PIC18F4320-E/ML - 8-bit MCU, 8KB Flash, 44-QFN | Microchip
MPN: PIC18F4320-E/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $6.42 | $6.42 |
| 10 | $5.78 | $57.80 |
| 100 | $5.16 | $516.00 |
| 500 | $4.61 | $2,305.00 |
| 1,000 | $4.1 | $4,100.00 |
PIC18F4320-E/ML Overview
A microcontroller (MCU) is a single-chip computer containing a CPU core, program and data memory, and integrated peripherals such as timers, ADC, communication ports, and GPIO. The PIC18F family sits at the upper end of Microchip's 8-bit portfolio, offering an enhanced instruction set with C-friendly addressing, prioritized interrupts, and a 16-bit instruction word. Within the wider taxonomy, MCUs belong to embedded computing, which sits below microprocessors in the system hierarchy; the PIC18F family targets cost-sensitive real-time control rather than high-throughput digital signal processing.
Key features include 36 digital I/O pins, 13 channels of 10-bit Analog-to-Digital converter (ADC), 2 analog comparators, 2 Capture/Compare/PWM modules, a master Synchronous Serial Port configurable as SPI or I2C, an Addressable Universal Asynchronous Receiver/Transmitter (AUSART), and self-programming Flash with In-Circuit Debug support. The device supports 1,000,000 erase/write cycles on Flash and 100,000 cycles on EEPROM, with 40-year data retention. The 'E' suffix indicates the extended (-40C to +125C) industrial temperature range, while the 'ML' suffix designates the 44-lead QFN package.
The PIC18F4320 uses a Harvard RISC architecture with separate program and data buses, hardware multiply, and a 31-level stack, enabling deterministic real-time response. The 10-bit ADC integrates with the analog comparators for sensor conditioning, while the ECCP and CCP modules generate PWM for motor and power control. Self-programmability allows field firmware updates without an external programmer.
Typical applications include industrial control, automotive body electronics, sensor interfacing, low-end motor control, and consumer appliances. The 44-QFN package suits space-constrained designs requiring up to 36 GPIO plus analog and serial connectivity. The PIC18F4320 pairs naturally with the PIC18F4220/4520 family siblings for upgrade/downgrade flexibility within the same 44-QFN footprint.
When designing with this MCU, ensure adequate decoupling (100 nF ceramic per VDD pin) and route the exposed thermal pad to a continuous ground plane for thermal dissipation and low-impedance ground return. Verify ICP/ICD pin assignments against Microchip's programming specification to avoid debugger conflicts in production units.
This page synthesizes distributor pricing, verified drop-in alternatives, and practical design notes not found in the bare manufacturer datasheet.
Drop-in alternatives for PIC18F4320-E/ML — 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 PIC18F4320-E/ML (same form factor and footprint) — differing in Package, Core Architecture, Operating Temperature, Power-Saving Modes, ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC18F4520-E/ML
✅ Drop-In✓ In Stock
$2.78 / Unit
View Datasheet →PIC18F4220-E/ML
✅ Drop-In✓ In Stock
$4.62 / Unit
View Datasheet →PIC18F4320-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4320-E/P
✅ Drop-In ⚠️ Specs Unverified✓ In Stock
$2.95 / Unit
View Datasheet →PIC18F4420-I/ML
✅ Drop-In📋 Reference alternative (not in catalog)
PIC18F4320-E/ML Maximum Ratings & Electrical Characteristics
| Core Processor | PIC |
| Core Size | 8-bit |
| Max CPU Speed | 25 MHz (40 MHz on selected speed grades) |
