PIC16LC73A-04I/SO - 8-Bit 4MHz MCU, 7KB OTP, 28-SOIC | Microchip
MPN: PIC16LC73A-04I/SO β End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.42 | $7.42 |
| 10 | $6.68 | $66.80 |
| 100 | $5.49 | $549.00 |
| 500 | $4.86 | $2,430.00 |
| 1,000 | $4.19 | $4,190.00 |
PIC16LC73A-04I/SO Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, program memory, data RAM, and peripheral interfaces such as timers, communication ports, and analog-to-digital converters. Within the broader embedded semiconductor taxonomy, MCUs sit under microcontrollers -> 8-bit microcontrollers -> PIC microcontrollers -> mid-range PIC16 family. The PIC16LC73A specifically belongs to the PIC16C7X sub-family, which added integrated A/D converters to the PIC16CXX mid-range architecture and is widely used in mixed-signal embedded designs.
Key features include Harvard-architecture RISC CPU with 35 single-cycle instructions, 8-level hardware stack, 4 MHz internal clock with 1 s instruction cycle, integrated 8-bit A/D converter (5 channels, 8 channels depending on variant), two 8-bit timers and one 16-bit timer, USART with 9-bit address detection, capture/compare/PWM module, and synchronous serial port (SSP) supporting SPI and I2C. The wide 2.5 V to 5.5 V operating range allows battery-powered and 5 V regulated designs to share the same firmware, while the CMOS process keeps quiescent current low for sleep-mode applications.
Architecturally, the PIC16LC73A uses a 14-bit instruction word with separate program and data buses, enabling most instructions to execute in a single oscillator cycle. The 22 I/O pins are arranged across ports A, B, and C, with individual pin direction control via TRIS registers. On-chip peripherals include a five-channel 8-bit A/D converter with 25 s conversion time, making the part suitable for sensor signal acquisition and process control where modest precision is sufficient.
Typical applications include industrial control and sensor interface boards, automotive body electronics (non-safety), HVAC thermostat controllers, appliance front-panel controllers, low-cost motor control drivers, uninterruptible power supply (UPS) supervisory logic, and battery chargers. The combination of integrated A/D, USART, and PWM makes the PIC16LC73A especially attractive in designs that previously required a discrete MCU plus an external A/D converter.
When designing with this device, pay attention to the OTP program memory: code cannot be erased or rewritten, so OTP is suitable only for production-volume parts where in-circuit reprogramming is not needed. For prototyping or field-upgradeable firmware, consider the flash-based PIC16F73 in the same 28-SOIC footprint as a drop-in alternative with the same peripheral map. Always include the recommended decoupling capacitors (100 nF + 10 uF) close to VDD/VSS and follow Microchip's oscillator layout guidelines to avoid noise on the OSC1/OSC2 pins.
This page synthesizes distributor pricing, verified drop-in alternatives sourced from Microchip's own cross-reference database, and practical design notes not found in the standalone datasheet, giving engineers a single reference for sourcing, replacement selection, and PCB integration decisions.
Drop-in alternatives for PIC16LC73A-04I/SO β 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 PIC16LC73A-04I/SO (same form factor and footprint) β differing in Package, Program Memory Type, Operating Temperature, Program Memory Size, Timers.
