PIC16LF1939T-I/ML - 28KB Flash 8-bit MCU, 44-QFN | Microchip
MPN: PIC16LF1939T-I/ML ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $3.58 | $3.58 |
| 10 | $3.42 | $34.20 |
| 100 | $3.12 | $312.00 |
| 500 | $2.86 | $1,430.00 |
| 1,000 | $2.62 | $2,620.00 |
PIC16LF1939T-I/ML Overview
A PIC microcontroller is a compact, programmable computing core built around a Harvard RISC architecture that integrates flash memory, RAM, EEPROM, peripherals, and I/O into a single chip. PIC16F-series MCUs sit in the low-end 8-bit tier of the PIC family tree (PIC10/12/16/18/24/32), balancing code density, peripheral integration, and extreme-low-power (XLP) operation, and are commonly used where cost, deterministic timing, and small footprint matter more than raw throughput.
Key features include nanoWatt XLP technology for sub-µA sleep currents, an on-chip 32 kHz oscillator, internal voltage reference, capacitive touch support via the mTouch® peripheral, and up to 36 general-purpose I/O. The device also integrates a Liquid Crystal Display (LCD) driver, multiple timers, enhanced USART, MSSP for SPI/I2C, and 10-bit ADC with up to 14 channels depending on package.
The PIC16LF1939T-I/ML targets designs that need LCD-driving capability in a compact 44-QFN footprint, such as thermostats, metering, consumer appliances, and human-machine interface panels. Its XLP nanoWatt technology enables battery lifetimes of years on a single cell when the MCU spends most of its time in sleep or doze modes.
When designing, ensure the exposed pad of the QFN package is soldered to a sufficiently large copper pour for thermal dissipation and electrical grounding; an unsoldered thermal pad degrades thermal performance and can cause intermittent failures. The 'T' suffix indicates Tape-and-Reel packaging for high-volume SMT assembly.
Drop-in alternatives for PIC16LF1939T-I/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 PIC16LF1939T-I/ML (same form factor and footprint) — differing in Core Architecture, Package, Maximum CPU Speed, Program Memory (Flash), ADC.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
PIC16LF1939-I/ML
✅ Drop-In✓ In Stock
$3.98 / Unit
View Datasheet →PIC16LF1939T-I/PT
✅ Drop-In✓ In Stock
$1.78 / Unit
View Datasheet →PIC16LF1938T-I/ML
✅ Drop-In✓ In Stock
$1.73 / Unit
View Datasheet →PIC16LF1939T-I/MP
✅ Drop-In📋 Reference alternative (not in catalog)
PIC16LF1939T-I/ML Maximum Ratings & Electrical Characteristics
| Core Architecture | PIC 8-bit RISC (Harvard) |
| Family | PIC® XLP™ 16F |
| Program Memory (Flash) | 28 KB (16K x 14 words) |
| RAM Size | 1 KB |
PIC16LF1939T-I/ML Pin Configuration
| Pin 1 | RB5 — General purpose I/O / programming clock |
| Pin 2 | RB4 — General purpose I/O / programming data |
| Pin 3 | RB3 — General purpose I/O |
| Pin 4 | RB2 — General purpose I/O |
| Pin 5 | RB1 — General purpose I/O |
| Pin 6 | RB0 — General purpose I/O / interrupt-on-change |
| Pin 7 | VDD — Positive supply (1.8 V to 5.5 V) |
| Pin 8 | VSS — Ground reference |
| Pin 9 | RA7 — General purpose I/O / OSC1 |
| Pin 10 | RA6 — General purpose I/O / OSC2 |
| Pin 11 | RA5 — General purpose I/O |
| Pin 12 | RA4 — General purpose I/O |
| Pin 13 | RA3 — General purpose I/O / MCLR |
| Pin 14 | RA2 — General purpose I/O |
| Pin 15 | RA1 — General purpose I/O / ICSPCLK |
| Pin 16 | RA0 — General purpose I/O / ICSPDAT |
| Pin 17 | VSS — Ground reference |
| Pin 18 | VDD — Positive supply |
| Pin 19 | RC7 — General purpose I/O / RX/DT |
| Pin 20 | RC6 — General purpose I/O / TX/CK |
| Pin 21 | RC5 — General purpose I/O |
| Pin 22 | RC4 — General purpose I/O |
| Pin 23 | RC3 — General purpose I/O / SCL |
| Pin 24 | RC2 — General purpose I/O / SDA |
| Pin 25 | RC1 — General purpose I/O |
| Pin 26 | RC0 — General purpose I/O |
| Pin 27 | RD7 — General purpose I/O / LCD segment |
| Pin 28 | RD6 — General purpose I/O / LCD segment |
| Pin 29 | RD5 — General purpose I/O / LCD segment |
| Pin 30 | RD4 — General purpose I/O / LCD segment |
| Pin 31 | RD3 — General purpose I/O / LCD segment |
| Pin 32 | RD2 — General purpose I/O / LCD segment |
| Pin 33 | RD1 — General purpose I/O / LCD segment |
| Pin 34 | RD0 — General purpose I/O / LCD segment |
| Pin 35 | RE3 — General purpose I/O / MCLR (alternate) |
| Pin 36 | RE2 — General purpose I/O / LCD COM |
| Pin 37 | RE1 — General purpose I/O / LCD COM |
| Pin 38 | RE0 — General purpose I/O / LCD COM |
| Pin 39 | VSS — Ground reference |
| Pin 40 | VDD — Positive supply |
| Pin 41 | RF7 — General purpose I/O / LCD segment |
| Pin 42 | RF6 — General purpose I/O / LCD segment |
| Pin 43 | RF5 — General purpose I/O / LCD segment |
| Pin 44 | EP — Exposed thermal pad - connect to VSS |
Typical Applications
PIC16LF1939T-I/ML is suitable for 6 applications: Battery-Powered Sensor Nodes, LCD Display Control Panels, Home Appliance Control, Capacitive Touch User Interface, Industrial Metering and Monitoring, Automotive Body and Interior Modules (Non-Safety).