| Program Memory Type | Flash |
| Program Memory Size | 8 KB (4K x 16) |
| RAM Size | 512 bytes |
| EEPROM Size | 256 bytes |
| Number of I/O | 36 |
| Package | 44-QFN (8x8 mm) with exposed thermal pad |
| Supply Voltage Range | 2.0 V to 5.5 V |
| Operating Temperature Range | -40C to +125C (E suffix = extended industrial) |
| ADC | 10-bit, 13 channels |
| Comparators | 2 analog comparators |
| PWM / CCP / ECCP | 2 Capture/Compare/PWM modules |
| Communication | SPI, I2C (MSSP), AUSART |
| Mounting Type | Surface Mount |
| RoHS Status | Compliant |
| Lead-Free | Yes |
PIC18F4320-E/ML Pin Configuration
| Pin 1 | OSC1/CLKI/RA7 — Oscillator crystal input / external clock / GPIO RA7 |
| Pin 2 | OSC2/CLKO/RA6 — Oscillator crystal output / clock out / GPIO RA6 |
| Pin 3 | MCLR/VPP/RE3 — Master Clear (reset) / programming voltage / GPIO RE3 |
| Pin 4 | RA0/AN0 — GPIO RA0 / analog input AN0 |
| Pin 5 | RA1/AN1 — GPIO RA1 / analog input AN1 |
| Pin 6 | RA2/AN2/VREF- — GPIO RA2 / analog input AN2 / ADC VREF- |
| Pin 7 | RA3/AN3/VREF+ — GPIO RA3 / analog input AN3 / ADC VREF+ |
| Pin 8 | RA4/AN4/T0CKI — GPIO RA4 / analog AN4 / Timer0 clock input |
| Pin 9 | RA5/AN5/SS/LVDIN — GPIO RA5 / AN5 / SPI slave select / LVD input |
| Pin 10 | VSS — Ground reference |
| Pin 11 | VDD — Positive supply voltage (2.0-5.5 V) |
| Pin 12 | RB0/AN12/INT0 — GPIO RB0 / AN12 / external interrupt 0 |
| Pin 13 | RB1/AN10/INT1 — GPIO RB1 / AN10 / external interrupt 1 |
| Pin 14 | RB2/AN8/INT2 — GPIO RB2 / AN8 / external interrupt 2 |
| Pin 15 | RB3/AN9/CCP2A — GPIO RB3 / AN9 / CCP2 PWM output A |
| Pin 16 | RB4/AN11 — GPIO RB4 / analog AN11 |
| Pin 17 | RB5/CCP3A — GPIO RB5 / CCP3 PWM output A |
| Pin 18 | RB6/PGC — GPIO RB6 / ICSP clock (ICD clock) |
| Pin 19 | RB7/PGD — GPIO RB7 / ICSP data (ICD data) |
| Pin 20 | VSS — Ground reference |
| Pin 21 | VDD — Positive supply voltage (2.0-5.5 V) |
| Pin 22 | RC0/T1OSO/T1CKI — GPIO RC0 / Timer1 oscillator out / Timer1 clock in |
| Pin 23 | RC1/T1OSI/CCP2B — GPIO RC1 / Timer1 oscillator in / CCP2 PWM output B |
| Pin 24 | RC2/CCP1 — GPIO RC2 / CCP1 PWM |
| Pin 25 | RC3/SCK/SCL — GPIO RC3 / SPI clock / I2C clock |
| Pin 26 | RC4/SDI/SDA — GPIO RC4 / SPI data in / I2C data |
| Pin 27 | RC5/SDO — GPIO RC5 / SPI data out |
| Pin 28 | RC6/TX/CK — GPIO RC6 / AUSART TX / clock |
| Pin 29 | RC7/RX/DT — GPIO RC7 / AUSART RX / data |
| Pin 30 | VSS — Ground reference |
| Pin 31 | VDD — Positive supply voltage (2.0-5.5 V) |
| Pin 32 | RD0/PSP0 — GPIO RD0 / parallel slave port bit 0 |
| Pin 33 | RD1/PSP1 — GPIO RD1 / parallel slave port bit 1 |
| Pin 34 | RD2/PSP2 — GPIO RD2 / parallel slave port bit 2 |
| Pin 35 | RD3/PSP3 — GPIO RD3 / parallel slave port bit 3 |
| Pin 36 | RD4/PSP4 — GPIO RD4 / parallel slave port bit 4 |
| Pin 37 | RD5/PSP5 — GPIO RD5 / parallel slave port bit 5 |
| Pin 38 | RD6/PSP6 — GPIO RD6 / parallel slave port bit 6 |
| Pin 39 | RD7/PSP7 — GPIO RD7 / parallel slave port bit 7 |
| Pin 40 | VSS — Ground reference |
| Pin 41 | VDD — Positive supply voltage (2.0-5.5 V) |
| Pin 42 | RE0/RD/AN5 — GPIO RE0 / parallel read / AN5 |
| Pin 43 | RE1/WR/AN6 — GPIO RE1 / parallel write / AN6 |
| Pin 44 | RE2/CS/AN7 — GPIO RE2 / parallel chip select / AN7 |
Typical Applications
PIC18F4320-E/ML is suitable for 6 applications: Industrial Sensor Interface, Automotive Body Electronics, Low-End Motor Control (BLDC / Stepper), Consumer Appliance Control, Data Acquisition / Instrumentation Front-End, Home Automation / IoT Edge Node.
