AP1117DL-U Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The AP1117DL-U is a linear voltage regulator IC from Diodes Incorporated designed for positive adjustable output applications. This Surface Mount device delivers 1A output current in a TO-252-3 (DPAK) package and operates across an input voltage range of up to 18V with adjustable output from 1.25V to 5V. The part is classified as Obsolete, making identification of active equivalent alternatives necessary for ongoing design support and procurement.

Substiute Parts

AP1117DL-U

Diodes IncorporatedIn Stock: 1020AP1117DL-U Datasheet

Current PartRFQ

LD1117DTC-R

STMicroelectronicsIn Stock: 17928LD1117DTC-R Datasheet

MFR RecommendedRFQ

LD1117DTTR

STMicroelectronicsIn Stock: 17054LD1117DTTR Datasheet

MFR RecommendedRFQ

Key Parameters

Substitute Part Grouping Explanation

Substitution of the AP1117DL-U is determined by the following critical parameters:

Output configuration (Positive) and output type (Adjustable) establish the functional category. The adjustable output range of 1.25V to 5V defines the voltage regulation capability. Current output capacity, dropout voltage, and quiescent current determine operational suitability in power delivery applications. Package compatibility (TO-252-3 DPAK) ensures mechanical and thermal fit on existing PCBs. Protection features (Over Current, Over Temperature) and compliance certifications (ROHS3, REACH Unaffected) must be maintained.

The substitute parts LD1117DTC-R and LD1117DTTR from STMicroelectronics share identical package geometry, positive adjustable output configuration, and protection feature sets. Both maintain ROHS3 compliance and REACH unaffected status. The primary differences are reduced output current capacity (800mA versus 1A) and lower maximum input voltage (15V versus 18V), which represent functional constraints that must be evaluated against specific application requirements.

Parameter Comparison

Engineering Selection Recommendations

Both LD1117DTC-R and LD1117DTTR are Active products from STMicroelectronics, providing continuity for designs currently using the obsolete AP1117DL-U. Both substitute parts maintain identical package geometry (TO-252-3 DPAK), enabling direct PCB compatibility without layout modifications.

Selection between the two STMicroelectronics alternatives depends on operating temperature requirements. The LD1117DTC-R supports extended low-temperature operation (-40°C to 125°C), while the LD1117DTTR operates within the standard industrial range (0°C to 125°C), matching the original AP1117DL-U specification.

Both substitutes feature reduced output current capacity (800mA versus 1A) and lower maximum input voltage (15V versus 18V). Applications requiring the full 1A output current or input voltages exceeding 15V cannot use these substitutes without circuit redesign. The LD1117DTTR offers marginally lower dropout voltage (1.2V @ 800mA) compared to the LD1117DTC-R (1.3V @ 800mA), providing improved efficiency in low-headroom applications.

Both parts maintain ROHS3 compliance and REACH unaffected status, satisfying regulatory requirements equivalent to the original part.

Frequently Asked Questions (FAQ)

Q: Can the LD1117DTC-R or LD1117DTTR directly replace the AP1117DL-U without circuit modifications?

A: Direct PCB replacement is possible due to identical TO-252-3 DPAK package geometry and pinout. However, circuit-level evaluation is required if your application demands the full 1A output current or input voltages above 15V. Both substitutes are rated for 800mA maximum output and 15V maximum input.

Q: What is the difference between LD1117DTC-R and LD1117DTTR?

A: Both parts are functionally equivalent with identical electrical specifications except for operating temperature range and dropout voltage. The LD1117DTC-R operates from -40°C to 125°C with 1.3V dropout at 800mA. The LD1117DTTR operates from 0°C to 125°C with 1.2V dropout at 800mA. Select based on your application's temperature requirements and efficiency needs.

Q: Are the substitute parts compliant with the same regulatory standards as the AP1117DL-U?

A: Yes. Both LD1117DTC-R and LD1117DTTR are ROHS3 compliant and REACH unaffected, matching the compliance profile of the original AP1117DL-U. Both carry MSL 1 (Unlimited) moisture sensitivity rating.

Q: What happens if my circuit requires more than 800mA output current?

A: The substitute parts are rated for 800mA maximum output. Applications requiring 1A output cannot use these substitutes. Alternative regulators with higher current ratings must be evaluated.

Q: Can I use these substitutes if my input voltage exceeds 15V?

A: No. Both LD1117DTC-R and LD1117DTTR are rated for maximum 15V input, compared to the AP1117DL-U's 18V maximum. Input voltages above 15V will exceed the absolute maximum ratings of the substitute parts.

Q: Do the substitute parts have the same quiescent current as the AP1117DL-U?

A: No. The AP1117DL-U draws 10mA quiescent current, while both LD1117DTC-R and LD1117DTTR draw 5mA. This lower quiescent current in the substitutes improves standby power efficiency.