MC68HC908QT1CFQ - 8-Bit 8MHz HC08 MCU 1.5KB Flash | NXP
MPN: MC68HC908QT1CFQ ⚠ Last Time Buy| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $2.85 | $2.85 |
| 10 | $2.46 | $24.60 |
| 100 | $1.95 | $195.00 |
| 500 | $1.62 | $810.00 |
| 1,000 | $1.4 | $1,400.00 |
MC68HC908QT1CFQ Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory (FLASH or ROM), volatile data memory (RAM), and peripherals such as timers, I/O ports, and communication interfaces onto one die. Within the broader taxonomy, the M68HC08 belongs to the CISC (Complex Instruction Set Computer) family with a Von Neumann architecture, where program and data share a single bus - simpler and lower-cost than Harvard-architecture RISC alternatives. The 'low-cost Q-family' sub-line targets cost-sensitive, pin-constrained applications where DIP-8/SOIC-8 footprints are too large.
Key features of the MC68HC908QT1CFQ include an 8 MHz internal bus clock (4 MHz bus rate in standard mode, doubled to 8 MHz via the internal phase-locked-loop-like bus generator), 6 general-purpose I/O pins, a 6-channel 8-bit timer with PWM capability, an analog comparator on-chip, and an on-chip oscillator trimmable via the user FLASH. The wide 2.7 V to 5.5 V operating range allows direct operation from a single Li-ion cell, three alkaline cells, or a regulated 3.3 V/5 V rail.
From an architectural standpoint, the QT1 uses the same HC08 CPU core as the larger QY/QT family members, sharing the instruction set, addressing modes, and on-chip debug (OCD) interface - so code is portable across the family. The 1.5 K FLASH is split into a 1 K user region and a 512-byte monitor/Bootloader ROM region used for in-circuit FLASH programming and debug.
Typical applications include ultra-low-cost consumer appliances, IR remote-control transmitters, single-cell Li-ion toys, LED controllers, simple sensor readouts, and replacement of discrete logic in legacy designs where the Q-family's small 8-pin DFN footprint saves board area. The device is also a popular teaching and hobby MCU because of its free Freescale/NXP CodeWarrior toolchain and the low-cost USBMULTILINKBDM programmer.
When designing with this MCU, note that FLASH endurance is rated at 100 program/erase cycles minimum (typical 1000) and in-application programming must be performed from the monitor ROM area - plan your firmware update flow accordingly. The 8-pin DFN-EP package requires careful PCB thermal pad soldering to meet MSL1 moisture-sensitivity and to keep the exposed pad at ground potential for EMI suppression.
Drop-in alternatives for MC68HC908QT1CFQ — 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 MC68HC908QT1CFQ (same form factor and footprint) — differing in Package, RAM Size, Supply Voltage, ADC, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC908QT2ACFQE
✅ Drop-In✓ In Stock
$0.65 / Unit
View Datasheet →MC908QT1ACFQE
✅ Drop-In✓ In Stock
$1.7 / Unit
View Datasheet →MC908QT4CPE-FR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08QG84CFFE
✅ Drop-In✓ In Stock
$1.21 / Unit
View Datasheet →MC68HC908QY2CPE
✅ Drop-In✓ In Stock
$2.69 / Unit
View Datasheet →MCHC908QY1MDWE
✅ Drop-In✓ In Stock
$3.42 / Unit
View Datasheet →MC9S08QD4CITE
✅ Drop-In📋 Reference alternative (not in catalog)
MC68HC908QT1CFQ Maximum Ratings & Electrical Characteristics
| Family | M68HC08 (HC08) |
| Core | 8-bit CISC, Von Neumann architecture |
| CPU Core | HC08 |
| Program Memory | 1.5 KB FLASH (1K user + 512B monitor) |
| RAM | 128 bytes |
| Maximum Clock Frequency | 8 MHz internal bus |
| Operating Voltage | 2.7 V to 5.5 V |
| I/O Pins | 6 GPIO |
| Timers | 1 x 16-bit, 2-channel with PWM |
| On-Chip Analog Comparator | Yes |
| ADC | None |
| Package | 8-DFN-EP (4x4 mm) |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited at <=30C/85% RH) |
| Operating Temperature | -40C to +85C (industrial) |
| FLASH Endurance | 100 program/erase cycles min (typ 1000) |
| On-Chip Debug | Background Debug Mode (BDM) |
| RoHS Status | Compliant (lead-free 'CFQ' suffix) |
MC68HC908QT1CFQ Pin Configuration
| Pin 1 | RST — External reset input, active low |
| Pin 2 | IRQ/PTB0 — External interrupt / GPIO |
| Pin 3 | PTA0 — GPIO / Timer channel |
| Pin 4 | VSS — Ground |
| Pin 5 | VDD — Positive supply (2.7 V-5.5 V) |
| Pin 6 | PTA1 — GPIO / Analog comparator input |
| Pin 7 | PTA2 — GPIO / Timer channel |
| Pin 8 | PTA3 — GPIO / TCLK / Analog comparator reference |
Typical Applications
MC68HC908QT1CFQ is suitable for 6 applications: IR Remote Control Transmitter, Single-Cell Li-Ion Toy and Hobby Device, LED Lighting Controller, Simple Sensor Readout Module, Replacement of Discrete Logic in Legacy Designs, Educational / Hobby MCU Platform.
