SC9RS08KA2J3CSCR - 8-bit RS08 2KB Flash MCU | NXP Semiconductors
MPN: SC9RS08KA2J3CSCR ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $1.85 | $1.85 |
| 10 | $1.62 | $16.20 |
| 100 | $1.41 | $141.00 |
| 500 | $1.18 | $590.00 |
| 1,000 | $0.98 | $980.00 |
| 3,000 | $0.86 | $2,580.00 |
SC9RS08KA2J3CSCR Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory (flash), working memory (RAM), and a set of peripherals such as timers, comparators, ADCs, and communication interfaces. The RS08 is a streamlined CISC core that retains the HC08 instruction set for code portability while reducing silicon area and power consumption. Within the NXP product hierarchy, RS08 sits below the S08 and Kinetis E families, positioning SC9RS08KA2J3CSCR for applications that need more than a timer or analog switch but do not justify a 32-bit MCU.
Key features include a 2KB flash program memory, 62 bytes RAM, an integrated analog comparator for sensor thresholding, and broad supply-voltage tolerance from 2.5V to 5V. The 8-pin SOIC footprint enables hand-solderable prototypes and very compact PCB layouts, while the CISC instruction set preserves a familiar programming model for engineers migrating from legacy HC08 designs.
Technically, the device leverages a 20 MHz bus architecture with reduced-power modes and a low quiescent current profile, supporting battery-operated duty-cycled designs. The integrated analog comparator eliminates the need for an external op-amp in many threshold-detection circuits, and the small flash footprint simplifies in-system programming. Together, these features make SC9RS08KA2J3CSCR well suited to appliance user interfaces, sensor front-ends, and simple motor or relay control loops.
Typical applications include battery-powered sensor nodes, AC mains zero-cross detection when paired with an optocoupler, smoke-detector signal conditioning, and small home-appliance control boards. It also fits logic-replacement designs where a handful of discrete gates or a timer IC would otherwise be needed.
When designing with this part, evaluate the 2KB flash and 62-byte RAM ceilings against the worst-case state and code size of the application. Use the on-chip analog comparator in place of an external op-amp to reduce BOM cost and PCB area, and add a 0.1uF bypass capacitor adjacent to the supply pin for noise immunity.
This page synthesizes distributor pricing, drop-in and same-family alternatives, and practical design notes not consolidated on any single distributor listing.
Drop-in alternatives for SC9RS08KA2J3CSCR — same package, pin-to-pin compatible. Different-package parts requiring PCB rework are excluded.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
MC9RS08KA2CSCR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9RS08KA2CSC
✅ Drop-In📋 Reference alternative (not in catalog)
MC9RS08KA4CSCR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9RS08KA1CSCR
✅ Drop-In📋 Reference alternative (not in catalog)
MC9RS08KA8CSCR
✅ Drop-In📋 Reference alternative (not in catalog)
SC9RS08KA2J3CSCR Maximum Ratings & Electrical Characteristics
| Manufacturer | NXP Semiconductors (formerly Freescale) |
| Core | RS08 (CISC, HC08-compatible instruction set) |
| Program Memory (Flash) | 2 KB |
| RAM | 62 B |
| Supply Voltage | 2.5 V / 3.3 V / 5 V |
| Package | 8-pin SOIC |
| Mounting Type | Surface Mount |
| Analog Comparator | Integrated (on-chip) |
| Peripherals | Analog comparator, timer, GPIO |
| MSL Level | MSL-1 or MSL-3 (manufacturer specific) |
| RoHS Status | Compliant |
| Lead-Free | Yes |
SC9RS08KA2J3CSCR Pin Configuration
| Pin 1 | PTA0/TCLK — General-purpose I/O / external clock input |
| Pin 2 | PTA1/ACMP- — GPIO / analog comparator inverting input |
| Pin 3 | PTA2/ACMP+ — GPIO / analog comparator non-inverting input |
| Pin 4 | VSS — Ground reference |
| Pin 5 | PTA3/RESET — GPIO / active-low reset input |
| Pin 6 | PTA4/ACMPO — GPIO / analog comparator output |
| Pin 7 | PTA5/IRQ — GPIO / external interrupt request |
| Pin 8 | VDD — Positive supply voltage (2.5V-5V) |
Typical Applications
SC9RS08KA2J3CSCR is suitable for 6 applications: Smoke Detector Front-End, AC Mains Zero-Cross Detector, Battery-Powered Sensor Node, Home Appliance Control Board, Discrete Logic Replacement Module, Industrial Threshold Switch.
