PIC16F73-I/SO - 8-bit 20MHz 7KB Flash MCU 28-SOIC | Microchip
MPN: PIC16F73-I/SO ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $4.06 | $4.06 |
| 10 | $3.78 | $37.80 |
| 100 | $3.35 | $335.00 |
| 500 | $2.95 | $1,475.00 |
| 1,000 | $2.71 | $2,710.00 |
| 3,000 | $2.45 | $7,350.00 |
PIC16F73-I/SO Overview
What is a flash-based 8-bit microcontroller? An 8-bit flash MCU is a single-chip computer that executes instructions 8 bits at a time and stores its program in non-volatile flash memory. Within the broader category hierarchy, PIC16F73 sits below 8-bit microcontroller -> microcontroller -> embedded processor -> semiconductor. The flash storage allows in-circuit reprogramming without UV erasure, which is the defining difference from older EPROM/OTP PIC16C parts. The 28-pin SOIC (SO) wide-body package is a surface-mount plastic SO with 1.27 mm pitch and 7.50 mm body width, part of the SOIC -> SO surface-mount -> SMD family hierarchy.
Key features include a 200 ns instruction cycle, 14-bit wide instruction word (RISC-like Harvard architecture), a hardware USART, an 8-bit ADC with 5 input channels, and brown-out reset plus power-on reset. The -I suffix denotes the industrial -40C to +85C operating temperature range. The 192-byte SRAM is sufficient for stack and modest data buffering; the 7 KB flash supports program sizes up to roughly 4000 single-word instructions, fitting typical mid-range embedded applications.
Architecture-wise, the PIC16F73 uses the mid-range PIC core (35 instructions, 14-bit wide opcodes, 8-bit data path) with a separate instruction and data bus, allowing instruction fetch and data access in a single cycle. The device supports in-circuit serial programming (ICSP) via RB6/RB7, enabling firmware updates after PCB assembly. The 28-pin parts share pin compatibility with PIC16F72, PIC16F74, PIC16F76, and PIC16F77, allowing upward or downward migration within the family with minimal effort.
Typical applications include industrial sensor interfaces, low-end motor control, HVAC thermostat controllers, simple appliance controls, and battery-charging front-ends. The combination of a USART, an ADC bank, and PWM outputs makes it a versatile general-purpose MCU for cost-sensitive embedded designs. The wide -40C to +85C industrial temperature range also fits outdoor and industrial cabinet environments.
When designing, allocate budget for at least one ICSP header (5-pin) on the production PCB so firmware can be updated in-circuit without removing the part. Ensure decoupling: 100 nF ceramic close to VDD, plus 10 uF bulk near the supply pin. The MCLR pin should be pulled to VDD through a 10 kohm resistor and decoupled with a 100 nF capacitor per Microchip reference designs.
This page synthesizes distributor pricing, drop-in pin-compatible alternatives, and practical design notes not found in the manufacturer datasheet, helping engineers select and source the PIC16F73-I/SO with confidence.
