RC1117ST Linear Voltage Regulator Equivalent & Substitute Parts

Part Overview

The RC1117ST is a linear voltage regulator IC manufactured by onsemi, classified as a positive adjustable 1A output regulator in SOT-223-4 surface mount packaging. This device is currently listed as obsolete, making equivalent and substitute parts necessary for ongoing design support, production continuity, and component sourcing.

The RC1117ST functions as a positive adjustable linear regulator with 1A output capacity, suitable for applications requiring regulated power supply with adjustable output voltage. The obsolete status necessitates identification of active alternative components that maintain electrical and mechanical compatibility.

Key Parameters

Parameter	RC1117ST Value
Manufacturer	onsemi
Output Configuration	Positive
Output Type	Adjustable
Number of Regulators	1
Voltage - Input (Max)	7.5V
Voltage - Output (Min/Fixed)	1.25V
Voltage - Output (Max)	6.3V
Voltage Dropout (Max)	1.2V @ 1A
Current - Output	1A
PSRR	72dB (120Hz)
Protection Features	Over Current, Over Temperature
Operating Temperature	0°C ~ 125°C
Mounting Type	Surface Mount
Package / Case	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4
Product Status	Obsolete
Moisture Sensitivity Level (MSL)	1 (Unlimited)

Substitute Part Grouping Explanation

Substitution eligibility for the RC1117ST is determined by the following critical parameters:

Primary Compatibility Criteria:

Output Configuration: Positive
Output Type: Adjustable
Number of Regulators: 1
Mounting Type: Surface Mount
Package / Case: TO-261-4, TO-261AA (SOT-223 variants)
Voltage - Output (Min/Fixed): 1.25V minimum
Current - Output: 800mA minimum (RC1117ST rated at 1A)
Protection Features: Over Current and Over Temperature protection
Moisture Sensitivity Level (MSL): 1 (Unlimited)

Secondary Compatibility Considerations:

Voltage - Input (Max): RC1117ST at 7.5V; substitutes rated 15V are acceptable (higher rating does not preclude use)
Voltage - Output (Max): RC1117ST at 6.3V; substitutes with higher maximum output voltage are acceptable
Voltage Dropout (Max): RC1117ST at 1.2V @ 1A; substitutes at 1.2V or 1.3V @ 800mA are functionally equivalent
PSRR: RC1117ST at 72dB; substitutes at 75dB meet or exceed performance
Operating Temperature: RC1117ST at 0°C ~ 125°C; substitutes with extended range (-40°C ~ 125°C) are acceptable

All identified substitute parts meet the primary compatibility criteria and maintain functional equivalence within the specified electrical and mechanical parameters.

Parameter Comparison

Parameter	RC1117ST	LD1117SC-R	LD1117STR	LM1117MP-ADJ/NOPB	LM1117MPX-ADJ/NOPB	LT1117CST#PBF	LT1117CST#TRPBF	LT1117IST#PBF	LT1117IST#TRPBF	REG1117
Manufacturer	onsemi	STMicroelectronics	STMicroelectronics	Texas Instruments	Texas Instruments	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Analog Devices Inc.	Texas Instruments
Output Configuration	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive	Positive
Output Type	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable	Adjustable
Voltage - Input (Max)	7.5V	15V	15V	15V	15V	15V	15V	15V	15V	15V
Voltage - Output (Min/Fixed)	1.25V	1.25V	1.25V	1.25V	1.25V	1.25V	1.25V	1.25V	1.25V	1.25V
Voltage - Output (Max)	6.3V	15V	15V	13.8V	13.8V	13.8V	13.8V	13.8V	13.8V	14.6V
Voltage Dropout (Max)	1.2V @ 1A	1.3V @ 800mA	1.2V @ 800mA	1.2V @ 800mA	1.2V @ 800mA	1.2V @ 800mA	1.2V @ 800mA	1.3V @ 800mA	1.3V @ 800mA	1.2V @ 800mA
Current - Output	1A	800mA	800mA	800mA	800mA	800mA	800mA	800mA	800mA	800mA
PSRR	72dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	75dB (120Hz)	62dB (120Hz)
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature	Over Temperature	Over Temperature	Over Temperature	Over Temperature	Over Current, Over Temperature
Operating Temperature	0°C ~ 125°C	-40°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
Mounting Type	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount	Surface Mount
Package / Case	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA	TO-261-4, TO-261AA
Supplier Device Package	SOT-223-4	SOT-223	SOT-223	SOT-223	SOT-223	SOT-223-3	SOT-223-3	SOT-223-3	SOT-223-3	SOT-223-4
Product Status	Obsolete	Active	Active	Active	Active	Active	Active	Active	Active	Last Time Buy
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Moisture Sensitivity Level (MSL)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)	1 (Unlimited)