Smoke Detector Front-End
The SC9RS08KA2J3CSCR fits smoke-detector front-ends because its integrated analog comparator handles ionization-chamber threshold detection without an external op-amp, while its 2KB flash and 62-byte RAM cover the alarm-state firmware. Operating from 2.5V-5V, it runs directly from a 9V battery through a regulator or from a 3V lithium backup cell. The SOIC-8 footprint fits inside the detector housing alongside a piezo buzzer driver and a low-battery test circuit. The 5V tolerance also lets the MCU share a regulated rail with photoelectric IR sensing chains, simplifying BOM cost in cost-driven residential safety devices.
Recommended
AC Mains Zero-Cross Detector
The SC9RS08KA2J3CSCR detects zero-cross events for triac dimming and SSR timing in AC mains control. The integrated analog comparator senses the optocoupler-isolated mains waveform, while the MCU computes the firing delay for phase-angle or zero-cross switching. Its 5V tolerance is comfortable for the rectified mains-derived rail, and the SOIC-8 package fits inside wall-switch form factors. The 2KB flash holds the timing algorithm and a soft-start ramp, and the on-chip analog comparator eliminates a discrete comparator IC. Pair the device with an optocoupler (e.g., MOC3021) and a triac for a complete dimmer.
Recommended
Battery-Powered Sensor Node
The SC9RS08KA2J3CSCR operates as the controller in duty-cycled IoT sensor nodes where power budget is the primary constraint. The 2.5V minimum operating voltage tracks battery depletion down to 2.5V on a 3V coin cell, while the integrated analog comparator wakes the MCU on threshold crossings instead of polling with an ADC. The 2KB flash holds a small sensing-state machine, and the SOIC-8 footprint enables sub-50 mm² PCB nodes. Compared with a discrete op-amp-plus-timer implementation, the integrated comparator reduces quiescent current and BOM count, extending battery life in wireless sensor designs.
Recommended
Home Appliance Control Board
The SC9RS08KA2J3CSCR serves as the main controller on low-end home-appliance boards such as small fans, air purifiers, and countertop appliances. The 2KB flash holds mode-selection and timer firmware, while the analog comparator monitors motor current or temperature sensors for fault detection. The 5V tolerance simplifies integration with white-goods 5V rails, and the SOIC-8 footprint supports compact PCBs behind membrane keypads. Compared with discrete CMOS-logic implementations, this part reduces component count, enables firmware updates, and adds diagnostics via firmware state machines rather than hardware rework.
Recommended
Discrete Logic Replacement Module
The SC9RS08KA2J3CSCR replaces legacy 74HC-style glue logic in legacy designs where a handful of gates, timers, or latches were used. Its 2KB flash holds the equivalent state machine, and the analog comparator handles thresholds formerly implemented with discrete op-amps. Operating at 2.5V-5V, it plugs into existing 5V logic rails and reduces PCB area by collapsing several SOIC packages into one SOIC-8 footprint. Compared with discrete logic, the firmware-based approach also adds diagnostics, configuration modes, and field-update capability.
Recommended
Industrial Threshold Switch
The SC9RS08KA2J3CSCR implements a configurable threshold switch for industrial sensors and process-control retrofits. The integrated analog comparator reads a 4-20 mA loop-derived voltage, and the firmware drives an optocoupler-isolated output. The wide 2.5V-5V tolerance lets it run from a 24V loop through a small linear regulator, and the SOIC-8 footprint supports DIN-rail PCB modules. Compared with discrete analog designs, firmware-configurable thresholds simplify calibration via in-system programming, and the 2KB flash stores unit-specific settings.
