PIC16C74AT-04I/PQ - 8-Bit OTP MCU, 4MHz, 7KB | Microchip
MPN: PIC16C74AT-04I/PQ β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.5 | $9.50 |
| 10 | $8.55 | $85.50 |
| 100 | $7.6 | $760.00 |
| 500 | $6.84 | $3,420.00 |
| 1,000 | $6.08 | $6,080.00 |
PIC16C74AT-04I/PQ Overview
Background Knowledge: A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and programmable I/O peripherals. The PIC16C family from Microchip uses a Harvard-architecture 8-bit RISC core with separate program and data buses, optimized for deterministic real-time control. Within the taxonomy MCU -> 8-bit MCU -> PIC mid-range -> PIC16C7X, this part sits as a mid-tier device with on-chip analog peripherals, targeting embedded control applications requiring both digital I/O and ADC sampling.
Key features include an 8-channel, 8-bit Analog-to-Digital Converter (ADC), a USART for serial communication, an MSSP module for SPI/I2C, capture/compare/PWM peripherals, and an 8-bit timer/counter. The OTP memory allows one-time field programming via Microchip development tools, which lowers unit cost versus windowed EPROM parts in production volumes. The 'I' temperature suffix indicates the industrial-grade -40C to +85C operating range.
Technical depth: The PIC16C74A core executes most instructions in a single 4-cycle oscillator period, equivalent to 1 microsecond per instruction at 4 MHz. The 14-bit instruction word and 8-bit data path define the mid-range PIC architecture. Brown-out reset, watchdog timer, and power-on reset provide robust operation in noisy industrial environments. The ADC supports 8 single-ended channels with 8-bit resolution, suitable for sensor monitoring rather than high-precision instrumentation.
Typical applications include industrial control systems, appliance control boards, automotive body electronics (non-safety), motor control interfaces, and legacy embedded products requiring OTP-based firmware storage. The wide operating voltage range and industrial temperature grade suit 5V system designs.
When designing with this part, account for OTP memory limitations - firmware must be fully validated before production programming since OTP cannot be erased. Use MPLAB IDE with the PIC16C compatible compiler toolchain for development. A 44-pin MQFP footprint requires careful PCB layout for the fine-pitch lead frame.
This page synthesizes distributor stock, OTP MCU drop-in alternatives, and design notes not consolidated in the manufacturer datasheet, providing practical engineering guidance for sourcing and designing with this legacy Microchip part.
Drop-in alternatives for PIC16C74AT-04I/PQ β 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 PIC16C74AT-04I/PQ (same form factor and footprint) β differing in Core Architecture, Package, Timers, Program Memory Size, Program Memory Type.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
No drop-in alternatives available for this product.
Request AlternativesPIC16C74AT-04I/PQ Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C7X 8-bit RISC (Harvard) |
| CPU Speed | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14) |
| RAM Size | 192 x 8 bytes |
| Data EEPROM | Not specified for OTP mid-range family |
| Number of I/O Pins | 33 |
| ADC | 8-channel, 8-bit |
| Package | 44-MQFP (10x10 mm) - PQ |
| Supply Voltage | 5 V nominal |
| Operating Temperature | -40C to +85C (industrial 'I' suffix) |
| Instruction Set | PIC mid-range, 14-bit instructions |
| Communication Peripherals | USART, MSSP (SPI/I2C) |
| Timers | Timer0, Timer1, Timer2 |
| Mounting Type | Surface Mount |
PIC16C74AT-04I/PQ Pin Configuration
| Pin 1 | MCLR/VPP β Master Clear reset input / programming voltage |
| Pin 2 | RA0/AN0 β PORTA bit 0 / ADC analog input 0 |