Industrial Sensor Interface
The PIC18F4320-E/ML is well suited for industrial sensor hubs that aggregate multiple analog and digital signals. Its 13-channel 10-bit ADC directly samples thermistor bridges, pressure transducers, and 4-20 mA loop signals with no external multiplexer, while the 2 analog comparators handle threshold detection for over-temperature or over-current events. With 36 GPIO the MCU can also drive status LEDs and read push-buttons or rotary switches, eliminating a glue-logic ASIC. Running at 25 MHz with the AUSART, the device streams conditioned data to a host PLC or HMI at 115.2 kbps. The extended -40C to +125C temperature range and 2.0-5.5 V supply tolerance make it compatible with 24 V industrial rails after regulation.
Recommended
Automotive Body Electronics
Within automotive body modules such as door controllers, seat controllers, and lighting drivers, the PIC18F4320-E/ML delivers the right mix of analog integration and PWM channels. The 2 CCP/ECCP modules generate PWM for LED dimming or mirror-position servo control, while the 13-channel ADC monitors battery voltage, switch states, and motor current. Its extended industrial temperature range handles under-hood and cabin thermal stress, and the self-programming Flash supports OEM firmware updates during service. The MSSP serves SPI peripherals such as LED drivers or I2C sensors. Although not AEC-Q100 qualified, the part is widely used in non-safety automotive body functions where extended temperature operation is sufficient.
Recommended
Low-End Motor Control (BLDC / Stepper)
The PIC18F4320-E/ML controls small brushless DC and stepper motors in appliance fans, pumps, and small-format robotics. Its 2 CCP/ECCP modules generate complementary PWM with dead-band control, while the 13-channel ADC samples back-EMF or phase current for sensorless commutation. The 25 MHz / 10 MIPS throughput is sufficient for FOC or trapezoidal commutation of motors up to several hundred watts. Six of the 36 GPIO can be dedicated to high-current gate-driver control. EEPROM stores calibration and ramp profiles, allowing identical hardware to support multiple motor SKUs without firmware re-flash in production.
Recommended
Consumer Appliance Control
White-goods appliances - washing machines, dishwashers, refrigerators, and air-conditioner indoor units - are a natural fit for the PIC18F4320-E/ML. The MCU drives user-interface keypads and 7-segment or character LCDs, runs the main wash/refrigeration cycle state machine, and interfaces to triac-driven heater or compressor loads via optocouplers. The 256-byte EEPROM preserves user settings (temperature, mode, timer) across power cycles, while 512 bytes of RAM is sufficient for a 32-step cycle descriptor. The extended temperature grade survives compressor compartment thermal swings, and the 44-QFN compact footprint frees PCB area for relay and triac footprints.
Recommended
Data Acquisition / Instrumentation Front-End
Portable and bench-top data-acquisition front-ends benefit from the PIC18F4320-E/ML's 13-channel 10-bit ADC, generous SRAM, and on-chip EEPROM for calibration constants. The MSSP provides SPI or I2C to external high-precision ADCs or DACs, while the AUSART streams acquired samples to a host PC. The device's deterministic interrupt latency and 8-bit instruction set make it suitable for sequencing multi-channel sweeps at known sample rates. The exposed thermal pad of the 44-QFN keeps junction temperature low during continuous ADC conversion, improving measurement repeatability in calibration environments.
Recommended
Home Automation / IoT Edge Node
The PIC18F4320-E/ML acts as an edge node in home-automation installations where on-board intelligence outweighs wireless complexity. It reads wall switches, dimmer sliders, and contact sensors, drives local relays, and communicates with a central hub via RS-485, I2C, or simple UART protocols. The 36 GPIO handle multi-zone lighting without external expanders, and the 256-byte EEPROM stores zone configuration and last-known states for power-loss recovery. The AUSART and MSSP run Modbus-RTU or DMX512 protocols used in residential lighting and HVAC control. The extended temperature grade supports outdoor junction boxes and garage-mounted control panels.
