PIC16C73B-04/SO - 4MHz 8-Bit OTP MCU, 7KB, 28-SOIC | Microchip
MPN: PIC16C73B-04/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.1 | $7.10 |
| 10 | $6.4 | $64.00 |
| 100 | $5.72 | $572.00 |
| 500 | $5.18 | $2,590.00 |
| 1,000 | $4.65 | $4,650.00 |
PIC16C73B-04/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU, memory (ROM/Flash/OTP for program storage and RAM for data), and programmable I/O peripherals. Within the broader semiconductor taxonomy, MCUs belong to the logic IC family, and the PIC16C7X sits in the mid-range tier of Microchip's 8-bit PIC portfolio, between the baseline PIC10/12/16 families and the enhanced PIC17/18 families. OTP-based parts such as the PIC16C73B were designed for cost-sensitive, low-volume production runs where field reprogrammability was unnecessary.
Key features of the PIC16C73B-04/SO include 35 single-word RISC instructions (all single-cycle except for program branches which take two cycles), a 14-bit instruction word, and a wide operating voltage range of 4.0 V to 5.5 V. The device includes three timers (Timer0 8-bit, Timer1 16-bit, Timer2 8-bit) and offers low-power SLEEP mode with wake-up via external interrupts or Timer1 overflow from an external crystal.
Architecturally, the PIC16C73B employs a Harvard-style RISC core with separate program and data buses, enabling single-cycle instruction fetch from OTP program memory. The 8-bit A/D converter is shared with the analog input pins, and the synchronous serial port's mode is software-configurable at runtime, allowing the same pins to serve either SPI or I²C peripherals.
Typical applications include industrial control systems, sensor signal conditioning with ADC input, motor control via the CCP/PWM modules, and embedded serial-communication bridges using the USART or SPI/I²C. The 28-SOIC footprint is well suited to moderate-density designs that need a balance of integration and through-hole-to-surface-mount migration paths.
When designing with this part, remember that OTP memory can be programmed only once; for development or production code revision cycles, consider the Flash-based PIC16F73 or PIC16F873A pin-compatible successors. Decoupling requires a 0.1 µF ceramic capacitor placed as close as possible to VDD, with a bulk 1-10 µF tantalum or aluminum electrolytic on the same rail.
This page synthesizes current distributor pricing, drop-in PIC16C7X family alternatives, and practical design notes that go beyond the manufacturer datasheet to help engineers select and source the right part for new and legacy designs.
Drop-in alternatives for PIC16C73B-04/SO — 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-04/SO (same form factor and footprint) — differing in Package, Serial Interfaces, Timers, Mounting Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C73B-04I/SO
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16C73B-20/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73B-20I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F73-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F873A-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73A-10I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73B-04/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 8-bit RISC (mid-range family) |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| RAM | 192 bytes |
| Maximum CPU Clock | 4 MHz |
| Instruction Cycle | 200 ns |
| Supply Voltage (VDD) | 4.0 V to 5.5 V |
| I/O Pins | 22 |
| A/D Converter | 8-bit, 5 channels |
| Timers | Timer0 (8-bit), Timer1 (16-bit), Timer2 (8-bit) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Serial Interfaces | SSP (SPI/I²C), USART |
| Instruction Set | 35 single-word instructions |
| Operating Temperature | 0°C to +70°C (commercial SO) |
| Package | 28-pin SOIC (SO, 7.50 mm body) |
| Mounting Type | Surface Mount |
| Speed Grade Suffix | -04 = 4 MHz maximum clock |
| RoHS Status | compliant |
PIC16C73B-04/SO Pin Configuration
| Pin 1 | MCLR/VPP — Master clear reset input / programming voltage input |
| Pin 2 | RA0/AN0 — Port A bit 0 / analog input channel 0 |
| Pin 3 | RA1/AN1 — Port A bit 1 / analog input channel 1 |
| Pin 4 | RA2/AN2 — Port A bit 2 / analog input channel 2 |
| Pin 5 | RA3/AN3/VREF — Port A bit 3 / analog input channel 3 / ADC reference |
| Pin 6 | RA4/T0CKI — Port A bit 4 / Timer0 clock input |
| Pin 7 | RA5/AN4/SS — Port A bit 5 / analog input channel 4 / SPI slave select |
