PIC16C74B-20/PT - 8-Bit 20MHz OTP MCU 7KB | 44-TQFP | Microchip
MPN: PIC16C74B-20/PT ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.13 | $3.13 |
| 10 | $2.95 | $29.50 |
| 100 | $2.62 | $262.00 |
| 500 | $2.31 | $1,155.00 |
| 1,000 | $2.05 | $2,050.00 |
PIC16C74B-20/PT Overview
What is an 8-bit OTP microcontroller? An OTP (One-Time-Programmable) microcontroller is a class of embedded controller that uses non-erasable PROM (programmable read-only memory) for code storage, sitting within the broader hierarchy of microcontroller -> embedded controller -> semiconductor. OTP parts offer a lower-cost alternative to windowed UV-erasable parts in volume production, since the program is written once during manufacturing test and the die lacks the expensive quartz erasure window. PIC mid-range devices use a RISC instruction set (35 single-word instructions) so every instruction executes in one cycle (200 ns at 20 MHz), with program branches taking two cycles.
Key features include 33 I/O pins, hardware USART for serial communication, dual-mode master/slave SSP for SPI or I2C peripherals, and an integrated 8-channel 8-bit ADC that simplifies sensor-interface designs. The PIC16C7X family is code- and pin-compatible with the earlier PIC16C6X family, easing migration. The Watchdog Timer, power-on reset, brown-out reset, and code protection provide robust embedded reliability for industrial control, instrumentation, and consumer appliances.
Architecturally, the PIC16C74B uses a 14-bit instruction word and a Harvard bus architecture that separates program and data memory, allowing instruction fetch and operand read in the same cycle. The mid-range core implements a hardware multiplier-free ALU that performs arithmetic, logical, and bit-manipulation operations on the working register W, with file registers mapped into banked SRAM. The 8-bit ADC uses successive approximation with a sample-and-hold, capable of 20 µs conversion time.
Typical applications include industrial process control, motor drive front-ends (via CCP/PWM), HVAC control boards, instrumentation front-panels, sensor conditioning, security-system panels, and white-goods controllers. Designers select the PIC16C74B-20/PT when they need more I/O and ADC channels than the smaller 28-pin PIC16C73B.
When designing with this part, confirm the production-fit OTP variant is acceptable for your volume (OTP cannot be reprogrammed). For field-updatable firmware, migrate to the flash-based PIC16F74 or PIC18F equivalents, which are drop-in compatible at the pin level. Use MPLAB X IDE with MPASM or XC8 for code development, and the ICD-series in-circuit debuggers for early prototypes.
This page synthesizes verified distributor pricing, pin-compatible same-family alternatives, and practical design guidance specific to the 44-TQFP variant of the PIC16C74B-20/PT - information not found in a single manufacturer datasheet.
Drop-in alternatives for PIC16C74B-20/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-20/PT (same form factor and footprint) — differing in Package, Program Memory Size, Program Memory Type, Serial Interfaces, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74AT-20/PT
✅ Drop-In✓ In Stock
$5.55 / Unit
View Datasheet →PIC16C67-20/PT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$5.95 / Unit
View Datasheet →PIC16F74-I/PT
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C77-20/PT
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$7.5 / Unit
View Datasheet →PIC16C74B-20/PT Maximum Ratings & Electrical Characteristics
| Family | PIC16C7X (PIC® 16C, mid-range) |
| Core | 8-bit RISC, 35 single-word instructions |
| Clock Speed | 20 MHz maximum |
| Instruction Cycle | 200 ns (4 clock periods) |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 7 KB (4K x 14 bits) |
| Data RAM | 192 bytes |
| I/O Pins | 33 |
| ADC | 8 channels x 8-bit |
| Timers | Timer0 (8-bit), Timer1 (16-bit), Timer2 (8-bit) |
| CCP/PWM Modules | 2 (Capture/Compare/PWM) |
| Serial Interfaces | SSP (SPI master/slave or I2C) + USART/SCI |
| Supply Voltage | 4.0 V to 5.5 V |
| Package | 44-pin TQFP (10x10 mm), PT |
| Mounting Type | Surface Mount |
| Operating Temperature | 0C to +70C (commercial) |
PIC16C74B-20/PT Pin Configuration
| Pin 1 | RA0/AN0 — PORTA bit 0 / Analog input 0 |
| Pin 2 | RA1/AN1 — PORTA bit 1 / Analog input 1 |
| Pin 3 | RA2/AN2 — PORTA bit 2 / Analog input 2 |
| Pin 4 | RA3/AN3/VREF+ — PORTA bit 3 / Analog input 3 / VREF+ |
| Pin 5 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 6 | RA5/AN4/SS — PORTA bit 5 / Analog input 4 / SPI Slave Select |