Recommended
Recommended Products Summary
Engineering reference data for PIC18F4320-E/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC18F4520-E/ML | PIC18F4220-E/ML | PIC18F4320-I/ML | PIC18F4420-I/ML |
|---|---|---|---|---|---|
| Package | 44-QFN (8x8 mm) | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology |
| Flash Memory | 8 KB | 32 KB | 4 KB | 8 KB (identical) | 16 KB |
| SRAM | 512 bytes | 1536 bytes | 512 bytes | 512 bytes (identical) | 768 bytes |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes (identical) | 256 bytes |
| Max CPU Speed | 25 MHz | 25 MHz | 25 MHz | 25 MHz | 25 MHz |
| ADC Channels | 13 (10-bit) | 13 (10-bit) | 13 (10-bit) | 13 (10-bit) | 13 (10-bit) |
| Temperature Range | -40C to +125C (E) | -40C to +125C (E) | -40C to +125C (E) | -40C to +85C (I) | -40C to +85C (I) |
| GPIO Count | 36 | 36 | 36 | 36 | 36 |
Key Differentiators
- Industry-standard 8-bit PIC18 architecture with C-friendly instruction set (vs PIC16F series)
- 44-QFN compact footprint with 36 GPIO plus 13 ADC channels (vs PIC18F2520/2523 (28-pin SOIC variants))
- Extended industrial -40C to +125C temperature grade (vs PIC18F4320-I/ML)
- Self-programming Flash with 1M erase/write cycles (vs External EEPROM storage for firmware parameters)
Design Notes
The PIC18F4320-E/ML has four VDD pins (11, 21, 31, 41) and four VSS pins (10, 20, 30, 40). Place a 100 nF ceramic decoupling capacitor as close as possible to each VDD/VSS pair. For noisy environments (motor control, relay boards) add a bulk 10 uF tantalum or polymer capacitor near the package. Keep analog and digital VDD traces separated if possible, joining them only at a single point to reduce digital switching noise coupling into the ADC reference.
The 44-QFN package exposes a metal pad on its underside (pin 'EP'). This pad is the primary thermal path to the PCB and must be soldered to a continuous ground copper plane of at least 1 square inch. With the EP properly soldered, theta_JA falls from approximately 35 C/W (no EP) to under 20 C/W, enabling full-speed operation in enclosed industrial enclosures. Without proper EP soldering, the junction temperature may exceed 125 C at high ambient.
Route the ICSP pins RB6/PGC and RB7/PGD with short traces to a programming header or test pad. Do NOT populate external pull-ups on these pins because the ICD/PICkit debugger uses its own drive scheme. Place a 10 kohm pull-up on MCLR for normal operation. If you use an in-circuit debugger, route PGC/PGD as a twisted pair or with ground on adjacent layers to avoid noise injection during live debugging of high-speed ADC sequences.
Do not leave unused I/O pins floating. Configure all unused pins as outputs driving low, or as inputs with the internal weak pull-up enabled (RBPU cleared, individual WPUx set). Floating pins can cause excess supply current (typically 100 uA per floating input) and may trigger false interrupts. Also note that pins shared with ADC inputs should be configured as analog (ANSELx set) when used as analog, or digital noise will couple into the ADC readings. Estimated: typical ADC SNR degradation from unconfigured digital inputs is 4-6 dB.
For ADC accuracy, place a small RC filter (10 ohm + 100 nF) on each analog input pin near the MCU to attenuate transient spikes from digital switching. Route analog signals with ground guard traces on both sides, and keep analog traces away from switching nodes like PWM outputs or oscillator traces. Avoid running analog traces parallel to high-current traces; if you must cross, do so at 90 degrees. These layout practices will preserve the 10-bit ADC linearity at full throughput.
Compliance Information
RoHS compliant and lead-free per Microchip product environmental compliance documentation. Not AEC-Q100 qualified - use PIC18FxxK80 family for automotive safety applications. REACH compliance status published in Microchip material declaration database.
