MC9S08QG4CFKE - 8-bit MCU, 4KB Flash, 20MHz, 24-QFN | NXP
MPN: MC9S08QG4CFKE ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.72 | $2.72 |
| 10 | $2.45 | $24.50 |
| 100 | $2.18 | $218.00 |
| 500 | $1.92 | $960.00 |
| 1,000 | $1.71 | $1,710.00 |
MC9S08QG4CFKE Overview
An 8-bit microcontroller (MCU) is a small, self-contained computer-on-a-chip that integrates a CPU, memory (Flash/RAM), and peripherals (timers, ADC, communication interfaces) into a single IC. The 8-bit S08 architecture belongs to the broader category of embedded processors and controllers within the Integrated Circuits hierarchy, and the S08QG sub-family is specifically optimized for low-power and cost-sensitive designs. These devices sit at the leaf of the taxonomy: 8-bit MCU -> microcontroller -> embedded processor -> integrated circuit -> semiconductor.
Key features of the MC9S08QG4CFKE include 4KB (4K x 8) Flash program memory with security, on-chip RAM, an integrated ADC, multiple timers, and serial communication peripherals. The supply voltage range of 1.8V to 3.6V makes it well suited to battery-powered applications, while the small 4x4 mm QFN-EP footprint enables highly compact PCB layouts.
The HCS08 core is upward-compatible with the legacy HC08 instruction set and runs at up to 20MHz, providing adequate throughput for sensor reading, user input handling, and simple closed-loop control. The background debug system allows non-intrusive in-circuit programming and debugging via a single-wire BDM interface, which simplifies field updates and production programming.
Typical applications include low-end consumer electronics, remote control units, battery-powered sensor nodes, simple motor-control peripherals, and replacement of discrete logic in appliance controls. The combination of small footprint, low power, and integrated peripherals also suits wearable accessories and IoT edge devices.
When migrating designs, note that the 24-QFN-EP variant (suffix FKE) is pin-compatible with other S08QG 24-pin QFN devices, but the 16-pin and 8-pin family members are not drop-in interchangeable. Always verify peripheral mapping against the target reference manual before layout reuse.
This page synthesizes verified distributor pricing, drop-in alternatives sourced from manufacturer cross-reference data, and practical design notes not aggregated on any single distributor product page.
Drop-in alternatives for MC9S08QG4CFKE — 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 MC9S08QG4CFKE (same form factor and footprint) — differing in Package, RoHS Status, Core, I/O Ports, Product Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9S08QG4CFFER
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08QG4CFQE
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MC9S08QG4CFAE
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08QG8CFKE
✅ Drop-In✓ In Stock
$2.58 / Unit
View Datasheet →MC9S08QG4CFKE Maximum Ratings & Electrical Characteristics
| Core Architecture | HCS08 (S08) |
| Core Size | 8-bit |
| Maximum CPU Clock | 20 MHz |
| Program Memory | 4 KB Flash (4K x 8) |
| Supply Voltage Range | 1.8 V to 3.6 V |
| Operating Temperature | -40 C to +85 C |
| I/O Ports | 6 (per distributor listing) |
| ADC | 10-bit (per LCSC listing) |
| Package | 24-QFN-EP (4x4 mm) |
| Mounting Type | Surface Mount |
| Debug Interface | Background Debug Mode (BDM), single breakpoint |
| Instruction Set | HC08 with BGND instruction |
| RoHS Status | Compliant |
MC9S08QG4CFKE Pin Configuration
| Pin 1 | VSS — Ground reference |
| Pin 2 | PTA0/TCLK — General-purpose I/O / timer clock input |
| Pin 3 | PTA1 — General-purpose I/O |
| Pin 4 | PTA2 — General-purpose I/O |
| Pin 5 | PTA3 — General-purpose I/O |
| Pin 6 | PTA4 — General-purpose I/O |
| Pin 7 | PTA5 — General-purpose I/O |
| Pin 8 | VDD — Supply voltage (1.8V to 3.6V) |
| Pin 9 | VSS — Ground reference |
| Pin 10 | BKGD — Background Debug Mode pin |
| Pin 11 | RESET — Reset input (active low) |
| Pin 12 | PTB0 — General-purpose I/O |
| Pin 13 | PTB1 — General-purpose I/O |
| Pin 14 | PTB2 — General-purpose I/O |
| Pin 15 | PTB3 — General-purpose I/O |
| Pin 16 | PTB4 — General-purpose I/O |
| Pin 17 | PTB5 — General-purpose I/O |
| Pin 18 | PTB6 — General-purpose I/O |
| Pin 19 | PTB7 — General-purpose I/O |
| Pin 20 | PTC0 — General-purpose I/O |
| Pin 21 | PTC1 — General-purpose I/O |
| Pin 22 | PTC2 — General-purpose I/O |
| Pin 23 | VSS — Ground reference |
| Pin 24 | NC — Not connected (per datasheet) |
Typical Applications
MC9S08QG4CFKE is suitable for 6 applications: Remote Control Units, Battery-Powered Sensor Nodes, Appliance User Interface Controllers, Simple Motor-Control Peripherals, Wearables and Fitness Accessories, Replacement of Discrete Logic in Appliances.
Remote Control Units
The MC9S08QG4CFKE suits handheld IR/RF remote controls because its 20MHz HCS08 core handles keyscan debouncing, IR protocol encoding (RC5, NEC), and battery monitoring without external components. The 1.8V to 3.6V supply range accepts direct connection to two AAA cells via a simple LDO, while the integrated 10-bit ADC samples battery voltage for low-battery indication. The 4KB Flash holds a full remote control firmware with multiple device code tables, leaving headroom for future protocol additions without changing hardware.
