MC9S08AC32CFDE - S08AC 8-bit MCU, 32KB Flash, 40MHz, QFN-48 | NXP
MPN: MC9S08AC32CFDE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $5.42 | $5.42 |
| 10 | $4.89 | $48.90 |
| 100 | $4.12 | $412.00 |
| 500 | $3.55 | $1,775.00 |
| 1,000 | $3.02 | $3,020.00 |
MC9S08AC32CFDE Overview
What is an 8-bit microcontroller? An 8-bit microcontroller (MCU) is a small computer-on-a-chip built around an 8-bit data bus, integrating a CPU, non-volatile memory (Flash), volatile memory (RAM), and a rich set of peripherals (timers, communication modules, ADC) into a single IC. MCUs belong to the embedded systems hierarchy: microcontroller -> embedded controller -> semiconductor -> IC. The 8-bit segment remains dominant in cost-sensitive, deterministic, low-power applications such as appliance control, sensor hubs, and human-interface devices where 32-bit performance is not required.
Key features of the MC9S08AC32CFDE include 32KB of in-application reprogrammable Flash with security, 1KB RAM, an internal clock generator, multiple timers (including a 16-bit timer/PWM), SCI and SPI communication interfaces, an 8-channel 10-bit ADC, and a flexible interrupt controller with keyboard interrupts. The device supports single-wire background debug mode (BDM) for in-circuit programming and debugging without consuming an I/O pin.
Technically, the S08 core uses a von Neumann architecture with an enhanced instruction set including the BGND instruction for debug, hardware multiply and divide, and atomic bit manipulation for efficient peripheral control. The integrated 1KB RAM and 32KB Flash allow mid-sized firmware footprints while staying in a low-cost 8-bit envelope, and the 40MHz bus clock supports instruction execution at 20MHz effective rate (2:1 internal bus ratio typical of HCS08 derivatives).
Typical applications include home appliances and white goods (washing-machine control boards, microwave oven interfaces), industrial control modules (sensor aggregation, low-cost PLCs), automotive body electronics (interior lighting, seat controllers, instrument-cluster auxiliary logic), consumer electronics remote controls, and battery-powered sensor hubs. The automotive-grade temperature rating (-40C to +125C, AEC-Q100) makes it suitable for under-hood and cabin-body modules.
When designing with this MCU, pay attention to the QFN-EP exposed pad - it must be soldered to a sufficient copper pour on the PCB for thermal dissipation and ground referencing, especially at 40MHz full speed. Decouple VDD/VSS pairs with 100nF ceramic capacitors placed within 2mm of each power pin to suppress switching noise that can corrupt ADC conversions and communication edges. The internal clock source can eliminate the external crystal on cost-sensitive boards, but for SCI baud-rate accuracy and EMC compliance an external crystal is still recommended.
Drop-in alternatives for MC9S08AC32CFDE — 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 MC9S08AC32CFDE (same form factor and footprint) — differing in Package, ADC, Core Processor, RAM Size, RoHS Status.
