PIC16LC73A-04I/SP - 8-bit 4MHz 7KB OTP MCU 28-SPDIP | Microchip
MPN: PIC16LC73A-04I/SP ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.95 | $7.95 |
| 10 | $7.15 | $71.50 |
| 100 | $6.1 | $610.00 |
| 500 | $5.4 | $2,700.00 |
| 1,000 | $4.75 | $4,750.00 |
PIC16LC73A-04I/SP Overview
An 8-bit microcontroller (MCU) is a single-chip computer that integrates a CPU, program memory (ROM/Flash/OTP), data RAM, I/O peripherals, and timers on a single die. The "LC" prefix in PIC16LC73A denotes a low-voltage CMOS variant suitable for battery-powered systems, while the "7X" suffix indicates a mid-range core with integrated analog peripherals such as 8-bit A/D converters. MCUs sit within the broader taxonomy of microcontrollers -> embedded controllers -> semiconductors -> integrated circuits.
Key features include 192 bytes of data RAM, 22 general-purpose digital I/O lines, three timer/counter modules (Timer0, Timer1, Timer2), a 5-channel 8-bit Analog-to-Digital Converter (ADC), and on-chip communication peripherals including I2C/SPI (Synchronous Serial Port, SSP) and a USART. The PIC16C7X family uses a 14-bit instruction word architecture with single-cycle execution for most instructions except branches, delivering roughly 4 MIPS at 4 MHz.
Typical applications include industrial control logic, sensor signal conditioning, low-speed serial communication bridges, battery-powered instrumentation, and legacy embedded systems requiring OTP one-time-programmable code storage. The wide -40C to +85C industrial temperature range makes it suitable for factory automation, HVAC controllers, and automotive aftermarket accessories.
When designing with this device, allocate sufficient decoupling (0.1 uF ceramic plus 10 uF bulk) close to VDD/VSS pins, and respect the 5.5 V absolute maximum on VDD for LC variants. The ICD (In-Circuit Debugger) interface is not available on -04 (4 MHz) variants; for development, use an equivalent -10 or -20 variant with a debug header or program the OTP device directly with a production programmer.
This page synthesizes distributor pricing, drop-in same-package alternatives (same-brand and cross-brand), and practical design notes not aggregated on a single manufacturer or distributor page.
Drop-in alternatives for PIC16LC73A-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 PIC16LC73A-04I/SP (same form factor and footprint) — differing in Core Architecture, MSL Level, Package, Mounting Type, Timers.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LC73A-04/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16LC73A-04I/SO
✅ Drop-In✓ In Stock
$4.19 / Unit
View Datasheet →PIC16LC73-04I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16F73-I/SP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16LF73-I/SP
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC16LC73A-04I/SP Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC16C7X mid-range 8-bit RISC |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 7 KB (4K x 14 words) |
| Data RAM | 192 bytes |
| Data EEPROM | Not present (OTP device) |
| Maximum Clock Frequency | 4 MHz |
| Instruction Word Width | 14 bits |
| Operating Voltage Range | 2.5 V to 5.5 V (LC variant) |
| I/O Pins | 22 |
| A/D Converter | 8-bit, 5 channels |
| Timers | Timer0, Timer1, Timer2 (3 modules) |
| Communication Peripherals | SSP (I2C/SPI), USART |
| Operating Temperature Range | -40C to +85C (Industrial, "I" suffix) |
| Package | 28-SPDIP (Skinny Plastic DIP, through-hole) |
| Pin Count | 28 |
| Mounting Type | Through-Hole |
| MSL Level | Not applicable (through-hole) |
PIC16LC73A-04I/SP Pin Configuration
| Pin 1 | MCLR/VPP — Master Clear reset input / programming voltage |
| 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 |
| 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 |
| 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 module |
| Pin 13 | RC2/CCP1 — PORTC bit 2 / CCP1 (Capture/Compare/PWM) |
| Pin 14 | RC3/SCK/SCL — PORTC bit 3 / SPI clock / I2C clock |
| Pin 15 | RC4/SDI/SDA — PORTC bit 4 / SPI data in / I2C data |
| Pin 16 | RC5/SDO — PORTC bit 5 / SPI data out |
| Pin 17 | RC6/TX/CK — PORTC bit 6 / USART transmit / USART clock |
| Pin 18 | RC7/RX/DT — PORTC bit 7 / USART receive / USART data |
| Pin 19 | VSS — Ground reference (second VSS pin) |
| Pin 20 | VDD — Positive supply voltage (2.5V to 5.5V) |
| Pin 21 | RB0/INT — PORTB bit 0 / External interrupt input |
| Pin 22 | RB1 — PORTB bit 1 |
| Pin 23 | RB2 — PORTB bit 2 |
| Pin 24 | RB3 — PORTB bit 3 (low-voltage programming) |
| Pin 25 | RB4 — PORTB bit 4 (interrupt-on-change) |
| Pin 26 | RB5 — PORTB bit 5 (interrupt-on-change) |
| Pin 27 | RB6 — PORTB bit 6 (interrupt-on-change / ICSP clock) |
| Pin 28 | RB7 — PORTB bit 7 (interrupt-on-change / ICSP data) |
Typical Applications
PIC16LC73A-04I/SP is suitable for 7 applications: Industrial Control Logic, Sensor Interface Module, Serial Communication Bridge, Battery-Powered Instrumentation, Legacy Embedded System Replacement, HVAC and Building Automation, Automotive Aftermarket Accessories.
