PIC16C73A-04I/SP - 8-Bit 4MHz OTP MCU 7KB | Microchip
MPN: PIC16C73A-04I/SP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.5 | $7.50 |
| 10 | $6.8 | $68.00 |
| 100 | $5.95 | $595.00 |
| 500 | $5.2 | $2,600.00 |
| 1,000 | $4.55 | $4,550.00 |
PIC16C73A-04I/SP Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory (program + data), and programmable I/O peripherals. The PIC16C73A belongs to the PIC16CXX mid-range family, which uses a Harvard architecture with separate program and data buses, an accumulator-based ALU, and a compact 35-instruction instruction set where most instructions execute in a single 200 ns cycle at 4 MHz. This category sits below 16-bit and 32-bit MCUs in capability but excels in deterministic real-time control with very low cost.
Key features include 4 MHz maximum clock speed, 5 MIPS throughput, 25 mA source/sink current per I/O, integrated brown-out reset, power-on reset, watchdog timer with its own on-chip RC oscillator, and an EPROM-based program memory that allows windowed erasure for prototype iteration. The 'A' revision improved ADC accuracy and added the enhanced CCP module compared to the original PIC16C73.
The architecture uses a 14-bit instruction word and an 8-bit data path, with separate program and data buses preventing pipeline stalls. The integrated 8-bit ADC achieves 8-bit resolution across up to 5 input channels with conversion completed by successive approximation. The device operates over a 2.5V to 6.0V supply range with typical 5V/4 MHz active current of 15 uA, demonstrating CMOS-class low power for industrial embedded designs.
Typical applications include industrial control systems, automotive body electronics, sensor signal conditioning, motor drive interfaces, and consumer appliance controllers. The integrated ADC and CCP module make the PIC16C73A well suited for closed-loop analog control such as temperature regulation, fan speed control, and battery charging.
When designing with this OTP device, consider that program memory is one-time programmable and cannot be erased in-circuit; for in-system reprogrammability, consider the pin-compatible PIC16F73 with Flash memory. The I suffix denotes industrial temperature grade (-40C to +85C), and the SP suffix denotes 28-pin SPDIP through-hole package.
This page synthesizes distributor pricing, drop-in alternatives within the PIC16C7x family, and practical design notes not found in the manufacturer datasheet alone.
Drop-in alternatives for PIC16C73A-04I/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 PIC16C73A-04I/SP (same form factor and footprint) — differing in Package, Core Architecture, Timers, Mounting Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16C73B-04I/SP
✅ Drop-In✓ In Stock
$4.75 / Unit
View Datasheet →PIC16C73B-04I/SO
✅ Drop-In✓ In Stock
$7.1 / Unit
View Datasheet →PIC16F73-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16C73A-04I/SO
✅ Drop-In✓ In Stock
$4.78 / Unit
View Datasheet →PIC16C73A-04E/SP
✅ Drop-In✓ In Stock
$7.75 / Unit
View Datasheet →PIC16C73A-04I/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16 mid-range 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) EPROM |
| Program Memory Size | 7 KB (4K x 14 words) |
| Data RAM | 192 bytes |
| Data EEPROM | Not present (OTP MCU) |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 200 ns |
| MIPS Performance | 5 MIPS |
| Number of I/O Pins | 22 |
| ADC | 8-bit, 5 channels |
| CCP Modules | 1 (Capture/Compare/PWM) |
| Serial Interfaces | USART, SSP (SPI/I2C) |
| Supply Voltage Range | 2.5 V to 6.0 V |
| Operating Temperature Range | -40 C to +85 C (Industrial, suffix I) |
| Package | 28-pin SPDIP (SP) |
| Mounting Type | Through-Hole |
| I/O Sink/Source Current | 25 mA / 25 mA |
| Watchdog Timer | Yes (with dedicated on-chip RC oscillator) |
| Brown-out Reset | Yes |
| Power-on Reset | Yes |
| Instruction Set | 35 single-word instructions |
PIC16C73A-04I/SP Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear (Reset) input or 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 reference voltage |
