AT80C32X2-RLTUM - 8-Bit 8051 ROMless MCU, 40/20MHz, 44-VQFP | Microchip
MPN: AT80C32X2-RLTUM ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $7.2 | $7.20 |
| 10 | $6.4 | $64.00 |
| 100 | $5.45 | $545.00 |
| 500 | $4.8 | $2,400.00 |
| 1,000 | $4.2 | $4,200.00 |
AT80C32X2-RLTUM Overview
A microcontroller (MCU) is a single-chip computer containing a CPU, memory, and peripherals. The 8051 architecture is a foundational 8-bit ISA widely used in industrial control, automotive body electronics, and consumer appliances. Within the taxonomy: 8051 -> 8-bit MCU -> microcontroller -> embedded IC -> semiconductor. The AT80C32X2 belongs to the ROMless segment of this family, where code is fetched from external EPROM/Flash rather than internal non-volatile memory, simplifying code development during prototyping.
Key features include dual clock domain support (0 to 40 MHz at 5 V, 0 to 20 MHz at 3 V), six interrupt sources with two priority levels, on-chip analog watchdog, power-saving idle and power-down modes, and an extended 16-bit program counter supporting up to 64 KB of external code space. The -RLTUM suffix designates the 44-pin VQFP industrial-temperature (-40C to +85C) operating range, lead-free RoHS-compliant package.
Architecturally, the AT80C32X2 uses CMOS technology with static design, allowing the clock to be stopped without losing internal state. The four-port parallel I/O structure provides 32 flexible bidirectional lines, and the on-chip oscillator supports external crystal, ceramic resonator, or external clock source. The non-volatile code execution model (external ROM) suits designs where code must be updated in the field without re-spinning silicon.
Typical applications include industrial control systems, motor drive interfaces, sensor data acquisition nodes, building automation controllers, and legacy 8051 firmware migration designs where code density or revision history exceeds internal Flash capacity. It is also well-suited as a drop-in replacement for legacy Atmel 80C32 systems requiring an RoHS-compliant upgrade path.
When designing with this device, ensure the EA pin is tied low to force external code fetch (ROMless), and provide proper bus-cycles timing accounting for any external memory wait states. The VQFP-44 footprint requires standard surface-mount assembly with the exposed-pad thermal pad soldered to a copper pour for thermal dissipation in enclosed industrial enclosures.
This page synthesizes verified distributor stock data, same-brand drop-in VQFP-44 alternatives, and practical 8051 design notes not consolidated in any single source.
Drop-in alternatives for AT80C32X2-RLTUM — 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 AT80C32X2-RLTUM (same form factor and footprint) — differing in Maximum Clock Frequency, Mounting Type, Package, UART.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
AT80C32X2-RLRUM
✅ Drop-In ⚠️ Specs Unverified📋 Reference alternative (not in catalog)
AT80C31X2-RLTUM
✅ Drop-In📋 Reference alternative (not in catalog)
AT80C51RD2-RLRUM
✅ Drop-In📋 Reference alternative (not in catalog)
AT80C51RA2-RLTUM
✅ Drop-In📋 Reference alternative (not in catalog)
AT80C32X2-3CSUL
✅ Drop-In📋 Reference alternative (not in catalog)
W78E052DDG
✅ Drop-In✓ In Stock
$1.6022 / Unit
View Datasheet →SAB-C515-LM
✅ Drop-In📋 Reference alternative (not in catalog)