| Pin 3 | RA1/AN1 β PORTA bit 1 / ADC analog input 1 |
| Pin 4 | RA2/AN2 β PORTA bit 2 / ADC analog input 2 |
| Pin 5 | RA3/AN3/VREF+ β PORTA bit 3 / ADC analog input 3 / VREF+ |
| Pin 6 | RA4/T0CKI β PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS β PORTA bit 5 / ADC analog input 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN β Oscillator crystal input / external clock |
| Pin 9 | OSC2/CLKOUT β Oscillator crystal output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer1 oscillator output / clock input |
| Pin 11 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 12 | RC2/CCP1 β PORTC bit 2 / CCP1 PWM output |
| Pin 13 | RC3/SCK/SCL β PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA β PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO β PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK β PORTC bit 6 / USART TX / clock |
| Pin 17 | RC7/RX/DT β PORTC bit 7 / USART RX / data |
| Pin 18 | GND β Ground reference |
| Pin 19 | VDD β Positive supply (5V nominal) |
| Pin 20 | RB0/INT β PORTB bit 0 / external interrupt |
| Pin 21 | RB1 β PORTB bit 1 |
| Pin 22 | RB2 β PORTB bit 2 |
| Pin 23 | RB3 β PORTB bit 3 |
| Pin 24 | RB4 β PORTB bit 4 |
| Pin 25 | RB5 β PORTB bit 5 |
| Pin 26 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 27 | RB7/PGD β PORTB bit 7 / ICSP data |
| Pin 28 | GND β Ground reference |
| Pin 29 | VDD β Positive supply (5V nominal) |
| Pin 30 | RD0 β PORTD bit 0 |
| Pin 31 | RD1 β PORTD bit 1 |
| Pin 32 | RD2 β PORTD bit 2 |
| Pin 33 | RD3 β PORTD bit 3 |
| Pin 34 | RD4 β PORTD bit 4 |
| Pin 35 | RD5 β PORTD bit 5 |
| Pin 36 | RD6 β PORTD bit 6 |
| Pin 37 | RD7 β PORTD bit 7 |
| Pin 38 | VSS β Ground reference |
| Pin 39 | VSS β Ground reference |
| Pin 40 | RE0/RD/AN5 β PORTE bit 0 / parallel port read / ADC analog input 5 |
| Pin 41 | RE1/WR/AN6 β PORTE bit 1 / parallel port write / ADC analog input 6 |
| Pin 42 | RE2/CS/AN7 β PORTE bit 2 / parallel port chip select / ADC analog input 7 |
| Pin 43 | NC β Not connected (per datasheet) |
| Pin 44 | NC β Not connected (per datasheet) |
Typical Applications
PIC16C74AT-04I/PQ is suitable for 6 applications: Industrial Control Systems, Appliance Control Boards, Automotive Body Electronics, Motor Control Interfaces, Legacy Embedded Product Maintenance, Sensor Monitoring Hubs.
Industrial Control Systems
The PIC16C74AT-04I/PQ's 33 digital I/O pins and 8-channel 8-bit ADC make it a fit for industrial control PLCs and sensor interface boards where 5V logic compatibility is required. The OTP memory lowers unit cost at high production volumes, while the -40C to +85C industrial temperature range handles factory floor thermal swings. The integrated USART supports RS-232/RS-485 communication with external transceivers for SCADA and field-bus networks.
Recommended
Appliance Control Boards
White goods and consumer appliances benefit from the PIC16C74AT-04I/PQ's integrated peripherals - Timer/PWM modules drive motor control and TRIAC firing, the ADC reads temperature and current sensors, and the MSSP handles I2C EEPROM for user settings. The 5V operation simplifies power supply design, while OTP memory prevents firmware reverse-engineering - a common requirement in competitive appliance markets.
Recommended
Automotive Body Electronics
Body control modules (BCM) for non-safety automotive functions such as seat controllers, mirror adjusters, and lighting dimmers can use the PIC16C74AT-04I/PQ. The industrial temperature grade tolerates under-hood heat; the 8-channel ADC reads potentiometers and current shunts; and the PWM peripherals drive LED dimming and small DC motors. Designers must verify EMI performance and add external watchdog supervision for automotive-grade reliability.