| 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 | OSC1/CLKIN — Oscillator input / external clock input |
| Pin 9 | OSC2/CLKOUT — Oscillator output / clock output |
| Pin 10 | RC0/T1OSO/T1CKI — PORTC bit 0 / Timer1 oscillator output / Timer1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — PORTC bit 1 / Timer1 oscillator input / CCP2 output |
| Pin 12 | RC2/CCP1 — PORTC bit 2 / CCP1 PWM output |
| Pin 13 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 14 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 15 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 16 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 17 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 18 | VSS — Ground reference |
| Pin 19 | VDD — Positive supply voltage (2.5V-6.0V) |
| Pin 20 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 21 | RB1 — PORTB bit 1 |
| Pin 22 | RB2 — PORTB bit 2 |
| Pin 23 | RB3 — PORTB bit 3 |
| Pin 24 | RB4 — PORTB bit 4 |
| Pin 25 | RB5 — PORTB bit 5 |
| Pin 26 | RB6 — PORTB bit 6 |
| Pin 27 | RB7 — PORTB bit 7 |
| Pin 28 | VSS — Ground reference |
Typical Applications
PIC16C73A-04I/SP is suitable for 6 applications: Industrial Sensor Monitoring, Automotive Body Electronics, Battery Charging Controller, HVAC Fan Speed Controller, Consumer Appliance Control Board, Motor Drive Interface Board.
Industrial Sensor Monitoring
The PIC16C73A-04I/SP integrates a 5-channel 8-bit ADC, 192 bytes of RAM, and 22 digital I/O, making it well-suited for multi-sensor monitoring panels in industrial environments. At 4 MHz the MCU achieves 5 MIPS throughput, easily handling periodic ADC scans across temperature, pressure, and humidity sensors at sub-second intervals. The wide 2.5V-6.0V supply range lets it run directly from a 24V industrial bus with a simple linear regulator, while the 25 mA source/sink current per I/O can drive relays, LEDs, and optocouplers without buffer transistors. The integrated USART supports RS-232 or RS-485 communication to a host PLC.
Recommended
Automotive Body Electronics
The PIC16C73A-04I/SP industrial-grade variant operates from -40C to +85C and tolerates the electrical noise typical of automotive 12V body networks, making it suitable for non-safety modules such as lighting controllers, seat adjusters, and wiper logic. The integrated 8-bit ADC reads potentiometers and switch-position sensors, while the CCP module generates PWM outputs for dimming incandescent lamps or driving small DC motors. The 35-instruction RISC core executes deterministic control loops in microseconds, critical for debouncing mechanical switches and timing relay closures. Brown-out and power-on reset circuits ensure clean cold-start behavior across automotive cranking transients.
Recommended
Battery Charging Controller
Charging lead-acid or NiMH battery packs requires precise voltage and current regulation with temperature compensation, exactly what the PIC16C73A-04I/SP delivers through its integrated 8-bit ADC and PWM-capable CCP module. The 5-channel ADC can simultaneously monitor battery voltage, charge current, and thermistor temperature, while the PWM output drives a switching MOSFET at variable duty cycle to maintain the desired charge profile. The 2.5V-6.0V supply range aligns with single-cell Li-ion monitoring applications. The PIC's low 15 uA active current at 5V/4 MHz preserves battery life during standby, and brown-out reset prevents deep-discharge damage.
Recommended
HVAC Fan Speed Controller
The PIC16C73A-04I/SP's enhanced CCP module generates precise PWM signals to drive triac-phase-controlled or DC brushless fan motors across a wide speed range. The integrated ADC reads temperature sensors (typically NTC thermistors) in multiple zones and adjusts fan speed proportionally, while 22 digital I/O accept manual override switches, status LEDs, and tachometer feedback from the fan. The 4 MHz clock provides 200 ns instruction cycle time, sufficient for closed-loop PID fan control without lag. The wide operating voltage (2.5V-6.0V) accepts directly-regulated 5V or 3.3V supplies from HVAC control boards.
