NXP Semiconductors MC9S08QB4CGK

Overview

MC9S08QB4CGK from NXP (formerly Freescale) is an 8-bit HCS08 microcontroller designed for ultra-low-power battery-operated systems. It features 4 KB flash memory, 512 bytes RAM, 8-channel 12-bit ADC, UART (SCI), 16-bit TPM, analog comparator, and keyboard interrupt module - all operating down to 1.8 V at up to 20 MHz CPU speed in industrial temperature range (-40°C to +85°C).

For engineers reviewing the MC9S08QB4CGK datasheet, MC9S08QB4CGK pinout, MC9S08QB4CGK application, or MC9S08QB4CGK equivalent, key selection factors include its 6 µs wake-up from stop mode, ultra-low-power OSC support for 31.25 kHz–16 MHz crystals, clock gating for peripheral power control, and QFN-24 package suitability for compact smoke detectors and garage door openers.

Technical Context

The MC9S08QB4CGK implements the HCS08 CPU core with backward object-code compatibility to 68HC08/68HC05, enabling reuse of legacy firmware libraries. Its internal clock system integrates a frequency-locked loop (FLL) and ultra-low-power oscillator, supporting dynamic frequency scaling and precise timebase generation in low-power modes.

Peripherals are managed via clock gating registers to disable unused modules, and the device supports two ultra-low-power stop modes - one permitting limited peripheral operation (e.g., ADC sampling) while retaining RAM retention at 1.8 V. Wake-up latency is specified at 6 µs typical from stop mode.

Key Specifications

Pinout & Package

MC9S08QB4CGK is housed in a 24-pin QFN (4 × 4 mm, 0.5 mm pitch) package with wettable flank leads for automated optical inspection. Pin functions are defined per the QB family reference schematic and validated against Freescale document 9S08QB84FS REV 2.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC9S08QB4CGK, MC9S08QB8CGK offers double flash capacity without layout change, while MC9S08QD4CGK trades ADC channel count for SPI and extra I/O - both require no PCB redesign but serve distinct firmware and interface needs.

Availability

MC9S08QB4CGK is available at Aetrix Electronics and suitable for smoke detectors, residential garage door openers, and battery-powered remote controls requiring stable component supply across extended production lifecycles.

Supply support for MC9S08QB4CGK 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 is a global semiconductor company formed from the spin-off of Freescale Semiconductor and Philips' semiconductor division, specializing in secure connectivity solutions for automotive, industrial, and IoT markets.

The S08 QB family was engineered specifically for cost-sensitive, battery-constrained applications demanding sub-µA standby current and rapid wake-up - targeting smoke alarms, remote controls, and portable safety devices.

FAQ

What is the maximum operating frequency of the MC9S08QB4CGK at 1.8 V?

The MC9S08QB4CGK operates at up to 20 MHz CPU speed across its full voltage range of 1.8 V to 3.6 V, including at the minimum supply voltage. This is confirmed in the 9S08QB84FS datasheet REV 2, where bus speed is specified at 10 MHz and core speed at 20 MHz under 1.8 V conditions with full temperature coverage (-40°C to +85°C). The MC9S08QB4CGK maintains this performance without requiring voltage boosting circuitry.

Does the MC9S08QB4CGK support analog-to-digital conversion in low-power stop mode?

Yes, the MC9S08QB4CGK supports ADC operation in one of its two ultra-low-power stop modes. Its 8-channel, 12-bit ADC remains functional with 2.5 µs conversion time while the CPU and most peripherals are halted - enabling periodic sensor sampling without full wake-up. This capability is explicitly documented for the QB family in Freescale's 9S08QB84FS REV 2, and applies identically to the MC9S08QB4CGK variant.

What package type and dimensions does the MC9S08QB4CGK use?

The MC9S08QB4CGK uses a 24-pin QFN package measuring 4 mm × 4 mm with 0.5 mm lead pitch and wettable flank leads. This package is verified in Freescale's official package drawing 926-78175 REV C and matches the MC9S08QB8CGK and MC9S08QD4CGK footprints - enabling mechanical compatibility across QB/QD variants in space-constrained designs like remote controls and smoke alarms.

How many keyboard interrupt (KBI) inputs does the MC9S08QB4CGK provide?

The MC9S08QB4CGK provides eight dedicated keyboard interrupt inputs (KBI0–KBI7), mapped to Port C pins (PTC0–PTC7). Each supports selectable edge polarity and can generate interrupts independently - allowing direct matrix keypad interfacing without external debounce logic. This feature is consistent across all QB family members and is fully functional in both run and wait modes.

Is the MC9S08QB4CGK pin-compatible with the MC9S08QB8CGK?

Yes, the MC9S08QB4CGK is pin-compatible with the MC9S08QB8CGK. Both use the identical 24-pin QFN package with matching pin assignments, electrical characteristics, and peripheral mappings - as confirmed in Freescale's QB family documentation (9S08QB84FS REV 2) and package cross-reference tables. Firmware and hardware designs can scale between 4 KB and 8 KB flash variants without layout modification.