MC908QT2ACFQE - 8-Bit HC08 MCU, 1.5KB Flash, 8MHz | NXP
MPN: MC908QT2ACFQE ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.0202 | $1.02 |
| 10 | $0.92 | $9.20 |
| 100 | $0.81 | $81.00 |
| 500 | $0.73 | $365.00 |
| 1,000 | $0.65 | $650.00 |
MC908QT2ACFQE Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (Flash/ROM), data memory (RAM), and programmable I/O on one die; it sits beneath 'microcontroller' and above '8-bit CPU core' in the semiconductor taxonomy. The HC08 core uses a von Neumann architecture with on-chip Flash and is engineered for deterministic, low-power operation in human-interface and consumer products, where an MCU replaces discrete analog timing/control circuitry.
Key features of the MC908QT2ACFQE include 1.5KB Flash (1.5K x 8), 128 bytes of RAM, an internal oscillator eliminating the need for an external crystal in many designs, 5 general-purpose I/O pins, and an 8-VDFN exposed-pad package (4x4 mm) that doubles as a thermal path to PCB copper. The part supports in-circuit programming and is optimized for low-power sleep modes and keyboard/touch/wake-up tasks typical of the QT family.
The HC08 QT-series architecture pairs a simple accumulator-based CPU with a robust instruction set, integrated brown-out detection, and multiple low-power stop modes. The exposed-pad DFN package provides a low thermal-resistance path that allows the small die to dissipate heat generated by internal blocks such as the ADC reference and IRC oscillator.
Typical applications include low-cost consumer appliances, remote-control transmitters, simple user-interface keypads, low-end toys, and any embedded system that needs a small, inexpensive 8-bit controller with internal clocking and minimal external components. It is also widely used as an analog-circuit replacement and as a glue MCU in mixed-signal PCBs.
When designing with the MC908QT2ACFQE, take care that the exposed pad is soldered to a sufficient copper area for thermal and electrical grounding, and follow NXP's recommended decoupling of VDD/VDDA with a 0.1uF ceramic cap placed as close as possible to the supply pin. Note that this part is mature; verify long-term availability for new designs against NXP's product longevity program.
This page synthesizes distributor pricing, Flash/RAM/IO specifications, drop-in QT-series pin-compatible alternatives, and practical design notes not bundled in the manufacturer datasheet.
Drop-in alternatives for MC908QT2ACFQE — 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 MC908QT2ACFQE (same form factor and footprint) — differing in Package, Core Architecture, Program Memory Size, Timers, Mounting Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC908QT1ACFQE
✅ Drop-In✓ In Stock
$1.7 / Unit
View Datasheet →MC908QT1ACPE
✅ Drop-In✓ In Stock
$2.3 / Unit
View Datasheet →MC908QT2ACPE
✅ Drop-In✓ In Stock
$0.75 / Unit
View Datasheet →MC908QT4ACFQE
✅ Drop-In📋 Reference alternative (not in catalog)
MC908QT4ACPE
✅ Drop-In✓ In Stock
$1.05 / Unit
View Datasheet →MC908QT2ACFQE Maximum Ratings & Electrical Characteristics
| Core Architecture | HC08 (M68HC08 family) |
| Data Bus Width | 8-bit |
| Program Memory Size | 1.5 KB (1.5K x 8) Flash |
| RAM Size | 128 bytes (128 x 8) |
| Maximum Clock Frequency | 8 MHz |
| Number of I/O Pins | 5 |
| Oscillator Type | Internal |
| Package / Case | 8-VDFN Exposed Pad (4x4 mm) |
| Mounting Type | Surface Mount |
| Packaging | Tube |
MC908QT2ACFQE Pin Configuration
| Pin 1 | PTA0/TCLK — General purpose I/O / Timer clock input |
| Pin 2 | PTA1 — General purpose I/O |
| Pin 3 | VDD — Positive supply voltage |
| Pin 4 | VSS — Ground reference |
| Pin 5 | PTA2 — General purpose I/O |
| Pin 6 | PTA3 — General purpose I/O |
| Pin 7 | PTA4/RESET — General purpose I/O / Reset (open-drain) |
| Pin 8 | PTA5 — General purpose I/O |
| Pin EP | Exposed Pad — Must be soldered to PCB ground copper for thermal dissipation and electrical ground reference |
Typical Applications
MC908QT2ACFQE is suitable for 6 applications: Remote Control Transmitter, Low-End Consumer Appliance UI, Toy and Hobby Electronics, Analog Circuit Replacement, Sensor Interface / Signal Conditioning Front-End, Simple Human-Interface / Keypad Scanner.
