PIC16C74BT-20I/L - 8-Bit 20MHz OTP MCU 7KB | Microchip
MPN: PIC16C74BT-20I/L ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.59 | $4.59 |
| 10 | $4.3 | $43.00 |
| 100 | $3.95 | $395.00 |
| 500 | $3.6 | $1,800.00 |
| 1,000 | $3.25 | $3,250.00 |
PIC16C74BT-20I/L Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, volatile data memory, and programmable I/O peripherals. The PIC16CXX family uses Microchip's enhanced Harvard RISC architecture with separate program and data buses, allowing instruction fetch and operand read in a single cycle for most instructions. The mid-range PIC16C74B specifically targets embedded control applications that require moderate code density, multiple communication peripherals (UART, SPI, I2C), and on-chip analog peripherals such as 8-channel 8-bit A/D converters.
Key features include 35 single-word instructions to learn, 14-bit instruction word, 8-bit data path, programmable code protection, power-on reset, brown-out detection, watchdog timer with on-chip RC oscillator, and dual analog comparators. The 8-bit core executes instructions in 200 ns at 20 MHz, delivering approximately 5 MIPS of throughput. The CMOS design provides low power consumption with several sleep/idle modes.
Typical applications include industrial control systems, automotive body and chassis electronics, consumer appliance controllers, security and alarm systems, and measurement instrumentation where on-chip ADC, PWM, and communication peripherals reduce external component count. The 44-pin PLCC package also allows socketed prototyping via through-hole adaptors.
When designing with this OTP part, plan programming strategy early since OTP devices can be programmed only once and cannot be erased. Consider flash-based PIC16F74 equivalents for development and pilot runs.
Drop-in alternatives for PIC16C74BT-20I/L — 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 PIC16C74BT-20I/L (same form factor and footprint) — differing in Core Architecture, Operating Temperature Range, Program Memory Size, Timers, Watchdog Timer.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C74B-20I/L
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$8.92 / Unit
View Datasheet →PIC16C74BT-04I/L
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$4.33 / Unit
View Datasheet →PIC16F74-I/L
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C74B-20/L
✅ Drop-In ⚠️ 参数待验证✓ In Stock
$8.2 / Unit
View Datasheet →ATMEGA8515-16JI
✅ Drop-In✓ In Stock
$5.44 / Unit
View Datasheet →PIC16C74BT-20I/L Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX mid-range 8-bit RISC (Harvard) |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| RAM Size | 192 x 8 bytes |
| Maximum Clock Frequency | 20 MHz |
| Instruction Word Size | 14 bits |
| Number of I/O Pins | 33 |
| Supply Voltage Range | 4.0 V to 5.5 V |
| A/D Converter | 8-channel x 8-bit |
| PWM Modules | Yes (Capture/Compare/PWM) |
| Communication Peripherals | UART/USART, SPI, I2C (MSSP) |
| Brown-out Detect/Reset | Yes |
| Watchdog Timer | Yes (with on-chip RC oscillator) |
| Operating Temperature Range | -40 C to +85 C (Industrial grade "I") |
| Package Type | 44-pin PLCC (Plastic Leaded Chip Carrier, J-lead) |
PIC16C74BT-20I/L Pin Configuration
| Pin 1 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / A/D channel 0 input |
| Pin 3 | RA1/AN1 — PORTA bit 1 / A/D channel 1 input |
| Pin 4 | RA2/AN2 — PORTA bit 2 / A/D channel 2 input |
| Pin 5 | RA3/AN3/VREF — PORTA bit 3 / A/D channel 3 / A/D reference voltage |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / A/D channel 4 / SPI slave select |
| Pin 8 | RE0/RD/AN5 — PORTE bit 0 / read control for parallel slave port / A/D ch5 |
| Pin 9 | RE1/WR/AN6 — PORTE bit 1 / write control for parallel slave port / A/D ch6 |
| Pin 10 | RE2/CS/AN7 — PORTE bit 2 / chip select for PSP / A/D channel 7 |
| Pin 11 | VDD — Positive supply voltage (4.0 V to 5.5 V) |
| Pin 12 | VSS — Ground reference |
| Pin 13 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 14 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 15 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 I/O |
| Pin 16 | RC2/CCP1 — PORTC bit 2 / Capture/Compare/PWM 1 output |
