MC9S08AC8CFJE - 8KB Flash S08 8-bit MCU, 40MHz, 32-LQFP | NXP
MPN: MC9S08AC8CFJE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.9 | $3.90 |
| 10 | $3.51 | $35.10 |
| 100 | $3.12 | $312.00 |
| 500 | $2.79 | $1,395.00 |
| 1,000 | $2.48 | $2,480.00 |
MC9S08AC8CFJE Overview
An 8-bit MCU (microcontroller unit) is a single-chip computer that integrates a CPU, non-volatile program memory (typically Flash), volatile data memory (RAM), and a variety of analog and digital peripherals onto one silicon die. Within the embedded hierarchy, the MC9S08AC8CFJE belongs to the 8-bit microcontroller category, which sits below 16-/32-bit families in raw computing power but offers lower cost, simpler toolchains, and ultra-low active and standby power for high-volume applications. The HCS08 core executes most instructions in 1-2 clock cycles, providing an effective 40 MIPS throughput at 40 MHz bus speed.
Key features of the MC9S08AC8CFJE include 25 General-Purpose I/O (GPIO) pins with interrupt capability, an integrated 10-bit Analog-to-Digital Converter (ADC) with up to 8 channels, multiple serial interfaces including SCI (UART) and SPI, a timer/PWM module (TPM) for motor and lighting control, and an internal clock generator with a trimming capability. The device supports a wide operating voltage range suitable for 3.3V and 5V systems, includes a low-power Run, Wait, and Stop mode set, and provides on-chip in-circuit debug (BDC) and Flash programming support for low-cost development. Note that the NXP product page also mentions integrated USB, which is more characteristic of other S08AC family members - the -CFJE suffix combination should be verified against the specific datasheet for peripheral inclusion.
The MC9S08AC8CFJE uses a von-Neumann-style Harvard-adjacent memory architecture with separate Flash and RAM buses, allowing Flash reads to occur in parallel with data accesses. Its BDM (Background Debug Mode) interface enables non-intrusive in-circuit programming and debugging via a single-wire background pin, dramatically reducing design-tool cost compared to JTAG-only families.
Typical applications include consumer appliance control boards, industrial sensor interfaces, small motor drivers, low-end metering devices, HVAC controls, USB-CDC bridges, and battery-powered sensor nodes where code density and low BOM cost matter more than raw compute throughput. The wide operating temperature range (typically -40C to +85C for the FJE suffix) supports both indoor and outdoor enclosures.
When designing with this device, ensure that the supply decoupling (one 100 nF plus one 10 uF bulk capacitor near the VDD pins) and that the RESET pin is held low for the minimum reset delay. Engineers migrating from the 32-bit counterpart (e.g., MCF51AC-family FlexIS pair) can reuse PCB layout because the 32-LQFP pinout is shared.
This page synthesizes distributor pricing, package-level alternatives, and design notes not aggregated anywhere else on the web, including known EOL status for this part number, so procurement teams can plan last-time buys and engineers can evaluate same-package variants.
Drop-in alternatives for MC9S08AC8CFJE — 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 MC9S08AC8CFJE (same form factor and footprint) — differing in Package, Lifecycle Status, Connectivity, Operating Temperature, Operating Temperature Range.
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MC9S08AC16CFJER
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MC9S08AC32CFJE
✅ Drop-In✓ In Stock
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View Datasheet →MC9S08AC8CFGE
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
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View Datasheet →MC9S08AC8CFDE
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View Datasheet →MC9S08AC8CFJE Maximum Ratings & Electrical Characteristics
| Core | S08 (HCS08) |
| Data Bus Width | 8-bit |
| Maximum Clock Frequency | 40 MHz |
| Program Memory Size | 8 KB Flash |
| Program Memory Type | Flash |
| Package | 32-LQFP (7x7 mm) |
| Mounting Type | Surface Mount |
| Pin Count | 32 |
| ADC | 10-bit, up to 8 channels |
| Operating Temperature Range | -40 C to +85 C |
| Connectivity | SCI (UART), SPI |
| Timers | TPM (Timer/PWM Module) |
| Debug Interface | BDM (Background Debug Mode) |
| RoHS Status | Compliant |
| Family | S08AC (FlexIS, 8-bit) |
MC9S08AC8CFJE Pin Configuration
| Pin 1 | PTB4/KBI4 — Port B bit 4 / Keyboard interrupt 4 |
| Pin 2 | PTB5/KBI5 — Port B bit 5 / Keyboard interrupt 5 |
| Pin 3 | PTB6/KBI6 — Port B bit 6 / Keyboard interrupt 6 |
| Pin 4 | PTB7/KBI7 — Port B bit 7 / Keyboard interrupt 7 |
| Pin 5 | VREFH — ADC reference voltage high |
| Pin 6 | VREFL — ADC reference voltage low |
| Pin 7 | VDD — Positive supply voltage |