| Pin 7 | AVDD — Analog supply voltage |
| Pin 8 | AVSS — Analog ground |
| Pin 9 | OSC1/CLKIN — Oscillator input / external clock |
| Pin 10 | OSC2/CLKOUT — Oscillator output / clock out |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator out / Timer1 clock |
| Pin 12 | RC1/T1OSI/CCP1 — PORTC bit 1 / Timer1 oscillator in / CCP1 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART TX / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART RX / USART data |
| Pin 19 | VSS — Ground |
| Pin 20 | VDD — Digital supply voltage |
| Pin 21 | RB0/INT — PORTB bit 0 / External interrupt |
| Pin 22 | RB1 — PORTB bit 1 |
| Pin 23 | RB2 — PORTB bit 2 |
| Pin 24 | RB3 — PORTB bit 3 |
| Pin 25 | RB4 — PORTB bit 4 |
| Pin 26 | RB5 — PORTB bit 5 |
| Pin 27 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 29 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 30 | RD1/PSP1 — PORTD bit 1 / PSP bit 1 |
| Pin 31 | RD2/PSP2 — PORTD bit 2 / PSP bit 2 |
| Pin 32 | RD3/PSP3 — PORTD bit 3 / PSP bit 3 |
| Pin 33 | RC4/PSP4 — PORTE bit 0 / PSP read / PSP bit 4 |
| Pin 34 | RE1/WR/PSP5 — PORTE bit 1 / PSP write / PSP bit 5 |
| Pin 35 | RE2/CS/PSP6 — PORTE bit 2 / PSP chip select / PSP bit 6 |
| Pin 36 | RD4/PSP7 — PORTD bit 4 / PSP bit 7 |
| Pin 37 | RD5/PSP6 — PORTD bit 5 / PSP bit 6 |
| Pin 38 | RD6/PSP7 — PORTD bit 6 / PSP bit 7 |
| Pin 39 | RD7/PSP7 — PORTD bit 7 / PSP bit 7 |
| Pin 40 | VSS — Ground |
| Pin 41 | VDD — Digital supply voltage |
| Pin 42 | RB0 — [DATA_NEEDED: secondary function assignment] |
| Pin 43 | OSC1 — [DATA_NEEDED: secondary function] |
| Pin 44 | MCLR/VPP — Master clear / ICSP programming voltage |
Typical Applications
PIC16C74B-20/PT is suitable for 6 applications: Industrial Process Control, HVAC Control Board, Motor Drive Front-End, Instrumentation Front-Panel, Security System Panel, White-Goods / Appliance Controller.
Industrial Process Control
The PIC16C74B-20/PT's 8-channel 8-bit ADC and 33 digital I/O make it well-suited for PLC-style industrial process control boards monitoring temperature, pressure, and flow sensors. The 20 MHz RISC core with 200 ns instruction cycle provides deterministic loop times for PID control, while the 4.0-5.5 V supply range tolerates 5 V industrial backplanes. The USART enables Modbus RTU or proprietary RS-485 communication with a transceiver, and the CCP/PWM modules drive valve actuators and SSR control outputs. The integrated brown-out reset protects against brown-out corruption in plant 24 V/5 V rails.
Recommended
HVAC Control Board
The PIC16C74B-20/PT integrates the I/O count and ADC channels needed for HVAC controller boards driving relays, triacs, and variable-speed fans. The 8-channel ADC digitizes thermistor temperature sensors (NTC/PTC), while two CCP/PWM modules generate phase-cut dimming or motor speed-control signals. The MSSP in I2C mode talks to EEPROM or RTC companions, while the USART links to a wall thermostat or building management system. The commercial 0C to +70C temperature range suits indoor equipment enclosures.
Recommended
Motor Drive Front-End
For BLDC or stepper motor front-ends, the PIC16C74B-20/PT uses its dual CCP/PWM modules to generate complementary PWM signals at up to 20 MHz timer resolution, while the 8-bit ADC samples back-EMF or current-sense shunt signals. The 33 I/O drive Hall-sensor inputs, fault flags, and gate-driver enable lines without external muxing. OTP program memory is acceptable for fixed-commutation trapezoidal drives in high-volume appliance motors (washing machines, fans, pumps) where firmware is factory-locked.
Recommended
Instrumentation Front-Panel
Laboratory instruments and test-equipment front-panels benefit from the PIC16C74B-20/PT's SPI master port driving LCD or dot-matrix displays, plus the USART streaming measurement data to a host PC. The 192-byte RAM is sufficient for menu state machines and peak/average calculation buffers, while the 8-bit ADC reads front-panel knob positions or analog trim pots. The 5 V supply simplifies integration with legacy op-amp signal chains in benchtop multimeters, oscilloscopes, and calibrators.
Recommended
Security System Panel
Alarm panels for intrusion detection use the PIC16C74B-20/PT to scan 8+ zone inputs through the on-chip ADC or digital I/O, while the USART links to a central monitoring station via dialer or GSM module. OTP program memory prevents firmware tampering - a security advantage over flash parts that can be reprogrammed via debug ports. The PIC16C74B-20/PT 20 MHz core handles keypad scanning and encryption-light protocol framing for low-cost residential and small-commercial panels.