Recommended
Recommended Products Summary
Engineering reference data for SC9RS08KA2J3CSCR — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | MC9RS08KA2CSCR | MC9RS08KA2CSC | MC9RS08KA4CSCR | MC9RS08KA1CSCR | MC9RS08KA8CSCR |
|---|---|---|---|---|---|---|
| Package | 8-pin SOIC | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) | 8-pin SOIC (same) |
| Brand | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors | NXP Semiconductors |
| Program Flash | 2 KB | 2 KB | 2 KB | 4 KB | 1 KB | 8 KB |
| RAM | 62 B | 62 B | 62 B | 62 B | 62 B | 62 B |
| Supply Voltage | 2.5V - 5V | 2.5V - 5V | 2.5V - 5V | 2.5V - 5V | 2.5V - 5V | 2.5V - 5V |
| Analog Comparator | Yes (on-chip) | Yes | Yes | Yes | Yes | Yes |
| Core | RS08 CISC | RS08 CISC | RS08 CISC | RS08 CISC | RS08 CISC | RS08 CISC |
| Reel Packaging | Tape & Reel (R suffix) | Tape & Reel | Tube (no reel suffix) | Tape & Reel | Tape & Reel | Tape & Reel |
| Single-Unit Price (approx, 2026-10-16) | $1.85 | ~$1.85 | ~$1.80 (tube pricing) | ~$2.10 | ~$1.55 | ~$2.65 |
Key Differentiators
- On-chip analog comparator eliminates external op-amp (vs MC9RS08KA1CSCR (1KB flash variant))
- 2KB flash at SOIC-8 footprint (vs MC9RS08KA4CSCR (4KB flash))
- Reel packaging by default (vs MC9RS08KA2CSC (tube variant))
Design Notes
Place a 0.1uF ceramic bypass capacitor as close as possible to the VDD pin (pin 8) and a 10uF bulk capacitor on the supply rail. The wide 2.5V-5V tolerance tolerates most MCUs but does not tolerate reverse polarity or inductive kick above 5V; add a TVS or Schottky for protection if the supply is battery-derived. Estimated: at 5V supply and a 2 mA active current, quiescent losses are ~10 mW; in stop mode the device drops to single-digit uA per Freescale family docs.
The 8-pin SOIC footprint uses 1.27 mm (50 mil) pin pitch. Keep analog comparator traces (PTA1/ACMP-, PTA2/ACMP+, PTA4/ACMPO) short and guarded by a ground pour to prevent digital switching noise from coupling into threshold detection. Avoid routing the PTA3/RESET line near switching regulators. Estimated: trace lengths under 20 mm preserve the comparator's sub-1 mV threshold accuracy.
Do not exceed 5V on VDD - the part has no internal regulator above 5V. The 2KB flash limit is absolute; firmware must fit in roughly 1900 bytes after boot vectors. The 62-byte RAM ceiling means stack and globals must total under ~50 bytes; plan data structures accordingly. In-system programming requires the PTA3/RESET pin to be accessible at programming time; do not hardwire it low. Per Freescale RS08KA documentation, holding RESET low during power-up enters programming mode.
At a 2 mA active current and 5V supply, power dissipation is ~10 mW, well within SOIC-8's thermal limits. The thermal resistance theta_JA of an SOIC-8 is ~160 C/W, so even at 85C ambient the junction is around 87C. Designers targeting 125C ambient should still verify the part's industrial-grade suffix supports that range. Estimated: worst-case active current of 5 mA at 5V gives 25 mW dissipation and a ~4C junction rise, far below the SOIC-8 limit.
Compliance Information
RoHS and lead-free confirmed per distributor listings (Hotenda, Components-House) as of 2026-10-16. Halogen-free status not stated explicitly in the verified web data. AEC-Q100 not applicable - this is a general-purpose industrial/consumer MCU rather than an automotive-qualified part.