAK) package. Packaging format varies (Tape & Reel, Cut Tape, Tube) but does not affect electrical performance or PCB compatibility. Select based on procurement and assembly requirements.

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