PIC16LC71-04/SO - 8-Bit 4MHz OTP MCU 1.75KB | Microchip
MPN: PIC16LC71-04/SO ✗ End of Life| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.57 | $6.57 |
| 10 | $5.92 | $59.20 |
| 100 | $5.27 | $527.00 |
| 500 | $4.62 | $2,310.00 |
| 1,000 | $4.1 | $4,100.00 |
PIC16LC71-04/SO Overview
What is a PIC16C71 microcontroller? The PIC16C71 is an early member of Microchip's PIC® 16C mid-range 8-bit microcontroller family, which combined a Harvard-architecture RISC CPU core with on-chip peripherals such as an Analog-to-Digital Converter (ADC). These MCUs sit within the hierarchy: PIC16C71 → PIC16C7x family → PIC® 16C series → 8-bit PIC microcontrollers → microcontrollers (MCU) → integrated circuits → semiconductors. The LC sub-designation denotes a low-power CMOS process variant.
Key features of the PIC16LC71-04/SO include a 4-channel 8-bit ADC, 13 digital I/O pins, an 8-bit timer/counter, watchdog timer, and 35 single-word instructions. The Harvard RISC core executes most instructions in a single 200 ns instruction cycle at 4 MHz. Its 14-bit-wide instruction word allows compact code density compared to 12-bit PIC16C5X devices, and the architecture is upward-compatible with the PIC16C5X and PIC12CXXX families.
Typical applications include low-power embedded control, sensor signal acquisition, battery-operated instruments, simple motor control, and consumer products requiring on-chip ADC and minimal external components. The 18-pin SOIC footprint is well-suited for through-hole-replacement surface-mount designs where board space is at a premium.
Design consideration: the OTP program memory means firmware is mask-set at programming time and cannot be erased or rewritten - choose this part for mature production designs, not prototypes requiring firmware iteration. For development, consider the PIC16C71 JW (windowed EPROM) or a Flash-based PIC16F equivalent.
This page synthesizes distributor pricing, pin-compatible drop-in alternatives, and practical design notes that complement, but do not duplicate, the Microchip datasheet.
Drop-in alternatives for PIC16LC71-04/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 PIC16LC71-04/SO (same form factor and footprint) — differing in Package, Timers, ADC, Family, Operating Temperature.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LC71T-04/SO
✅ Drop-In✓ In Stock
$2.45 / Unit
View Datasheet →PIC16LC71-04I/SO
✅ Drop-In✓ In Stock
$1.85 / Unit
View Datasheet →PIC16LC71-04/SO
✅ Drop-In✓ In Stock
$4.1 / Unit
View Datasheet →PIC16C71-04/SO
✅ Drop-In✓ In Stock
$3.95 / Unit
View Datasheet →PIC16LC71-04/SO Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Family | PIC16C7x |
| Instruction Set Width | 14-bit |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle Time | 200 ns at 4 MHz |
| Program Memory Type | OTP (One-Time Programmable) |
| Program Memory Size | 1.75 KB (1K x 14) |
| RAM | 36 bytes |
| I/O Pins | 13 |
| ADC | 4-channel, 8-bit |
| Timers | 1 x 8-bit timer/counter + WDT |
| Operating Voltage Range | 3.0 V to 6.0 V |
| Package | 18-SOIC (300 mil) |
| Operating Temperature Grade | Commercial |
| Mounting Type | Surface Mount (Gull-wing) |
| RoHS Status | Compliant |
| Number of Instructions | 35 single-word |
PIC16LC71-04/SO Pin Configuration
| Pin 1 | RA2/AN2 — Bidirectional I/O pin / Analog input channel 2 |
| Pin 2 | RA3/AN3 — Bidirectional I/O pin / Analog input channel 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O pin / Timer0 clock input |
| Pin 4 | MCLR — Master Clear (Reset) input, active low |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O pin / External interrupt input |
| Pin 7 | RB1 — Bidirectional I/O pin |
| Pin 8 | RB2 — Bidirectional I/O pin |
| Pin 9 | RB3 — bidirectional I/O pin |
| Pin 10 | RB4 — Bidirectional I/O pin |
