FAN1112DX Equivalent & Substitute Parts

Part Overview

The FAN1112DX is a linear voltage regulator IC manufactured by onsemi, designed for positive fixed 1.2V output at 1A in a TO-252AA (DPAK) package. This part is classified as obsolete, making equivalent substitutes necessary for new designs and production continuity. The FAN1112DX serves applications requiring low-dropout regulation with integrated over-current and over-temperature protection in a compact surface-mount form factor.

Key Parameters

Parameter	FAN1112DX
Manufacturer	onsemi
Product Status	Obsolete
Output Voltage (Fixed)	1.2V
Output Current	1A
Input Voltage (Max)	18V
Voltage Dropout (Max)	1.2V @ 1A
Package / Case	TO-252-3, DPAK (2 Leads + Tab), SC-63
Mounting Type	Surface Mount
Protection Features	Over Current, Over Temperature
Operating Temperature	25°C ~ 125°C
PSRR	72dB (120Hz)

Substitute Part Grouping Explanation

Substitution for the FAN1112DX is determined by the following critical parameters:

Output Voltage: Fixed 1.2V regulation
Output Current Capability: 1A minimum
Package Compatibility: TO-252-3 (DPAK) form factor for direct PCB footprint compatibility
Input Voltage Range: Maximum 15V to 20V acceptable
Voltage Dropout: Maximum 1.35V @ 1A acceptable
Protection Features: Over-current and over-temperature protection required
Mounting Type: Surface mount only

All three substitute parts meet these core substitution criteria. The LD1117ADT12TR provides the closest electrical match with identical package and output voltage. The NCV1117ST12T3G and ZLDO1117QK12TC offer alternative sourcing with extended temperature ranges and automotive qualification.

Parameter Comparison

Parameter	FAN1112DX	LD1117ADT12TR	NCV1117ST12T3G	ZLDO1117QK12TC
Manufacturer	onsemi	STMicroelectronics	onsemi	Diodes Incorporated
Product Status	Obsolete	Active	Active	Active
Output Voltage (Fixed)	1.2V	1.2V	12V	1.2V
Output Current	1A	1A	1A	1A
Input Voltage (Max)	18V	15V	20V	18V
Voltage Dropout (Max)	1.2V @ 1A	1.3V @ 1A	1.2V @ 800mA	1.35V @ 1A
Package / Case	TO-252-3, DPAK	TO-252-3, DPAK	TO-261-4, SOT-223	TO-252-3, DPAK
Operating Temperature	25°C ~ 125°C	0°C ~ 125°C	-40°C ~ 125°C	-40°C ~ 125°C
PSRR	72dB (120Hz)	80dB (120Hz)	54dB (120Hz)	80dB (120Hz)
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature	Over Current, Over Temperature, Short Circuit
RoHS Status	Not specified	ROHS3 Compliant	ROHS3 Compliant	ROHS3 Compliant
Automotive Grade	Not specified	AEC-Q100	AEC-Q100	AEC-Q100

Engineering Selection Recommendations

LD1117ADT12TR is the primary substitute for direct replacement. It maintains identical output voltage (1.2V), output current (1A), and DPAK package footprint. The part is active and ROHS3 compliant with AEC-Q100 automotive qualification. Input voltage maximum of 15V is within acceptable range for most applications using the FAN1112DX (18V max). Operating temperature range extends to 0°C, providing broader environmental coverage than the original part.

ZLDO1117QK12TC is an alternative substitute offering identical output voltage and package with extended operating temperature range (-40°C to 125°C) and automotive qualification. This part includes short-circuit protection in addition to over-current and over-temperature protection. Input voltage maximum of 18V matches the original specification exactly.

NCV1117ST12T3G is not recommended as a direct substitute due to output voltage mismatch (12V vs. 1.2V required) and package incompatibility (SOT-223 vs. DPAK). This part does not meet the core substitution criteria for the FAN1112DX application.

Frequently Asked Questions (FAQ)

Q: Can the NCV1117ST12T3G replace the FAN1112DX? A: No. The NCV1117ST12T3G has a fixed output voltage of 12V, while the FAN1112DX requires 1.2V. Additionally, the SOT-223 package is not compatible with DPAK PCB footprints. This part does not meet substitution requirements.

Q: What is the key difference between LD1117ADT12TR and ZLDO1117QK12TC? A: Both parts provide 1.2V output in DPAK packages and are suitable substitutes. The LD1117ADT12TR has a narrower operating temperature range (0°C to 125°C) and lower input voltage maximum (15V). The ZLDO1117QK12TC extends to -40°C minimum temperature, matches the original 18V input maximum, and includes short-circuit protection. Select based on application temperature requirements and input voltage specifications.

Q: Are all substitute parts ROHS3 compliant? A: Yes. LD1117ADT12TR, NCV1117ST12T3G, and ZLDO1117QK12TC are all ROHS3 compliant. The original FAN1112DX compliance status is not specified in available documentation.

Q: Can I use these substitutes in automotive applications? A: LD1117ADT12TR and ZLDO1117QK12TC both carry AEC-Q100 automotive qualification. NCV1117ST12T3G also has AEC-Q100 qualification but is not a functional substitute due to voltage mismatch. Verify application-specific automotive requirements before selection.

Q: What is the impact of different dropout voltages? A: The FAN1112DX specifies 1.2V dropout at 1A. LD1117ADT12TR has 1.3V dropout, and ZLDO1117QK12TC has 1.35V dropout. These differences are acceptable for most applications but may affect minimum input voltage requirements in power-constrained designs. Calculate minimum input voltage as: Vout + Vdropout = Vin(min).

Q: Is package footprint compatibility guaranteed? A: LD1117ADT12TR and ZLDO1117QK12TC use identical TO-252-3 DPAK packages and are direct footprint replacements. No PCB layout modifications are required. NCV1117ST12T3G uses SOT-223 package and requires PCB redesign.

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