| Pin 8 | VSS — Ground reference |
| Pin 9 | XTAL — Crystal oscillator input (external clock option) |
| Pin 10 | EXTAL — Crystal oscillator input/output |
| Pin 11 | RESET_b — External reset (active-low) |
| Pin 12 | BKGD/MS — Background Debug / Mode Select |
| Pin 13 | IRQ/TCLK — External interrupt / Timer clock |
| Pin 14 | PTA0/TXD1 — Port A bit 0 / SCI1 transmit |
| Pin 15 | PTA1/RXD1 — Port A bit 1 / SCI1 receive |
| Pin 16 | PTA2/MISO — Port A bit 2 / SPI MISO |
| Pin 17 | PTA3/MOSI — Port A bit 3 / SPI MOSI |
| Pin 18 | PTA4/SPSCK — Port A bit 4 / SPI clock |
| Pin 19 | PTA5/SS_b — Port A bit 5 / SPI slave select (active-low) |
| Pin 20 | PTA6/ADP0 — Port A bit 6 / ADC channel 0 |
| Pin 21 | PTA7/ADP1 — Port A bit 7 / ADC channel 1 |
| Pin 22 | PTD0/ADP2 — Port D bit 0 / ADC channel 2 |
| Pin 23 | PTD1/ADP3 — Port D bit 1 / ADC channel 3 |
| Pin 24 | PTD2/ADP4 — Port D bit 2 / ADC channel 4 |
| Pin 25 | PTD3/ADP5 — Port D bit 3 / ADC channel 5 |
| Pin 26 | PTD4/ADP6 — Port D bit 4 / ADC channel 6 |
| Pin 27 | PTD5/ADP7 — Port D bit 5 / ADC channel 7 |
| Pin 28 | PTC0 — Port C bit 0 |
| Pin 29 | PTC1 — Port C bit 1 |
| Pin 30 | PTC2 — Port C bit 2 |
| Pin 31 | PTC3 — Port C bit 3 |
| Pin 32 | NC — Not connected (per datasheet) |
Typical Applications
MC9S08AC8CFJE is suitable for 6 applications: Industrial Sensor Interface Module, Consumer Appliance Control Board, USB-CDC Bridge / Serial Adapter, Small DC Motor / Fan Speed Controller, Low-Cost HVAC Thermostat / Room Controller, Battery-Powered Wireless Sensor Node.
Industrial Sensor Interface Module
The MC9S08AC8CFJE is well-suited for industrial 4-20 mA or 0-10 V sensor interface boards that need a deterministic 8-bit MCU running a tight measurement loop. Its 10-bit ADC with up to 8 channels can sample thermocouple, pressure, or flow-rate inputs at the kHz rates typical of process instrumentation, while the HCS08's predictable interrupt latency keeps the control loop deterministic. The 32-LQFP package exposes ample GPIO for opto-isolated digital I/O and the integrated SCI (UART) supports Modbus RTU over RS-485 with an external transceiver. Designed for -40 C to +85 C operation, the part tolerates factory-floor thermal stress without derating, and its on-chip BDM background-debug interface simplifies field firmware updates through the same BDM header used at production programming.
Recommended
Consumer Appliance Control Board
In washing machines, microwaves, dishwashers, and small kitchen appliances, the MC9S08AC8CFJE drives keypads, drives 7-segment LED or LCD displays, and times the relay-controlled motors. The TPM (Timer/PWM Module) generates the PWM signals for triac-based heater phase-angle control or brushed DC motor speed loops, while the SCI port supports in-system firmware upgrade via a service-port UART. Code density is excellent thanks to the HCS08's compact instruction set - a full appliance control state-machine fits easily within the 8 KB Flash budget. The 32-LQFP footprint is small enough to fit behind the display panel and provides sufficient GPIO for switch-matrix keypads and LED status rows without external I/O expanders, keeping BOM cost low.
Recommended
USB-CDC Bridge / Serial Adapter
The MC9S08AC8CFJE serves as a low-cost USB-to-UART bridge in industrial programming cables and metering accessories. With the S08AC family's integrated USB 2.0 Full-Speed peripheral (where present in the silicon revision), the MCU enumerates as a Communications Device Class (CDC) device and presents a virtual COM port to the host - no external USB controller IC required. The host-side SCI bridges to the target board via DMA-friendly interrupt-driven UART. The 40 MHz core handles USB's 1.5 Mbps signaling with no risk of dropped packets, and the integrated 3.3V regulator (when enabled) can source the upstream USB pull-up resistor. A complete USB-CDC firmware stack fits in well under the 8 KB Flash budget, leaving room for vendor-specific commands.
Recommended
Small DC Motor / Fan Speed Controller
PWM-driven DC fans, small BLDC tool motors, and 12 V brushed motors are well-matched to the MC9S08AC8CFJE. The TPM module outputs complementary or independent PWM channels at frequencies from a few hundred Hz to >20 kHz, allowing silent operation above the audible range. Hall-sensor or BEMF feedback is read via the ADC, and a PI control loop runs comfortably inside the HCS08's interrupt-driven scheduler. The 32-LQFP package sits flat on the back of a small motor-driver PCB next to an H-bridge like the MC33886 or MC33926. With the wide supply tolerance of the S08AC family, the same firmware scales from 5 V to 24 V motor rails (with external regulators), making it ideal for handheld power-tool and small-appliance motor control.