| Pin 8 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 9 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI — Port C bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer1 oscillator input / CCP2 output |
| Pin 12 | RC2/CCP1 — Port C bit 2 / CCP1 I/O |
| Pin 13 | RC3/SCK/SCL — Port C bit 3 / SPI clock / I²C clock |
| Pin 14 | RC4/SDI/SDA — Port C bit 4 / SPI data in / I²C data |
| Pin 15 | RC5/SDO — Port C bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — Port C bit 6 / USART transmit / USART clock |
| Pin 17 | RC7/RX/DT — Port C bit 7 / USART receive / USART data |
| Pin 18 | VSS — Ground reference |
| Pin 19 | VDD — Positive supply voltage |
| Pin 20 | RB0/INT — Port B bit 0 / external interrupt |
| Pin 21 | RB1 — Port B bit 1 |
| Pin 22 | RB2 — Port B bit 2 |
| Pin 23 | RB3/PGM — Port B bit 3 / low-voltage programming input |
| Pin 24 | RB4 — Port B bit 4 |
| Pin 25 | RB5 — Port B bit 5 |
| Pin 26 | RB6/PGC — Port B bit 6 / ICSP clock |
| Pin 27 | RB7/PGD — Port B bit 7 / ICSP data |
| Pin 28 | VSS — Ground reference (second VSS pin) |
Typical Applications
PIC16C73B-04/SO is suitable for 6 applications: Industrial Control and Sensor Interfacing, Motor Control with PWM and CCP, Embedded Serial Communication Bridges, Consumer Appliance and White-Goods Control, Automotive Body and Convenience Electronics, Hobby and Educational Embedded Projects.
Industrial Control and Sensor Interfacing
The PIC16C73B-04/SO fits industrial control and sensor interfacing applications because its 5-channel 8-bit ADC (10-bit equivalent on the PIC16F873A) digitizes analog inputs from temperature, pressure, and flow sensors, while 22 I/O lines drive relays, contactors, and indicator LEDs. The 200 ns instruction cycle is fast enough for sampled-data control loops with 1 kHz update rates, and the USART connects to RS-485 transceivers for multi-drop industrial networks. The 4.0-5.5 V supply aligns with the 5 V rails used in PLC backplanes and motor-driver interfaces. Watch for the commercial 0-70 °C limit - the -I suffix variant is mandatory for outdoor cabinets.
Recommended
Motor Control with PWM and CCP
The PIC16C73B-04/SO is well suited to small DC motor and stepper motor control thanks to its two Capture/Compare/PWM (CCP) modules that generate precise PWM drive signals up to the 4 MHz clock / 4 prescaler limit, equivalent to ~1 kHz PWM at 10-bit resolution. Timer2 provides a configurable PWM time base, and the analog inputs sample motor current or back-EMF for closed-loop control. The 28-SOIC footprint leaves room for gate-driver discretes on a small PCB. Consider the PIC16F873A for higher-frequency BLDC commutation loops needing 20 MIPS throughput.
Recommended
Embedded Serial Communication Bridges
The PIC16C73B-04/SO serves as a low-cost protocol-bridging MCU because its Synchronous Serial Port (SSP) supports both 3-wire SPI for sensors, EEPROMs, and shift-register I/O expansion, and 2-wire I²C for inter-IC communication with up to 127 nodes on the bus. The independent USART handles asynchronous links to RS-232 or LIN-bus masters. With 7 KB of OTP program memory, the part can hold complete bridging firmware, application state machines, and small protocol stacks. The 28-SOIC form factor is friendly to mixed-signal PCBs that combine analog front-ends with serial peripherals.
Recommended
Consumer Appliance and White-Goods Control
The PIC16C73B-04/SO targets consumer appliance control (washing machines, dishwashers, microwave ovens, coffee machines) where the 5-channel 8-bit ADC monitors water level, temperature, and door-switch state, the USART drives LED/LCD display modules, and the 22 I/O lines actuate relays, triacs, and buzzer drivers. The 4.0-5.5 V VDD matches rectified-12 V step-down 5 V rails. The OTP memory prevents post-production firmware tampering, an important consideration for safety-certified appliances. For products sold in extreme climates, the -I industrial variant is the right choice.
Recommended
Automotive Body and Convenience Electronics
The PIC16C73B-04/SO is suitable for non-safety automotive body electronics such as seat controllers, mirror adjusters, sunroof modules, and interior lighting drivers. The 8-bit ADC reads potentiometer wiper voltages and thermistor networks, the PWM modules dim LED strings, and the USART links to body-control modules via LIN bus with an external transceiver. Note that this part is commercial 0-70 °C only, so the -I industrial variant is mandatory for under-hood or cabin deployments where temperatures can exceed 70 °C. The 28-SOIC is friendly to conformal-coated automotive PCBs.