| Pin 17 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 18 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 19 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 20 | RC6/TX/CK — PORTC bit 6 / UART transmit / UART clock |
| Pin 21 | RC7/RX/DT — PORTC bit 7 / UART receive / UART data |
| Pin 22 | RD0/PSP0 — PORTD bit 0 / Parallel Slave Port bit 0 |
| Pin 23 | RD1/PSP1 — PORTD bit 1 / Parallel Slave Port bit 1 |
| Pin 24 | RD2/PSP2 — PORTD bit 2 / Parallel Slave Port bit 2 |
| Pin 25 | RD3/PSP3 — PORTD bit 3 / Parallel Slave Port bit 3 |
| Pin 26 | RD4/PSP4 — PORTD bit 4 / Parallel Slave Port bit 4 |
| Pin 27 | RD5/PSP5 — PORTD bit 5 / Parallel Slave Port bit 5 |
| Pin 28 | RD6/PSP6 — PORTD bit 6 / Parallel Slave Port bit 6 |
| Pin 29 | RD7/PSP7 — PORTD bit 7 / Parallel Slave Port bit 7 |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VSS — Ground reference |
| Pin 32 | RB0/INT — PORTB bit 0 / external interrupt input |
| Pin 33 | RB1 — PORTB bit 1 |
| Pin 34 | RB2 — PORTB bit 2 |
| Pin 35 | RB3 — PORTB bit 3 |
| Pin 36 | RB4 — PORTB bit 4 |
| Pin 37 | RB5 — PORTB bit 5 |
| Pin 38 | RB6/PGC — PORTB bit 6 / ICSP clock |
| Pin 39 | RB7/PGD — PORTB bit 7 / ICSP data |
| Pin 40 | MCLR/VPP — Master clear reset / programming voltage input |
| Pin 41 | RA6 — PORTA bit 6 (oscillator pin on some variants) |
| Pin 42 | RA7 — PORTA bit 7 (oscillator pin on some variants) |
| Pin 43 | VDD — Positive supply voltage (4.0 V to 5.5 V) |
| Pin 44 | VSS — Ground reference |
Typical Applications
PIC16C74BT-20I/L is suitable for 6 applications: Industrial Process Control, Automotive Body Electronics, Consumer Appliance Controllers, Security and Alarm Systems, Measurement Instrumentation, HVAC Control Units.
Industrial Process Control
The PIC16C74BT-20I/L fits industrial process control applications where deterministic 8-bit performance and on-chip peripherals reduce BOM. Its 8-channel 8-bit A/D converter monitors multiple sensor inputs (temperature, pressure, flow) without external ADC, while the UART and SPI/I2C MSSP modules connect to HMI panels and remote sensors. The 20 MHz clock (5 MIPS) handles PID control loops at sub-millisecond intervals. Industrial-grade temperature range (-40 C to +85 C) tolerates factory-floor environments, and the brown-out reset plus watchdog timer protect against supply transients and firmware lockups.
Recommended
Automotive Body Electronics
The PIC16C74BT-20I/L is well suited to automotive body and chassis subsystems such as window lift controllers, seat controllers, mirror adjusters, and climate control panels. The 33 digital I/O pins directly drive relays, H-bridges, and LEDs without external logic, while the on-chip PWM module generates variable-duty control signals for motors and lighting. Operating from 4.0 V to 5.5 V matches 5 V automotive rails (post-regulation), and the industrial temperature range covers cabin environments. Brown-out detection protects against cranking transients typical of 12 V lead-acid automotive systems.
Recommended
Consumer Appliance Controllers
White goods and small appliances - washing machines, dishwashers, microwave ovens, coffee machines - use the PIC16C74BT-20I/L as the main control MCU because it integrates the key peripherals on-chip. The 8-bit ADC reads temperature, humidity, and weight sensors; the PWM drives motor speed controllers and heating elements; the UART interfaces with display modules and inverter boards. OTP memory locks the firmware at production cost levels below flash parts, while the 44-PLCC socket allows easy factory programming and end-of-line rework.
Recommended
Security and Alarm Systems
Alarm panels, motion detectors with embedded controllers, and access control systems leverage the PIC16C74BT-20I/L for low-power always-on operation. The watchdog timer and brown-out reset ensure field reliability; the A/D converter digitizes battery voltage and PIR sensor signals; the UART communicates with cellular or IP alarm transmitters. OTP memory prevents firmware reverse engineering, an important consideration for security products. Industrial temperature range supports outdoor enclosures and unheated garages in cold climates.