| Pin 11 | RB5 — Bidirectional I/O pin |
| Pin 12 | RB6 — Bidirectional I/O pin |
| Pin 13 | RB7 — Bidirectional I/O pin |
| Pin 14 | VDD — Positive supply voltage (3.0 V to 6.0 V) |
| Pin 15 | OSC2/CLKOUT — Oscillator crystal output / Clock output (Fosc/4) |
| Pin 16 | OSC1/CLKIN — Oscillator crystal input / External clock input |
| Pin 17 | RA0/AN0 — Bidirectional I/O pin / Analog input channel 0 |
| Pin 18 | RA1/AN1 — Bidirectional I/O pin / Analog input channel 1 |
Typical Applications
PIC16LC71-04/SO is suitable for 6 applications: Battery-Powered Sensor Interface, Consumer Appliance Control, Automotive Interior Lighting, Industrial Process Monitoring, Hobbyist and Educational Projects, Simple Motor Speed Control.
Battery-Powered Sensor Interface
The PIC16LC71-04/SO suits low-power sensor interfaces that read analog signals and actuate simple digital outputs. Its 4-channel 8-bit ADC handles thermistor, photocell, and potentiometer inputs with approximately 20 us conversion time at 4 MHz, while the LC process variant minimizes quiescent current for coin-cell or two-AA battery operation between 3.0 V and 4.5 V. The 13 I/O pins accommodate four ADC inputs plus nine digital lines for switch inputs, LED indicators, and a low-side load driver. Compared with PIC16C71 standard parts, the LC variant reduces sleep current, extending battery life in wireless sensor nodes.
Recommended
Consumer Appliance Control
The PIC16LC71-04/SO fits consumer appliance controllers that require on-chip ADC for sensor feedback and a small number of digital I/O for switches, relays, and indicator LEDs. With 1.75 KB OTP program memory, the MCU can hold simple state-machine firmware for microwave ovens, coffee makers, and small kitchen appliances. The 200 ns instruction cycle at 4 MHz provides sufficient throughput for keypad scanning and PWM output without an external timer IC. Its commercial temperature range (0C-70C) and SOIC-18 footprint suit through-hole-replacement surface-mount designs in cost-sensitive consumer products.
Recommended
Automotive Interior Lighting
The PIC16LC71-04/SO, while not AEC-Q100 qualified, has historically been used in non-safety automotive interior lighting applications such as dome-light dimmers and ambient-LED controllers. Its 4 MHz RISC core and 8-bit ADC enable closed-loop current sensing for LED brightness control, while 13 I/O pins drive multiple PWM channels directly. Designers should note that for safety-critical automotive applications, AEC-Q100 qualified PIC16F-series alternatives are strongly recommended over the obsolete LC71 OTP variant.
Recommended
Industrial Process Monitoring
The PIC16LC71-04/SO integrates well into industrial process monitoring modules that read 4-20 mA loop signals via the on-chip 8-bit ADC and translate them to relay or transistor outputs. With 36 bytes of RAM, the MCU handles small scaling and linearization tables without external memory. The 18-SOIC package supports surface-mount manufacturing, and the 4 MHz clock rate is sufficient for slow-loop control (sub-100 Hz bandwidth). For harsher industrial environments, the PIC16LC71-04I/SO industrial-temperature variant extends operation to -40C to +85C.
Recommended
Hobbyist and Educational Projects
The PIC16LC71-04/SO remains popular in hobbyist and educational environments where students learn 8-bit embedded programming on a classic PIC architecture. Its 35-instruction RISC set, 200 ns cycle time, and on-chip peripherals (ADC, timer, watchdog) provide a complete learning platform. Note that for repeated firmware iteration, the OTP memory limitation is a drawback - development should use a PIC16C71 JW (windowed EPROM) part or migrate to a PIC16F-series Flash-based MCU. The 18-SOIC footprint accepts standard SOIC breakout boards.
