PIC16LC621-04E/P - 4MHz 8-bit OTP MCU 1.75KB DIP-18 | Microchip
MPN: PIC16LC621-04E/P ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.85 | $3.85 |
| 10 | $3.46 | $34.60 |
| 100 | $3.08 | $308.00 |
| 500 | $2.77 | $1,385.00 |
| 1,000 | $2.46 | $2,460.00 |
PIC16LC621-04E/P Overview
A microcontroller (MCU) is a single-chip computer that integrates a CPU core, non-volatile program memory, working RAM, and peripheral I/O onto one silicon die. Within the broader hierarchy, an MCU is a type of embedded processor, sitting below microprocessors in computational capability but above discrete logic in functional density. The PIC16C/LC62x family targets cost-sensitive 8-bit embedded applications, providing RISC architecture with a small instruction set (35 instructions) and single-cycle execution (200 ns at 20 MHz).
Key features of the PIC16LC621 include 4 MHz maximum clock, 12-bit-wide instructions, 8-bit-wide data path, seven or eight special function hardware registers, and a two-level deep hardware stack. The device supports direct, indirect, and relative addressing modes, and offers 13 bidirectional I/O pins capable of driving segmented LED displays or interfacing to sensors.
The architecture uses a Harvard-style separate code and data bus, with 14-bit wide instruction words for compact code density. The low-power 'LC' designation indicates the 2.5V to 6.25V supply voltage range, suiting battery-powered designs. The '04' speed grade caps operation at 4 MHz, and the 'E' suffix denotes the automotive (-40C to +125C) operating temperature range.
Typical applications include automotive body controllers, simple sensor interfaces, low-end consumer appliances, LED lighting controllers, and industrial control replacement of discrete logic. The OTP program memory enables rapid prototyping and low-volume production without the tooling cost of mask-ROM devices.
When designing with this MCU, ensure the clock source (RC, crystal, or resonator) is placed close to the OSC1/OSC2 pins and that decoupling capacitors (0.1 uF) are placed adjacent to VDD. The MCLR reset pin must be pulled high through a resistor for normal operation.
This page synthesizes distributor pricing, drop-in alternatives, and practical design notes not found in the manufacturer datasheet, giving engineers a single source for sourcing and engineering decisions.
Drop-in alternatives for PIC16LC621-04E/P — 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 PIC16LC621-04E/P (same form factor and footprint) — differing in Operating Temperature Range, Core Architecture, Package, Program Memory Type, Program Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LC621-04/P
✅ Drop-In✓ In Stock
$1.65 / Unit
View Datasheet →PIC16LC620-04E/P
✅ Drop-In✓ In Stock
$1.5 / Unit
View Datasheet →PIC16LC620A-04E/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.85 / Unit
View Datasheet →PIC16LC620A-04/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.3 / Unit
View Datasheet →PIC16LC56A-04I/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$1.18 / Unit
View Datasheet →PIC16LC621-04E/P Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC |
| Family | PIC16C/LC62x |
| Program Memory Size | 1.75 KB (1K x 14) |
| Program Memory Type | OTP (One-Time Programmable) / EPROM |
| RAM Size | 80 bytes |
| EEPROM Size | None |
| Maximum Clock Frequency | 4 MHz |
| Instruction Cycle | 200 ns (single-cycle) |
| Instruction Set Size | 35 instructions |
| I/O Pins | 13 |
| Supply Voltage (VDD) | 2.5 V to 6.25 V |
| Operating Temperature Range | -40C to +125C (Automotive) |
| Package | 18-pin PDIP (DIP-18) |
| Mounting Type | Through-Hole |
| Timers | 1 x 8-bit |
| ADC | None |
| Stack Depth | 2 levels (hardware) |
PIC16LC621-04E/P Pin Configuration
| Pin 1 | RA2 — Bidirectional I/O pin, PORTA bit 2 |
| Pin 2 | RA3 — Bidirectional I/O pin, PORTA bit 3 |
