PIC16C74B-20I/PT - 8-Bit CMOS MCU, 7KB EPROM, 20MHz, TQFP-44 | Microchip
MPN: PIC16C74B-20I/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.5 | $7.50 |
| 10 | $6.78 | $67.80 |
| 100 | $5.92 | $592.00 |
| 500 | $5.15 | $2,575.00 |
| 1,000 | $4.62 | $4,620.00 |
PIC16C74B-20I/PT Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (ROM/EPROM/Flash), data memory (RAM), and peripheral interfaces on one silicon die. Within the taxonomy of embedded processors, an 8-bit MCU sits below 16-bit and 32-bit MCUs in data-path width but excels in deterministic real-time control, low cost, and ultra-low power consumption. The PIC16C74B belongs to Microchip's mid-range PIC16 family, which provides a RISC instruction set (35 single-word instructions), Harvard memory architecture, and rich on-chip peripherals including 8-channel 8-bit ADC, two CCP modules, a USART, and a synchronous serial port configurable for SPI or I²C.
Key features of the PIC16C74B-20I/PT include a 20 MHz maximum clock speed (200 ns instruction cycle), a wide operating voltage range of 2.5 V to 6.0 V with the canonical 4.0 V to 5.5 V operating range typical for this -20 variant, 25 mA source/sink current per I/O pin, and low power consumption of typically <15 µA at 5 V/4 MHz and <1 µA standby at 3 V/32 kHz. The 8-channel 8-bit ADC delivers 8-bit resolution across PORTA and PORTE analog inputs, while the USART and SSP peripherals enable asynchronous serial and SPI/I²C synchronous communication respectively.
The PIC16C74B uses a 14-bit instruction word with an 8-bit data path, enabling direct, deterministic interrupt response times and single-cycle instruction execution for most opcodes (program branches take two cycles). The device supports in-circuit serial programming (ICSP) via two pins, allowing firmware updates without removing the part from the board. Industrial temperature grade (-40°C to +85°C) and EPROM program memory make this variant suitable for development and low-volume production where in-system reprogrammability is not required.
Typical applications include industrial control systems, sensor signal conditioning, motor control (via CCP/PWM), embedded instrumentation, and legacy equipment maintenance. The 33 I/O pins and 8 ADC channels suit applications requiring multiple sensor inputs and digital outputs. The PIC16C74B-20I/PT remains in active production and is widely used as a drop-in upgrade for PIC16C74A designs where higher clock speed is needed.
Drop-in alternatives for PIC16C74B-20I/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-20I/PT (same form factor and footprint) — differing in Mounting Type, Package, Serial Interfaces, Maximum Clock Frequency, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F74-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-04I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74B-10I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C77-20I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C76-20I/PT
✅ Drop-In ⚠️ 参数待验证📋 Reference alternative (not in catalog)
PIC16C74B-20I/PT Maximum Ratings & Electrical Characteristics
| Program Memory Type | EPROM (OTP) |
| Program Memory Size | 7 KB |
| RAM Size | 192 bytes |
| CPU Architecture | 8-bit PIC16 RISC mid-range |
| Maximum Clock Frequency | 20 MHz |
| Instruction Cycle Time | 200 ns |
| Supply Voltage Range | 4.0 V to 5.5 V |
| Wide Operating Voltage Range | 2.5 V to 6.0 V (per datasheet) |
| I/O Pins | 33 |
| ADC Channels | 8 channels, 8-bit resolution |
| Timers | 3 (Timer0, Timer1, Timer2) |
| Capture/Compare/PWM Modules | 2 CCP modules |
| Serial Interfaces | USART + SSP (SPI/I²C) |
| I/O Sink/Source Current | 25 mA / 25 mA |
| Operating Temperature Range | -40°C to +85°C (Industrial) |
| Package | TQFP-44 (PT), 10x10 mm |
| Mounting Type | Surface Mount |
| Instruction Set Size | 35 instructions (14-bit word) |
| In-Circuit Programming | ICSP supported |
| RoHS Status | Compliant |
PIC16C74B-20I/PT Pin Configuration
| Pin 1 | MCLR — Master Clear (Reset) input, active low |
| Pin 2 | OSC1 — Oscillator input / external clock input |
| Pin 3 | OSC2 — Oscillator output |
| Pin 4 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 5 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 6 | RA2/AN2 — PORTA bit 2 / Analog input 2 |
| Pin 7 | RA3/AN3 — PORTA bit 3 / Analog input 3 |
| Pin 8 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 9 | RA5/AN4 — PORTA bit 5 / Analog input 4 |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage |
| Pin 12 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 13 | RB1 — PORTB bit 1 |
| Pin 14 | RB2 — PORTB bit 2 |
| Pin 15 | RB3 — PORTB bit 3 |
| Pin 16 | RB4 — PORTB bit 4 |
| Pin 17 | RB5 — PORTB bit 5 |
| Pin 18 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 19 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage |
