NXP Semiconductors MC705B16NBE

Overview

MC705B16NBE from NXP Semiconductors (formerly Motorola/Freescale) is an 8-bit HCMOS microcontroller in the M68HC05 family, featuring 16 KB on-chip ROM, 256 bytes RAM, 128 bytes EEPROM, 8-channel 8-bit ADC, dual PLM outputs, SCI serial interface, and a programmable timer. It operates at up to 4 MHz with 5 V supply and targets embedded control in automotive body electronics and industrial sensor nodes.

For engineers reviewing the MC705B16NBE datasheet, MC705B16NBE pinout, MC705B16NBE application, or MC705B16NBE equivalent, key selection criteria include its integrated EEPROM retention, single-chip mode operation without external bus, low-power STOP/WAIT modes, and compatibility with legacy HC05 toolchains and mask-programmed firmware workflows.

Technical Context

The MC705B16NBE implements the M68HC05 CPU core with 10-bit index register, 16-bit program counter, and condition code register supporting 72 instructions. Its memory map includes fixed ROM starting at $E000, mirrored RAM at $0000–$00FF, and EEPROM mapped at $F000–$F07F with dedicated control registers (EECR, EEADR, EEDATA).

Peripheral integration includes a 16-bit programmable timer with input capture (TCAP1/TCAP2), output compare (TCMP1/TCMP2), and pulse-length modulation (PLMA/PLMB); a full-duplex SCI with baud rate generator and wake-up capability; and an 8-channel analog-to-digital converter with conversion time of 72 µs per sample and software-triggered start.

Key Specifications

Pinout & Package

MC705B16NBE is housed in a 56-pin Shrink Dual In-Line Package (SDIP) with 0.3-inch body width and 0.1-inch lead pitch. The package supports through-hole mounting and provides thermal performance suitable for ambient temperatures up to +85°C in sealed enclosures.

Key Features

Applications

Equivalent & Alternatives

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

Compared with MC705B16NBE, MC68HC908JK3 offers faster execution but removes EEPROM-based data logging, while STM8S003F3P6 provides richer development tools and speed at the cost of legacy HC05 firmware compatibility and integrated nonvolatile memory.

Availability

MC705B16NBE is available at Aetrix Electronics and suitable for automotive body electronics, industrial sensor nodes, and appliance control systems requiring stable component supply and long-term lifecycle support.

Supply support for MC705B16NBE 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 leader focused on secure connectivity solutions for automotive, industrial, and IoT applications, with roots in Motorola's semiconductor division.

The M68HC05 product line was designed for cost-sensitive, high-reliability embedded control in automotive and industrial environments, emphasizing single-chip integration, low-power operation, and mask-ROM firmware security - precisely embodied by the MC705B16NBE.

FAQ

What is the maximum operating frequency of the MC705B16NBE?

The MC705B16NBE operates at a maximum frequency of 4 MHz when powered at 5 V. This limit is defined by its HCMOS process and internal timing constraints, including instruction cycle duration and peripheral setup/hold requirements. Exceeding 4 MHz may cause undefined behavior in the timer, ADC, or SCI modules. The MC705B16NBE datasheet specifies that all DC and AC electrical characteristics are guaranteed only within this frequency range under rated voltage and temperature conditions.

Does the MC705B16NBE include on-chip EEPROM, and what is its endurance?

Yes, the MC705B16NBE integrates 128 bytes of on-chip EEPROM with guaranteed endurance of 100,000 write/erase cycles and data retention exceeding 10 years at +85°C. This EEPROM is accessed via dedicated registers (EECR, EEADR, EEDATA) and supports byte-level programming and sector erase. Its inclusion eliminates the need for external nonvolatile memory in applications such as calibration storage or user preference retention within the MC705B16NBE-based design.

How does the MC705B16NBE handle power-down modes, and what are the typical current draws?

The MC705B16NBE supports two low-power modes: STOP mode draws approximately 10 µA and halts the CPU and all clocks except the real-time interrupt (RTI) source; WAIT mode draws about 250 µA and stops the CPU while preserving RAM and peripheral register contents. Both modes are entered via software instruction and exited by RESET or enabled interrupts. These values are measured at VDD = 5 V and TA = 25°C per the MC705B16NBE electrical specifications table.

Can the MC705B16NBE's ADC operate during low-power modes?

No, the MC705B16NBE's 8-bit ADC cannot perform conversions in STOP mode and is disabled in WAIT mode unless explicitly re-enabled after wake-up. The ADC requires the main system clock to function, and both STOP and WAIT modes disable the oscillator driving it. Conversion must be initiated in active mode, and results read before entering low-power states. This behavior is documented in Section 8.3 and 8.4 of the MC705B16NBE technical data manual.

What packaging options are available for the MC705B16NBE?

The MC705B16NBE is exclusively offered in a 56-pin Shrink Dual In-Line Package (SDIP) with 0.3-inch body width and 0.1-inch lead pitch. This through-hole package is specified in Section 12.1.3 and Figure 12-3 of the MC705B16NBE mechanical data documentation. No QFP, PLCC, or SOIC variants exist for this specific part number - the 'NBE' suffix denotes the SDIP configuration per Freescale's ordering nomenclature.