Quick Comparison Tool β Select alternative parts for side-by-side comparison:
PIC16F73-I/SO
β Drop-Inβ In Stock
$2.45 / Unit
View Datasheet βPIC16C73A-04/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16LC73A-04/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F73T-I/SO
β Drop-Inπ Reference alternative (not in catalog)
PIC16F76-I/SO
β Drop-Inβ In Stock
$2.9 / Unit
View Datasheet βPIC16LC73A-04I/SO Maximum Ratings & Electrical Characteristics
| Product Family | PIC16C7X (mid-range 8-bit MCU) |
| Core Architecture | 8-bit RISC Harvard |
| CPU Clock Frequency | 4 MHz (-04 suffix) |
| Instruction Cycle | 1 us (4 clock cycles per instruction) |
| Program Memory Type | OTP (One-Time-Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| Data RAM | 192 bytes |
| Data EEPROM | None |
| I/O Pins | 22 |
| Operating Voltage (Vdd) | 2.5 V to 5.5 V (3.3 V / 5 V nominal) |
| Operating Temperature | -40C to +85C (industrial, 'I' suffix) |
| A/D Converter | 8-bit, 5 channels |
| Timers | 2 x 8-bit + 1 x 16-bit |
| Communication | USART, SSP (SPI/I2C) |
| Package | 28-SOIC (SO), 7.50 mm width |
| Mounting Type | Surface Mount |
| MSL Level | 1 (unlimited floor life at <30C/85% RH) |
| RoHS Status | Compliant |
PIC16LC73A-04I/SO Pin Configuration
| Pin 1 | /MCLR β Master Clear (active-low reset, must be pulled high via 10 kohm) |
| Pin 2 | RA0/AN0 β PORTA bit 0 / Analog input channel 0 |
| Pin 3 | RA1/AN1 β PORTA bit 1 / Analog input channel 1 |
| Pin 4 | RA2/AN2 β PORTA bit 2 / Analog input channel 2 |
| Pin 5 | RA3/AN3/VREF β PORTA bit 3 / Analog input channel 3 / A/D voltage reference |
| Pin 6 | RA4/T0CKI β PORTA bit 4 / Timer 0 clock input |
| Pin 7 | RA5/AN4/SS β PORTA bit 5 / Analog input channel 4 / SPI slave select |
| Pin 8 | Vss β Ground reference |
| Pin 9 | OSC1/CLKIN β Oscillator crystal input / external clock input |
| Pin 10 | OSC2/CLKOUT β Oscillator crystal output / 4x clock output |
| Pin 11 | RC0/T1OSO/T1CKI β PORTC bit 0 / Timer 1 oscillator output / Timer 1 clock input |
| Pin 12 | RC1/T1OSI/CCP2 β PORTC bit 1 / Timer 1 oscillator input / CCP2 PWM output |
| Pin 13 | RC2/CCP1 β PORTC bit 2 / CCP1 PWM output |
| Pin 14 | RC3/SCK/SCL β PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA β PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO β PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK β PORTC bit 6 / USART TX / USART clock |
| Pin 18 | RC7/RX/DT β PORTC bit 7 / USART RX / USART data |
| Pin 19 | Vss β Ground reference (digital) |
| Pin 20 | Vdd β Positive supply voltage 2.5 V to 5.5 V |
| Pin 21 | RB0/INT β PORTB bit 0 / external interrupt input |
| Pin 22 | RB1 β PORTB bit 1 (interrupt-on-change) |
| Pin 23 | RB2 β PORTB bit 2 (interrupt-on-change) |
| Pin 24 | RB3/PGM β PORTB bit 3 / low-voltage programming input |
| Pin 25 | RB4 β PORTB bit 4 (interrupt-on-change) |
| Pin 26 | RB5 β PORTB bit 5 (interrupt-on-change) |
| Pin 27 | RB6/PGC β PORTB bit 6 / ICSP clock |
| Pin 28 | RB7/PGD β PORTB bit 7 / ICSP data |
Typical Applications
PIC16LC73A-04I/SO is suitable for 6 applications: Industrial Sensor Interface Board, HVAC Thermostat Controller, Appliance Front-Panel Controller, Battery Charger Controller, Uninterruptible Power Supply (UPS) Supervisory Logic, Automotive Body Electronics (Non-Safety).
Industrial Sensor Interface Board
The PIC16LC73A-04I/SO fits industrial sensor interface boards where moderate-resolution analog acquisition is required. Its integrated 5-channel 8-bit A/D converter provides 25 us conversion time, sufficient for temperature, pressure, and level sensors where 1% accuracy is acceptable. The 2.5 V to 5.5 V supply range allows direct connection to 3.3 V sensor bridges or 5 V regulated rails, while the -40C to +85C industrial temperature grade supports factory-floor and outdoor enclosures. The 22 I/O pins drive status LEDs, relay coils, and discrete logic, and the USART links the board to a host PLC or HMI over RS-232/RS-485 at up to 19.2 kbaud. Placed between the sensor connector and the communication transceiver, the MCU adds programmable thresholding, hysteresis, and digital filtering that would otherwise require a dedicated analog ASIC.
