PIC16C74B-04I/PT - 8-Bit 4MHz OTP MCU, 7KB Flash | Microchip
MPN: PIC16C74B-04I/PT ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $9.85 | $9.85 |
| 10 | $8.95 | $89.50 |
| 100 | $7.65 | $765.00 |
| 500 | $6.8 | $3,400.00 |
| 1,000 | $6.1 | $6,100.00 |
PIC16C74B-04I/PT Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, non-volatile program memory, working RAM, and peripheral interfaces on one silicon die. The PIC16CXX mid-range family sits between the baseline PIC16C5X and the enhanced PIC17CXX families, balancing code density, peripheral set, and cost for embedded control applications such as industrial sensors, appliance controls, automotive body electronics, and low-cost consumer devices.
Key differentiating features include 8 channels of 8-bit ADC, 2 CCP (Capture/Compare/PWM) modules for motor and lighting control, hardware I2C/SPI/USART enabling direct connection to sensors and EEPROMs, and a wide operating voltage range suitable for both 5V and 3.3V systems. The OTP memory and industrial-grade temperature rating (-40C to +85C) make this part well suited for medium-volume production where field reprogrammability is not required.
The PIC16C74B-04I/PT uses Microchip's classic Harvard RISC architecture with separate program and data buses, enabling single-cycle instruction execution for most opcodes and deterministic interrupt response. Its CMOS fully-static design allows the clock to be stopped without losing register state, an advantage for battery-powered or power-cycled applications where the controller must wake, execute, and return to sleep quickly.
Typical applications include industrial automation controllers, HVAC sensor interfaces, automotive body and lighting modules, consumer appliance control boards, and low-end embedded data acquisition. Designers commonly pair this MCU with external EEPROMs for parameter storage and with discrete MOSFET drivers for switching solenoids, relays, or small DC motors.
A key design consideration is the OTP memory window: once programmed, code is permanent, so engineering teams must use a windowed or flash sibling (such as PIC16F74 or PIC16F877A) for development. Also note that the 4 MHz speed grade (the "-04" suffix) is the slowest in this family; if timing margins are tight, the 10 MHz or 20 MHz grade variants of the same die are drop-in substitutes.
Drop-in alternatives for PIC16C74B-04I/PT — 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 PIC16C74B-04I/PT (same form factor and footprint) — differing in Program Memory Size, Package, Core Architecture, Serial Interfaces, Program Memory Type.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-04I/P
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC16C74B-04E/PT
✅ Drop-In✓ In Stock
$5.7 / Unit
View Datasheet →PIC16C74B-10I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74B-20I/PT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.62 / Unit
View Datasheet →PIC16F74-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F877A-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F452-I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74B-04I/PT Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX mid-range 8-bit RISC |
| Program Memory Size | 7 KB (4K x 14 words) OTP |
| RAM Size | 192 bytes |
| Data EEPROM | Not available (OTP only) |
| Maximum CPU Clock | 4 MHz |
| Instruction Cycle | 200 ns (single cycle) |
| Instruction Set Size | 35 single-word instructions |
| I/O Pins | 33 |
| ADC | 8 channels, 8-bit resolution |
| Timers | 3 (Timer0, Timer1, Timer2) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Serial Interfaces | SPI, I2C, USART |
| Package | 44-pin TQFP (10x10 mm) |
| Operating Temperature Range | -40C to +85C (Industrial) |
| Mounting Type | Surface Mount |
| RoHS Status | Non-RoHS (OTP windowed silicon) |
PIC16C74B-04I/PT Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input channel 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input channel 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / Analog input channel 2 |
| Pin 4 | RA3/AN3/VREF — PORTA bit 3 / Analog input channel 3 / ADC reference |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/AN4/SS — PORTA bit 5 / Analog input channel 4 / SPI slave select |
| Pin 7 | RA6/OSC2/CLKOUT — PORTA bit 6 / Oscillator output / Clock out |
| Pin 8 | RA7/OSC1/CLKIN — PORTA bit 7 / Oscillator input / Clock in |
| Pin 9 | RC0 — PORTC bit 0 |
| Pin 10 | RC1 — PORTC bit 1 |
| Pin 11 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM 1 |
| Pin 12 | RC3/SCL/SCK — PORTC bit 3 / I2C clock or SPI clock |
| Pin 13 | RC4/SDA/SDI — PORTC bit 4 / I2C data or SPI data in |
| Pin 14 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 15 | RC6/TX/CK — PORTC bit 6 / USART TX or clock |
| Pin 16 | RC7/RX/DT — PORTC bit 7 / USART RX or data |
| Pin 17 | GND — Ground (logic ground) |
| Pin 18 | GND — Ground (logic ground) |
