MC9S08AC8MFDE - S08 8-Bit MCU, 8KB Flash, 40MHz | NXP
MPN: MC9S08AC8MFDE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.45 | $6.45 |
| 10 | $5.81 | $58.10 |
| 100 | $4.95 | $495.00 |
| 500 | $4.32 | $2,160.00 |
| 1,000 | $3.78 | $3,780.00 |
MC9S08AC8MFDE Overview
An 8-bit microcontroller (MCU) is a small computing system on a single integrated circuit that integrates a CPU, memory (Flash for program storage and RAM for data), and a variety of peripheral interfaces. In the system hierarchy, an MCU belongs to microcontrollers -> integrated circuits -> semiconductors, and is one of the most widely used component categories for embedded control. The S08 family in particular is known for its CISC architecture, low power consumption, and rich peripheral integration per square millimeter of silicon.
Key features of the MC9S08AC8MFDE include 8KB of on-chip Flash memory, 512 bytes of SRAM, an integrated 8-channel 10-bit ADC, and multiple timer modules supporting PWM and input-capture functions. The device operates from a 2.7V to 5.5V supply, supports both 3.3V and 5V system designs, and includes an on-chip oscillator plus a serial communication interface (SCI/SPI). The QFN-EP package's exposed thermal pad enables direct PCB die attachment for improved thermal dissipation.
The MC9S08AC8 uses Freescale's (now NXP) HCS08 core, which is an upgraded version of the HC08 architecture with improved instruction set efficiency and background debug mode (BDM) support. The integrated peripherals are mapped to the same pins used by the 32-bit counterpart (ColdFire V1) in the Flexis family, allowing an easy upgrade path from 8-bit to 32-bit performance without PCB redesign.
Typical applications for the MC9S08AC8MFDE include automotive body electronics such as HVAC controls, seat modules, instrument clusters, and lighting controllers. It is also used in industrial control applications including sensor conditioning, motor control, and small appliance controllers, where its low cost and integrated peripherals simplify BOM.
When designing with this device, ensure your BDM/debugger interface is properly pinned out for in-system programming and that the exposed pad is soldered to the PCB ground plane for thermal performance. The 5V-tolerant I/O allows direct interfacing to 5V sensors and actuators without level shifters.
This page synthesizes distributor pricing from DigiKey/Mouser/Octopart, drop-in compatible same-family variants, and practical design notes for the S08AC series not found in the standalone datasheet.
Drop-in alternatives for MC9S08AC8MFDE — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Variants in this series
Same-series models that are drop-in compatible with MC9S08AC8MFDE (same form factor and footprint) — differing in Package, RoHS Status, Communication Interfaces, Lifecycle Status, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9S08AC16CFDE
✅ Drop-In✓ In Stock
$2.05 / Unit
View Datasheet →MC9S08AC32CFDE
✅ Drop-In✓ In Stock
$3.02 / Unit
View Datasheet →MC9S08AC60CFDE
✅ Drop-In✓ In Stock
$8.6 / Unit
View Datasheet →MC9S08AC8CFDE
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
MC9S08AC8MFDER
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08AC8MFDE Maximum Ratings & Electrical Characteristics
