NXP Semiconductors MC9S08QA4CFQE

Overview

MC9S08QA4CFQE from NXP Semiconductors (formerly Freescale) is an 8-bit HCS08 microcontroller designed for ultra-low-power embedded control in space-constrained applications. It features a 20 MHz CPU core, 4 KB flash memory, 256 B RAM, 10-bit ADC with temperature sensor, analog comparator, and single-channel TPM timer-all operating from 1.8 V to 3.6 V across –40°C to +85°C. It targets battery-powered sensor nodes and simple motor control.

For engineers reviewing the MC9S08QA4CFQE datasheet, MC9S08QA4CFQE pinout, MC9S08QA4CFQE application, or MC9S08QA4CFQE equivalent, this page delivers verified electrical specs, package mapping to 8-pin DFN (Case 1452-02), validated peripheral timing, real-world power consumption data in Stop3 mode (750 nA), and two confirmed alternative parts with documented functional and packaging differences.

Technical Context

The MC9S08QA4CFQE integrates an HCS08 CPU core with BGND instruction support and handles up to 32 interrupt/reset sources. Its internal clock source (ICS) uses a frequency-locked loop (FLL) with trimmed internal reference enabling ±0.2% resolution and ≤2% deviation over voltage and temperature-supporting bus frequencies from 1 MHz to 10 MHz without external crystals.

System-level protection includes COP watchdog with dual-clock options (1 kHz internal or bus clock), low-voltage detection with configurable trip points (VLVD = 1.80–1.91 V), illegal opcode/address reset, and flash block protection. Debug is enabled via single-wire background interface with one hardware breakpoint.

Key Specifications

Pinout & Package

MC9S08QA4CFQE is housed in an 8-pin DFN package (Case 1452-02), measuring 3 mm × 3 mm with 0.5 mm lead pitch and wettable flank leads for automated optical inspection. Thermal resistance θ_JA is 41°C/W on a four-layer board.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar 8-bit microcontroller applications.

Compared with S08QD4CFQE and MC9RS08KA2CFQE, the MC9S08QA4CFQE provides optimal balance of analog integration (ACMP+temp sensor), ultra-low-power stop modes, and compact footprint-making it the preferred choice for cost-sensitive, battery-operated sensor nodes where feature completeness matters more than raw memory headroom or lowest unit price.

Availability

MC9S08QA4CFQE is available at Aetrix Electronics and suitable for smart thermostat sensor nodes, industrial pushbutton panels, low-cost motor speed monitors, and portable medical device alert modules requiring stable component supply and long-term lifecycle support.

Supply support for MC9S08QA4CFQE includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

NXP Semiconductors acquired Freescale in 2015 and maintains full support for the legacy S08 MCU portfolio, including documentation, toolchains, and qualified manufacturing.

The MC9S08QA4CFQE belongs to the S08Q family-designed specifically for ultra-low-power, cost-optimized 8-bit control in space-constrained industrial and consumer applications where analog integration and robust debug capability are essential.

FAQ

What is the minimum supply voltage required for MC9S08QA4CFQE to retain RAM data?

The MC9S08QA4CFQE retains RAM data down to the power-on reset (POR) re-arm voltage of 1.4 V. Below this level, RAM contents are not guaranteed. The device operates functionally from 1.8 V to 3.6 V, and low-voltage detection (LVD) can be configured to generate an interrupt or reset at thresholds as low as 1.80 V (falling). This behavior is verified in the DC characteristics table (Table 6) of the official datasheet Rev. 3.

Does MC9S08QA4CFQE support crystal oscillator input?

No, the MC9S08QA4CFQE does not support external crystal oscillator input. It relies exclusively on its internal clock source (ICS) module, which includes a frequency-locked loop (FLL) driven by a trimmed internal reference oscillator. The ICS supports bus frequencies from 1 MHz to 10 MHz without any external timing components-eliminating crystal BOM cost and PCB area. This is explicitly stated in the "Clock Source Options" section of the MC9S08QA4 datasheet Rev. 3.

Can MC9S08QA4CFQE operate in Stop3 mode while using the ADC?

Yes, the MC9S08QA4CFQE supports full ADC operation-including conversions, automatic compare, and temperature sensor readings-in Stop3 mode. This capability is documented in the "Peripherals" section of the datasheet and confirmed in Table 12 (ADC Operating Conditions), which lists "operation in stop3" as a supported feature. The ADC remains fully functional from 1.8 V to 3.6 V in this mode, enabling wake-on-threshold event detection with sub-microamp quiescent current.

What is the maximum allowed input voltage on PTA5/IRQ/TCLK/RESET pin of MC9S08QA4CFQE?

The PTA5 pin (configured as IRQ/TCLK/RESET) has no internal clamp diode to VDD and must not be driven above the applied VDD voltage. Absolute maximum rating for digital input voltage is VDD + 0.3 V, but the datasheet explicitly warns that exceeding VDD risks reliability or damage. This limitation is detailed in Figure 2 notes and Table 2 (Absolute Maximum Ratings), making external level-shifting mandatory when interfacing with higher-voltage logic families.

How many interrupt sources does MC9S08QA4CFQE support?

The MC9S08QA4CFQE supports up to 32 interrupt and reset sources, including IRQ, keyboard interrupts (KBI), ADC conversion complete, ACMP output transition, TPM overflow/capture, RTI, COP timeout, LVD, and illegal opcode/address exceptions. This count is specified in the "Features" section of the MC9S08QA4 datasheet Rev. 3 and aligns with the interrupt vector table structure defined in the MC9S08QA4 Reference Manual.