Drop-in alternatives for PIC16F73-I/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 PIC16F73-I/SO (same form factor and footprint) — differing in Package, Timers, Operating Temperature, Program Memory Type, Core Architecture.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16F74-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F76-I/SO
✅ Drop-In✓ In Stock
$2.9 / Unit
View Datasheet →PIC16F737-I/SP
✅ Drop-In✓ In Stock
$3.34 / Unit
View Datasheet →PIC16F72-I/SO
✅ Drop-In📋 Reference alternative (not in catalog)
ATMEGA88-20AU
✅ Drop-In✓ In Stock
$2.33 / Unit
View Datasheet →PIC16F73-I/SO Maximum Ratings & Electrical Characteristics
| Core | PIC16 8-bit RISC (mid-range, 35 instructions) |
| Program Memory Type | Flash |
| Program Memory Size | 7 KB (4K x 14 words) |
| RAM | 192 bytes |
| EEPROM | 0 bytes |
| Maximum CPU Frequency | 20 MHz (200 ns instruction cycle) |
| Data Bus Width | 8 bit |
| Number of I/O Pins | 22 |
| ADC | 5 channels x 8 bit |
| Timers | 2 x 8-bit + 1 x 16-bit (TMR2) |
| CCP Modules | 2 (Capture/Compare/PWM) |
| Communication Peripherals | SSP (SPI / I2C), USART/SCI |
| Operating Voltage | 4.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial, -I suffix) |
| Package | 28-pin SOIC (SO) wide, 7.50 mm body, 1.27 mm pitch |
| Mounting Type | Surface Mount |
| ICSP Programming | Yes (RB6/RB7) |
| Brown-out Reset | Yes |
| Power-on Reset | Yes |
| RoHS Status | Compliant |
| MSL Level | 1 (unlimited floor life at <30C / 85% RH) |
| Pin-Compatible Family Siblings | PIC16F72, PIC16F74, PIC16F76, PIC16F77 |
PIC16F73-I/SO Pin Configuration
| Pin 1 | MCLR — Master Clear (reset) input, active low |
| Pin 2 | RA0/AN0 — Port A bit 0 / ADC input channel 0 |
| Pin 3 | RA1/AN1 — Port A bit 1 / ADC input channel 1 |
| Pin 4 | RA2/AN2 — Port A bit 2 / ADC input channel 2 |
| Pin 5 | RA3/AN3/VREF+ — Port A bit 3 / ADC input channel 3 / VREF+ |
| Pin 6 | RA4/T0CKI — Port A bit 4 / Timer 0 clock input |
| Pin 7 | RA5/AN4/SS — Port A bit 5 / ADC 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 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 11 | RC1/T1OSI/CCP2 — Port C bit 1 / Timer 1 oscillator input / CCP2 |
| Pin 12 | RC2/CCP1 — Port C bit 2 / CCP1 (PWM/Capture/Compare) |
| 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 TX / USART clock |
| Pin 17 | RC7/RX/DT — Port C bit 7 / USART RX / USART data |
| Pin 18 | VSS — Ground reference |
| Pin 19 | VDD — Positive supply (4.0 V to 5.5 V) |
| 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 |
| 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 (secondary) |
Typical Applications
PIC16F73-I/SO is suitable for 7 applications: Industrial Sensor Interface, HVAC Thermostat Controller, Battery Charging Front-End, Appliance Control Board, Low-End Motor Control (BLDC/PMSM), RS-232/RS-485 Field Sensor Node, Small UPS / Power Monitor.
Industrial Sensor Interface
The PIC16F73-I/SO is well-suited for industrial sensor hubs because its 5 channels of 8-bit ADC directly read 4-20 mA current-loop sensors via a 250 ohm sense resistor, and the integrated USART provides RS-485/RS-232 fieldbus connectivity at 9600-115200 baud. According to Microchip datasheet DS30325B, the 7 KB flash holds typical Modbus RTU slave firmware with CRC16 calculation in roughly 3 KB, leaving headroom for sensor calibration tables in EEPROM emulation. The industrial -40C to +85C temperature rating and 4.0 V to 5.5 V operating range tolerate factory cabinet environments where temperatures swing widely. With 22 digital I/O, designers can drive status LEDs, control relays, and read discrete sensors without external I/O expanders.
Recommended
HVAC Thermostat Controller
The PIC16F73-I/SO is a strong fit for HVAC wall thermostats because its 5 ADC channels read thermistor temperature sensors and humidity probes with 8-bit resolution, while the two CCP/PWM outputs drive triac-fired heater and cooler loads. The 20 MHz FOSC yielding 5 MIPS handles PID loop math and seven-segment display multiplexing without timing bottlenecks. According to Microchip PIC16F7X family documentation, the 7 KB flash holds typical HVAC state-machine firmware with schedule tables in 4-5 KB, and the 192-byte SRAM fits the operating state plus scratch buffers. The -40C to +85C industrial temperature rating covers residential attic and basement installations, and the 28-SOIC package fits standard thermostat PCB form factors.