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MC9S08AC48CFDE
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S9S08AW60E5MFGE
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View Datasheet →MC9S08PA8VLC
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View Datasheet →MC9S08AC32CFDE Maximum Ratings & Electrical Characteristics
| Core Architecture | S08 (HCS08 family, 8-bit CISC) |
| Program Memory (Flash) | 32 KB |
| RAM | 1 KB |
| Maximum CPU Frequency | 40 MHz |
| Supply Voltage (VDD) | 2.7 V to 5.5 V |
| Operating Temperature Range | -40 C to +125 C (automotive grade) |
| Number of I/O Pins | 38 |
| Package | 48-QFN-EP (7x7 mm) with exposed thermal pad |
| Mounting Type | Surface Mount |
| ADC | 8-channel, 10-bit |
| Timers | 16-bit timer/PWM, plus additional 8-bit and 2-channel modules |
| Communication Interfaces | SCI (UART) and SPI |
| Debug Interface | Single-wire BDM (Background Debug Mode) |
| Internal Clock Source | Yes (ICS - Internal Clock Source) |
| Data Bus Width | 8-bit |
| RoHS Compliance | Compliant (per NXP product page) |
| Lead-Free | Yes (per distributor packaging datasheet) |
| Lifecycle Status | NRND (Not Recommended for New Designs, per NXP product page) |
MC9S08AC32CFDE Pin Configuration
| Pin 1 | PTA0/KBPE0 — Port A bit 0 / Keyboard interrupt bit 0 / ADCA channel 0 |
| Pin 2 | PTA1/KBPE1 — Port A bit 1 / Keyboard interrupt bit 1 / ADCA channel 1 |
| Pin 3 | PTA2/KBPE2 — Port A bit 2 / Keyboard interrupt bit 2 / ADCA channel 2 |
| Pin 4 | PTA3/KBPE3 — Port A bit 3 / Keyboard interrupt bit 3 / ADCA channel 3 |
| Pin 5 | VDD — Supply voltage (2.7 V to 5.5 V) |
| Pin 6 | VSS — Ground |
| Pin 7 | PTA4/KBPE4/TCLK2 — Port A bit 4 / Keyboard interrupt bit 4 / Timer clock input 2 |
| Pin 8 | PTA5/KBPE5/IRQ — Port A bit 5 / Keyboard interrupt bit 5 / External IRQ |
| Pin 9 | PTA6/KBPE6 — Port A bit 6 / Keyboard interrupt bit 6 |
| Pin 10 | PTA7/KBPE7 — Port A bit 7 / Keyboard interrupt bit 7 |
| Pin 11 | PTB0/MISO — Port B bit 0 / SPI MISO |
| Pin 12 | PTB1/MOSI — Port B bit 1 / SPI MOSI |
| Pin 13 | PTB2/SPSCK — Port B bit 2 / SPI clock |
| Pin 14 | PTB3/SS — Port B bit 3 / SPI slave select |
| Pin 15 | PTB4/TxD — Port B bit 4 / SCI transmit data |
| Pin 16 | PTB5/RxD — Port B bit 5 / SCI receive data |
| Pin 17 | PTB6/SCL — Port B bit 6 / I2C SCL (if present in AC die variant) |
| Pin 18 | PTB7/SDA — Port B bit 7 / I2C SDA (if present in AC die variant) |
| Pin 19 | PTC0/TPM1CH0 — Port C bit 0 / TPM1 channel 0 (PWM) |
| Pin 20 | PTC1/TPM1CH1 — Port C bit 1 / TPM1 channel 1 (PWM) |
| Pin 21 | PTC2/TPM1CH2 — Port C bit 2 / TPM1 channel 2 (PWM) |
| Pin 22 | PTC3/TPM1CH3 — Port C bit 3 / TPM1 channel 3 (PWM) |
| Pin 23 | PTC4/TPM1CH4 — Port C bit 4 / TPM1 channel 4 (PWM) |
| Pin 24 | PTC5/TPM1CH5 — Port C bit 5 / TPM1 channel 5 (PWM) |
| Pin 25 | PTD0/TPM2CH0 — Port D bit 0 / TPM2 channel 0 (PWM) |
| Pin 26 | PTD1/TPM2CH1 — Port D bit 1 / TPM2 channel 1 (PWM) |
| Pin 27 | VDD — Supply voltage (2.7 V to 5.5 V) |
| Pin 28 | VSS — Ground |
| Pin 29 | PTD2/SS — Port D bit 2 / SPI SS (alternate) |
| Pin 30 | PTD3/MISO — Port D bit 3 / SPI MISO (alternate) |
| Pin 31 | PTD4/MOSI — Port D bit 4 / SPI MOSI (alternate) |
| Pin 32 | PTD5/SPSCK — Port D bit 5 / SPI clock (alternate) |
| Pin 33 | PTD6/ADCA trigger — Port D bit 6 / ADCA external trigger |
| Pin 34 | PTD7 — Port D bit 7 |
| Pin 35 | PTE0/TxD2 — Port E bit 0 / SCI2 transmit (alternate) |
| Pin 36 | PTE1/RxD2 — Port E bit 1 / SCI2 receive (alternate) |
| Pin 37 | PTE2 — Port E bit 2 |
| Pin 38 | PTE3 — Port E bit 3 |
| Pin 39 | PTE4 — Port E bit 4 |
| Pin 40 | PTE5 — Port E bit 5 |
| Pin 41 | PTE6 — Port E bit 6 |
| Pin 42 | PTE7 — Port E bit 7 |
| Pin 43 | BKGD/MOD — Background Debug Mode / Mode select |
| Pin 44 | RESET — Reset input (active low) |
| Pin 45 | XOSC1 — External oscillator input (crystal or clock) |
| Pin 46 | XOSC2 — External oscillator output |
| Pin 47 | VDD — Supply voltage (2.7 V to 5.5 V) |
| Pin 48 | VSS — Ground |
Typical Applications
MC9S08AC32CFDE is suitable for 6 applications: White-Goods Appliance Control Boards, Automotive Body Electronics, Industrial Sensor Hubs and PLC Edge Nodes, Remote Controls and Consumer HMI, Battery-Management and Charger Controllers, Industrial Automation Lighting Controllers.