Recommended
Hobby and Educational Embedded Projects
The PIC16C73B-04/SO is a popular choice in hobbyist and university course work because it exposes a manageable 8-bit RISC architecture (35 instructions) with on-chip ADC, PWM, and both SPI/I²C + USART peripherals, all from a 5 V supply that is forgiving of breadboard wiring mistakes. The 28-SOIC breakout boards and PIC-ICD programmers support quick firmware iteration; for new designs the PIC16F73 or PIC16F873A Flash variants are recommended because the OTP can only be programmed once. Use a 4 MHz ceramic resonator or crystal as the clock source for stable timing.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C73B-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C73B-04I/SO | PIC16C73B-20/SO | PIC16F73-I/SO | PIC16F873A-I/SO | PIC16C73A-10I/SO |
|---|---|---|---|---|---|---|
| Package | 28-SOIC | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Max CPU Clock | 4 MHz | 4 MHz | 20 MHz | 20 MHz | 20 MHz | 10 MHz |
| Program Memory | 7 KB OTP | 7 KB OTP | 7 KB OTP | 4 KB Flash | 7 KB Flash | 7 KB OTP |
| ADC Resolution | 8-bit, 5 ch | 8-bit, 5 ch | 8-bit, 5 ch | 8-bit, 5 ch | 10-bit, 5 ch | 8-bit, 5 ch |
| Operating Temperature | 0°C to +70°C | -40°C to +85°C | 0°C to +70°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C |
| Reprogrammable | No (OTP) | No (OTP) | No (OTP) | Yes (Flash) | Yes (Flash) | No (OTP) |
| CCP/PWM Modules | 2 | 2 | 2 | 2 | 2 | 2 |
| RAM | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes | 192 bytes |
Key Differentiators
- Lower-cost OTP memory for high-volume mature designs (vs PIC16F73-I/SO)
- Wider temperature range variant available in same package (vs PIC16C73B-04/SO (commercial) vs PIC16C73B-04I/SO (industrial))
- Flash-based migration path is pin-compatible (vs PIC16F873A-I/SO)
Design Notes
Place a 0.1 µF ceramic decoupling capacitor as close as possible to the VDD pin (pin 11) and a bulk 1-10 µF tantalum or aluminum electrolytic on the same 5 V rail. For designs using the 28-SOIC, route the second VSS pin (pin 28) to the ground plane directly to reduce ground bounce on ADC channels. The PIC16C73B-04/SO draws typically 2-5 mA active at 4 MHz and <1 µA in SLEEP, so power supply sizing is dominated by peripheral current rather than the MCU itself. Estimated: at 4 MHz and 5 V, the core current is approximately 2 mA per the datasheet typical characteristics.
OTP memory can be programmed only once. Engineers iterating on firmware should NOT use the PIC16C73B-04/SO during development; instead, build the prototype on the Flash-based PIC16F73-I/SO or PIC16F873A-I/SO in the same 28-SOIC footprint, then port the final firmware to the OTP part for production. Another common pitfall is using the standard -04/SO (0-70 °C) in an environment that exceeds 70 °C, such as inside an unenclosed industrial cabinet in summer - the -04I/SO industrial variant is mandatory for that scenario.
Keep the analog inputs (RA0-RA5) traces short and away from digital switching nodes such as the USART TX line or PWM outputs to minimize ADC crosstalk. The A/D conversion accuracy of 8 bits is approximately ±2 LSB at 5 V, equivalent to ±40 mV - sufficient for sensor applications but not for precision instrumentation. For designs needing better than 8-bit ADC accuracy, the PIC16F873A-I/SO with 10-bit ADC is a drop-in alternative in the same 28-SOIC footprint.
Route the MCLR/VPP pin (pin 1) directly to a pull-up resistor to VDD; if a manual reset button is used, add a 100 nF capacitor from MCLR to ground to filter switch bounce. For ICSP (in-circuit serial programming), expose pins RB6/PGC (pin 26) and RB7/PGD (pin 27) on a header to allow field firmware updates during development or service. The oscillator traces for OSC1/OSC2 (pins 13-14) should be short and surrounded by a ground guard ring to reduce EMI susceptibility.
Compliance Information
RoHS compliant per Microchip product page. The OTP 28-SOIC variant is not AEC-Q100 qualified; for automotive applications select the PIC16F73T-I/SO industrial Flash variant and validate under AEC-Q100 customer requirements.