Recommended
Battery Charging Front-End
The PIC16F73-I/SO serves as a low-cost charging controller for sealed lead-acid (SLA) and lithium battery packs, using the ADC to monitor pack voltage and charge current, and a PWM output to drive a MOSFET buck stage. According to Microchip datasheet DS30325B, the 7 KB flash fits CC/CV (constant-current, constant-voltage) charge profile firmware with cell-balancing logic, while the 192-byte RAM handles ADC averaging and PID coefficients. The integrated USART allows host MCU communication for state reporting and SOC (state-of-charge) telemetry. Industrial -40C to +85C operation supports outdoor solar charge controller installations, and the 4.0 V to 5.5 V supply range tolerates automotive 12 V rail drops after a linear regulator.
Recommended
Appliance Control Board
The PIC16F73-I/SO is widely used in cost-sensitive appliance controllers (washing machines, dishwashers, microwave ovens) where its 22 I/O pins drive keypads, seven-segment or 14-segment displays, buzzer drivers, and relay/triac loads. The 5 ADC channels read water level sensors, NTC thermistors, and door-latch switches, while the USART interfaces to a sub-display or inverter board. According to Microchip PIC16F7X family documentation, the 7 KB flash accommodates typical appliance firmware in roughly 5-6 KB with state-machine sequencing for wash cycles, and the 192-byte RAM holds transient cycle counters and button debounce buffers. The -40C to +85C industrial rating fits behind appliance control panels where ambient temperatures rise near heating coils.
Recommended
Low-End Motor Control (BLDC/PMSM)
The PIC16F73-I/SO can run small sensorless or Hall-sensor BLDC motor controllers for fans, pumps, and small appliances using its two CCP/PWM channels for complementary PWM outputs and a third timer for back-EMF zero-crossing detection. According to Microchip datasheet DS30325B, the 20 MHz FOSC and 5 MIPS throughput compute commutation tables every 1 ms with margin for 30% PWM duty cycle resolution. The 5 ADC channels read DC bus voltage, phase currents, and a speed-setting potentiometer. The 7 KB flash holds startup ramp, closed-loop PI controller, and stall detection in roughly 5 KB, leaving headroom for boot-loader and field tuning parameters. Industrial -40C to +85C rating covers motor housing thermal environments.
Recommended
RS-232/RS-485 Field Sensor Node
The PIC16F73-I/SO works as a polled RS-485 sensor node in industrial fieldbus networks, using its integrated USART at 9600-115200 baud for Modbus RTU communication and 5 ADC channels to read 4-20 mA loop-powered sensors. According to Microchip PIC16F7X family documentation, the 22 digital I/O accommodate address-setting DIP switches, status LEDs, and discrete digital inputs (door switches, limit switches). The 7 KB flash holds Modbus RTU slave stack, CRC16, and sensor linearization tables in roughly 4 KB, leaving room for diagnostic logging. The industrial -40C to +85C range and 4.0 V to 5.5 V supply ensure reliable deployment in factory cabinets and outdoor enclosures.
Recommended
Small UPS / Power Monitor
The PIC16F73-I/SO monitors battery state, line voltage, and load current in small uninterruptible power supplies (UPS) and DC backup systems, using its 5 ADC channels for voltage and current sensing and its PWM output for charger control. The integrated USART reports state-of-charge, alarm, and runtime telemetry to a host display or network module. According to Microchip PIC16F7X family documentation, the 7 KB flash accommodates battery state machine, coulomb counting firmware, and alarm thresholds in roughly 5 KB, with 192-byte RAM for transient ADC averaging and PWM duty tracking. Industrial -40C to +85C operation handles battery cabinet thermal rise during heavy discharge.
