PIC16C73B-04E/SP - 8-bit 4MHz OTP MCU 7KB Flash | Microchip
MPN: PIC16C73B-04E/SP ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.89 | $6.89 |
| 10 | $6.2 | $62.00 |
| 100 | $5.55 | $555.00 |
| 500 | $4.95 | $2,475.00 |
| 1,000 | $4.4 | $4,400.00 |
PIC16C73B-04E/SP Overview
An 8-bit microcontroller (MCU) is a single-chip computer with an 8-bit data path, integrating a CPU core, non-volatile program memory, volatile data memory, and programmable peripherals. Within the broader taxonomy it is a microcontroller -> embedded processor -> integrated circuit -> semiconductor. The PIC mid-range architecture falls between PIC10/12/16 baseline 8-pin devices and PIC18 high-performance 16-bit-path cores, optimized for deterministic real-time control with a small instruction set (35 single-word instructions).
Key differentiating features of the PIC16C73B-04E/SP include: 4 MHz maximum operating frequency, 7 KB OTP program memory (one-time programmable; cannot be erased), 192-byte data RAM, 5 channels of 8-bit ADC, and a flexible synchronous serial port that supports both SPI master/slave and I²C master/slave modes in hardware. Wide operating voltage 2.5 V to 6.0 V (per the family datasheet) and high sink/source current of 25/25 mA per I/O pin allow direct drive of LEDs, relays, and small power transistors without buffering.
Architecturally, the device uses a Harvard architecture with separate program and data buses, allowing instruction fetch and operand read in a single cycle for most instructions (only program branches require two cycles). The CMOS process delivers typical standby current of 1 µA at 3 V / 32 kHz and active current of ~15 µA at 5 V / 4 MHz, and the device supports external clock, RC, LP, XT, and HS oscillator modes selectable via configuration fuses.
Typical applications for the PIC16C73B-04E/SP include industrial control systems, sensor signal conditioning with built-in ADC, low-cost motor control, HVAC thermostats, appliance controls, automotive body electronics (Extended temp range), and battery-powered instrumentation. Combined with the USART, the device is well-suited for legacy RS-232 / RS-485 networked sensors and Modbus slave nodes.
When designing with this MCU, note that the OTP memory cannot be erased - prototypes should be implemented on UV-erasable CERDIP (JW) or flash-based PIC16F73 equivalents. Decoupling the VDD/VSS pins with 100 nF ceramic caps placed within 5 mm of the package, leaving MCLR reset pulled high through 10 kΩ, and respecting the 6.0 V absolute-maximum VDD are all critical design habits.
This page consolidates distributor stock, drop-in cross-brand alternatives, and engineering design notes not found in any single manufacturer source.
Drop-in alternatives for PIC16C73B-04E/SP — 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 PIC16C73B-04E/SP (same form factor and footprint) — differing in Mounting Type, Operating Temperature Range, Package, Program Memory Size, RoHS Status.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F73-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F873A-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73B-04/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73B-20/SP
✅ Drop-In✓ In Stock
$4.95 / Unit
View Datasheet →PIC16C73B-04I/SP
✅ Drop-In✓ In Stock
$4.75 / Unit
View Datasheet →PIC16C73B-04E/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16CXX mid-range 8-bit RISC |
| Instruction Set Width | 14-bit |
| Number of Instructions | 35 single-word instructions |
| Instruction Cycle Time | 200 ns at 4 MHz |
| Maximum Clock Frequency | 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| Data RAM | 192 bytes |
| Data EEPROM | Not present on this family |
| Digital I/O Pins | 22 |
| ADC Channels | 5 x 8-bit |
| Timers | 2 x 8-bit (Timer0, Timer2) + 1 x 16-bit (Timer1) |
| Capture/Compare/PWM | 2 CCP modules |
| Serial Interfaces | 1 SSP (SPI / I²C) + 1 USART (SCI) |
| Supply Voltage (VDD) | 2.5 V to 6.0 V (family typical); verified operating at 4.0 V to 5.5 V on this part |
| I/O Sink/Source Current | 25 mA / 25 mA per pin |
| Operating Temperature Range | -40 °C to +125 °C (Extended, 'E' suffix) |
| Standby Current (typ.) | 1 µA at 3 V / 32 kHz |
| Active Current (typ.) | 15 µA at 5 V / 4 MHz |
| Package | 28-pin SPDIP (Skinny Plastic DIP), 0.300" / 7.62 mm row spacing |