Recommended
HVAC Thermostat Controller
The PIC16LC73A-04I/SO is well-suited for HVAC thermostat controllers that integrate temperature sensing, user input, and relay control. Its 8-bit A/D converter digitizes thermistor or analog temperature sensor signals, while the integrated PWM module drives a TRIAC for staged fan or compressor control. The USART connects to a wall-mounted display module or remote thermostat link, and the MSSP SPI/I2C port talks to a real-time clock for scheduling. The wide 2.5 V to 5.5 V operation allows the board to share the same MCU across 24 VAC transformer-derived 5 V and battery-backed 3.3 V designs. The 192-byte RAM comfortably holds PID coefficients, setpoint buffers, and 7-segment display refresh tables. Placed between the AC mains interface and the user display, this MCU provides programmable hysteresis, multi-stage fan curves, and adaptive learning without external logic.
Recommended
Appliance Front-Panel Controller
The PIC16LC73A-04I/SO is a strong fit for washing-machine, dishwasher, and microwave front-panel controllers that need mixed-signal I/O, user interface, and motor or heating control. Its 22 I/O pins scan a 4x4 matrix keypad and drive a multiplexed 7-segment or character LCD without external logic, while the 8-bit A/D converter monitors motor current and water level. The PWM module regulates universal motor speed or heating element power via zero-cross TRIAC drive. Operating from 2.5 V to 5.5 V, the same MCU works across 5 V regulated supplies and 3.3 V battery-equipped models. The OTP program memory is ideal for production appliances where firmware is finalized at launch and low per-unit cost is essential. Place between the keypad connector and the TRIAC outputs; the MCU handles all timing, safety interlocks, and user feedback without external decoder ICs.
Recommended
Battery Charger Controller
The PIC16LC73A-04I/SO fits sealed lead-acid (SLA), NiMH, and Li-ion charger controllers that need analog monitoring plus precise timing control. Its 8-bit A/D converter measures battery voltage and charge current with 0.2% resolution, while the integrated PWM module regulates a buck or flyback converter at up to 20 kHz. The USART reports state-of-charge and charging status to an external indicator or host system. The wide 2.5 V to 5.5 V supply range allows the MCU to operate directly from a regulated 5 V rail or a 3.3 V low-power standby supply. With 7 KB OTP memory, the firmware can implement CC/CV charge profiles, temperature-compensated end-of-charge detection, and safety timers. Place between the current-sense amplifier and the MOSFET gate driver; the MCU handles all control loop timing without requiring a separate analog controller IC.
Recommended
Uninterruptible Power Supply (UPS) Supervisory Logic
The PIC16LC73A-04I/SO serves as the supervisory MCU in low-power UPS systems, where it monitors mains presence, battery voltage, and inverter status to manage automatic failover. Its 5-channel 8-bit A/D converter digitizes the mains voltage, battery voltage, and load current sense signals, while a digital input monitors the mains-zero-cross signal. The USART reports UPS state and battery health to a status LED panel or RS-232 host. The MSSP I2C port reads a serial EEPROM for logging brownout events. Operating from 2.5 V to 5.5 V, the MCU can be supplied from the same 5 V standby rail that powers the relay drivers. The 22 I/O pins drive relay coils, audible alarms, and front-panel LEDs. Place between the current-sense resistor and the relay driver; the MCU handles all sequencing logic and audible alarm timing.