| Pin 22 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output or clock input |
| Pin 23 | RC1/T1OSI — PORTC bit 1 / Timer1 oscillator input |
| Pin 24 | RC2/CCP1 — PORTC bit 2 / CCP1 module I/O |
| Pin 25 | RC3/SCK/SCL — PORTC bit 3 / SPI clock or I²C clock |
| Pin 26 | RC4/SDI/SDA — PORTC bit 4 / SPI data in or I²C data |
| Pin 27 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 28 | RC6/TX/CK — PORTC bit 6 / USART transmit or clock |
| Pin 29 | RC7/RX/DT — PORTC bit 7 / USART receive or data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply voltage |
| Pin 32 | RD0 — PORTD bit 0 |
| Pin 33 | RD1 — PORTD bit 1 |
| Pin 34 | RD2 — PORTD bit 2 |
| Pin 35 | RD3 — PORTD bit 3 |
| Pin 36 | RD4 — PORTD bit 4 |
| Pin 37 | RD5 — PORTD bit 5 |
| Pin 38 | RD6 — PORTD bit 6 |
| Pin 39 | RD7 — PORTD bit 7 |
| Pin 40 | RE0/RD/AN5 — PORTE bit 0 / Read control or Analog input 5 |
| Pin 41 | RE1/WR/AN6 — PORTE bit 1 / Write control or Analog input 6 |
| Pin 42 | RE2/CS/AN7 — PORTE bit 2 / Chip select or Analog input 7 |
| Pin 43 | VSS — Ground reference |
| Pin 44 | VDD — Positive supply voltage |
Typical Applications
PIC16C74B-20I/PT is suitable for 7 applications: Industrial Control Systems, Motor Control and PWM Drive, Sensor Signal Conditioning and Data Acquisition, Embedded Instrumentation and Metering, HVAC and Building Automation, Legacy Equipment Maintenance and Repair, Educational and Development Platforms.
Industrial Control Systems
The PIC16C74B-20I/PT is well suited for industrial control applications requiring deterministic real-time response and multi-channel analog sensing. Its 8-channel 8-bit ADC, 33 I/O pins, and USART/SSP peripherals allow direct interfacing with sensors, relays, and operator panels. The 20 MHz clock provides 200 ns instruction execution, sufficient for PID loop computation at typical industrial sampling rates, while the industrial -40°C to +85°C temperature range supports factory-floor deployment. The 25 mA source/sink per I/O pin drives opto-isolators and small relays without buffering.
Recommended
Motor Control and PWM Drive
The PIC16C74B-20I/PT's two Capture/Compare/PWM (CCP) modules and 20 MHz clock make it suitable for brushed DC motor speed control, servo position control, and PWM-driven LED dimming. Timer2 provides the PWM time base, while the ADC samples motor current or position feedback. The 8-bit PWM resolution at 20 MHz yields acceptable resolution for small motors. H-bridge driver companion chips accept the 25 mA I/O drive directly, simplifying PCB design.
Recommended
Sensor Signal Conditioning and Data Acquisition
The PIC16C74B-20I/PT's 8-channel 8-bit ADC and 33 I/O pins support multi-sensor data acquisition systems such as environmental monitors, HVAC controllers, and process instrumentation. The 19.2 µs ADC conversion time at 20 MHz enables sampling of up to 8 channels within a few hundred microseconds total, sufficient for slow-changing process variables. The SSP module (SPI or I²C) connects to external digital sensors and EEPROM storage for calibration data and logging.
Recommended
Embedded Instrumentation and Metering
The PIC16C74B-20I/PT powers digital panel meters, benchtop test instruments, and portable measurement devices where its 8-bit ADC, USART, and PWM outputs provide display driving and serial data export. The wide 4.0 V to 5.5 V supply range simplifies integration with battery charging ICs and 5 V regulated rails common in handheld instruments. The 192-byte RAM and 7 KB EPROM accommodate lookup tables for sensor linearization and menu-driven user interfaces on character LCD displays.
Recommended
HVAC and Building Automation
The PIC16C74B-20I/PT serves HVAC thermostats, zone controllers, and building automation nodes requiring reliable operation across the industrial temperature range. Its multiple timers support scheduling and watchdog tasks, while the ADC reads temperature sensors, humidity transducers, and occupancy detectors. The USART enables Modbus RTU communication with central building management systems, and the SSP bus interfaces to keypad entry or expansion I/O chips for multi-zone control panels.
Recommended
Legacy Equipment Maintenance and Repair
The PIC16C74B-20I/PT remains a critical replacement part for legacy industrial and medical equipment originally designed around PIC16C7X-series microcontrollers. Its active Microchip lifecycle status and continuing production availability make it a reliable source for service and refurbishment rather than redesign. Engineers maintaining older systems benefit from its EPROM memory (no reprogramming concern during field service) and exact pin/pin compatibility with original PIC16C74A designs needing higher clock speed.