IR Remote Control Transmitter
The MC68HC908QT1CFQ fits IR remote-control transmitters because its 1.5 KB FLASH holds a full NEC/RC5/Philips RC6 transmit state machine plus carrier-generation timer, and its 6 GPIO pins can directly drive an IR LED with PWM carrier (typically 38 kHz) while sensing 2-4 keypad buttons via the analog comparator or ADC-less matrix scheme. Operating from 2.7 V to 5.5 V lets the design run from two or three alkaline cells without a voltage regulator, reducing BOM cost. The 8-DFN-EP (4x4 mm) package fits behind a small membrane keypad, and the on-chip internal oscillator eliminates the external crystal used in earlier HC05 designs. Trade-off: limited 128-byte RAM restricts on-the-fly protocol translation tables - designs needing universal-remote flexibility should consider the QT2 or QY2 with more memory.
Recommended
Single-Cell Li-Ion Toy and Hobby Device
The MC68HC908QT1CFQ is well-suited to single-cell Li-ion (3.0-4.2 V) toys and hobby electronics where its 2.7 V-5.5 V operating range directly accepts the battery voltage with no LDO needed, and the HC08 core at 8 MHz is fast enough for LED chase patterns, sound effects, and motor PWM control. The 1.5 KB FLASH accommodates toy control firmware, while the 16-bit timer with 2-channel PWM drives motors, LEDs, or a piezo buzzer. Its ultra-low-power HC08 STOP/WAIT modes extend battery life between play sessions. The 8-DFN-EP package fits in the tightest toy enclosures, and the exposed pad gives good thermal dissipation for sustained PWM output. Trade-off: 100 program/erase cycle FLASH endurance limits frequent firmware updates during toy development.
Recommended
LED Lighting Controller
The MC68HC908QT1CFQ drives LED lighting controllers where its on-chip 16-bit timer with 2-channel PWM provides smooth dimming without flicker, and the wide 2.7 V-5.5 V supply range accepts 3-AA battery packs, regulated 5 V USB supplies, or 12 V automotive rails (with a small pre-regulator). The 1.5 KB FLASH holds color-mixing look-up tables (for RGB controllers), brightness curves, and fade-in/fade-out algorithms, while the 6 GPIO pins can drive 3-6 LED channels via MOSFETs. The internal trimmable oscillator eliminates external components, shrinking the LED driver PCB to less than 1 square centimeter. Trade-off: only 128 bytes of RAM restricts fade-memory depth - consider the QY2 variant for applications requiring more buffer memory.
Recommended
Simple Sensor Readout Module
The MC68HC908QT1CFQ is appropriate for simple sensor readout modules where its analog comparator can threshold a thermistor, photocell, or Hall-effect sensor signal, and its 8 MHz HC08 core runs linearization and hysteresis algorithms. The 1.5 KB FLASH holds sensor compensation tables and serial output protocols, and the 6 GPIO provide digital I/O for switching or relay control. The 2.7 V-5.5 V supply range lets the module share the sensor's supply rail without a separate regulator. The 8-DFN-EP (4x4 mm) footprint fits in the smallest sensor housing. Trade-off: no on-chip ADC means ratiometric or precision measurements need an external ADC - upgrade to the QY4 (10-bit ADC) for those applications.
Recommended
Replacement of Discrete Logic in Legacy Designs
The MC68HC908QT1CFQ replaces discrete 74-series logic gates in legacy designs where 4-6 gates of CMOS logic are needed for sequencing, latching, or state-machine functions. The HC08 at 8 MHz emulates dozens of gates in software while fitting in the 8-DFN-EP footprint of a single SOIC-8 gate package, dramatically reducing board area and BOM cost. The 1.5 KB FLASH holds complex sequential control algorithms that would be impractical with discrete logic. The 2.7 V-5.5 V supply range matches the legacy 5 V logic rails, eliminating level shifters. The internal oscillator also eliminates RC timing components used in many 74-series designs. Trade-off: discrete-logic replacement requires a small firmware development effort rather than wiring changes.