| Pin 3 | RA4/T0CKI — Bidirectional I/O pin / Timer0 clock input, PORTA bit 4 |
| Pin 4 | MCLR — Master Clear (reset) input, active low |
| Pin 5 | VSS — Ground reference |
| Pin 6 | RB0/INT — Bidirectional I/O pin / External interrupt, PORTB bit 0 |
| Pin 7 | RB1 — Bidirectional I/O pin, PORTB bit 1 |
| Pin 8 | RB2 — Bidirectional I/O pin, PORTB bit 2 |
| Pin 9 | RB3 — Bidirectional I/O pin, PORTB bit 3 |
| Pin 10 | RB4 — Bidirectional I/O pin, PORTB bit 4 |
| Pin 11 | RB5 — Bidirectional I/O pin, PORTB bit 5 |
| Pin 12 | RB6 — Bidirectional I/O pin, PORTB bit 6 |
| Pin 13 | RB7 — Bidirectional I/O pin, PORTB bit 7 |
| Pin 14 | VDD — Positive supply voltage (2.5V to 6.25V) |
| Pin 15 | OSC2/CLKOUT — Oscillator output / Clock output (Fosc/4) |
| Pin 16 | OSC1/CLKIN — Oscillator input / External clock input |
| Pin 17 | RA0 — Bidirectional I/O pin, PORTA bit 0 |
| Pin 18 | RA1 — Bidirectional I/O pin, PORTA bit 1 |
Typical Applications
PIC16LC621-04E/P is suitable for 6 applications: Automotive Body Controller, LED Lighting Controller, Industrial Sensor Interface, Consumer Appliance Control, Replacement of Discrete Logic, Low-Volume Production Controller.
Automotive Body Controller
The PIC16LC621-04E/P's automotive -40C to +125C temperature grade makes it suitable for automotive body electronics where the MCU sits in the cabin or engine compartment. Its 1.75 KB OTP program memory is sufficient for simple body control tasks such as interior lighting sequencing, mirror adjustment, seat-position memory recall, and basic window lift logic. The 13 I/O pins can directly drive low-side MOSFETs for relay switching, while the 2.5V to 6.25V supply range accepts the noisy 12V vehicle bus after a simple regulator. Compared with Flash-based PIC16F equivalents, the OTP variant reduces per-unit cost in high-volume automotive programs where firmware is fixed at production time.
Recommended
LED Lighting Controller
The PIC16LC621-04E/P's 25 mA per-pin sink/source capability lets it directly drive small LED matrices and seven-segment displays without external transistor buffers. The 35-instruction RISC core and 200 ns instruction cycle at 4 MHz provide enough bandwidth for multiplexed LED refresh at typical 100+ Hz rates, eliminating flicker. With 1.75 KB of code space, designers can implement chase patterns, dimming via PWM, and basic color-mixing algorithms for architectural or decorative LED strips. The 2.5V to 6.25V supply range simplifies designs using 3.3V or 5V LED driver rails.
Recommended
Industrial Sensor Interface
For industrial 4-20 mA loop-powered sensors, the PIC16LC621-04E/P offers sufficient compute for linearization, filtering, and HART-like communication protocols. Its 80 bytes of RAM can buffer sensor samples, while the 1.75 KB program memory holds calibration constants and simple digital-filter algorithms. The wide 2.5V to 6.25V supply tolerance accommodates industrial 24V rails after a small LDO. The automotive temperature grade is over-spec but cost-effective for industrial environments with extreme thermal cycling, and the 18-pin PDIP package supports hand-solderable prototyping and field-replaceable modules.
Recommended
Consumer Appliance Control
Small kitchen and personal-care appliances such as coffee makers, blenders, and hair dryers benefit from the PIC16LC621-04E/P's low-cost OTP memory and compact 18-pin PDIP form factor. The MCU can handle switch debouncing, timer sequencing, motor PWM control via its single 8-bit timer, and simple LED user-interface patterns. With 13 I/O pins, designers can interface directly to membrane keypads and seven-segment displays without glue logic. The 2.5V to 6.25V operating range simplifies designs powered by 3xAA batteries or 5V wall adapters, while automotive temperature grade ensures reliability in warm appliance enclosures.
