C8051F040 Equivalent & Substitute Parts

Part Overview

The C8051F040 is an 8-bit microcontroller from Silicon Labs' C8051F04x series, featuring a 25MHz 8051 core with 64KB Flash program memory and integrated analog/digital conversion capabilities. This part is classified as Obsolete, making identification of compatible substitutes essential for ongoing system support and new design considerations. The part's discontinuation status necessitates evaluation of available alternatives that maintain electrical and mechanical compatibility.

Key Parameters

Parameter	Value
Core Processor	8051
Core Size	8-Bit
Speed	25MHz
Program Memory Size	64KB (64K x 8)
Program Memory Type	FLASH
RAM Size	4.25K x 8
Voltage Supply (Vcc/Vdd)	2.7V ~ 3.6V
Number of I/O	64
Package / Case	100-TQFP (14x14)
Mounting Type	Surface Mount
Operating Temperature	-40°C ~ 85°C (TA)

Substitute Part Grouping Explanation

Substitution eligibility for the C8051F040 is determined by strict equivalence across the following critical parameters:

Core Architecture: 8051 processor core
Memory Configuration: 64KB Flash program memory, 4.25K x 8 RAM
Clock Speed: 25MHz operation
Electrical Specifications: 2.7V to 3.6V supply voltage range
Package Compatibility: 100-TQFP (14x14) surface mount form factor
I/O Count: 64 I/O pins
Peripheral Set: CANbus, EBI/EMI, SMBus (2-Wire/I2C), SPI, UART/USART connectivity with Brown-out Detect/Reset, POR, PWM, Temperature Sensor, and WDT
Data Conversion: A/D converters (8x8-bit, 13x12-bit), D/A converters (2x10-bit, 2x12-bit)

The C8051F040-GQ qualifies as a direct substitute based on identical electrical and mechanical specifications within the C8051F04x series.

Parameter Comparison

Parameter	C8051F040	C8051F040-GQ	Match
Manufacturer	Silicon Labs	Silicon Labs	✓
Series	C8051F04x	C8051F04x	✓
Core Processor	8051	8051	✓
Core Size	8-Bit	8-Bit	✓
Speed	25MHz	25MHz	✓
Program Memory Size	64KB (64K x 8)	64KB (64K x 8)	✓
Program Memory Type	FLASH	FLASH	✓
RAM Size	4.25K x 8	4.25K x 8	✓
Voltage Supply (Vcc/Vdd)	2.7V ~ 3.6V	2.7V ~ 3.6V	✓
Number of I/O	64	64	✓
Connectivity	CANbus, EBI/EMI, SMBus, SPI, UART/USART	CANbus, EBI/EMI, SMBus, SPI, UART/USART	✓
Peripherals	Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT	Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT	✓
Data Converters	A/D 8x8b, 13x12b; D/A 2x10b, 2x12b	A/D 8x8b, 13x12b; D/A 2x10b, 2x12b	✓
Oscillator Type	Internal	Internal	✓
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	✓
Mounting Type	Surface Mount	Surface Mount	✓
Package / Case	100-TQFP (14x14)	100-TQFP (14x14)	✓
Moisture Sensitivity Level (MSL)	3 (168 Hours)	3 (168 Hours)	✓
ECCN	EAR99	EAR99	✓
HTSUS	8542.31.0001	8542.31.0001	✓
Product Status	Obsolete	Not For New Designs	Different
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Different
Packaging	Not specified	Tray	Different

Engineering Selection Recommendations

The C8051F040-GQ is electrically and mechanically equivalent to the C8051F040 across all functional parameters. Selection between these parts should be based on the following criteria:

For Legacy System Support: The C8051F040-GQ maintains full compatibility with existing designs using the C8051F040. Both parts share identical core architecture, memory configuration, I/O count, and peripheral functionality.

For Compliance Requirements: The C8051F040-GQ offers ROHS3 compliance, whereas the original C8051F040 is RoHS non-compliant. Systems requiring RoHS certification should prioritize the C8051F040-GQ.

For New Designs: Both parts carry discontinuation-related status designations (Obsolete and Not For New Designs). New design initiatives should evaluate alternative microcontroller families from Silicon Labs' current product portfolio rather than relying on C8051F04x series components.

For Supply Chain Considerations: The C8051F040-GQ is available in Tray packaging, which may differ from the original part's packaging specification. Verify packaging compatibility with assembly and handling requirements.

Frequently Asked Questions (FAQ)

Q: Can C8051F040-GQ be used as a direct replacement for C8051F040?

A: Yes. The C8051F040-GQ is electrically and mechanically equivalent. All functional parameters—processor core, memory size, clock speed, voltage range, I/O count, peripheral set, and package form factor—are identical. Existing firmware and PCB layouts require no modification.

Q: What is the difference between C8051F040 and C8051F040-GQ?

A: The primary differences are product status, RoHS compliance, and packaging. The C8051F040-GQ is ROHS3 compliant and supplied in Tray packaging, while the C8051F040 is RoHS non-compliant with unspecified packaging. Electrical and functional specifications are identical.

Q: Why is the C8051F040 marked as Obsolete?

A: The Obsolete designation indicates that Silicon Labs has discontinued this product line. The C8051F04x series is no longer in active production. The C8051F040-GQ carries a "Not For New Designs" status, reflecting the same discontinuation trajectory.

Q: Are there any pin compatibility issues between C8051F040 and C8051F040-GQ?

A: No. Both parts use the 100-TQFP (14x14) package with identical pin assignments, voltage specifications, and I/O functionality. PCB layouts and connector designs are fully compatible.

Q: What is the Moisture Sensitivity Level (MSL) for these parts?

A: Both the C8051F040 and C8051F040-GQ have an MSL rating of 3 (168 Hours). This indicates standard moisture sensitivity requiring controlled storage and handling conditions during assembly.

Q: Can these parts be used in new product designs?

A: Both parts carry discontinuation-related status. For new designs, evaluate current-generation microcontroller alternatives from Silicon Labs or other manufacturers that meet your functional and compliance requirements.

Q: What export control classifications apply to these parts?

A: Both parts are classified under ECCN EAR99 and HTSUS 8542.31.0001, indicating standard commercial microcontroller export treatment.

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