Engineering Selection Recommendations

Active Product Status Priority: All substitute parts listed carry Active product status except REG1117, which is Last Time Buy. For new designs and long-term production continuity, prioritize components with Active status: LD1117SC-R, LD1117STR, LM1117MP-ADJ/NOPB, LM1117MPX-ADJ/NOPB, LT1117CST#PBF, LT1117CST#TRPBF, LT1117IST#PBF, and LT1117IST#TRPBF.

Compliance and Certification: All substitute parts are ROHS3 Compliant and REACH Unaffected, meeting current environmental and regulatory requirements. The RC1117ST does not specify RoHS status, making compliant substitutes necessary for applications subject to RoHS directives.

Current Output Consideration: The RC1117ST is rated at 1A output current. All identified substitutes are rated at 800mA. Applications requiring the full 1A output capacity must evaluate whether 800mA substitutes meet load requirements. For applications with load currents at or below 800mA, substitutes are directly compatible.

Temperature Range: The RC1117ST operates from 0°C to 125°C. Substitutes offering extended temperature range (-40°C to 125°C) provide additional operational flexibility without compromising compatibility in the RC1117ST temperature window.

Packaging Variants: Substitutes are available in multiple packaging formats (Tube, Cut Tape & Digi-Reel, Tape & Reel). Selection depends on procurement and assembly requirements. SOT-223-3 and SOT-223-4 variants are mechanically compatible within the TO-261-4 and TO-261AA package families.

Frequently Asked Questions (FAQ)

Q: Can I directly replace RC1117ST with any of the listed substitutes? A: Direct replacement is possible for applications with load currents at or below 800mA. All substitutes maintain identical output configuration (positive adjustable), number of regulators (1), mounting type (surface mount), and package compatibility (TO-261-4, TO-261AA). Verify your application's current requirements against the 800mA rating of substitute parts.

Q: What is the difference between SOT-223-3 and SOT-223-4 packaging? A: Both are mechanically compatible within the TO-261-4 and TO-261AA package families. The primary difference is pin count: SOT-223-3 has 3 pins, SOT-223-4 has 4 pins. Consult device datasheets for specific pin configurations and ensure PCB layout compatibility.

Q: Why do substitute parts have higher maximum input voltage (15V vs 7.5V)? A: Higher input voltage ratings indicate broader operational capability. Substitutes rated at 15V maximum input can operate safely at the RC1117ST's 7.5V maximum input specification. This does not affect compatibility; it provides additional design flexibility.

Q: Are the Analog Devices LT1117 variants interchangeable with Texas Instruments and STMicroelectronics parts? A: Yes, within the specified electrical and mechanical parameters. All parts share identical output configuration, adjustable output type, minimum output voltage (1.25V), and SOT-223 packaging. Verify PSRR, dropout voltage, and protection features for your specific application requirements.

Q: What does "Last Time Buy" status mean for REG1117? A: Last Time Buy indicates the manufacturer will no longer produce this component after a specified date. REG1117 remains functionally compatible but should not be selected for new designs requiring long-term component availability. Prioritize Active status parts for production continuity.

Q: Do all substitutes provide over-current protection? A: No. Analog Devices LT1117 variants (LT1117CST#PBF, LT1117CST#TRPBF, LT1117IST#PBF, LT1117IST#TRPBF) provide over-temperature protection only. STMicroelectronics LD1117 and Texas Instruments LM1117 and REG1117 variants provide both over-current and over-temperature protection, matching the RC1117ST protection feature set.

Q: Can I use these substitutes in applications requiring the full 1A output current? A: No. All identified substitutes are rated at 800mA maximum output current. Applications requiring 1A output must either use the original RC1117ST (if available) or select alternative regulators with 1A or higher current ratings. Exceeding the 800mA rating will cause thermal shutdown and potential device damage.

Q: Are there inventory considerations when selecting substitutes? A: Yes. Inventory levels vary significantly: LM1117MPX-ADJ/NOPB has 650,655 units in stock, while LM1117MP-ADJ/NOPB has 1,454 units. Higher inventory levels generally indicate better long-term availability and lower procurement risk.

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