| Pin 19 | GND — Ground (logic ground) |
| Pin 20 | GND — Ground (logic ground) |
| Pin 21 | GND — Ground (logic ground) |
| Pin 22 | GND — Ground (logic ground) |
| Pin 23 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 24 | RB1 — PORTB bit 1 |
| Pin 25 | RB2 — PORTB bit 2 |
| Pin 26 | RB3/CCP2 — PORTB bit 3 / Capture/Compare/PWM 2 |
| Pin 27 | RB4 — PORTB bit 4 |
| Pin 28 | RB5 — PORTB bit 5 |
| Pin 29 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 30 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 31 | GND — Ground (logic ground) |
| Pin 32 | GND — Ground (logic ground) |
| Pin 33 | GND — Ground (logic ground) |
| Pin 34 | VDD — Positive supply (logic supply) |
| Pin 35 | VDD — Positive supply (logic supply) |
| Pin 36 | VDD — Positive supply (logic supply) |
| Pin 37 | RD0 — PORTD bit 0 |
| Pin 38 | RD1 — PORTD bit 1 |
| Pin 39 | RD2 — PORTD bit 2 |
| Pin 40 | RD3 — PORTD bit 3 |
| Pin 41 | RD4 — PORTD bit 4 |
| Pin 42 | RD5 — PORTD bit 5 |
| Pin 43 | RD6 — PORTD bit 6 |
| Pin 44 | RD7 — PORTD bit 7 |
Typical Applications
PIC16C74B-04I/PT is suitable for 6 applications: Industrial Automation Controllers, HVAC Sensor Interface Boards, Automotive Body Electronics, Consumer Appliance Control Boards, Low-End Data Acquisition Modules, Educational and Hobby Robotics.
Industrial Automation Controllers
The PIC16C74B-04I/PT fits industrial automation controllers because its 8-channel 8-bit ADC accepts up to eight sensor inputs simultaneously (temperature, pressure, flow, level), while the 33 GPIO pins drive relays, solenoids, and indicator LEDs without external mux. Industrial-grade -40C to +85C operation covers factory floor environments, and the OTP memory locks firmware against accidental field rewriting. The 4 MHz CPU and 200 ns instruction cycle support scan times well under 10 ms for typical PLC ladder-equivalent logic, and the USART interfaces directly to RS-485 transceivers for multi-drop Modbus networks. Pair this MCU with the MAX485 transceiver and 24LC256 EEPROM for a complete sensor hub.
Recommended
HVAC Sensor Interface Boards
HVAC control boards rely on the PIC16C74B-04I/PT for reading multiple analog thermistor inputs (8 ADC channels), driving triac outputs for fan and compressor stages via the 2 CCP/PWM modules, and communicating with indoor wall thermostats through the USART. The 35-instruction RISC core keeps firmware compact enough to fit in 7 KB OTP, leaving room for PID control loops, fault detection, and EEPROM-backed setpoint storage. Its CMOS fully-static design allows the clock to halt during low-power standby, supporting ENERGY STAR standby targets for HVAC equipment. The wide industrial temperature range and stable 5V operation ensure reliable performance in unconditioned equipment closets.
Recommended
Automotive Body Electronics
Automotive body modules such as lighting controllers, seat position memory, and mirror adjusters are good fits for the PIC16C74B-04I/PT because the 33 GPIO pins directly drive LED arrays and small DC motors through discrete MOSFETs without external I/O expanders. The 2 CCP modules generate the PWM signals needed for fade-in/fade-out headlamp control or progressive mirror movement. The SSP block handles SPI communication with dashboard clusters, while the USART supports diagnostic protocols such as K-Line or LIN. For under-hood or engine-bay applications choose the -04E (extended) variant; for cabin electronics the -04I industrial grade is sufficient.
Recommended
Consumer Appliance Control Boards
Consumer appliances (washing machines, microwave ovens, dishwashers, coffee machines) use the PIC16C74B-04I/PT as the main controller because the OTP memory locks in the appliance firmware permanently, protecting against unauthorized firmware swaps in the field. The 8-bit ADC reads water level sensors, thermistors, and rotary encoder positions, while the PWM channels control motor speed and heater duty cycle. The 4 MHz speed grade is more than adequate for time-sliced appliance control loops. Designers appreciate the low unit cost at 1000-piece reels and the small 10x10 mm TQFP footprint that fits compact control boards inside appliance chassis.
Recommended
Low-End Data Acquisition Modules
Compact data acquisition modules (DAQ) for laboratory, agricultural, or environmental monitoring use the PIC16C74B-04I/PT to digitize up to 8 analog channels with 8-bit resolution and forward the readings to a host PC via USART or to an SD card via SPI. The 192-byte RAM buffers incoming samples while the slower OTP firmware performs averaging and alarm checking in the background. The 2 CCP modules timestamp events using Timer1, supporting sample rates up to about 20 ksamples/s aggregate. Because this part is OTP, it is best suited for finished, validated DAQ products rather than research prototypes where firmware changes are frequent.