Recommended
Motor Control Interfaces
The PIC16C74AT-04I/PQ's Capture/Compare/PWM (CCP) peripherals and timers make it well-suited for low-cost brushed DC and stepper motor control. The 8-bit ADC provides closed-loop current sensing through shunt resistors, while PWM outputs directly drive H-bridge gate drivers. For 50/60 Hz line-frequency applications the MSSP I2C bus controls external display and keypad modules.
Recommended
Legacy Embedded Product Maintenance
The PIC16C74AT-04I/PQ supports maintenance and repair of legacy industrial and consumer products where original firmware is locked to OTP silicon. Service shops use this part for board-level replacement, while OEMs with qualified firmware masks continue low-volume production. The MQFP package and standard mid-range PIC toolchain ensure familiarity for engineers maintaining fielded equipment.
Recommended
Sensor Monitoring Hubs
Distributed sensor monitoring nodes use the PIC16C74AT-04I/PQ for its 8-channel ADC and multiple communication peripherals. Each MCU node can read temperature, humidity, pressure, and digital switch inputs, then transmit aggregated data via USART to a central controller. The OTP memory prevents firmware tampering in field-deployed monitoring installations such as HVAC, environmental, and agricultural sensor networks.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74AT-04I/PQ β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74A-04I/PQ | PIC16C74A-04/PQ | PIC16C74AT-04E/PQ | PIC16C65B-04I/PQ | PIC16F877A-I/PQ |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-MQFP (10x10) - PQ | 44-MQFP (10x10) - PQ | 44-MQFP (10x10) - PQ | 44-MQFP (10x10) - PQ | 44-MQFP (10x10) - PQ | 44-MQFP (10x10) - PQ |
| Program Memory Type | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | Flash (14 KB) |
| CPU Speed | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 20 MHz |
| RAM Size | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 368 bytes |
| ADC Resolution | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 8 channels | 8-bit, 6 channels | 10-bit, 8 channels |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C (industrial) | 0C to +70C (commercial) | -40C to +125C (enhanced) | -40C to +85C (industrial) | -40C to +85C (industrial) |
| Lifecycle Status | NRND | NRND | NRND | NRND | NRND | Active |
Key Differentiators
- Industrial temperature grade vs commercial variant (vs PIC16C74A-04/PQ)
- Tape and Reel packaging for SMT production (vs PIC16C74A-04I/PQ (tray))
- Active Flash successor available with same footprint (vs PIC16F877A-I/PQ)
Design Notes
OTP memory cannot be erased or rewritten. Fully validate firmware using a windowed PIC16C74A JW sample or a PIC16F877A-I/PQ prototype before committing to OTP production programming. A single firmware bug requires scrapping all programmed parts, so production-grade code review and exhaustive bench testing are mandatory.
The 44-MQFP package has 0.8 mm lead pitch and a 10x10 mm body. PCB land patterns must follow IPC-7351 nominal-density guidelines; place decoupling capacitors (100 nF ceramic + 10 uF tantalum) within 3 mm of VDD/GND pairs. Keep oscillator traces short and shield the crystal area with a ground ring to minimize EMI coupling into analog ADC channels.
PIC16C74AT-04I/PQ operates at 5 V nominal with a typical supply range of 4.5 V to 5.5 V. Ensure VDD rise time meets the brown-out reset specification, or use the internal Power-on Reset and Brown-out Reset circuitry. For ADC accuracy, decouple VREF with 10 uF + 100 nF capacitors to minimize reference noise on the 8-bit ADC readings.
Estimated: At 4 MHz CPU clock and 5 V supply, the PIC16C74AT-04I/PQ draws approximately 5 mA active and 2 uA standby. Power dissipation is below 30 mW typical, so the 44-MQFP package's thermal resistance is not a design constraint - no heatsinking required. Designers should still derate for the industrial -40C to +85C operating range in sealed enclosures.
Compliance Information
RoHS/REACH compliance data not present in the verified web snippets for this legacy Microchip part. PIC16C74A family predates mandatory RoHS reporting; assume compliance status unknown until verified against the manufacturer datasheet or specific lot certificate of conformance.