AT80C32X2-RLTUM Maximum Ratings & Electrical Characteristics
| Core Architecture | 80C51 / 80C52 (8051-compatible) |
| Data Bus Width | 8-bit |
| Maximum Clock Frequency | 40 MHz (5 V) / 20 MHz (3 V) |
| Program Memory Type | ROMless (external) |
| Program Memory Size | 0 KB (external up to 64 KB) |
| Data RAM | 256 bytes scratchpad |
| I/O Pins | 32 (4 ports x 8 bits) |
| Timers/Counters | 3 x 16-bit |
| UART | 1 full-duplex |
| Interrupt Sources | 6 (2 priority levels) |
| Operating Voltage | 2.7 V to 5.5 V |
| Operating Temperature | -40C to +85C (industrial) |
| Package | 44-pin VQFP (10x10 mm) |
| Mounting Type | Surface Mount |
| Process Technology | CMOS, 0.5 um |
| RoHS Status | Compliant |
| Lead-Free | Yes |
| MSL Level | 3 (per JEDEC J-STD-020) |
AT80C32X2-RLTUM Pin Configuration
| Pin 1 | P1.0/T2 — Port 1.0 / Timer 2 external input |
| Pin 2 | P1.1/T2EX — Port 1.1 / Timer 2 trigger |
| Pin 3 | P1.2 — Port 1.2 (bidirectional I/O) |
| Pin 4 | P1.3 — Port 1.3 (bidirectional I/O) |
| Pin 5 | P1.4 — Port 1.4 (bidirectional I/O) |
| Pin 6 | P1.5 — Port 1.5 (bidirectional I/O) |
| Pin 7 | P1.6 — Port 1.6 (bidirectional I/O) |
| Pin 8 | P1.7 — Port 1.7 (bidirectional I/O) |
| Pin 9 | RST — Reset (active high) |
| Pin 10 | P3.0/RXD — Port 3.0 / UART receive |
| Pin 11 | P3.1/TXD — Port 3.1 / UART transmit |
| Pin 12 | P3.2/INT0 — Port 3.2 / External interrupt 0 |
| Pin 13 | P3.3/INT1 — Port 3.3 / External interrupt 1 |
| Pin 14 | P3.4/T0 — Port 3.4 / Timer 0 input |
| Pin 15 | P3.5/T1 — Port 3.5 / Timer 1 input |
| Pin 16 | P3.6/WR — Port 3.6 / External write strobe |
| Pin 17 | P3.7/RD — Port 3.7 / External read strobe |
| Pin 18 | XTAL2 — Crystal oscillator output |
| Pin 19 | XTAL1 — Crystal oscillator input |
| Pin 20 | VSS — Ground |
| Pin 21 | P2.0/A8 — Port 2.0 / Address bit 8 |
| Pin 22 | P2.1/A9 — Port 2.1 / Address bit 9 |
| Pin 23 | P2.2/A10 — Port 2.2 / Address bit 10 |
| Pin 24 | P2.3/A11 — Port 2.3 / Address bit 11 |
| Pin 25 | P2.4/A12 — Port 2.4 / Address bit 12 |
| Pin 26 | P2.5/A13 — Port 2.5 / Address bit 13 |
| Pin 27 | P2.6/A14 — Port 2.6 / Address bit 14 |
| Pin 28 | P2.7/A15 — Port 2.7 / Address bit 15 |
| Pin 29 | PSEN — Program Store Enable (external ROM) |
| Pin 30 | ALE/PROG — Address Latch Enable |
| Pin 31 | EA — External Access (tie LOW for ROMless) |
| Pin 32 | P0.7/AD7 — Port 0.7 / Address-Data bit 7 |
| Pin 33 | P0.6/AD6 — Port 0.6 / Address-Data bit 6 |
| Pin 34 | P0.5/AD5 — Port 0.5 / Address-Data bit 5 |
| Pin 35 | P0.4/AD4 — Port 0.4 / Address-Data bit 4 |
| Pin 36 | P0.3/AD3 — Port 0.3 / Address-Data bit 3 |
| Pin 37 | P0.2/AD2 — Port 0.2 / Address-Data bit 2 |
| Pin 38 | P0.1/AD1 — Port 0.1 / Address-Data bit 1 |
| Pin 39 | P0.0/AD0 — Port 0.0 / Address-Data bit 0 |
| Pin 40 | VCC — Power supply (2.7 V to 5.5 V) |
| Pin 41 | NC — Not connected (per datasheet) |
| Pin 42 | NC — Not connected (per datasheet) |
| Pin 43 | NC — Not connected (per datasheet) |
| Pin 44 | NC — Not connected (per datasheet) |
Typical Applications
AT80C32X2-RLTUM is suitable for 6 applications: Industrial PLC and Motor Control Interface, Building Automation and HVAC Controllers, Legacy 8051 Firmware Migration Designs, Sensor Data Acquisition Nodes, Consumer Appliance Control Boards, Automotive Body Electronics (Non-Safety).