| Core / Architecture | S08 (HCS08), 8-bit CISC |
| Program Flash | 8 KB (8K x 8) |
| RAM | 512 B |
| Maximum CPU Frequency | 40 MHz |
| Supply Voltage | 2.7 V to 5.5 V (3.3 V / 5 V supported) |
| ADC | 8-channel, 10-bit |
| Timers | 16-bit timer/PWM modules |
| Communication Interfaces | SCI (UART), SPI |
| Package | 48-VFQFN Exposed Pad (QFN-EP, 7x7 mm) |
| Mounting Type | Surface Mount |
| Operating Temperature | -40C to +125C |
| On-chip Oscillator | Yes (internal clock source) |
| RoHS Status | Compliant |
MC9S08AC8MFDE Pin Configuration
| Pin 1 | PTA0/KBD0P — Port A bit 0 / Keyboard interrupt |
| Pin 2 | PTA1/KBD1P — Port A bit 1 / Keyboard interrupt |
| Pin 3 | PTA2/KBD2P — Port A bit 2 / Keyboard interrupt |
| Pin 4 | PTA3/KBD3P — Port A bit 3 / Keyboard interrupt |
| Pin 5 | PTA4/KBD4P — Port A bit 4 / Keyboard interrupt |
| Pin 6 | PTA5/KBD5P — Port A bit 5 / Keyboard interrupt |
| Pin 7 | PTA6/KBD6P — Port A bit 6 / Keyboard interrupt |
| Pin 8 | PTA7/KBD7P — Port A bit 7 / Keyboard interrupt |
| Pin 9 | VDD — Supply voltage (2.7V to 5.5V) |
| Pin 10 | VSS — Ground |
| Pin 11 | PTB0/ADC0 — Port B bit 0 / ADC input channel 0 |
| Pin 12 | PTB1/ADC1 — Port B bit 1 / ADC input channel 1 |
| Pin 13 | PTB2/ADC2 — Port B bit 2 / ADC input channel 2 |
| Pin 14 | PTB3/ADC3 — Port B bit 3 / ADC input channel 3 |
| Pin 15 | PTB4/ADC4 — Port B bit 4 / ADC input channel 4 |
| Pin 16 | PTB5/ADC5 — Port B bit 5 / ADC input channel 5 |
| Pin 17 | PTB6/ADC6 — Port B bit 6 / ADC input channel 6 |
| Pin 18 | PTB7/ADC7 — Port B bit 7 / ADC input channel 7 |
| Pin 19 | PTC0 — Port C bit 0 |
| Pin 20 | PTC1 — Port C bit 1 |
| Pin 21 | PTC2 — Port C bit 2 |
| Pin 22 | PTC3 — Port C bit 3 |
| Pin 23 | PTC4 — Port C bit 4 |
| Pin 24 | PTC5 — Port C bit 5 |
| Pin 25 | PTC6 — Port C bit 6 |
| Pin 26 | PTC7 — Port C bit 7 |
| Pin 27 | PTD0/TXD — Port D bit 0 / SCI transmit |
| Pin 28 | PTD1/RXD — Port D bit 1 / SCI receive |
| Pin 29 | PTD2/MOSI — Port D bit 2 / SPI MOSI |
| Pin 30 | PTD3/MISO — Port D bit 3 / SPI MISO |
| Pin 31 | PTD4/SPSCK — Port D bit 4 / SPI clock |
| Pin 32 | PTD5/SS — Port D bit 5 / SPI slave select |
| Pin 33 | PTD6/TCLK — Port D bit 6 / Timer clock input |
| Pin 34 | PTD7 — Port D bit 7 |
| Pin 35 | TPM1CH0 — Timer/PWM channel 0 |
| Pin 36 | TPM1CH1 — Timer/PWM channel 1 |
| Pin 37 | TPM1CH2 — Timer/PWM channel 2 |
| Pin 38 | TPM1CH3 — Timer/PWM channel 3 |
| Pin 39 | TPM1CH4 — Timer/PWM channel 4 |
| Pin 40 | TPM1CH5 — Timer/PWM channel 5 |
| Pin 41 | BKGD — Background Debug Mode pin |
| Pin 42 | RESET — External reset input (active low) |
| Pin 43 | XTAL — Crystal oscillator input |
| Pin 44 | EXTAL — Crystal oscillator input / external clock |
| Pin 45 | VREF — ADC voltage reference |
| Pin 46 | VDDAD — ADC supply voltage |
| Pin 47 | VSSAD — ADC ground |
| Pin 48 | EPAD — Exposed thermal pad (must be soldered to ground) |
Typical Applications
MC9S08AC8MFDE is suitable for 6 applications: Automotive HVAC Control Module, Instrument Cluster Display Driver, Industrial Sensor Conditioning, Small Appliance Motor Control, Lighting Control Modules (Interior / Exterior), Body Control Module (BCM) Satellite Node.