Recommended
Replacement of Discrete Logic
The PIC16LC621-04E/P can replace multiple 74HC-series logic gates, flip-flops, and counters in legacy designs, reducing PCB area and BOM cost. With 1.75 KB of code space, designers can implement custom state machines, glue logic, and timing functions in firmware rather than hardware. The 13 I/O pins handle typical glue-logic signal counts, and the 200 ns instruction cycle supports real-time control of high-speed logic-replacement applications. The automotive temperature grade is a bonus for industrial or vehicular retrofits of older discrete-logic designs.
Recommended
Low-Volume Production Controller
For low-to-medium-volume production runs (under 10k units), the PIC16LC621-04E/P's OTP memory is more cost-effective than Flash or mask-ROM parts, which carry NRE charges or higher per-unit prices. Designers can iterate firmware using windowed CERDIP prototypes, then commit to plastic OTP for production. The 18-pin PDIP package supports both prototyping on breadboards and through-hole production assemblies, and the automotive -40C to +125C range covers most commercial and industrial environments without separate qualification.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LC621-04E/P — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LC621-04/P | PIC16LC620-04E/P | PIC16LC620A-04E/P | PIC16LC620A-04/P | PIC16LC56A-04I/P |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Package | PDIP-18 | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same | PDIP-18 - same |
| Program Memory | 1.75 KB (1K x 14) | 1.75 KB (1K x 14) - same | 1 KB (512 x 14) - smaller | 1 KB (512 x 14) - smaller | 1 KB (512 x 14) - smaller | 1 KB (512 x 12) - older architecture |
| RAM Size | 80 bytes | 80 bytes - same | 80 bytes - same | 80 bytes - same | 80 bytes - same | 32 bytes - smaller |
| Maximum Clock Speed | 4 MHz | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same | 4 MHz - same |
| I/O Pins | 13 | 13 - same | 13 - same | 13 - same | 13 - same | 12 - slightly fewer |
| Temperature Grade | Automotive (-40C to +125C) | Industrial (-40C to +85C) | Automotive (-40C to +125C) - same | Automotive (-40C to +125C) - same | Industrial (-40C to +85C) | Industrial (-40C to +85C) |
| Memory Type | OTP/EPROM | OTP/EPROM - same | OTP/EPROM - same | OTP/EPROM - same | OTP/EPROM - same | OTP/EPROM - same |
Key Differentiators
- Automotive temperature grade at PIC16LC62x price point (vs PIC16LC621-04/P)
- 1.75 KB program memory versus 1 KB on PIC16LC620 (vs PIC16LC620-04E/P)
- Richer instruction set and peripherals than PIC16C5x legacy (vs PIC16LC56A-04I/P)
Design Notes
Place a 0.1 uF ceramic decoupling capacitor as close as possible to the VDD pin (pin 14) with the ground return to VSS (pin 5) within 5 mm. For designs with switching loads or noisy relays, add a 10 uF tantalum or electrolytic bulk capacitor on the VDD rail. The PIC16LC621-04E/P's 2.5V to 6.25V supply range allows direct connection to a 5V regulated rail or to a 3.3V low-power rail without level shifting.
Route the OSC1/OSC2 traces (pins 16 and 15) as short and symmetric as possible to minimize clock skew and EMI. When using a crystal or ceramic resonator, keep the load capacitors within 5 mm of the oscillator pins. The MCLR pin (pin 4) must be pulled high to VDD through a 10 kohm resistor for normal operation; add a 100 nF capacitor to VSS if a manual reset button is connected to suppress noise-induced resets.
Do not assume unused I/O pins default to inputs - they must be configured as outputs and driven low to minimize power consumption and reduce EMI susceptibility. The 2-level hardware stack means the PIC16LC621 cannot handle deep subroutine nesting or interrupts within interrupts without stack overflow; keep call depth to 1-2 levels. The OTP memory is one-time-programmable - any code bug requires a new chip, so verify firmware on a windowed CERDIP prototype (e.g., PIC16C621-04/JW) before committing to OTP production.
Compliance Information
RoHS/REACH status not explicitly stated in provided web data. The 'E' suffix indicates automotive temperature grade per Microchip naming conventions; this predates AEC-Q100 qualification for older PIC16C OTP parts. Verify RoHS compliance with Microchip directly before using in RoHS-restricted designs.