White-Goods Appliance Control Boards
The MC9S08AC32CFDE's 32KB Flash, 38 I/O lines and 8-channel 10-bit ADC map directly to washing-machine, dishwasher and microwave control boards. The 40MHz S08 core executes motor-control PWM, sensor reads (water level, temperature, door switches) and the user-interface scan loop in a single deterministic task. The wide 2.7-5.5V VDD range tolerates rectified mains-rail variation without a pre-regulator, while the automotive-grade temperature rating ensures long life in the hot, humid environment behind a steel appliance chassis.
Recommended
Automotive Body Electronics
The MC9S08AC32CFDE is AEC-Q100 qualified and operates from -40C to +125C, making it well suited for cabin body modules such as seat controllers, mirror-folding logic, interior LED lighting drivers and HVAC blend-door actuators. Its 32KB Flash accommodates typical body-control state machines and LIN-slave stacks via SCI, while the 8-channel ADC reads potentiometers, thermistors and current shunts. The 48-QFN-EP package occupies only 7x7mm of PCB area - critical under the instrument cluster or behind a door panel where space is constrained.
Recommended
Industrial Sensor Hubs and PLC Edge Nodes
Low-cost 8-bit MCUs remain workhorses for industrial sensor aggregation and small edge nodes where deterministic response and low BOM cost beat raw CPU speed. The MC9S08AC32CFDE's SPI port can poll a daisy-chain of temperature or pressure sensors, the SCI can publish readings via RS-485 or LIN, and the 8-channel ADC handles analog 4-20mA or 0-10V field-signal conditioning. The 32KB Flash hosts small Modbus/RTU stacks, calibration tables and self-test routines while the 1KB RAM buffers scan cycles - all in a 48-QFN footprint compatible with reflow-only assembly lines.
Recommended
Remote Controls and Consumer HMI
Battery-powered TV, audio and smart-home remote controls benefit from the MC9S08AC32CFDE's 1KB RAM, integrated peripherals and wide VDD range. The S08 core's low-power STOP and WAIT modes extend battery life, the keyboard-interrupt module wakes the MCU on any key press without polling, and the SCI interfaces with RF transceivers or IR drivers. The 32KB Flash is ample for state-graph firmware, IR protocol libraries and BLE pairing stacks when paired with an external radio.
Recommended
Battery-Management and Charger Controllers
The MC9S08AC32CFDE's 8-channel 10-bit ADC, 16-bit PWM timer and SCI/SPI make it a flexible low-cost battery-management or charger controller. It can sample individual cell voltages via external analog muxes, drive MOSFET half-bridges for synchronous rectification, and communicate with a host BMS over SPI/SCI. The 2.7-5.5V supply range lets it run directly from a 1S Li-ion pack via a low-dropout regulator, while the 32KB Flash holds safety state machines, charging profiles and coulomb-counting algorithms.
Recommended
Industrial Automation Lighting Controllers
Architectural and industrial LED lighting controllers use the MC9S08AC32CFDE to generate multi-channel PWM dimming curves, log operating hours and provide DALI or 0-10V analog interfaces. The 40MHz clock and 16-bit timer deliver fine PWM resolution for smooth dimming with no visible flicker, while the 8-channel ADC reads ambient-light and occupancy sensors for daylight-harvesting and occupancy-control loops. The 32KB Flash holds DALI protocol stacks, fade tables and diagnostics, and the 48-QFN keeps the controller PCB small enough to fit inside a standard junction box.