Recommended
Educational and Hobby Robotics
Hobby robotics platforms and university embedded systems courses use the PIC16C74B-04I/PT as an introduction to mid-range microcontroller programming because the 35-instruction PIC instruction set is easy to learn in assembly and is well documented in textbooks. The 33 GPIO pins can drive up to 4 small DC gearmotors via H-bridge drivers using PWM from the CCP modules, and the ADC reads IR sensor arrays for line-following robots. Programming via ICSP with a PICkit 3 is straightforward, although students should prototype on the flash-based PIC16F74-I/PT (same pinout) to avoid wasting OTP parts during iterative firmware development.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-04I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-04E/PT | PIC16F74-I/PT | PIC16F877A-I/PT | PIC18F452-I/PT |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-pin TQFP (10x10 mm) | 44-pin TQFP (10x10 mm) - same | 44-pin TQFP (10x10 mm) - same | 44-pin TQFP (10x10 mm) - same | 44-pin TQFP (10x10 mm) - same |
| Program Memory Type | 7 KB OTP | 7 KB OTP - same | 7 KB Flash | 14 KB Flash | 32 KB Flash |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 20 MHz | 20 MHz | 40 MHz (10 MIPS) |
| ADC Resolution | 8-bit | 8-bit | 8-bit | 10-bit | 10-bit |
| Operating Temperature Range | -40C to +85C (Industrial) | -40C to +125C (Extended) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| Data EEPROM | Not available | Not available | Not available | 256 bytes | 256 bytes |
| Lifecycle Status | NRND | NRND | Active | Active | Active |
Key Differentiators
- Pin-compatible flash upgrade path with PIC16F877A-I/PT (vs PIC16C74B-04I/PT (this product))
- Wider temperature range than -04I variant (vs PIC16C74B-04E/PT)
- 5x faster execution at same footprint (vs PIC16C74B-20I/PT)
- In-system reprogrammability for field updates (vs PIC16F74-I/PT)
Design Notes
The PIC16C74B-04I/PT is OTP (One-Time Programmable) - once a bit is programmed from 1 to 0 it cannot be changed. This makes development costly because every firmware iteration consumes a part. For prototypes and dev work use the flash-based PIC16F74-I/PT (same 44-TQFP pinout), or a windowed PIC16C74B JW (ceramic DIP) that can be UV-erased. Only program the OTP units after firmware is fully validated and locked.
Place a 0.1 uF ceramic decoupling capacitor as close as possible to each VDD pin (pins 34, 35, 36) and a single 10 uF bulk tantalum or aluminum electrolytic on the main 5V rail. The PIC16C74B has three VDD and three VSS pins arranged around the package center; tying all of them through a low-impedance ground plane is essential to keep digital switching noise out of the analog ADC measurements. Without proper decoupling the 8-bit ADC readings will show 1-2 LSB of noise that varies with CPU activity.
Use an external 4 MHz ceramic resonator or crystal on OSC1 (pin 8) and OSC2 (pin 7) with 22 pF load capacitors to GND. The internal RC oscillator option is rarely accurate enough for USART-based RS-232/RS-485 communication because the baud-rate error can exceed 2%. If the design needs reliable serial communication above 9600 baud, always use an external crystal. Reserve MCLR (pin 1) with a 10 kohm pull-up to VDD and a 100 nF capacitor to ground for clean in-circuit reset behavior.
At 4 MHz clock and 5V supply the PIC16C74B-04I/PT typically draws about 5 mA active and 1 uA sleep. The TQFP-44 package has a thermal resistance of about 50 C/W which is more than adequate for these power levels; no heatsink or thermal copper pour is required. However, in sealed automotive under-hood enclosures operating above +85C, the microcontroller should be placed away from heat sources and the PCB should have adequate thermal relief to the surrounding chassis.
The ADC analog inputs AN0-AN7 share pins with PORTA digital lines. To get clean ADC readings, configure ANx pins as analog inputs by clearing the corresponding PCFG bits in the ADCON1 register, and avoid driving these pins with digital signals during conversions. Add a small RC filter (1 kohm + 100 pF) on any analog input sourced from a high-impedance sensor to prevent charge kickback from the sample-and-hold capacitor from corrupting the measurement. Estimated: 100 pF x 1 kohm = 100 ns filter time constant, well below the 1.6 us ADC acquisition time at 4 MHz / 32 Tosc.
Compliance Information
This OTP windowed-silicon part is generally non-RoHS (lead-bearing) because the original PIC16C74B family pre-dates lead-free mandates. For RoHS-compliant designs use the flash-based PIC16F877A-I/PT or PIC18F452-I/PT in the same 44-TQFP footprint. AEC-Q100 qualification not available for this OTP part.