MC9S08QD2CSCR - 8-bit MCU 2KB Flash 16MHz SOIC-8 | NXP
MPN: MC9S08QD2CSCR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.66 | $16.60 |
| 100 | $1.39 | $139.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.98 | $980.00 |
MC9S08QD2CSCR Overview
An 8-bit MCU is a single-chip computer that integrates a processor core, program and data memory, oscillators, timers, and peripheral functions such as ADC and communication interfaces. Within the power-management hierarchy of embedded systems, an MCU acts as the intelligent control element, replacing discrete logic and analog control circuits in cost-sensitive products. The S08 family is NXP (formerly Freescale) successor to the HC08 architecture, and the QD series is its minimum-pin-count, minimum-footprint derivative, packaged in surface-mount SOIC and MSOP outlines.
Key features of the MC9S08QD2CSCR include the low-pin-count 8-SOIC package that fits standard small-outline footprints, an internal oscillator that eliminates an external crystal for most applications, and operation from 3.3V or 5V supplies. The 2KB Flash is in-application reprogrammable, and 128 bytes of RAM support compact C or assembly firmware. The device suits applications where board area and BOM cost dominate, such as small appliance and motor control loops.
Technically, the S08 core is a CMOS CISC processor with the HC08 instruction set extended by BGND and low-power wait/stop modes, providing 16 MHz bus speed with single-cycle most-instruction execution efficiency typical of 8-bit architectures. Integrated peripherals of the QD family typically include an 8-channel 10-bit ADC, 16-bit timers with PWM capability, and serial interfaces, allowing the 4 available I/O pins to be multiplexed flexibly.
Typical applications listed for this device include DC cooling fan control in computers and low-power power supplies, battery chargers, capacitive discharge ignition (CDI) modules for motorcycles, and industrial compressor control. The 8-pin SOIC fits directly onto small motor driver or charger PCBs.
Design consideration: verify supply-voltage margin and ADC pin multiplexing early, since only 4 I/O pins are available and Flash capacity is small; plan firmware within the 2KB limit.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet.
Drop-in alternatives for MC9S08QD2CSCR — 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 MC9S08QD2CSCR (same form factor and footprint) — differing in Core Processor, Flash Memory, Package, Packaging, RAM.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9S08QD2CSC
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08QD4CSC
✅ Drop-In✓ In Stock
Contact for price
View Datasheet →MC9S08QD4CSCR
✅ Drop-In📋 Reference alternative (not in catalog)
S9S08QD4J1MSCR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9S08QD2CSCR Maximum Ratings & Electrical Characteristics
| Core Processor | S08 |
| Core Size | 8-Bit |
| Instruction Set Architecture | CISC |
| Speed (Bus Frequency) | 16 MHz |
| Program Memory Type | Flash |
| Program Memory Size | 2KB (2K x 8) |
| RAM Size | 128 x 8 |
| Number of I/O | 4 |
| Supply Voltage | 3.3 V / 5 V |
| Oscillator Type | Internal |
| Package / Case | 8-SOIC (0.154 in, 3.90 mm Width) |
| Mounting Type | Surface Mount |
| Packaging | Tape & Reel |
| Technology | CMOS |
| Product Series | S08QD (9S08QD4 SERIES per distributor listing) |
MC9S08QD2CSCR Pin Configuration
| Pin 1 | VDD — Power supply input (3.3 V / 5 V) |
| Pin 2 | PTA2/IRQ/ADC — General-purpose I/O with external interrupt and ADC multiplexing |
| Pin 3 | PTA1 — General-purpose I/O |
| Pin 4 | PTA0 — General-purpose I/O |
| Pin 5 | VSS — Ground |
| Pin 6 | PTB0 — General-purpose I/O with ADC multiplexing |
| Pin 7 | PTB1 — General-purpose I/O with ADC multiplexing |
| Pin 8 | PTA3/BKGD/MS — General-purpose I/O and background debug / mode select pin |
Typical Applications
MC9S08QD2CSCR is suitable for 6 applications: DC Cooling Fan Control, Battery Chargers, Motorcycle Capacitive Discharge Ignition (CDI), Industrial Compressor Control, Small Appliance and Low-Power Power Supply Supervision, General Low-Pin-Count Embedded Control.
DC Cooling Fan Control
The MC9S08QD2CSCR is explicitly listed by the manufacturer for DC cooling fan applications in computers and low-power power supplies. The 16 MHz S08 core measures fan tachometer pulses and generates PWM drive signals with timing resolution far better than analog control, while the internal oscillator eliminates the crystal that would be impractical in a fan hub assembly. Operating from a 3.3V or 5V rail with only 4 I/O pins keeps the BOM to a minimum, and the 2KB Flash holds closed-loop speed control firmware comfortably. Designers should reserve one pin for tach input and one for PWM output, using the ADC channel for temperature-based speed scheduling where supported.
Recommended
Battery Chargers
Battery charger supervision is a listed target application for the S08QD2. The MCU monitors charge current and pack voltage through its ADC channels, implements CC/CV or trickle-charge state machines, and drives status LEDs from its limited I/O. The 16 MHz bus speed supports fast ADC sampling and precise charge-termination timing, while low-power stop and wait modes let the controller sip current in standby, which matters in adapters and portable chargers. The 8-SOIC 3.90 mm package fits space-constrained charger PCBs, and the internal oscillator removes frequency-setting components. Firmware fits easily in 2KB Flash for single-chemistry chargers; step up to the pin-compatible MC9S08QD4CSCR for multi-chemistry algorithms.