Industrial Control Logic
The PIC16LC73A-04I/SP fits industrial control logic because its 22 digital I/O lines can directly drive relays, solenoids, and indicator LEDs while the 4 MHz mid-range core executes scan loops fast enough for sub-millisecond response. The industrial -40C to +85C temperature grade tolerates factory floor environments and outdoor enclosures. The 8-bit ADC with 5 channels reads analog process variables (pressure, temperature, level) without external signal conditioning. Designers typically run a 10 MHz SPI peripheral bus to higher-level PLCs or HMI displays while polling GPIO at 1 kHz.
Recommended
Sensor Interface Module
The PIC16LC73A-04I/SP works as a sensor interface front end because the on-chip 8-bit ADC with 5 input channels handles multiple analog sensors simultaneously, and the I2C/SPI SSP port connects to digital sensors or EEPROMs for calibration storage. The 2.5 V minimum VDD enables two-cell battery operation, useful for wireless or remote sensor nodes. The 192-byte RAM is sufficient for moving-average filtering of sensor readings. Code compiled to ~4K words fits the 7 KB OTP budget with headroom for lookup tables and calibration constants.
Recommended
Serial Communication Bridge
The PIC16LC73A-04I/SP operates as a protocol bridge because its USART and SSP (I2C/SPI) peripherals enable simultaneous handling of two serial interfaces, allowing UART-to-I2C, SPI-to-UART, or I2C-to-SPI conversions. The 4 MHz clock provides enough bandwidth for moderate-speed bridging (115200 baud USART plus 1 MHz SPI). Industrial temperature rating supports deployment in machinery cabinets and process-control racks. The 28-SPDIP package allows hand-soldered prototypes and field-replaceable modules.
Recommended
Battery-Powered Instrumentation
The PIC16LC73A-04I/SP suits battery-powered instruments because its LC low-voltage CMOS process operates down to 2.5 V, enabling direct connection to two alkaline or NiMH cells (2.0-3.0 V) with a boost or low-drop regulator. Sleep current is microamp-level, supporting multi-year battery life in intermittently-active measurement devices. The 22 I/O lines handle LCD segment drivers, button inputs, and sensor enable signals. OTP program memory prevents firmware tampering in field-deployed metering and monitoring equipment.
Recommended
Legacy Embedded System Replacement
The PIC16LC73A-04I/SP is widely used as a replacement in legacy designs originally built around the PIC16C73A or PIC16C73, because the 28-SPDIP pinout and instruction-set compatibility allow direct PCB drop-in replacement without firmware rewrite. The OTP memory and industrial temperature grade match the original component specifications. For service boards and industrial equipment still in production for decades, the PIC16LC73A-04I/SP provides a stable, long-life source. The 4 MHz speed grade is appropriate for the original scan-loop architectures of mid-1990s designs.
Recommended
HVAC and Building Automation
The PIC16LC73A-04I/SP serves HVAC and building automation controllers because its 22 I/O pins can read multiple thermistor inputs via the 8-bit ADC and drive TRIAC optocouplers for fan and damper control. The industrial -40C to +85C rating tolerates unconditioned mechanical rooms and rooftop unit enclosures. The USART connects to building automation networks (BACnet MS-TP, Modbus RTU) at 9600-38400 baud. The OTP memory prevents unauthorized firmware modification in deployed commercial HVAC equipment where reliability and security are paramount.
