IRU1117-18CS Equivalent & Substitute Parts

Part Overview

The IRU1117-18CS is a linear voltage regulator IC manufactured by Infineon Technologies, designed to deliver a fixed 1.8V output at up to 800mA. This Surface Mount device in 8-SOIC packaging is classified as obsolete, making equivalent substitute parts necessary for new designs and ongoing production requirements. The part provides over-current and over-temperature protection suitable for power management applications requiring low-dropout regulation.

Key Parameters

Parameter	IRU1117-18CS
Manufacturer	Infineon Technologies
Product Status	Obsolete
Output Voltage (Fixed)	1.8V
Output Current	800mA
Input Voltage (Max)	7V
Voltage Dropout (Max)	1.3V @ 1A
Package / Case	8-SOIC (0.154", 3.90mm Width)
Operating Temperature Range	0°C ~ 125°C
Protection Features	Over Current, Over Temperature
RoHS Status	RoHS non-compliant

Substitute Part Grouping Explanation

Substitution of the IRU1117-18CS is based on the following critical parameters:

Package Compatibility: Both parts must use 8-SOIC (0.154", 3.90mm Width) Surface Mount packaging to ensure PCB layout compatibility
Output Current Rating: Minimum 800mA output current capability required
Voltage Dropout Characteristics: Maximum dropout voltage of 1.3V or lower to maintain regulation performance
Protection Features: Over-current and over-temperature protection must be present
Output Configuration: Positive fixed output voltage regulation topology

The LD1117D33CTR from STMicroelectronics meets these substitution criteria. While it provides a 3.3V fixed output (compared to the 1.8V of the IRU1117-18CS), it shares identical package geometry, equivalent current handling, matching dropout specifications, and identical protection architecture. Selection between these parts depends on the specific voltage requirement of the application circuit.

Parameter Comparison

Parameter	IRU1117-18CS	LD1117D33CTR	Notes
Manufacturer	Infineon Technologies	STMicroelectronics	Different manufacturers
Product Status	Obsolete	Active	LD1117D33CTR actively produced
Output Voltage (Fixed)	1.8V	3.3V	Different output voltages
Output Current	800mA	800mA	Identical current rating
Input Voltage (Max)	7V	15V	LD1117D33CTR accepts higher input
Voltage Dropout (Max)	1.3V @ 1A	1.3V @ 800mA	Equivalent dropout performance
Package / Case	8-SOIC (0.154", 3.90mm Width)	8-SOIC (0.154", 3.90mm Width)	Identical package
Operating Temperature Range	0°C ~ 125°C	-40°C ~ 125°C	LD1117D33CTR has extended low-temperature range
Protection Features	Over Current, Over Temperature	Over Current, Over Temperature	Identical protection
RoHS Status	RoHS non-compliant	ROHS3 Compliant	LD1117D33CTR meets RoHS requirements

Engineering Selection Recommendations

The IRU1117-18CS is classified as obsolete and no longer in active production. The LD1117D33CTR is the recommended substitute based on the following factors:

Active Production Status: The LD1117D33CTR is actively manufactured by STMicroelectronics, ensuring long-term availability and supply chain reliability
Package Compatibility: Identical 8-SOIC package enables direct PCB layout compatibility without redesign
Electrical Performance: Matching 800mA output current and 1.3V dropout voltage specifications maintain equivalent circuit performance
Regulatory Compliance: ROHS3 compliance of the LD1117D33CTR meets modern environmental and regulatory requirements, whereas the IRU1117-18CS is non-compliant
Extended Operating Range: The -40°C to 125°C operating temperature range of the LD1117D33CTR provides broader environmental capability

Critical Consideration: The output voltage differs (1.8V vs. 3.3V). Selection of the LD1117D33CTR requires verification that the application circuit is designed for or can accommodate 3.3V output. If 1.8V output is mandatory, alternative 1.8V fixed-output regulators in 8-SOIC packaging from active manufacturers must be evaluated.

Frequently Asked Questions (FAQ)

Q: Can the LD1117D33CTR be used as a direct pin-for-pin replacement for the IRU1117-18CS?

A: Yes, the LD1117D33CTR is a direct pin-for-pin replacement in terms of package geometry and pinout. Both devices use 8-SOIC packaging with identical pin assignments for linear voltage regulators. However, the output voltage differs (3.3V vs. 1.8V), so circuit-level compatibility must be verified before substitution.

Q: What are the key differences between these two parts?

A: The primary differences are: (1) Output voltage: IRU1117-18CS provides 1.8V fixed output, while LD1117D33CTR provides 3.3V; (2) Product status: IRU1117-18CS is obsolete, LD1117D33CTR is active; (3) RoHS compliance: IRU1117-18CS is non-compliant, LD1117D33CTR is ROHS3 compliant; (4) Input voltage rating: LD1117D33CTR accepts up to 15V versus 7V for the IRU1117-18CS; (5) Operating temperature range: LD1117D33CTR extends to -40°C versus 0°C minimum for the IRU1117-18CS.

Q: Are there any inventory or supply chain advantages to using the LD1117D33CTR?

A: Yes. The LD1117D33CTR is actively produced by STMicroelectronics with significantly higher inventory availability (7277 pieces in stock versus 734 pieces for the obsolete IRU1117-18CS). Active production status ensures continued availability for future orders and production runs.

Q: What packaging considerations apply to these regulators?

A: Both devices use Surface Mount 8-SOIC packaging with identical dimensions (0.154" width, 3.90mm). This ensures compatibility with existing PCB layouts, solder reflow processes, and automated assembly equipment without modification.

Q: If my application requires 1.8V output, what should I do?

A: If 1.8V output is a circuit requirement, the LD1117D33CTR cannot be used as a substitute. Alternative active 1.8V fixed-output linear regulators in 8-SOIC packaging must be identified and evaluated based on the same substitution criteria: matching output current (800mA minimum), equivalent dropout voltage, identical package geometry, and required protection features.

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