Recommended
Educational and Development Platforms
The PIC16C74B-20I/PT is used in university embedded systems courses and Microchip PIC training kits to teach 8-bit RISC architecture, register-level programming, and peripheral configuration. The 35-instruction PIC16 instruction set provides a manageable learning curve, while the rich peripheral set (ADC, USART, SPI, I²C, PWM) covers the major embedded interfaces. The ICSP capability enables in-circuit programming demonstrations, and Microchip's MPLAB IDE with HI-TECH C compiler supports the device for academic coursework.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-20I/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F74-I/PT | PIC16C74B-04I/PT | PIC16C74B-10I/PT | PIC16C77-20I/PT | PIC16C76-20I/PT |
|---|---|---|---|---|---|---|
| Package | TQFP-44 (PT) 10x10 mm | TQFP-44 (PT) 10x10 mm - same | TQFP-44 (PT) 10x10 mm - same | TQFP-44 (PT) 10x10 mm - same | TQFP-44 (PT) 10x10 mm - same | TQFP-44 (PT) 10x10 mm - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory | 7 KB EPROM | 7 KB Flash | 7 KB EPROM | 7 KB EPROM | 8 KB EPROM | 14 KB EPROM |
| Max Clock Frequency | 20 MHz | 20 MHz | 4 MHz (-80%) | 10 MHz (-50%) | 20 MHz | 20 MHz |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 368 bytes (+92%) | 368 bytes (+92%) |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 33 |
| ADC Channels | 8 (8-bit) | 8 (8-bit) | 8 (8-bit) | 8 (8-bit) | 8 (8-bit) | 5 (8-bit) |
| Operating Temperature | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) | -40°C to +85°C (Industrial) |
| Memory Type | EPROM (one-time programmable) | Flash (reprogrammable) | EPROM | EPROM | EPROM | EPROM |
Key Differentiators
- One-time-programmable EPROM for firmware security (vs PIC16F74-I/PT)
- Active Microchip lifecycle status with continuing production (vs Older PIC16C74A-20I/PT variants)
- Industrial temperature range with full EPROM margin (vs Commercial-grade PIC16C74B-20/PQ)
- TQFP-44 package with 0.8 mm pitch for hand-solderable prototypes (vs MQFP / PQ-package variants)
Design Notes
The PIC16C74B-20I/PT operates from 4.0 V to 5.5 V with typical supply current of approximately 15 mA at 5 V/20 MHz active, plus 25 mA per I/O pin when sourcing or sinking. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of each VDD pin (the part has multiple VDD/VSS pairs: pins 11, 21, 31, 44 for VDD and 10, 20, 30, 43 for VSS). For battery-powered applications, the brown-out reset and watchdog timer features minimize current draw during fault conditions.
The PIC16C74B-20I/PT supports four oscillator modes: RC (low-cost), XT (standard crystal, up to 4 MHz), HS (high-speed crystal, up to 20 MHz), and LP (low-power, 32 kHz). For the -20 speed grade at 20 MHz, the HS mode with a 20 MHz crystal and 15-33 pF load capacitors is required. Connect the crystal between OSC1 (pin 2) and OSC2 (pin 3) with traces kept short and surrounded by a ground guard ring to minimize EMI susceptibility. Use an external clock driver on OSC1 if driving from a system clock source.
Common PIC16C74B-20I/PT design pitfalls: (1) MCLR pin (pin 1) must be pulled high through a 10 kΩ resistor and decoupled with 100 nF to VDD for proper reset; leaving MCLR floating causes intermittent operation. (2) The EPROM memory is one-time-programmable, so firmware bugs cannot be fixed in-circuit - plan for prototype cycles with windowed CERDIP variants before committing to TQFP production parts. (3) ICSP pins RB6 (PGC, pin 18) and RB7 (PGD, pin 19) must not be loaded with capacitance exceeding the ICSP specification during programming. (4) For ADC accuracy, allow adequate acquisition time based on source impedance - 19.72 µs minimum at 20 MHz for 8-bit conversion.
For reliable mixed-signal performance with the PIC16C74B-20I/PT, isolate analog VDD/AVDD and AGND from digital VDD/VSS using star-ground topology at the MCU. Place the 100 nF bypass capacitors on each VDD pin as close as physically possible to the package leads, ideally within 2-3 mm. Route analog signals (PORTA analog inputs AN0-AN4 and PORTE AN5-AN7) away from switching signals and the high-current 25 mA I/O traces to minimize ADC noise coupling. A continuous ground plane under the TQFP-44 package improves thermal dissipation and reduces EMI susceptibility.
Compliance Information
RoHS and REACH compliance per Microchip product declaration; lead-free TQFP-44 package. Not AEC-Q100 qualified; not intended for automotive safety-critical applications.