Recommended
Simple Motor Speed Control
The PIC16LC71-04/SO is suitable for low-cost brushed DC motor speed controllers in applications such as small fans, toys, and battery-powered tools. Its 8-bit timer generates PWM output for motor drive, while the ADC reads back-EMF or current-sense signals for closed-loop speed regulation. With 13 I/O pins, the MCU handles direction control, enable lines, tachometer input, and fault monitoring. The LC low-power variant suits battery-operated tools where standby current is critical.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC71-04/SO — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC71-04/P | PIC16LC71T-04/SO | PIC16LC71-04I/SO | PIC16LC71-04/SO (tube) | PIC16C71-04/SO |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | 18-SOIC (300 mil) | 18-PDIP (different footprint) | 18-SOIC (same footprint) | 18-SOIC (same footprint) | 18-SOIC (same footprint) | 18-SOIC (same footprint) |
| Program Memory | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP | 1.75 KB OTP |
| Maximum Clock | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz | 4 MHz |
| RAM | 36 bytes | 36 bytes | 36 bytes | 36 bytes | 36 bytes | 36 bytes |
| I/O Pins | 13 | 13 | 13 | 13 | 13 | 13 |
| Operating Voltage | 3.0 V to 6.0 V (LC) | 3.0 V to 6.0 V (LC) | 3.0 V to 6.0 V (LC) | 3.0 V to 6.0 V (LC) | 3.0 V to 6.0 V (LC) | 3.0 V to 6.0 V (standard) |
| Temperature Grade | Commercial (0C to +70C) | Commercial | Commercial | Industrial (-40C to +85C) | Commercial | Commercial |
| Lifecycle Status | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete | Obsolete |
Key Differentiators
- LC low-power CMOS process reduces quiescent current (vs PIC16C71-04/SO (standard CMOS))
- Industrial temperature variant available in same SOIC-18 footprint (vs PIC16LC71-04/SO (commercial grade))
- On-chip 4-channel 8-bit ADC eliminates external converter (vs PIC16C5x baseline PIC family)
Design Notes
OTP program memory cannot be erased or rewritten. Verify firmware thoroughly using a windowed EPROM sample (PIC16C71 JW) or a PIC16F-series Flash equivalent before committing to OTP for production. Once programmed, an OTP part with a firmware bug becomes e-waste - this is the single most common pitfall when designing with the PIC16LC71 family.
The MCLR (pin 4) reset pin requires a pull-up resistor to VDD for reliable operation. A 10 kohm pull-up to VDD with a 100 nF capacitor to ground on the MCLR line provides noise-immune reset. For in-circuit programming, MCLR must rise to approximately 13 V - ensure your programming fixture can supply this without disturbing other components on the VDD rail.
Place decoupling capacitor (100 nF ceramic) as close as possible to the VDD pin (pin 14). For analog applications using the on-chip ADC, add a 10 uF bulk capacitor at the VDD pin and route analog and digital supply traces separately to minimize ADC noise coupling. The 18-SOIC land pattern should follow the SOIC-18 (300 mil) standard JEDEC footprint with 0.050 inch lead pitch and 0.300 inch body width.
When using the on-chip ADC, configure the A/D conversion clock (TAD) for at least 1.6 us. At 4 MHz Fosc with Fosc/8 as ADC clock source, TAD = 2 us which satisfies this requirement. Sample acquisition time must also be at least 20 us (TACQ) for full 8-bit accuracy. Skipping these timing requirements is a common source of noisy or inaccurate ADC readings.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. Not AEC-Q100 qualified - choose PIC16F1823 or PIC16F193x for automotive applications. Lead-free matte-tin finish suitable for 260C peak reflow.