Recommended
White-Goods / Appliance Controller
Washing machines, dishwashers, ovens, and refrigerators use PIC16C74B-20/PT controllers for their 33 I/O driving user-interface keypads, segment LCDs, buzzer drivers, and triac-fired heater/valve outputs. The 8-channel ADC reads temperature, water level, and motor current, while the CCP/PWM modules generate proportional control signals. OTP memory locks the appliance firmware against field tampering, and the 44-TQFP PT package is a cost-optimized SMD form factor for high-volume white-goods manufacturing.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74B-20/PT — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74AT-20/PT | PIC16C67-20/PT | PIC16F74-I/PT | PIC16C77-20/PT |
|---|---|---|---|---|---|
| Package | 44-TQFP (PT) | 44-TQFP (PT) - same | 44-TQFP (PT) - same | 44-TQFP (PT) - same | 44-TQFP (PT) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | Flash (7 KB) - advantage | OTP (14 KB) - larger |
| Clock Speed | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| I/O Pins | 33 | 33 | 33 | 33 | 33 |
| ADC Channels | 8 ch x 8-bit | 8 ch x 8-bit | 0 ch (no ADC) | 8 ch x 8-bit | 8 ch x 8-bit |
| CCP/PWM | 2 modules | 2 modules | 2 modules | 2 modules | 2 modules |
| Serial Interfaces | SPI/I2C + USART | SPI/I2C + USART | SPI/I2C + USART | SPI/I2C + USART | SPI/I2C + USART |
| Lifecycle / Best Use | Active OTP (legacy cost-down) | Legacy 'A' silicon - not recommended for new designs | Active - choose when no ADC needed | Active flash - recommended replacement | Active - larger memory upgrade |
Key Differentiators
- Larger ADC channel count within PIC16C7X 44-pin family (vs PIC16C67-20/PT)
- Drop-in flash reprogrammability for field-updatable designs (vs PIC16F74-I/PT)
- Double program memory upward migration path (vs PIC16C77-20/PT)
Design Notes
Estimated: at VDD=5.0 V, 20 MHz clock, all peripherals active, the PIC16C74B-20/PT draws approximately 15-20 mA ICC; OTP read during execution is the largest contributor. Add a 100 nF ceramic decoupling cap as close as physically possible to VDD/VSS pins 20 and 19, plus a bulk 10 uF tantalum or aluminum on the 5 V rail. The internal brown-out reset (BOR) should be enabled in configuration bits to protect RAM contents during supply droops in 24 V/5 V industrial backplanes.
The 44-pin TQFP (PT) has a 0.8 mm pitch - place 4 vias under the exposed die-pad region for thermal relief and ground stitching. Keep the analog AVSS/AVDD pair shorted to the digital ground at a single point (star ground) to prevent ADC digital switching noise from coupling into analog readings. Place the 20 MHz crystal (or resonator) within 5 mm of OSC1/OSC2 (pins 9-10) with a grounded guard ring around the oscillator traces to suppress radiated EMI from the 20 MHz fundamental.
OTP (One-Time-Programmable) memory cannot be erased after programming - the 'C' in PIC16C74B signals erasable windowed UVPROM is NOT present on the PT package. Production programmers must verify code at runtime with a checksum or signature verification before locking the device via CONFIG bits. Also: the MCLR pin (44) is a programming-voltage input during ICSP; leave a 10 kohm pull-up to VDD and route the ICSP connector so production programming can occur after PCB assembly. Failure to disable ICD/ICSP via CONFIG will leave the test pins RB6/RB7 unavailable for GPIO.
Estimated: at full I/O toggle on all 33 pins driving 20 mA each (above spec), the PIC16C74B-20/PT in 44-TQFP could dissipate ~1.5 W; under typical 5-10 mA per-pin sourcing the dissipation is far lower (under 0.5 W). The 44-TQFP (PT) has theta_JA approximately 50 C/W on a 4-layer JEDEC test board - well within commercial 0-70C operation without a heatsink. In a sealed enclosure above 50 C ambient, derate the per-pin source current to 10 mA or migrate to the PIC18F equivalent with a wider temperature range.
Compliance Information
RoHS/REACH/lead-free compliance status for the PIC16C74B-20/PT commercial-grade 44-TQFP PT package is not confirmed in the verified web data and is marked [DATA_NEEDED]. The legacy PIC16C OTP 'B' family carries mixed compliance by date code; verify against Microchip's Certificate of Conformance for the specific date/lot code in production. AEC-Q100 is not applicable - this is a commercial-grade (0C to +70C) part; for automotive-grade pin-compatible alternatives consider PIC16F74T-I/PT (industrial) or PIC18F equivalents.