Recommended
Motorcycle Capacitive Discharge Ignition (CDI)
Digital CDI for motorcycles is a manufacturer-listed application of this device. The MCU receives engine pickup-coil pulses, computes ignition advance angle from crank speed in real time, and fires the SCR/thyristor trigger with microsecond precision, replacing fixed analog advance curves with programmable mapping stored in the 2KB Flash. The 16 MHz S08 core handles the interrupt-driven timing loop with margin, and the robust CMOS process plus 5V operation suits the electrically noisy 12V vehicle environment with proper transient protection. The 8-SOIC package withstands the vibration and thermal profile typical of CDI modules, and the small pin count keeps the potted module simple and low cost.
Recommended
Industrial Compressor Control
Industrial compressor control is a listed application for the S08QD2. The MCU cycles the compressor motor via relay or solid-state switch outputs, monitors pressure-switch and thermal-protect inputs through ADC or digital pins, and enforces minimum off-time interlocks to protect the motor. The internal oscillator provides sufficient timing accuracy for these control loops without external components, and the 3.3V/5V operation interfaces directly with industrial 5V logic rails. The 8-SOIC package survives control-board temperatures when derated per the datasheet, and the tiny footprint allows control logic to be embedded in existing PCB space. The 128-byte RAM supports a simple state machine plus fault-logging flags.
Recommended
Small Appliance and Low-Power Power Supply Supervision
For low-power power supplies and small appliances, the MC9S08QD2CSCR provides supervisory intelligence: monitoring output voltage and current via ADC, implementing soft-start and protection thresholds, and driving feedback or status outputs. The manufacturer groups these with the fan and charger applications, reflecting the part's positioning as a minimal-cost controller. Its 16 MHz core runs the control loop quickly enough for switch-mode housekeeping tasks, and low-power modes suit always-on standby supplies where no-load input power limits apply. The internal oscillator and 8-SOIC footprint keep the secondary-side control area compact, while the SCR tape-and-reel packing supports automated assembly in volume production of adapter and supply boards.
Recommended
General Low-Pin-Count Embedded Control
Beyond the listed verticals, the MC9S08QD2CSCR serves as a general 8-pin embedded controller for replacing discrete glue logic, implementing simple timers, generating PWM, or bridging simple serial tasks in cost-driven products. The S08 CISC core at 16 MHz executes compact C or assembly firmware efficiently, and the internal oscillator plus 3.3V/5V operation simplify power design. The industry-standard 8-SOIC outline fits hand-solderable prototypes and high-volume SMT lines alike, and the background debug pin enables low-cost flashing without removing the part from the board. When a project outgrows 2KB or 4 I/O, the same-footprint QD4 variants provide a no-rework upgrade path.
Recommended
Recommended Products Summary
Engineering reference data for MC9S08QD2CSCR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9S08QD2CSC | MC9S08QD4CSC | MC9S08QD4CSCR | S9S08QD4J1MSCR |
|---|---|---|---|---|---|
| Package | 8-SOIC (3.90 mm) | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same | 8-SOIC (3.90 mm) - same |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Core / ISA | S08, 8-bit CISC | S08, 8-bit CISC | S08, 8-bit CISC | S08, 8-bit CISC | S08, 8-bit CISC |
| Bus Speed | 16 MHz | 16 MHz | 16 MHz | 16 MHz | 16 MHz |
| Flash Memory | 2KB (2K x 8) | 2KB (2K x 8) | 4KB (4K x 8) | 4KB (4K x 8) | 4KB (4K x 8) |
| Supply Voltage | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V | 3.3 V / 5 V |
| Packaging | Tape & Reel | Tray / Tube (CSC suffix) | Tray / Tube (CSC suffix) | Tape & Reel | Tape & Reel |
Key Differentiators
- Smallest memory/lowest cost in the drop-in family (vs MC9S08QD4CSCR)
- Pin-identical second-source packing option (vs MC9S08QD2CSC)
- Trade-off: no automotive ordering family at 2KB (vs S9S08QD4J1MSCR)
Design Notes
With only 4 general-purpose I/O pins and 128 bytes of RAM, budget the pin map and memory before writing firmware. The background debug pin (BKGD/MS) doubles as an I/O, so reserving it for debugging during development and reclaiming it in production firmware is a common workflow - but a production pin assignment that uses it will block in-circuit reflashing. Verify the ADC channel assignment on each multiplexed pin against the S08QD datasheet signal multiplexing table, since not every alternate function is available on every pin simultaneously.
Place a 0.1 uF ceramic decoupling capacitor directly across VDD (pin 1) and VSS (pin 5) with a short, low-inductance return path; on an 8-SOIC this is best done on the top layer adjacent to the package. Because the internal oscillator is used, keep high-current loads (relay or motor drivers) on a separate ground return from the MCU ground to prevent reset-inducing ground bounce in fan, charger, and CDI environments where switched loads share the board.
The device operates from 3.3 V or 5 V; in noisy 12 V-derived automotive or compressor systems, regulate down to a clean 5 V rail with local transient suppression. Use the low-power stop and wait modes of the S08 core between control-loop iterations in battery-charger and standby-supply designs to reduce average current. Estimate supply budget as the datasheet run plus wait/stop currents plus I/O load; never size the regulator from run current alone in applications with frequent stop/wake cycling.
Compliance Information
Compliance statuses were not stated in the provided web data. Verify RoHS/REACH/lead-free status on the official NXP product page (nxp.com/part/MC9S08QD2CSC) before design release. No automotive AEC-Q100 ordering family exists at the 2KB memory size.