Recommended
Automotive Body Electronics (Non-Safety)
The PIC16LC73A-04I/SO fits non-safety automotive body electronics such as seat controllers, mirror adjusters, and accessory modules where its industrial -40C to +85C temperature range covers cabin and trunk environments. Its PWM module drives small DC motors for mirror positioning, while the A/D converter monitors potentiometer feedback for position sensing. The USART links the module to a body control module (BCM) over LIN or K-line transceivers. The 5 V operation aligns with automotive battery voltage after a 12 V to 5 V LDO regulator. With OTP memory, the firmware is locked at production for security against aftermarket tampering. Place between the LIN transceiver and the motor-driver H-bridge; the MCU manages soft-start, current limiting, and end-stop detection without external position-counter logic.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC73A-04I/SO β comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16F73-I/SO | PIC16C73A-04/SO | PIC16LC73A-04/SO | PIC16F76-I/SO |
|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 28-SOIC (wide body) | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same | 28-SOIC - same |
| Program Memory | 7 KB OTP | 7 KB Flash (10K cycles) | 7 KB OTP | 7 KB OTP | 14 KB Flash (10K cycles) |
| CPU Clock (max) | 4 MHz | 20 MHz | 4 MHz | 4 MHz | 20 MHz |
| Operating Voltage | 2.5 V to 5.5 V | 2.0 V to 5.5 V | 3.0 V to 6.0 V | 2.5 V to 5.5 V | 2.0 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial) | -40C to +85C (industrial) | 0C to +70C (commercial) | 0C to +70C (commercial) | -40C to +85C (industrial) |
| A/D Converter | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels |
| I/O Pins | 22 | 22 | 22 | 22 | 22 |
| Lifecycle Status | Obsolete (last-time-buy market) | Active | Obsolete | Obsolete | Active |
Key Differentiators
- Low-power CMOS process supports 2.5 V to 5.5 V operation (vs PIC16C73A-04/SO)
- Flash memory enables ICSP and field firmware upgrades (vs PIC16LC73A-04I/SO (this product))
- Industrial temperature range (-40C to +85C) (vs PIC16LC73A-04/SO)
Design Notes
Add a 100 nF ceramic decoupling capacitor as close as physically possible to the Vdd pin (pin 20) and a 10 uF bulk capacitor on the same supply trace. According to Microchip PIC16C7X family design guidelines, Vdd rise time during power-on-reset must be less than 50 ms for predictable POR behavior. For battery-powered designs with Vdd below 3.0 V, include a 100 kohm pull-up on /MCLR (pin 1) and ensure the brownout reset (BOR) is enabled in the configuration bits to prevent code corruption during voltage droops.
Place the external crystal or resonator within 1 cm of the OSC1 (pin 9) and OSC2 (pin 10) pins to minimize parasitic capacitance and EMI susceptibility. According to the PIC16C7X datasheet, ground the crystal case to a low-impedance ground pour, and route the two crystal traces with matched lengths and a guard ring tied to ground. Add a 1 Mohm feedback resistor across the crystal for Pierce oscillator topologies. Avoid routing digital signal traces (especially PWM and USART) directly under or adjacent to the crystal traces to prevent clock jitter from coupling noise.
Do not use the OTP device for development or pre-production builds: code cannot be erased or rewritten. Once a PIC16LC73A is programmed with incorrect firmware, the device must be discarded. For prototypes, use the flash-based PIC16F73-I/SO drop-in alternative, which is pin-to-pin compatible and supports ICSP in-circuit reprogramming via the RB6/PGC and RB7/PGD pins (27 and 28). When porting production firmware from PIC16F73 to PIC16LC73A for cost-down, verify BOR and watchdog timer (WDT) defaults in the configuration word, as flash and OTP versions may differ in default configuration.
Route the analog A/D inputs (RA0-RA5, pins 2-7) as short traces and keep them at least 2 trace widths away from any digital signal, especially PWM outputs on RC1/RC2 (pins 12, 13) and the USART on RC6/RC7 (pins 17, 18). According to Microchip PIC16C7X analog design notes, AES051 mandates a separate analog ground island connected to the digital ground at a single point near the Vss pin (pin 19). Add a 10 nF bypass capacitor on the A/D Vref pin (RA3/AN3/Vref, pin 5) if the internal Vref is not used, to reduce noise on the reference voltage.
Compliance Information
RoHS and lead-free per Microchip product page; AEC-Q100 not qualified - choose PIC16F73-I/SO (also not AEC-Q100) or dedicated automotive PIC16 families for safety applications. Halogen-free status not explicitly stated in Verified Web Data - confirm with specific distributor lot if required.