Recommended
Measurement Instrumentation
Digital multimeters, clamp meters, insulation testers, and bench-top instruments use the PIC16C74BT-20I/L as the main controller because of its on-chip A/D and accurate timing. The 8-channel ADC multiplexes multiple measurement ranges (voltage, current, resistance), while the PWM drives beepers and reference voltages. UART output streams measurement data to PCs or printers. The 20 MHz clock provides sufficient throughput for RMS calculation, autoranging, and display update without external DSP.
Recommended
HVAC Control Units
Heating, ventilation, and air conditioning controllers use the PIC16C74BT-20I/L to manage multi-zone temperature regulation, fan speed control, and communication with thermostats. The 8-bit ADC reads multiple thermistor inputs; PWM outputs drive TRIACs for AC load switching; the I2C/SPI bus interfaces with digital temperature sensors and EEPROM for setpoint storage. Industrial temperature range supports equipment rooms, attic installations, and rooftop units. Brown-out detection prevents undefined behavior during compressor inrush.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C74BT-20I/L — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C74B-20I/L | PIC16C74BT-04I/L | PIC16F74-I/L | PIC16C74B-20/L | ATmega8515-16JI |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 44-PLCC | 44-PLCC - same | 44-PLCC - same | 44-PLCC - same | 44-PLCC - same | 44-PLCC - same |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 7 KB Flash | 7 KB OTP | 8 KB Flash |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 512 bytes |
| Max Clock | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 20 MHz | 16 MHz |
| 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) | 0 C to +70 C (Commercial) | -40 C to +85 C (Industrial) |
| I/O Pins | 33 | 33 | 33 | 33 | 33 | 35 |
| A/D Converter | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | 8 ch x 8-bit | none on-chip |
| Memory Type | OTP | OTP | OTP | Flash (reprogrammable) | OTP | Flash (reprogrammable) |
Key Differentiators
- Industrial temperature grade with full 20 MHz clock performance (vs PIC16C74B-20/L)
- Reprogrammable flash alternative available with same footprint (vs PIC16F74-I/L)
- Higher clock speed than flash-based AVR alternative (vs ATmega8515-16JI)
Design Notes
The PIC16C74BT-20I/L is an OTP (One-Time-Programmable) device - once programmed, the program memory cannot be erased or rewritten. Plan your firmware versioning strategy carefully: build the final firmware image, validate it on a flash-based PIC16F74-I/L development board, then program the OTP device only once for production. Any code bug after programming requires a new MCU. Always use Microchip's ICSP (In-Circuit Serial Programming) header on your PCB to allow factory programming before final assembly.
Power supply design must hold VDD within 4.0 V to 5.5 V at all times, including transient dips from relay or motor switching on the same board. Use a bulk capacitor of at least 10 uF plus a 100 nF ceramic decoupling capacitor close to the VDD pins (pins 11 and 43 of the 44-PLCC package) to suppress switching transients. The on-chip brown-out reset (BOR) can be enabled via configuration bits to force a reset when VDD drops below a programmable threshold, preventing undefined execution at low voltage.
Place the 20 MHz crystal or resonator within 10 mm of the OSC1/OSC2 pins (pins 1 and 13) to minimize parasitic capacitance. Use short, symmetrical traces and a ground guard ring around the oscillator area to reduce EMI coupling into adjacent analog input pins. Add a 1 MOhm parallel resistor across the crystal if the oscillator gain is marginal at low supply voltage. Keep A/D analog traces (PORTA, PORTE) away from digital switching signals to preserve ADC accuracy.
The 44-PLCC package has J-leads that wrap under the package; allocate a PCB land pattern with 1.27 mm pitch and proper solder mask-defined pads to avoid solder bridges during reflow. For prototype work, use a 44-PLCC socket (e.g., Aries 44-6518-10 or equivalent) so the MCU can be easily removed for reprogramming on a device programmer. The socket adds ~3 mm of height - factor this into enclosure designs.
Compliance Information
RoHS/REACH compliance not confirmed in provided data; the original OTP PIC16C74B family pre-dates many lead-free mandates - verify with Microchip if lead-free is required. AEC-Q100 automotive qualification is not_applicable because the device is not listed in Microchip's automotive-grade catalog.