Recommended
Automotive Aftermarket Accessories
Although not AEC-Q100 qualified, the PIC16LC73A-04I/SP sees use in automotive aftermarket accessories (alarm systems, remote start modules, auxiliary lighting controllers) where industrial temperature grade suffices for under-dash and cabin environments. Its 22 I/O lines switch relays for accessories, and the USART interfaces with aftermarket telematics modules. The OTP memory locks the firmware against casual tampering. Engineers targeting OEM automotive should migrate to PIC16F1939 or dsPIC33 families with AEC-Q100 qualification instead.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC73A-04I/SP — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC73A-04/SP | PIC16LC73-04I/SP | PIC16F73-I/SP | PIC16LF73-I/SP |
|---|---|---|---|---|---|
| Package | 28-SPDIP | 28-SPDIP | 28-SPDIP | 28-SPDIP | 28-SPDIP |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Program Memory Type | OTP (7 KB) | OTP (7 KB) | OTP (7 KB) | Flash (7 KB) | Flash (7 KB) |
| Maximum Clock Frequency | 4 MHz | 4 MHz | 4 MHz | 20 MHz | 20 MHz |
| Operating Voltage Range | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 2.5 V to 5.5 V | 4.0 V to 5.5 V | 2.0 V to 5.5 V |
| Operating Temperature Range | -40C to +85C (Industrial) | 0C to +70C (Commercial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) | -40C to +85C (Industrial) |
| I/O Pins | 22 | 22 | 22 | 22 | 22 |
| ADC | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels | 8-bit, 5 channels |
| In-System Reprogrammable | No (OTP) | No (OTP) | No (OTP) | Yes (Flash) | Yes (Flash) |
| Lifecycle Status | NRND | NRND | NRND | Active | Active |
Key Differentiators
- Low-voltage CMOS process supports 2.5V to 5.5V VDD operation (vs PIC16C73A-04/SP)
- Industrial temperature grade -40C to +85C (vs PIC16LC73A-04/SP)
- OTP memory provides security and stability for production runs (vs PIC16F73-I/SP)
- 28-SPDIP package supports through-hole assembly and socket mounting (vs PIC16LC73A-04I/SO)
Design Notes
Estimated: power-supply decoupling must include a 0.1 uF ceramic capacitor placed within 5 mm of VDD (pin 20) and a second 0.1 uF near the second VSS (pin 19) to suppress switching noise from the internal CPU clock transitions. Add a 10 uF tantalum or aluminum bulk capacitor at the MCU socket entry point for high-current transient handling. For battery-powered applications, include a power-on reset delay (typically 72 ms) via configuration bits to allow VDD to stabilize before code execution begins.
The PIC16LC73A-04I/SP has no internal oscillator and requires an external crystal (typically 4 MHz fundamental mode with two 22 pF load capacitors), ceramic resonator, or external CMOS clock on OSC1/OSC2 (pins 9-10). Estimated: crystal ESR should be below 50 ohms and load capacitance matched to the resonator datasheet. For low-cost designs, ceramic resonators offer +/- 0.5% frequency tolerance versus +/- 50 ppm for crystals, but with less EMI immunity in noisy industrial environments.
The PIC16LC73A-04I/SP is OTP (One-Time Programmable) - once programmed, code cannot be erased or rewritten. This makes production programming flow critical: use a Microchip PICSTART Plus, MPLAB PM3, or compatible third-party programmer (e.g., PICkit 3 with OTG adapter) to write the device. Verify configuration bits (oscillator mode, watchdog timer, brown-out reset, code protection) match the application before bulk programming. For prototype and development work, substitute a PIC16F73 or PIC16LF73 in the same 28-SPDIP socket - they are Flash-based and reprogrammable.
Place decoupling capacitors as close as physically possible to VDD/VSS pins (within 5 mm recommended by Microchip AN588). Route MCLR (pin 1) directly to a 10 kohm pull-up to VDD with a 0.1 uF capacitor to VSS to prevent spurious resets from EMI. Keep crystal traces short (under 10 mm) and surround them with a ground pour for EMI rejection. The 28-SPDIP package leaves through-hole pads, allowing socket mounting for prototype replacement - useful when developing with a Flash-based PIC16F73 then committing to OTP PIC16LC73A-04I/SP for production.
Common pitfalls when using PIC16LC73A-04I/SP include: (1) confusing PIC16LC73A (low-voltage 2.5V) with PIC16C73A (4.0V minimum) - always verify VDD rail before substituting; (2) attempting in-circuit debugging on the -04 OTP variant - use PIC16F73 for development; (3) exceeding absolute maximum VDD of 7.0V - LC process is more sensitive than standard C process; (4) forgetting that PORTB RB6/RB7 are shared with ICSP (In-Circuit Serial Programming) and may be disturbed during low-voltage programming entry; (5) mixing up 4 MHz grade (-04) with 20 MHz grade (-20) - firmware timing loops must match oscillator frequency.
Compliance Information
Compliance status not explicitly stated in verified web data. Industrial temperature grade but not AEC-Q100 automotive qualified. For automotive applications, choose AEC-Q100 qualified PIC16F1939 or dsPIC33 families instead.