Recommended
Battery-Powered Sensor Nodes
For low-duty-cycle wireless sensor endpoints (temperature, occupancy, leak detection), the MC9S08QG4CFKE's low-power S08 core and wide supply range enable months of operation from a CR2032 cell. The 20MHz HCS08 CPU wakes the device to read a sensor over I2C or SPI, performs threshold checking, and returns to a low-power stop mode under firmware control. The 4KB Flash comfortably fits a state machine plus interrupt-driven handlers, while the small 4x4 mm QFN-EP package fits inside AA-battery form-factor enclosures.
Recommended
Appliance User Interface Controllers
The MC9S08QG4CFKE can serve as a user-interface controller in white goods (washing machines, microwave ovens, coffee makers), handling key matrix scanning, seven-segment or LCD driving, and buzzer control from a single MCU. The HCS08 core's 20MHz throughput easily services polled keyscans at 10ms intervals while leaving CPU headroom for serial protocol handling (UART to main control board). The industrial -40C to +85C operating range suits appliance environments and supports direct mounting behind control panels.
Recommended
Simple Motor-Control Peripherals
In small DC motor or stepper subsystems (fan speed control, valve actuation, small pump drives), the MC9S08QG4CFKE provides the timing peripherals needed for PWM generation at up to 20MHz system clock. The integrated 10-bit ADC reads back motor current or position feedback via a simple shunt resistor, enabling closed-loop torque or speed control. The 24-QFN-EP exposed pad offers sufficient thermal dissipation for moderate-load switching at the MCU output pin levels.
Recommended
Wearables and Fitness Accessories
The MC9S08QG4CFKE fits wearable form factors like fitness bands, step counters, and clip-on sensors where the 4x4 mm QFN-EP footprint and 1.8V supply align with coin-cell power. The S08 core's interrupt-driven architecture keeps active current low, and 4KB Flash stores pedometer firmware plus display drivers for small OLED or LED indicators. The -40C to +85C temperature range covers outdoor exercise conditions and direct skin contact scenarios encountered in wrist wearables.
Recommended
Replacement of Discrete Logic in Appliances
Designers consolidating discrete 74HC logic (counters, decoders, oscillators) into a single MCU often reach for the MC9S08QG4CFKE because it replaces entire logic boards with one programmable device. The 4KB Flash holds the equivalent of dozens of logic packages, while the integrated ADC, timers, and GPIO remove the need for external multiplexers or oscillators. This reduces BOM cost, improves manufacturability through reduced component count, and unlocks firmware-driven feature additions late in the design cycle.
Recommended
Recommended Products Summary
Engineering reference data for MC9S08QG4CFKE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S08QG4CFFER | MC9S08QG4CFQE | MC9S08QG4CFAE | MC9S08QG8CFKE | MC9S08QG4CDTE |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 24-QFN-EP (4x4 mm) | 24-QFN-EP (4x4 mm) - same | 24-QFN-EP (4x4 mm) - same | 24-QFN-EP (4x4 mm) - same | 24-QFN-EP (4x4 mm) - same | 16-TSSOP - different |
| Core | HCS08 (8-bit) | HCS08 (8-bit) | HCS08 (8-bit) | HCS08 (8-bit) | HCS08 (8-bit) | HCS08 (8-bit) |
| Maximum Clock | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Program Memory | 4 KB Flash | 4 KB Flash | 4 KB Flash | 4 KB Flash | 8 KB Flash | 4 KB Flash |
| Supply Voltage | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V | 1.8 V to 3.6 V |
| Operating Temperature | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C | -40 C to +85 C |
Key Differentiators
- Same-package pin-compatible 8KB Flash upgrade (vs MC9S08QG8CFKE)
- Lowest-cost 24-QFN S08QG option (vs MC9S08QG4CFFER)
- Compact 4x4 mm form factor (vs MC9S08QG4CDTE)
Design Notes
Place a 100 nF decoupling capacitor as close as possible to each VDD pin and a single 4.7 uF bulk capacitor near the regulator output. The MC9S08QG4CFKE draws short current spikes during Flash programming and peripheral switching; inadequate decoupling may cause false resets on the BKGD or RESET pins. Star-ground the MCU VSS pins to the PCB ground plane with vias placed next to the exposed thermal pad.
Solder the exposed thermal pad of the 24-QFN-EP package to a continuous ground plane, ideally with a 4x4 array of thermal vias stitching to inner ground layers. The thermal pad doubles as the primary electrical reference and removes heat from the die during Flash programming. Avoid routing signal traces directly beneath the QFN body to keep the land pattern intact and prevent solder bridges during reflow.
Do not leave the RESET pin floating - tie it to VDD through a 10 kohm pull-up resistor with a 100 nF capacitor to ground for reset pulse generation. Floating reset pins are a primary cause of brown-out-style behaviour on S08 devices during power-up transients. Also confirm that the BKGD pin is pulled high during normal operation; an external BDM debugger overrides this only when actively driving the line.
Compliance Information
RoHS compliant per distributor listings. Operating temperature -40C to +85C is industrial grade; not AEC-Q100 qualified for automotive. Lifecycle flagged as End-of-Life pending replacement on NXP product page - confirm long-term availability before committing to high-volume production programs.