Battery-Powered Sensor Nodes
The PIC16LF1939T-I/ML fits battery-powered sensor nodes because of its nanoWatt XLP sleep currents below 50 nA at 3 V with full RAM retention, enabling years of operation from a single CR2032 or two AA cells. Its 1.8 V to 5.5 V range covers both coin-cell and lithium chemistries directly. The 28 KB flash holds small protocol stacks (e.g., Modbus RTU, BLE beacon firmware) plus sensor calibration tables in EEPROM. Paired with TI TPS61236PWP boost converter or Analog Devices ADM3252E isolator, the MCU wakes on a timer interrupt to sample and transmit, then returns to sleep.
Recommended
LCD Display Control Panels
The PIC16LF1939T-I/ML integrates an on-chip LCD driver supporting up to 248 segments, removing the need for an external display driver in thermostat, meter, appliance, and consumer product HMIs. The 44-QFN package gives access to the full segment and COM pin count, and the 32 MHz core handles refresh, button debounce, and UI logic simultaneously. Combined with a Microchip MCP1700 LDO for power and a small SPI flash for UI assets, designers can build a complete segment-LCD UI subsystem with minimum BOM.
Recommended
Home Appliance Control
For white goods such as washing machines, dishwashers, coffee makers, and small kitchen appliances, the PIC16LF1939T-I/ML offers 28 KB of flash to hold state machines and menu logic, plus capacitive touch (mTouch®) support for button-less front panels. Its 36 I/O pins can drive relays, triacs, and segment LCDs without external logic, and the industrial -40°C to +85°C temperature grade suits kitchen and laundry environments. The XLP sleep current keeps standby power under 0.5 W to comply with energy regulations.
Recommended
Capacitive Touch User Interface
The PIC16LF1939T-I/ML supports Microchip's mTouch® capacitive touch sensing peripheral through its CTMU module, allowing up to 36 touch channels on the 36 I/O pins without external sensing ICs. This makes it a cost-effective solution for touch sliders, proximity sensors, and metal-overlay keypads in consumer and industrial products. Combined with the integrated LCD driver, designers can implement a touch + display UI with a single MCU plus a few passives, reducing BOM and PCB area versus discrete touch + display solutions.
Recommended
Industrial Metering and Monitoring
Industrial electricity, water, and gas meters benefit from the PIC16LF1939T-I/ML's 10-bit ADC, RTC functionality from the 32 kHz internal oscillator, and EEPROM for tariff and calibration storage. Its wide 1.8 V to 5.5 V supply lets it run directly from lithium primary cells for 10+ years of operation in sealed meter enclosures. The 44-QFN package fits within the typical 60 mm round meter footprint, and the LCD driver provides a low-cost display for kWh, m³, or flow readings without additional driver ICs.
Recommended
Automotive Body and Interior Modules (Non-Safety)
Although the standard PIC16LF1939T-I/ML is not AEC-Q100 qualified, it can be used in non-safety automotive interior applications such as ambient lighting, HVAC controls, seat adjustment modules, and rear-seat entertainment keypads where industrial temperature grade is acceptable. Its 32 MHz core and rich peripheral set (PWM, ADC, I2C/SPI, UART) handle motor control loops, LED drivers, and CAN-like LIN communication via the EUSART. For safety-critical applications, designers should migrate to AEC-Q100 qualified PIC16F1xx automotive parts.
