C8051F040R Equivalent & Substitute Parts

Part Overview

The C8051F040R is an 8-bit microcontroller from Silicon Labs' C8051F04x series, featuring a 25MHz 8051 core with 64KB Flash memory and integrated analog/digital conversion capabilities. This part is classified as Obsolete, making equivalent and substitute parts necessary for ongoing system support, maintenance, and component sourcing.

The C8051F040R is designed for embedded applications requiring CANbus, I2C, SPI, and UART connectivity with integrated analog signal processing. Due to its obsolete status, identifying compatible alternatives ensures design continuity and supply chain reliability.

Key Parameters

Parameter	Value
Core Processor	8051
Core Size	8-Bit
Speed	25MHz
Program Memory Size	64KB (64K x 8) FLASH
RAM Size	4.25K x 8
Voltage Supply (Vcc/Vdd)	2.7V ~ 3.6V
Number of I/O	64
Connectivity	CANbus, EBI/EMI, SMBus (2-Wire/I2C), SPI, UART/USART
Data Converters	A/D 8x8b, 13x12b; D/A 2x10b, 2x12b
Peripherals	Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT
Operating Temperature	-40°C ~ 85°C (TA)
Package / Case	100-TQFP (14x14)
Mounting Type	Surface Mount
Moisture Sensitivity Level (MSL)	3 (168 Hours)

Substitute Part Grouping Explanation

Substitution for the C8051F040R is based on strict electrical and mechanical parameter matching within the C8051F04x series. The primary substitute, C8051F040-GQ, maintains identical core specifications:

Key Substitution Parameters:

8051 core processor architecture
8-bit processing capability
25MHz clock speed
64KB Flash program memory
4.25K x 8 RAM configuration
64 I/O pins
Identical connectivity suite (CANbus, I2C, SPI, UART)
Matching analog/digital converter configuration
100-TQFP (14x14) package footprint
2.7V ~ 3.6V supply voltage range
-40°C ~ 85°C operating temperature range

The C8051F040-GQ differs only in packaging format (Tray vs. standard packaging) and compliance certifications, with no functional or electrical parameter variations.

Parameter Comparison

Parameter	C8051F040R	C8051F040-GQ	Match Status
Core Processor	8051	8051	Identical
Core Size	8-Bit	8-Bit	Identical
Speed	25MHz	25MHz	Identical
Program Memory Size	64KB (64K x 8) FLASH	64KB (64K x 8) FLASH	Identical
RAM Size	4.25K x 8	4.25K x 8	Identical
Voltage Supply (Vcc/Vdd)	2.7V ~ 3.6V	2.7V ~ 3.6V	Identical
Number of I/O	64	64	Identical
Connectivity	CANbus, EBI/EMI, SMBus (2-Wire/I2C), SPI, UART/USART	CANbus, EBI/EMI, SMBus (2-Wire/I2C), SPI, UART/USART	Identical
Data Converters	A/D 8x8b, 13x12b; D/A 2x10b, 2x12b	A/D 8x8b, 13x12b; D/A 2x10b, 2x12b	Identical
Peripherals	Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT	Brown-out Detect/Reset, POR, PWM, Temp Sensor, WDT	Identical
Operating Temperature	-40°C ~ 85°C (TA)	-40°C ~ 85°C (TA)	Identical
Package / Case	100-TQFP (14x14)	100-TQFP (14x14)	Identical
Mounting Type	Surface Mount	Surface Mount	Identical
Moisture Sensitivity Level (MSL)	3 (168 Hours)	3 (168 Hours)	Identical
RoHS Status	RoHS non-compliant	ROHS3 Compliant	Difference
Product Status	Obsolete	Not For New Designs	Difference

Engineering Selection Recommendations

The C8051F040-GQ serves as a direct functional equivalent to the C8051F040R with complete electrical and mechanical compatibility. Selection between these parts should be based on compliance and product lifecycle requirements:

C8051F040R Selection Criteria:

Legacy system maintenance where existing inventory is available
Applications where RoHS non-compliance is acceptable
Replacement of failed components in established designs

C8051F040-GQ Selection Criteria:

New designs requiring ROHS3 compliance
Systems requiring modern regulatory compliance certifications
Applications where REACH compliance status is specified
Preferred for long-term supply chain stability due to "Not For New Designs" status indicating broader availability

Both parts are electrically and mechanically interchangeable. The primary distinction is regulatory compliance posture, with C8051F040-GQ offering superior compliance certification coverage.

Frequently Asked Questions (FAQ)

Q: Are C8051F040R and C8051F040-GQ pin-for-pin compatible? A: Yes. Both parts use the 100-TQFP (14x14) package with identical pin assignments, I/O configuration, and electrical characteristics. Direct PCB substitution is possible without layout modifications.

Q: What is the difference between C8051F040R and C8051F040-GQ? A: The parts are functionally identical. Differences exist only in packaging format (Tray for -GQ variant) and compliance certifications. C8051F040-GQ is ROHS3 compliant and REACH unaffected, while C8051F040R is RoHS non-compliant.

Q: Can I use C8051F040-GQ as a replacement in existing C8051F040R designs? A: Yes. The C8051F040-GQ is a direct substitute with identical electrical performance, memory configuration, peripheral set, and package footprint. No firmware or hardware modifications are required.

Q: Why is the C8051F040R classified as Obsolete? A: Obsolete status indicates the part is no longer in active production. The C8051F040-GQ, classified as "Not For New Designs," represents the current available variant and should be used for ongoing sourcing and new applications.

Q: Are there any thermal or performance differences between these parts? A: No. Both parts operate at identical clock speeds (25MHz), voltage ranges (2.7V ~ 3.6V), and temperature specifications (-40°C ~ 85°C). Thermal and performance characteristics are equivalent.

Q: What is the significance of the MSL rating for these parts? A: Both parts carry MSL 3 (168 Hours) rating, indicating identical moisture sensitivity and storage requirements. Standard moisture control procedures apply to both variants.

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