Recommended
Low-Cost HVAC Thermostat / Room Controller
Smart thermostats and commercial-room controllers in the sub-$30 BOM bracket use the MC9S08AC8CFJE as the central brain to read temperature/humidity sensors (via the 10-bit ADC or I2C peripherals where present), drive a small e-paper or LCD user interface, and control a 24 VAC relay. The HCS08 core's ultra-low standby current extends battery life when running on backup supercaps or 2x AA cells. UART/SPI interfaces attach a Wi-Fi or Sub-GHz radio module for cloud connectivity. The Flash and RAM budget comfortably runs a simple PID thermostat algorithm plus capacitive-button handling, and the -40 C to +85 C rating supports unheated equipment-room enclosures.
Recommended
Battery-Powered Wireless Sensor Node
The MC9S08AC8CFJE's low-power Run, Wait, and Stop modes make it a strong match for battery-powered sensor nodes that sleep for most of their life and wake periodically to take a measurement and transmit. With Stop-mode current in the low-microamp range (depending on configuration), a single CR2032 cell can support a year or more of hourly wake-ups. The HCS08's fast wake-up time (a few microseconds from Stop to Run) preserves battery energy compared to slower MCUs, while the integrated ADC samples the sensor and the SPI/SCI block transmits via a paired sub-GHz radio. The 32-LQFP is compact enough to sit on a coin-cell-sized PCB next to the radio module.
Recommended
Recommended Products Summary
Engineering reference data for MC9S08AC8CFJE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S08AC16CFJER | MC9S08AC32CFJE | MC9S08AC8CFGE | MC9S08AC8CFDE |
|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 32-LQFP (7x7 mm) | 32-LQFP (7x7 mm) - same | 32-LQFP (7x7 mm) - same | 32-LQFP (7x7 mm) - same | 32-LQFP (7x7 mm) - same |
| Flash Memory | 8 KB | 16 KB (+100%) | 32 KB (+300%) | 8 KB (same) | 8 KB (same) |
| Core | S08 (HCS08) | S08 (HCS08) - same | S08 (HCS08) - same | S08 (HCS08) - same | S08 (HCS08) - same |
| Max Clock Frequency | 40 MHz | 40 MHz - same | 40 MHz - same | 40 MHz - same | 40 MHz - same |
| ADC | 10-bit, up to 8 channels | 10-bit, up to 8 channels - same | 10-bit, up to 8 channels - same | 10-bit, up to 8 channels - same | 10-bit, up to 8 channels - same |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C - same | -40 C to +85 C - same | -40 C to +85 C - same | -40 C to +85 C - same |
| Lifecycle Status | EOL | Active (last-time-buy transitioning) | EOL (last-time-buy transitioning) | EOL (packaging variant) | EOL (packaging variant) |
Key Differentiators
- Pin-compatible upgrade path to 32 KB Flash (vs MC9S08AC8CFJE vs MC9S08AC32CFJE)
- Tape-and-reel packaging option for high-volume assembly (vs MC9S08AC8CFJE vs MC9S08AC16CFJER (JER suffix))
- Single-vendor migration path within NXP S08AC FlexIS family (vs MC9S08AC8CFJE vs MC9S08FL8CLC)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD pin, plus a single 10 uF bulk tantalum or ceramic capacitor near the supply entry point. The S08AC family draws brief inrush currents during ADC conversion and Flash programming, and inadequate bulk capacitance can cause VDD droop and unexpected resets. For battery-powered designs, switch the internal voltage regulator to low-power Stop mode and gate the I/O ring supply separately to minimize quiescent current.
Route the BKGD/MS pin as a single dedicated trace to a 2-pin or 4-pin header for in-circuit programming - it must NOT be shared with regular GPIO. Place the crystal (if used) within 5 mm of the XTAL/EXTAL pins with a grounded guard ring around both traces to keep noise from coupling into the oscillator. For the 32-LQFP package, allow a 0.8 mm pad pitch on the PCB and respect the recommended land pattern from NXP's package drawings for hand-solder reworkability.
Do not leave the RESET pin floating - tie it to VDD through a 10 kohm pull-up and a 100 nF capacitor to ground to ensure a clean power-on reset. The ADC's VREFH/VREFL pins must be decoupled separately and NOT shared with digital VDD noise. When migrating from the S08AW to the S08AC family, verify that the FCDIV (Flash clock divider) setting is within the datasheet's maximum ratio - incorrectly set dividers will corrupt Flash programming and brick the device.
Estimated: At 40 MHz HCS08 core clock with 1-2 cycle instruction execution, the part generates approximately 20-40 MHz edge harmonics on VDD and digital output pins. To stay within typical FCC/CISPR class B limits, place a ferrite bead in series with VDD on the PCB entry and ensure the digital switching traces are short and ground-referenced.
Compliance Information
RoHS and REACH compliance indicated by Mouser/DigiKey listings. No AEC-Q100 automotive qualification on this part - choose -VFJE or other automotive-graded S08AC variants for vehicle use.