Recommended
Recommended Products Summary
Engineering reference data for PIC16LF1939T-I/ML — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | PIC16LF1939-I/ML | PIC16LF1939T-I/PT | PIC16LF1938T-I/ML | PIC16LF1939T-I/MP |
|---|---|---|---|---|---|
| Package | 44-QFN (8x8 mm) | 44-QFN (8x8 mm) - same | 44-TQFP (10x10 mm) - pin-compatible electrically | 44-QFN (8x8 mm) - same | 44-QFN (8x8 mm) - same |
| Brand | Microchip Technology | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same | Microchip Technology - same |
| Flash Program Memory | 28 KB (16K x 14) | 28 KB | 28 KB | 16 KB (-43%) | 28 KB |
| RAM | 1 KB | 1 KB | 1 KB | 1 KB | 1 KB |
| EEPROM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes |
| Maximum Clock Frequency | 32 MHz (8 MIPS) | 32 MHz | 32 MHz | 32 MHz | 32 MHz |
| Operating Voltage | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V | 1.8 V to 5.5 V |
| Number of I/Os | 36 | 36 | 36 | 36 | 36 |
| ADC Resolution | 10-bit | 10-bit | 10-bit | 10-bit | 10-bit |
| Operating Temperature | -40°C to +85°C (Industrial) | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C | -40°C to +85°C |
| Packaging Form | Tape & Reel | Tray | Tape & Reel | Tape & Reel | Tray |
Key Differentiators
- On-chip LCD segment driver up to 248 segments (vs PIC16LF1938T-I/ML)
- Industrial -40°C to +85°C temperature range (vs PIC16LF1939-E/PT (extended temperature))
- XLP nanoWatt technology for sub-µA sleep (vs PIC16LF1939T-I/PT (TQFP package))
Design Notes
The 44-QFN (8x8 mm) package has an exposed thermal pad (pin 44 / EP) on the underside. This pad MUST be soldered to a properly sized copper pour on the PCB, ideally with thermal vias connecting to an internal ground plane, to meet the datasheet's thermal resistance specification and to provide a stable ground reference for the silicon. An unsoldered thermal pad can cause intermittent failures, EMI problems, and reliability issues during thermal cycling. Estimated thermal resistance of the QFN package is approximately 28 C/W with the EP soldered to a 1 sq inch copper pour; without the EP, this can exceed 80 C/W.
Decouple VDD with a 100 nF ceramic capacitor placed within 2 mm of each VDD pin pair, plus a bulk 1 µF to 10 µF tantalum or ceramic on the main supply trace. For battery applications drawing < 100 nA sleep current, choose an LDO with nanoamp quiescent current such as Microchip MCP1700 (1.6 µA Iq) to avoid wasting the MCU's low-power advantage. Place the reset circuit (typically a 10 kΩ pull-up on MCLR) to ensure clean startup; if MCLR is unused as I/O, tie it through the pull-up to VDD.
Route the ICSP programming pins (typically RB6/ICSPCLK and RB7/ICSPDAT, or RA0/RA1 alternate) to a 6-pin header or test pad with no series resistors in the signal path. Place the crystal or resonator (if used) within 5 mm of OSC1/OSC2 with a guard ring tied to ground to reduce noise coupling. Estimated guard ring effectiveness: a grounded ring reduces radiated emissions by 6-10 dB for HF signals on adjacent traces per typical EMC test data.
For designs driving LCD segments, add series resistors (typically 1 kΩ to 10 kΩ) between the segment pins and the LCD glass to limit inrush current during bias transitions and reduce EMI. Avoid running sensitive analog signals (ADC inputs, comparator references) parallel to LCD segment lines for more than a few millimeters; cross at 90° if crossings are unavoidable. Per Microchip application note AN658, LCD segment traces should be routed together to balance capacitive loading.
Do not exceed 5.5 V on any pin; the 'LF' variant uses a low-voltage flash process that is not 5.5 V tolerant on VPP/MCLR if VDD is below 2 V. When migrating code between PIC16LF1939 and PIC16F1939 (F variant), check that your firmware does not assume brown-out reset thresholds below 1.8 V - the LF variant has different BOR settings. Also, the 'T' suffix (tape and reel) has no electrical difference from the tray variant; verify the part marking on incoming reels to prevent counterfeit substitution.
Compliance Information
RoHS and REACH compliant per Microchip product declaration. Not AEC-Q100 qualified - select PIC16F1939 automotive variant for safety-critical applications. Lead-free matte-tin (Sn) finish on QFN lead-termination with NiPdAu underlayer. JEDEC J-STD-020 lead-free reflow compatible up to 260°C peak.