Recommended
Educational / Hobby MCU Platform
The MC68HC908QT1CFQ remains popular as an educational and hobby MCU because the HC08 Q-family is supported by the free NXP CodeWarrior HC08 C compiler, the open-source SDCC compiler, and the low-cost P&E Cyclone / USBMULTILINKBDM programmer. The simple 8-pin DFN-EP package is easy to breadboard with adapter PCBs, and the well-documented BDM (Background Debug Mode) interface enables single-step debugging in a teaching lab. The 1.5 KB FLASH forces students to write tight, efficient code - good pedagogical discipline. The 6 GPIO pins are enough to interface with a handful of LEDs, pushbuttons, and a UART, making it suitable for introductory embedded-systems courses. Trade-off: 100 program/erase FLASH endurance means students need to manage code-upload discipline during lab sessions.
Recommended Products Summary
Engineering reference data for MC68HC908QT1CFQ — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC908QT2ACFQE | MC908QT1ACFQE | MC908QT4CPE-FR | MC68HC908QY2CPE |
|---|---|---|---|---|---|
| Brand | 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 - same | 8-DFN-EP - same |
| CPU Core | HC68 (HC08) | HC08 - same | HC08 - same | S08 (newer core) | HC08 - same |
| FLASH Program Memory | 1.5 KB | 2 KB (+33%) | 1.5 KB (same) | 4 KB (+167%) | 1.5 KB (same) |
| RAM | 128 bytes | 128 bytes (same) | 128 bytes (same) | 128 bytes (same) | 128 bytes (same) |
| Max Clock Frequency | 8 MHz | 8 MHz (same) | 8 MHz (same) | 20 MHz (faster) | 8 MHz (same) |
| Operating Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V (same) | 2.7 V to 5.5 V (same) | 2.7 V to 5.5 V (same) | 2.7 V to 5.5 V (same) |
| On-Chip ADC | No | No | No | Yes (10-bit, 8-ch) | Yes (10-bit) |
| Lifecycle Status | Last-Time-Buy | Active | Active | Active | Last-Time-Buy |
Key Differentiators
- Smallest available HC08 package (vs MC908QT1ACPE (DIP-8))
- Drop-in upgrade path to QT2 (vs MC908QT2ACFQE)
- Internal trimmable oscillator eliminates crystal (vs Older HC05 designs requiring external resonator)
Design Notes
The MC68HC908QT1CFQ draws approximately 5 mA active at 5 V and 8 MHz, dropping to under 1 micro-amp in STOP mode. For battery-powered designs, use the on-chip STOP instruction to enter the lowest-power state, and wake via the IRQ pin or RESET. The on-chip voltage monitor (LVI) must be enabled in user FLASH configuration if the supply can drop below 2.7 V - otherwise FLASH write/erase during low-voltage conditions can corrupt data. The internal oscillator trim should be calibrated against a known reference at production test to ensure accuracy within +/-2% across temperature.
The 8-DFN-EP (4x4 mm) package has an exposed thermal pad (EP) on the bottom that MUST be soldered to a ground pad of at least equal size on the PCB, with multiple thermal vias connecting to an internal ground plane. Failing to solder the EP can cause the part to overheat at sustained PWM loads and can degrade EMI/ESD performance. Place the external bypass capacitor (100 nF X7R) within 2 mm of the VDD pin, with a short, wide trace to the VDD pad. Keep digital switching traces (PWM, oscillator) away from the analog comparator input pins to minimize coupled noise.
Three common pitfalls: (1) The 1.5 KB FLASH is split between user- and monitor-areas - code that overflows the user region (typically 1 K) silently fails to program. (2) FLASH endurance is only 100 program/erase cycles minimum (typical 1000) - frequent firmware updates during development can wear out the FLASH. Use the RAM-based bootloader pattern for repeated flashing. (4) The 6 GPIO pins are NOT 5 V-tolerant when the part is powered from 3.3 V - check absolute-maximum VOH/IOH tables in the datasheet before connecting to 5 V peripherals.
Route the RST pin trace away from PWM-driven outputs to prevent false resets from capacitive coupling. Place the optional external reset pull-up resistor (4.7 kohm to VDD) within 5 mm of the RST pin. If using the on-chip analog comparator, route the comparator input traces as short as possible and guard them with a ground trace to reject digital switching noise. The internal oscillator requires no external crystal, but the FLASH trim register must be calibrated against an external reference at production test for tight timing accuracy.
