SPX1117M3-L-1-8 Equivalent & Substitute Parts

Part Overview

The SPX1117M3-L-1-8 is a linear voltage regulator IC from MaxLinear, Inc., designed to deliver a fixed 1.8V output at 800mA in a SOT-223-3 surface mount package. This part is classified as discontinued at DiGi Electronics, making equivalent substitute parts necessary for ongoing design support and procurement continuity. The device operates across an input voltage range up to 20V with a maximum dropout voltage of 1.3V at full load, suitable for low-power embedded systems and portable applications requiring stable 1.8V rails.

Key Parameters

Parameter	SPX1117M3-L-1-8
Output Voltage (Fixed)	1.8V
Output Current	800mA
Input Voltage (Max)	20V
Dropout Voltage (Max)	1.3V @ 800mA
Quiescent Current	10 mA
PSRR	70dB (120Hz)
Package	SOT-223-3
Operating Temperature	-40°C ~ 125°C
Protection Features	Over Current, Over Temperature
RoHS Status	RoHS Compliant

Substitute Part Grouping Explanation

Substitution eligibility for the SPX1117M3-L-1-8 is determined by the following critical parameters:

Fixed Output Voltage: All substitute parts must deliver 1.8V fixed output to maintain circuit compatibility.

Package Type: All substitutes use SOT-223-3 or SOT-223 surface mount packaging, ensuring mechanical and thermal compatibility.

Output Current Capability: The original part delivers 800mA. Substitutes rated at 800mA or higher (1A) are functionally equivalent, as higher-rated devices operate within the same thermal and electrical envelope.

Input Voltage Range: Maximum input voltage of 15V or higher accommodates the original 20V specification.

Dropout Voltage: Devices with dropout voltage ≤1.3V @ rated current maintain equivalent performance characteristics.

Protection Features: Over-current and over-temperature protection are standard across all listed substitutes.

Operating Temperature Range: Substitutes covering 0°C ~ 125°C or -40°C ~ 125°C are compatible; the original -40°C lower limit is preserved in select alternatives.

Parameter Comparison

Manufacturer Part Number	Manufacturer	Output Current	Input Voltage (Max)	Dropout Voltage (Max)	Quiescent Current	PSRR (120Hz)	Operating Temperature	Product Status
SPX1117M3-L-1-8	MaxLinear, Inc.	800mA	20V	1.3V @ 800mA	10 mA	70dB	-40°C ~ 125°C	Discontinued
AZ1117H-1.8TRE1	Diodes Incorporated	1A	15V	1.25V @ 1A	10 mA	75dB	-40°C ~ 125°C	Active
AZ1117H-1.8TRG1	Diodes Incorporated	1A	15V	1.25V @ 1A	10 mA	75dB	-40°C ~ 125°C	Active
LD1117AS18TR	STMicroelectronics	1A	15V	1.3V @ 1A	10 mA	80dB	0°C ~ 125°C	Active
LD1117S18CTR	STMicroelectronics	800mA	15V	1.3V @ 800mA	10 mA	75dB	-40°C ~ 125°C	Active
LD1117S18TR	STMicroelectronics	800mA	15V	1.2V @ 800mA	10 mA	75dB	0°C ~ 125°C	Active
LM1117MP-1.8/NOPB	Texas Instruments	800mA	15V	1.2V @ 800mA	5 mA	75dB	0°C ~ 125°C	Active
LM1117MPX-1.8/NOPB	Texas Instruments	800mA	15V	1.2V @ 800mA	5 mA	75dB	0°C ~ 125°C	Active
LMS8117AMP-1.8/NOPB	Texas Instruments	1A	15V	1.25V @ 1A	5 mA	60 ~ 75dB	0°C ~ 125°C	Active
LMS8117AMPX-1.8/NOPB	Texas Instruments	1A	15V	1.25V @ 1A	5 mA	60 ~ 75dB	0°C ~ 125°C	Active
NCP1117ST18T3G	onsemi	1A	20V	1.2V @ 800mA	10 mA	70dB	0°C ~ 125°C	Active

Engineering Selection Recommendations

All listed substitute parts are active products with ROHS3 compliance and REACH unaffected status, ensuring regulatory alignment for current manufacturing and procurement.

Direct Electrical Equivalents (800mA Output Current): LD1117S18CTR, LD1117S18TR, LM1117MP-1.8/NOPB, and LM1117MPX-1.8/NOPB match the original 800mA output specification. LD1117S18CTR preserves the -40°C lower operating temperature limit of the original part. LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB offer reduced quiescent current (5mA vs. 10mA), providing power efficiency benefits in standby applications.

Higher Current Capacity Alternatives (1A Output Current): AZ1117H-1.8TRE1, AZ1117H-1.8TRG1, LD1117AS18TR, LMS8117AMP-1.8/NOPB, LMS8117AMPX-1.8/NOPB, and NCP1117ST18T3G deliver 1A output, providing design margin for applications requiring higher transient current handling. These parts are suitable for designs where the original 800mA specification is conservative or where future current scaling is anticipated.

Input Voltage Consideration: NCP1117ST18T3G maintains the original 20V maximum input voltage specification, matching the SPX1117M3-L-1-8 exactly. All other substitutes operate at 15V maximum input, which is sufficient for most 12V and lower input rail applications.

Temperature Range: LD1117S18CTR and AZ1117H-1.8TRE1/TRG1 preserve the -40°C lower operating limit. Remaining substitutes operate from 0°C, suitable for commercial and industrial temperature ranges.

Frequently Asked Questions (FAQ)

Q: Can I use a 1A-rated substitute in place of the 800mA SPX1117M3-L-1-8?

A: Yes. Higher current-rated devices (1A) are functionally equivalent for 800mA applications. The regulator will operate within its safe operating area at reduced load. No circuit modification is required.

Q: What is the difference between LD1117S18CTR and LD1117S18TR?

A: Both are STMicroelectronics LD1117 800mA variants in SOT-223 packaging. LD1117S18CTR operates from -40°C ~ 125°C with 1.3V dropout at 800mA. LD1117S18TR operates from 0°C ~ 125°C with 1.2V dropout at 800mA. Select LD1117S18CTR for extended low-temperature applications.

Q: Are the AZ1117H-1.8TRE1 and AZ1117H-1.8TRG1 interchangeable?

A: Yes. Both are Diodes Incorporated AZ1117 1A variants with identical electrical specifications. The difference is packaging designation (TRE1 vs. TRG1 tape reel configurations). Electrical performance and pinout are identical.

Q: Which substitute offers the lowest quiescent current?

A: LM1117MP-1.8/NOPB and LM1117MPX-1.8/NOPB from Texas Instruments both specify 5mA quiescent current, compared to 10mA in the original part. These are preferred for battery-powered or low-power standby applications.

Q: Does the input voltage limit affect my design?

A: If your input voltage is 15V or lower, all substitutes are compatible. If your design requires 20V input capability, select NCP1117ST18T3G from onsemi or verify that your actual input voltage does not exceed 15V. The original SPX1117M3-L-1-8 and NCP1117ST18T3G both support 20V maximum input.

Q: Are all substitutes RoHS compliant?

A: Yes. All listed substitute parts carry ROHS3 compliance certification and REACH unaffected status, meeting current environmental and regulatory requirements.

Q: What is the significance of PSRR (Power Supply Rejection Ratio)?

A: PSRR measures the regulator's ability to reject input voltage ripple and noise. Higher PSRR values indicate better noise rejection. The original part specifies 70dB. Substitutes range from 70dB to 80dB, all providing equivalent or superior noise performance.

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