Remote Control Transmitter
The MC908QT2ACFQE fits low-cost IR/RF remote controls because its 8-bit HC08 CPU at 8MHz is sufficient for button-scan debouncing, encoding (RC5/RC6/SIRC), and timing of carrier bursts, while the on-chip Flash (1.5KB) holds encoding tables and the 128-byte RAM buffers the key matrix. The internal 8MHz IRC removes the need for an external resonator, cutting BOM cost and PCB area. Its 5 GPIO pairs naturally with 5-button keypads or a matrixed keypad decoder, and the 8-DFN-EP (4x4 mm) package fits the thin, battery-powered form factor of handheld remotes. Power consumption is dominated by the LED/IR-driver, not the MCU, so the HC08's low-power stop mode supports long battery life between user presses.
Recommended
Low-End Consumer Appliance UI
The MC908QT2ACFQE is well suited to white-goods and small-appliance UI boards (rice cookers, kettles, fans) where a low-cost MCU replaces analog timing/control circuitry. Its 8-bit HC08 core runs keypad, LED/buzzer driver, and simple PID loops for temperature or motor control, while the integrated 8MHz IRC and small 8-DFN-EP footprint keep the BOM and PCB area minimal. The HC08's deterministic instruction timing simplifies the implementation of zero-cross triac control, and 1.5KB Flash accommodates menu-state firmware plus lookup tables for sensor calibration. The exposed pad also dissipates heat from on-chip analog blocks, supporting the long duty cycles typical in appliances.
Recommended
Toy and Hobby Electronics
Battery-powered toys and hobby kits benefit from the MC908QT2ACFQE's small 8-DFN-EP (4x4 mm) package, low unit cost (~$1), and integrated 8MHz IRC that requires no external resonator. The HC08 8-bit core can drive simple sound patterns via PWM, control small DC motors with H-bridge FETs, and animate LED sequences using bit-banged protocols on its 5 GPIO pins. The 1.5KB Flash stores behavioral sequences, while 128 bytes of RAM holds toy-state variables. Low-power stop and wait modes extend battery life between play sessions, a key requirement in this application segment.
Recommended
Analog Circuit Replacement
The MC908QT2ACFQE frequently replaces discrete analog timing/control circuits (555-based timers, RC sequencers, encoder logic) with a software-defined solution. Its 8-bit HC08 at 8MHz easily emulates timing chains and encoder patterns, while 1.5KB Flash gives designers headroom for calibration tables and option bits. The 8-DFN-EP package is footprint-compatible with many 6/8-pin analog timer footprints, simplifying retrofit PCBs. Trade-off: the MCU adds software complexity and tooling cost, but it eliminates temperature drift and tolerance stack-up, which is the primary engineering motivation for the analog-replacement strategy in cost-sensitive consumer electronics.
Recommended
Sensor Interface / Signal Conditioning Front-End
In low-rate sensor front-ends (humidity, thermistor, simple switches), the MC908QT2ACFQE reads the sensor with its on-chip ADC/timer channels, applies linearization in firmware, and exposes the result via GPIO or PWM for downstream isolation or display. Its 128 bytes of RAM is adequate to hold recent samples and a moving-average filter, while 1.5KB Flash accommodates calibration tables. The integrated 8MHz IRC simplifies board layout by removing the crystal, and the 8-DFN-EP footprint keeps the sensor module small. Compared with discrete analog conditioning, the MCU solution offers programmable response curves and one-touch calibration at the factory.