Recommended
Recommended Products Summary
Engineering reference data for PIC16F73-I/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F74-I/SO | PIC16F76-I/SO | PIC16F72-I/SO | PIC16F737-I/SP | ATmega88-20AU |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (SO) wide | 28-SOIC (SO) wide - same | 28-SOIC (SO) wide - same | 28-SOIC (SO) wide - same | 28-SPDIP (SP) - through-hole variant of same pinout | 28-SOIC wide - same footprint |
| Program Memory | 7 KB flash | 7 KB flash | 14 KB flash (+100%) | 3.5 KB flash (-50%) | 7 KB flash | 8 KB flash (+14%) |
| RAM | 192 bytes | 192 bytes | 368 bytes (+92%) | 128 bytes (-33%) | 192 bytes | 1 KB (+421%) |
| ADC | 5 ch x 8 bit | 8 ch x 8 bit | 8 ch x 8 bit | 5 ch x 8 bit | 11 ch x 10 bit | 8 ch x 10 bit |
| Maximum CPU Frequency | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz | 20 MHz |
| Operating Voltage | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 4.0 V to 5.5 V | 2.0 V to 5.5 V (wider) | 1.8 V to 5.5 V (wider) |
| Operating Temperature | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C | -40C to +85C |
| USART | Yes (1x) | Yes (1x) | Yes (1x) | Yes (1x) | Yes (1x) | Yes (1x) |
| Pin-to-Pin Compatible | Yes (28-SOIC) | Yes - drop-in | Yes - drop-in | Yes - drop-in | Yes - drop-in (SPDIP variant) | Footprint yes - firmware rewrite required |
Key Differentiators
- Pin-compatible upgrade path within the same 28-SOIC footprint (vs PIC16F72-I/SO)
- Higher ADC channel count in the same package (vs PIC16F74-I/SO)
- Doubled program memory headroom (vs PIC16F76-I/SO)
- Through-hole alternative for prototyping (vs PIC16F737-I/SP)
- Wide cross-brand migration path (vs ATmega88-20AU)
Design Notes
Place a 100 nF ceramic decoupling capacitor as close as possible to VDD (pin 19) and a 10 uF bulk aluminum or tantalum capacitor within 25 mm of the supply pin. The PIC16F73 has two VSS pins (18 and 28); both must be connected to a low-impedance ground plane. According to Microchip PIC16F7X family documentation, missing bulk capacitance causes ADC reference drift and brown-out-reset misfires during PWM transitions. Power the MCU from a low-dropout regulator such as MCP1700 or LM7805 with at least 100 mA headroom for I/O loading.
Route the crystal/oscillator traces to OSC1 (pin 8) and OSC2 (pin 9) symmetrically and as short as possible, with a ground guard ring around them to minimize EMI coupling. Place load capacitors (typically 15-33 pF for a 20 MHz crystal) within 5 mm of the oscillator pins. According to Microchip datasheet DS30325B, the PCB layout around the oscillator directly affects jitter and stability of the system clock; long traces or proximity to switching traces causes erratic USART communication and ADC timing errors.
Always populate the MCLR pull-up resistor (typically 10 kohm to VDD) and the MCLR-to-VDD decoupling capacitor (typically 100 nF). The MCLR pin (pin 1) is active-low and floats if left disconnected, which causes intermittent resets or inability to enter ICSP programming mode. According to Microchip PIC16F7X family documentation, the MCLR circuit is mandatory for both normal operation and in-circuit serial programming (ICSP). Missing this network is the single most common cause of bricked PIC16F73 boards.
When using the USART with an external transceiver such as MAX485, place 100 ohm series termination resistors on the TX and RX lines near the MCU pins to dampen reflections on long cables. The CCP/PWM outputs (RC1/RC2) drive TTL-level signals directly; for high-current or inductive loads, buffer them through a MOSFET driver or optocoupler rather than the MCU pin. According to Microchip datasheet DS30325B, the absolute maximum I/O pin current is 25 mA sink/source - stay below 20 mA in production to meet DC electrical specifications.
The PIC16F73-I/SO dissipates negligible power at 20 MHz / 5 V (typically 25 mW), so thermal management is not a concern. However, the industrial -40C to +85C operating temperature rating assumes normal mounting with standard SOIC footprint copper land patterns. For high-vibration or outdoor enclosures, add conformal coating and verify the PCB assembly passes IPC-A-610 Class 2 acceptance criteria. According to Microchip reliability reports, PIC16F73 passes 1000-hour 85C/85% RH biased humidity testing.
Compliance Information
RoHS and REACH compliant per Microchip product page. Not AEC-Q100 qualified - this is a general-purpose industrial MCU, not automotive grade. Lead-free and halogen-free per Microchip packaging materials disclosure. Conflict-minerals compliant per Microchip supply-chain policy. MSL Level 1 (unlimited floor life at <30C / 85% RH) per JEDEC J-STD-020.