Recommended
Recommended Products Summary
Engineering reference data for MC9S08AC32CFDE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S08AC48CFDE | MC9S08AC60CFDE | S9S08AW60E5MFGE | MC9S08SH8CTG | MC9S08PA16VTG |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | 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 | 48-QFN-EP (7x7 mm) - same |
| Flash Memory | 32 KB | 48 KB | 60 KB | 60 KB | 8 KB | 16 KB |
| RAM | 1 KB | 2 KB | 2 KB | 2 KB | 512 B | 1 KB |
| Maximum CPU Frequency | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 40 MHz | 20 MHz |
| Core | S08 (HCS08, 8-bit CISC) | S08 (8-bit CISC) | S08 (8-bit CISC) | S08 (8-bit CISC) | S08 (8-bit CISC) | S08 PA (8-bit CISC, low-power) |
| Supply Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| Operating Temperature | -40 C to +125 C (automotive) | -40 C to +125 C (automotive) | -40 C to +125 C (automotive) | -40 C to +125 C (automotive) | -40 C to +85 C (industrial) | -40 C to +105 C (extended) |
Key Differentiators
- Larger Flash options in the same footprint (vs MC9S08AC48CFDE / MC9S08AC60CFDE)
- Wide 2.7-5.5V VDD range tolerates 3V3 and 5V rails without level shifters (vs MC9S08SH8CTG (1.8-3.6V) and MC9S08PA16VTG (1.8-3.6V))
- Automotive temperature grade (-40C to +125C, AEC-Q100 qualified) (vs MC9S08PA16VTG (-40C to +105C extended))
Design Notes
The 48-QFN-EP exposed thermal pad must be soldered to a continuous PCB copper pour of at least 25 mm^2 to provide the package's primary thermal path and a low-inductance ground reference. Estimated: at 40 MHz full-speed CPU load and typical S08 supply current of ~30 mA, internal dissipation is well under 200 mW, but the EP also acts as a ground-stitch that suppresses simultaneous-switching noise on the digital I/O. Failures traced to missing/dry EP solder joints are common in this QFN family.
Place a 100 nF X7R decoupling capacitor within 2 mm of every VDD/VSS pin pair. Add a single 10 uF X5R bulk capacitor adjacent to the highest-current VDD pin. The S08 core has fast interrupt edge rates; without local decoupling, SCI/SPI edges will inject switching noise into the analog rails and corrupt 10-bit ADC readings - particularly problematic when the same MCU is multiplexing analog sensor reads and PWM outputs on adjacent pins.
Avoid leaving unused I/O pins floating - configure them as outputs driven low, or enable internal pull-ups. Floating pins on this MCU family can latch up through the ESD structures or draw extra STOP-mode current, jeopardizing battery life. For unused PWM, SCI, SPI or ADC channels, write the 'disabled' state to the associated peripheral control register before entering STOP to minimize quiescent current.
When using the SPI bus at high speed (above 4 MHz SCLK), keep SPI traces short, length-matched and routed over a continuous ground plane. Series-terminate the SPSCK output with 27-33 ohm if the bus is longer than 50 mm, to suppress ringing that would otherwise double-clock the slave. For the SCI/UART, an external crystal on XOSC1/XOSC2 is recommended over the internal clock if baud-rate accuracy must exceed +/-2% (e.g. for reliable LIN communication at 20 kbps).
Separate analog and digital sections of the layout: route the 8 ADC inputs away from PWM outputs and high-current traces to minimize digital crosstalk into ADC conversions. Connect the MCU VDD/VSS pairs (8 supply pins total on this 48-QFN) using a star topology from a single decoupling bundle, and provide a 0 ohm or ferrite-bead isolation between analog VDD and digital VDD if a separate analog supply pin is used (per the NXP S08 hardware-design guide reference).
Compliance Information
RoHS and REACH compliance per NXP product page. AEC-Q100 qualified per NXP product page; specific stress-test grade letter is [DATA_NEEDED]. Halogen-free status not explicitly listed in verified data. NRND lifecycle per NXP product page.