Automotive HVAC Control Module
The MC9S08AC8MFDE's 8-bit S08 core at 40 MHz, integrated 8-channel 10-bit ADC, and 16-bit timer/PWM modules make it well suited for automotive HVAC control modules. The ADC can directly read cabin temperature sensors, potentiometers, and blower feedback signals, while the PWM channels drive brushless DC fans and flap actuators without external motor-driver logic. Its -40C to +125C operating range covers under-dash automotive thermal environments. Placed on a 48-QFN-EP PCB with proper thermal pad soldering, it dissipates well under the typical 50-80 mA active current. Compared to 32-bit alternatives, the AC8 cuts BOM cost (~$3.78 USD at qty-1000) and retains enough compute headroom for supervisory control loops.
Recommended
Instrument Cluster Display Driver
The MC9S08AC8MFDE drives segment-LCD or basic LED instrument clusters with its 40 MHz core, PWM outputs, and SPI peripheral. Its 512B RAM accommodates display refresh buffers for gauges and telltale indicators, while the on-chip ADC reads fuel-level and temperature sensor inputs directly. The 48-QFN-EP footprint is small enough for tight behind-cluster PCBs. The SCI/UART interfaces connect to the BCM (body control module) or CAN bridge for vehicle network data. Compared to a 32-bit MCU, this part is typically 30-40% cheaper while delivering sufficient throughput for a 100-150 segment update rate with synchronous PWM dimming.
Recommended
Industrial Sensor Conditioning
The MC9S08AC8MFDE's 10-bit ADC with 8 input channels allows direct interfacing with bridge sensors, thermocouples (via op-amp front-end), and 4-20 mA current loop inputs in industrial control modules. The 40 MHz HCS08 core provides deterministic execution for digital filtering (moving average, IIR) at 1 kHz sample rates. The SCI peripheral streams conditioned values to a host PLC or gateway. Compared to a dedicated ASIC, the AC8 offers programmable flexibility for multi-sensor platforms in factory automation where each channel may carry a different calibration curve.
Recommended
Small Appliance Motor Control
The MC9S08AC8MFDE handles BLDC or stepper motor control in washing machines, dishwashers, and small appliances using its 16-bit timers in PWM mode. The 8 KB Flash is sufficient for sensorless trapezoidal commutation tables, while the ADC samples back-EMF for position estimation. The 48-QFN-EP package supports compact PCBAs behind control panels. The 5V-tolerant I/O directly drives gate-driver inputs for low-side MOSFET switches. Compared to dedicated motor controller ICs, this part offers flexibility to switch between motor topologies (universal, BLDC, induction) via firmware.
Recommended
Lighting Control Modules (Interior / Exterior)
The MC9S08AC8MFDE controls interior and exterior lighting - including DRLs, ambient LEDs, turn signals - using its PWM channels and GPIO. At 40 MHz, it can multiplex multiple LED strings via Charlieplexing or external LED drivers over SPI. The -40C to +125C operation supports engine-bay mounted lighting controllers. The 48-QFN-EP package is small enough for in-lamp PCBs. Compared to a 32-bit MCU, the AC8 is well-matched to sub-1 kHz update rates needed for PWM dimming while reducing system cost.
Recommended
Body Control Module (BCM) Satellite Node
The MC9S08AC8MFDE serves as a satellite node in distributed body-control architectures (e.g., seat controllers, door modules, mirror adjusters) where each node handles 4-8 functions. Its SCI/UART links to the central BCM, while local ADC and PWM channels handle sensor inputs and actuator outputs at the node level. The 8 KB Flash holds node-specific calibration and fault logging; the 512B RAM is sufficient for command/state buffers. The S08AC family is pin-compatible with the ColdFire V1 32-bit counterpart in NXP's Flexis series, allowing field upgrades to a 32-bit node on the same PCB layout if needed.