| Mounting Type | Through-Hole (THT) |
| RoHS Status | Compliant (Pb-free SPDIP package per DigiKey listing) |
PIC16C73B-04E/SP Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (reset) input / programming voltage input |
| Pin 2 | RA0/AN0 — PORTA bit 0 / analog input channel 0 |
| Pin 3 | RA1/AN1 — PORTA bit 1 / analog input channel 1 |
| Pin 4 | RA2/AN2 — PORTA bit 2 / analog input channel 2 |
| Pin 5 | RA3/AN3/VREF+ — PORTA bit 3 / analog input channel 3 / ADC VREF+ |
| Pin 6 | RA4/T0CKI — PORTA bit 4 / Timer0 clock input (open-drain) |
| Pin 7 | RA5/AN4/SS — PORTA bit 5 / analog input channel 4 / SPI slave select |
| Pin 8 | VSS — Ground reference |
| Pin 9 | OSC1/CLKIN — Oscillator crystal input / external clock input |
| Pin 10 | OSC2/CLKOUT — Oscillator crystal output / clock output (Fosc/4) |
| Pin 11 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 (PWM output) |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SSP SPI clock / I²C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SSP SPI data in / I²C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SSP 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 reference |
| Pin 20 | VDD — Positive 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 |
Typical Applications
PIC16C73B-04E/SP is suitable for 6 applications: Industrial Sensor Conditioning & Monitoring, HVAC Thermostat & Climate Controller, Appliance Control (Washing Machine, Dishwasher), Battery-Powered Instrumentation & Data Loggers, RS-485 Sensor Network / Modbus Slave, Legacy Embedded Replacement / Industrial Retrofit.
Industrial Sensor Conditioning & Monitoring
The PIC16C73B-04E/SP's 5-channel 8-bit ADC and 22 digital I/O pins make it well suited to multi-sensor industrial monitoring nodes that read temperature, pressure, or level transducers and actuate relays or buzzers. With 192 bytes of RAM and 4 MHz RISC throughput, the MCU can sample three sensors at ~100 Hz, run linearization and threshold detection, and drive a 4-digit LED display via RB0-RB7. The Extended -40 °C to +125 °C temperature range supports factory-floor environments without additional thermal qualification.
Recommended
HVAC Thermostat & Climate Controller
Wall-mounted HVAC thermostats need a deterministic 8-bit MCU to read NTC thermistor voltages via the ADC, drive a triac-controlled HVAC compressor, and run a user interface on the RB port. The PIC16C73B-04E/SP's two CCP modules provide hardware PWM for proportional control valve actuation, while the USART supports Modbus RTU to a building management system. The 25 mA per-pin sink/source eliminates external LED driver transistors, simplifying the BOM in cost-sensitive residential controls.
Recommended
Appliance Control (Washing Machine, Dishwasher)
Major home appliances integrate the PIC16C73B-04E/SP as the main cycle controller: water level sensor, door interlock, motor triac drive, and user key/LED matrix. The synchronous serial peripheral can be configured as I²C master to read a child display board, and the 4 MHz OPPI speed of 200 ns per instruction is sufficient for the 50 ms timing loop used in IEC 60730 Class B safety software. Wide VDD (2.5 V to 6.0 V) supports direct connection to rectified-mains-derived rails after bulk filtering.
Recommended
Battery-Powered Instrumentation & Data Loggers
Low-power instrumentation benefits from the PIC16C73B-04E/SP's 1 µA typical standby current at 3 V / 32 kHz (LP oscillator mode), which lets a 2-AA battery-powered temperature/humidity logger run for years. The 5-channel ADC sequentially scans analog sensors while the USART streams logs to a host PC on demand. Using the Watchdog Timer (WDT) and Sleep mode, the device wakes every 60 seconds to take a measurement, then returns to sub-µA standby, maximizing field deployment intervals.
Recommended
RS-485 Sensor Network / Modbus Slave
The PIC16C73B-04E/SP's USART (SCI) connects directly to a MAX485 or LTC485 RS-485 transceiver to form a Modbus RTU slave node reading multiple 4-20 mA loop-powered sensors via the 8-bit ADC. The 4 MHz instruction throughput runs the Modbus CRC-16 and exception handler at less than 50 % CPU load at 9600 baud, leaving headroom for sensor linearization math. The 22 I/O can drive status LEDs, an address-select DIP switch, and a half-duplex direction control pin for the RS-485 transceiver.