Recommended
Simple Human-Interface / Keypad Scanner
The MC908QT2ACFQE excels at keypad scanning, debouncing, and wake-up interrupt tasks - one of NXP's QT-family design targets. With 5 GPIO it drives a 1x5 or matrixed 3x2 keypad, while the HC08 handles debounce state machines and wake-on-keypress routines. The 128-byte RAM holds current key status and a small ring buffer for inter-module communication, and 1.5KB Flash stores keymap tables and sleep-mode handling. The exposed-pad DFN package supports slim front-panel assemblies where board real estate is at a premium, and the internal 8MHz IRC eliminates an external resonator in keypad-only modules.
Recommended
Recommended Products Summary
Engineering reference data for MC908QT2ACFQE — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC908QT1ACFQE | MC908QT1ACPE | MC908QT2ACPE | MC908QT4ACFQE | MC908QT4ACPE |
|---|---|---|---|---|---|---|
| Brand | NXP Semiconductors (formerly Freescale) | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Package | 8-DFN-EP (4x4 mm) | 8-DFN-EP (4x4 mm) - same | 8-DFN-EP (4x4 mm) - same | 8-DFN-EP (4x4 mm) - same | 8-DFN-EP (4x4 mm) - same | 8-DFN-EP (4x4 mm) - same |
| Core | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit | HC08 8-bit |
| Max Clock Frequency | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8 MHz | 8 MHz |
| Program Memory (Flash) | 1.5 KB | 1.5 KB | 1.5 KB | 1.5 KB | 4 KB | 4 KB |
| RAM Size | 128 B | 128 B | 128 B | 128 B | 256 B | 256 B |
| Number of I/O Pins | 5 | 5 | 5 | 5 | 5 | 5 |
| Oscillator Type | Internal | Internal | Internal | Internal | Internal | Internal |
| Lifecycle / Recommendation | Mature (NRND), sustaining only | Mature (NRND) | Mature (NRND) | Mature (NRND) |
Key Differentiators
- Integrated 8MHz internal oscillator - eliminates external crystal (vs MC908QT4ACFQE)
- Lowest unit cost in the QT family for 1.5KB/128B configurations (vs MC908QT4ACFQE)
- Compact 8-DFN-EP (4x4 mm) package - smaller than most 8-bit MCU alternatives in SOIC (vs MC908QT1ACFQE)
Design Notes
The 8-VDFN-EP package on the MC908QT2ACFQE exposes the silicon die-pad on the bottom of the IC; this pad MUST be soldered to a continuous PCB ground copper pour for both thermal and electrical reasons. Inadequate soldering of the EP will starve the internal analog blocks of a low-impedance ground reference and may trigger latch-up. Estimate: with no EP copper, expected theta_JA exceeds 100 C/W; with a 1 square inch ground pour on a 1-oz 2-layer board, theta_JA typically drops below 50 C/W.
Place the 0.1uF VDD decoupling ceramic as close to the MC908QT2ACFQE supply pin as possible, ideally within 2 mm of pin 3, with a short, wide trace to the EP ground. Add a bulk electrolytic/ceramic of 1-10uF near the IC for transient load handling. The reset line (pin 7, shared with PTA4) typically requires a 4.7k-10k pull-up to VDD and may be left open in noise-tolerant applications, but adding a small capacitor (10-100nF) to ground improves noise immunity.
Common pitfalls with the MC908QT2ACFQE include: (1) relying on the internal oscillator without checking IRC trim across temperature for timing-critical applications - the IRC is trimmed at room temperature but varies with temperature; (2) forgetting the EP pad solder connection which leads to subtle reset/GPIO errors; (3) over-driving the shared PTA4/RESET pin as a push-pull output, which disables the reset function - always configure PTA4 as open-drain when reset sharing is required; (4) exceeding absolute maximum ratings on VDD - check datasheet for the exact limit before design freeze.
Compliance Information
Detailed compliance data (RoHS, REACH, lead-free, halogen-free) was not present in the Verified Web Data snippets for MC908QT2ACFQE; the part is mature and originally released by Freescale Semiconductor (now NXP). Consult NXP's product compliance documentation directly for an authoritative statement.