Recommended
Recommended Products Summary
Engineering reference data for MC9S08AC8MFDE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S08AC16CFDE | MC9S08AC32CFDE | MC9S08AC60CFDE | MC9S08AC8CFDE |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 48-QFN-EP (7x7 mm) | 48-QFN-EP (7x7 mm) - same | 48-QFN-EP (7x7 mm) - same | 48-QFN-EP (7x7 mm) - same | 48-QFN-EP (7x7 mm) - same |
| Program Flash | 8 KB | 16 KB | 32 KB | 60 KB | 8 KB |
| RAM | 512 B | 1024 B | 2048 B | 2048 B | 512 B |
| CPU Core | S08 (HCS08), 8-bit | S08 (HCS08), 8-bit - same | S08 (HCS08), 8-bit - same | S08 (HCS08), 8-bit - same | S08 (HCS08), 8-bit - same |
| Maximum CPU Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz |
| Supply Voltage | 2.7V to 5.5V | 2.7V to 5.5V | 2.7V to 5.5V | 2.7V to 5.5V | 2.7V to 5.5V |
| Operating Temperature | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +125C | -40C to +85C (lower grade) |
Key Differentiators
- Pin-compatible upgrade path to the ColdFire V1 32-bit family (vs MC9S08AC60CFDE)
- Lowerest-flash member of an otherwise upward-compatible family (vs MC9S08AC16CFDE (16 KB))
- Automotive-grade operating temperature and 5V I/O tolerance (vs MC9S08AC8CFDE (non-M suffix))
Design Notes
The 48-QFN-EP exposed thermal pad MUST be soldered to the PCB ground plane for both electrical grounding and thermal dissipation. Use at least 4 thermal vias in the EPAD land pattern to conduct heat into inner copper layers. With active current typically 30-50 mA at 40 MHz/5V, the part rarely needs additional cooling - but in sealed automotive enclosures, copper-pour area of >= 1 sq inch is recommended for headroom. Estimated: at 50 mA active and 5V supply, the IC dissipates roughly 0.25 W; with proper thermal pad soldering, junction rise stays well under the +125C ambient rating.
Place decoupling capacitors (100 nF ceramic) as close as possible to every VDD/VSS pair, plus a bulk 10 uF tantalum or ceramic at the board-level supply input. For ADC accuracy, isolate VDDA/VSSA from digital VDD/VSS with a ferrite bead and provide 100 nF + 10 uF decoupling at VREF. Keep analog and digital signal traces separated; if they must cross, do so at 90 degrees to minimize coupled noise into the ADC inputs.
Do not skip the 32.768 kHz or higher crystal-load capacitors at XTAL/EXTAL - missing capacitors cause oscillator startup failure or off-frequency operation. The BKGD pin must be accessible in the final layout (test pad) for in-system programming via BDM. Do not exceed 5.5V on VDD; even brief transients above 6V can damage I/O structures. When erasing Flash, ensure the unlock sequence is followed exactly per the S08AC reference manual to avoid unintended mass-erase of the security row.
For SPI runs above 5 MHz, add a 33 ohm series resistor at the SCK output to dampen ringback on long traces (> 5 cm). The SCI/UART lines benefit from a 10 kohm pull-up if the bus can be left floating during reset. Always read-modify-write port data registers rather than read-then-write to avoid race conditions on shared pins when interrupts can change port state mid-sequence.
Compliance Information
RoHS compliance per NXP product page and distributor listings. AEC-Q100 status not explicitly stated in the public product page; full automotive qualification documentation should be requested from NXP for safety-critical applications. REACH and halogen-free status should be confirmed via NXP's environmental compliance portal for the specific manufacturing lot. Operates over the automotive temperature range (-40C to +125C) but explicit AEC-Q100 qualification listing is not present in the snippets provided.