Recommended
Legacy Embedded Replacement / Industrial Retrofit
The PIC16C73B-04E/SP remains in active production for legacy industrial equipment that was designed around the PIC16C family in the 1990s and where re-qualification of firmware on a newer PIC18/PIC24 core is cost-prohibitive. Because the 28-SPDIP package and pinout match the PIC16F73 and PIC16F873A, factories can perform an MCU swap to fix bit-rotten flash devices without PCB rework, restoring long-life production equipment. The OTP memory is also considered more secure (no firmware read-back) than flash for proprietary algorithms.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C73B-04E/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F73-I/SP | PIC16F873A-I/SP | PIC16C73B-04/SP | PIC16C73B-20/SP | PIC16C73B-04I/SP |
|---|---|---|---|---|---|---|
| Package | 28-pin SPDIP | 28-pin SPDIP - same | 28-pin SPDIP - same | 28-pin SPDIP - same | 28-pin SPDIP - same | 28-pin SPDIP - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP (7 KB) | Flash (7 KB) | Flash (7 KB) | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) |
| Program Memory Size | 7 KB (4K x 14) | 7 KB (4K x 14) | 7 KB (4K x 14) | 7 KB (4K x 14) | 7 KB (4K x 14) | 7 KB (4K x 14) |
| Maximum Clock Frequency | 4 MHz | 20 MHz | 20 MHz | 4 MHz | 20 MHz | 4 MHz |
| ADC Resolution | 8-bit (5 channels) | 8-bit (5 channels) | 10-bit (5 channels) | 8-bit (5 channels) | 8-bit (5 channels) | 8-bit (5 channels) |
| Operating Temperature Range | -40 °C to +125 °C (Extended) | -40 °C to +85 °C (Industrial) | -40 °C to +85 °C (Industrial) | 0 °C to +70 °C (Commercial) | -40 °C to +125 °C (Extended) | -40 °C to +85 °C (Industrial) |
| Re-programmability | No (OTP) | Yes (Flash, 100k cycles) | Yes (Flash, 100k cycles) | No (OTP) | No (OTP) | No (OTP) |
Key Differentiators
- Extended temperature range -40 °C to +125 °C versus Industrial -40 °C to +85 °C (vs PIC16F73-I/SP)
- OTP memory for IP protection vs flash for re-programmability (vs PIC16F873A-I/SP)
- Higher clock speed variant available with same die (vs PIC16C73B-20/SP)
Design Notes
Decouple VDD/VSS with a 100 nF ceramic capacitor placed within 5 mm of pins 20 and 19. Add a 10 µF bulk electrolytic near the regulator output if VDD is sourced from a switching converter to suppress switching ripple. The PIC16C73B-04E/SP's VDD absolute maximum is 6.0 V per the family datasheet; transients above 6.5 V can permanently damage the device. Always use a 5.0 V LDO (e.g., MCP1700) for line-powered designs rather than resistive drops to ensure headroom.
The PIC16C73B-04E/SP uses OTP (one-time programmable) program memory that cannot be erased. After OTP programming the device will not respond to subsequent ICSP attempts - a faulty firmware image bricks the part permanently. Prototype and validate on a UV-erasable CERDIP (PIC16C73B-04E/JW) or flash-based PIC16F73-I/SP, then move to the OTP SPDIP only when code is verified. MCLR must be pulled to VDD through 10 kΩ; leaving it floating causes spurious resets.
Keep the 4 MHz crystal or ceramic resonator within 5 mm of pins 9-10 (OSC1/OSC2) and ground the oscillator case to the VSS plane to reduce EMI. Place analog reference decoupling (100 nF) on pin 5 (RA3/VREF+) if used as ADC reference. Route the USART lines (RC6/RC7) as a matched pair with ground guard traces; long parallel runs pick up switching noise from RB port LEDs.
Estimated: At 4 MHz clock, 5 V VDD, and all I/O idle, the PIC16C73B-04E/SP draws approximately 2.5 mA active. With all 22 I/O pins sourcing 25 mA simultaneously (not a realistic steady-state case), worst-case package dissipation is 28-pin SPDIP × ~95 °C/W θJA = roughly 11 W thermal limit. Practical designs drive no more than 4-6 LEDs simultaneously and use software PWM to limit average current; per-pin 25 mA is an absolute maximum, not a continuous rating.
The SSP peripheral pins (RC3/RC4/RC5) are not 5 V tolerant on this 5 V part, but when the I²C bus is pulled above VDD by external pull-ups during power sequencing, the RC4/SDA pin can latch up. Add a Schottky diode (e.g., BAT54) from SDA to VDD or use the I²C bus in slave-only configuration with software-controlled slew-rate limiting to avoid bus contention during MCU reset.
Compliance Information
RoHS-compliant Pb-free 28-SPDIP package per DigiKey listing. Not AEC-Q100 qualified; for safety-critical automotive ECUs, choose AEC-Q100-qualified PIC16F73 automotive grade or migrate to PIC18/dsPIC AEC-Q100 devices. Conflict-minerals statement available from Microchip under their standard CMRT filing.