Recommended
Consumer Appliance Control Board
White-goods appliances such as washing machines, dishwashers, and microwave ovens use the PIC16C73A-04I/SP for user interface scanning, motor timing, and sensor management. The 22 I/O pins interface with keypads, 7-segment displays, and indicator LEDs while the USART communicates with inverter boards or sensor modules. The 192-byte RAM accommodates user-mode state machines for cycle sequencing, and the 7 KB OTP program memory holds the appliance firmware. Low power consumption (15 uA typical at 5V/4 MHz) keeps standby power below 1W to meet energy-efficiency regulations.
Recommended
Motor Drive Interface Board
Stepper and DC brush motor controllers use the PIC16C73A-04I/SP to generate step/direction signals, monitor current-sense amplifiers, and manage end-stop switches. The integrated ADC reads current feedback at up to 5 channels for multi-axis coordination, while the CCP module produces the pulse trains that drive H-bridge gate drivers. The 25 mA per-pin I/O capability directly interfaces with logic-level MOSFET drivers without buffering. Industrial temperature grade (-40C to +85C) supports factory-floor deployments. The deterministic 200 ns instruction cycle ensures smooth stepper ramp profiles without audible jitter.
Recommended
Recommended Products Summary
Engineering reference data for PIC16C73A-04I/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16C73B-04I/SP | PIC16F73-I/SP | PIC16C73A-04E/SP |
|---|---|---|---|---|
| Package | 28-pin SPDIP | 28-pin SPDIP (same) | 28-pin SPDIP (same) | 28-pin SPDIP (same) |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP EPROM (7 KB) | OTP EPROM (7 KB) | Flash (7 KB) | OTP EPROM (7 KB) |
| Max Clock Frequency | 4 MHz | 4 MHz | 20 MHz | 4 MHz |
| Temperature Range | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +125C (Extended) |
| ADC Channels | 5 channels, 8-bit | 5 channels, 8-bit (improved) | 5 channels, 8-bit | 5 channels, 8-bit |
| In-Circuit Programming | No (OTP only) | No (OTP only) | Yes (ICSP) | No (OTP only) |
| Lifecycle Status | NRND | NRND | Active | NRND |
Key Differentiators
- Industrial temperature grade with recommended Flash migration path (vs PIC16F73-I/SP)
- Integrated 8-bit ADC and enhanced CCP module in a single 28-pin MCU (vs PIC16C73B-04I/SP)
- Industrial -40C to +85C operating range (vs PIC16C73A-04E/SP)
Design Notes
The PIC16C73A-04I/SP operates from 2.5V to 6.0V and draws approximately 15 uA active current at 5V/4 MHz, plus watchdog timer current during standby. Decouple VDD with a 100 nF ceramic capacitor placed within 5 mm of pin 19, with an additional 10 uF bulk capacitor near the IC. Avoid powering the device directly from a battery without a regulator, since voltage transients can trigger brown-out reset. For low-power designs, the watchdog timer should be disabled during sleep to reduce standby current to under 1 uA.
Because the PIC16C73A is OTP (one-time programmable), there is no in-circuit reprogramming. Engineering units must use the windowed ceramic package (PIC16C73A-04I/JW) for development and prototype iteration, then transition to the OTP SPDIP for production. Stock OTP parts that have been programmed but found to contain bugs become scrap - factor this into prototype budget. Additionally, ensure the MCLR pin (pin 1) is pulled high through a 10 kohm resistor; leaving it floating causes erratic resets and unreliable startup.
The 28-pin SPDIP through-hole package has a 0.1 inch (2.54 mm) pin pitch and standard 600 mil row spacing. For socketed prototypes, use a 28-pin DIP socket with machined-pin contacts to ensure reliable insertion. Keep clock-trace routing short: OSC1 and OSC2 traces should be less than 20 mm, surrounded by ground pour, and never routed near switching signals. Place a 22-33 pF load capacitor from each oscillator pin to ground when using a crystal oscillator, per datasheet crystal specification table.
Compliance Information
Compliance data not explicitly present in the verified web data. The PIC16C73A is a legacy 1990s-era OTP MCU; many original SPDIP variants predate RoHS directives. RoHS-compliant SOIC and modern variants are available; contact Microchip for specific compliance certificates.