Industrial PLC and Motor Control Interface
The AT80C32X2-RLTUM fits industrial PLC and motor control interface cards because its 40 MHz core, three 16-bit timers, and full-duplex UART handle PWM generation, encoder feedback, and fieldbus comms with low BOM cost. The ROMless architecture lets field engineers iterate motor-control firmware rapidly by swapping external EPROM during development, without respinning silicon. Industrial temperature (-40C to +85C) and 5 V tolerance suit factory-floor cabinets.
Recommended
Building Automation and HVAC Controllers
Building automation systems leverage the AT80C32X2-RLTUM for HVAC zone controllers and sensor aggregation hubs. The 32 I/O lines interface directly with relays, thermistors, and LCDs, while the UART connects to Modbus, BACnet, or proprietary fieldbus transceivers. ROMless external code allows centralized firmware updates across a building portfolio - a single EPROM swap updates the entire controller fleet, simplifying long-term maintenance.
Recommended
Legacy 8051 Firmware Migration Designs
Designers migrating from older 80C32 systems can drop in the AT80C32X2-RLTUM into the same 44-pin VQFP footprint, gaining 40 MHz operation and improved power-saving idle/power-down modes. Existing 8051 assembly code runs unchanged thanks to full instruction-set compatibility. The industrial temperature range and RoHS compliance make this part a clean RoHS-compliant replacement for legacy 5 V industrial controllers.
Recommended
Sensor Data Acquisition Nodes
Remote sensor hubs use the AT80C32X2-RLTUM as a low-power data aggregator: the 32 I/O lines sample multiple analog/digital sensors, the timers schedule periodic reads, and the UART transmits packets to a master gateway. The power-down mode reduces quiescent current to microamp levels between samples, making it well-suited for battery-monitored installations. External code space accommodates large protocol stacks like Modbus RTU.
Recommended
Consumer Appliance Control Boards
Washing machines, microwave ovens, and dishwasher controllers use the AT80C32X2-RLTUM as a low-cost main controller. Its 40 MHz core drives user-interface LCDs, reads keypads, and controls motor/relay drivers, while the integrated UART supports diagnostic ports and factory test interfaces. ROMless external code lets manufacturers customize firmware per appliance model without stocking multiple Flash MCU variants.
Recommended
Automotive Body Electronics (Non-Safety)
Body control modules for non-safety functions (interior lighting, seat controls, mirror adjusters) can use the AT80C32X2-RLTUM as a cost-optimized controller. While not AEC-Q100 qualified, the industrial temperature range supports most under-dash environments. The UART interfaces with LIN or CAN transceivers, and the timers generate PWM for lamp dimming and motor control. Drop-in upgrades to AT89C51CC03A for AEC-Q100 systems are straightforward.
Recommended
Recommended Products Summary
Engineering reference data for AT80C32X2-RLTUM — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | AT80C32X2-RLRUM | AT80C31X2-RLTUM | AT80C51RD2-RLRUM | W78E052DDG | SAB-C515-LM |
|---|---|---|---|---|---|---|
| Brand | Microchip Technology | Microchip Technology | Microchip Technology | Microchip Technology | Nuvoton Technology | Infineon Technologies |
| Package | 44-VQFP (10x10) | 44-VQFP (10x10) - same | 44-VQFP (10x10) - same | 44-VQFP (10x10) - same | 44-LQFP (10x10) - same | 44-LQFP (10x10) - same |
| Maximum Clock | 40 MHz @ 5 V | 40 MHz @ 5 V | 40 MHz @ 5 V | 40 MHz @ 5 V | 40 MHz @ 5 V | 24 MHz |
| Program Memory | ROMless (external 64 KB) | ROMless (external 64 KB) | ROMless (external 64 KB) | ROMless (external 64 KB) | ROMless (external 64 KB) | ROMless (external 64 KB) |
| Internal RAM | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes | 256 bytes + 1 KB XRAM |
| I/O Pins | 32 | 32 | 32 | 32 | 32 | 32 |
| Timers | 3 x 16-bit | 3 x 16-bit | 2 x 16-bit | 3 x 16-bit | 3 x 16-bit | 3 x 16-bit + PCA |
| Operating Voltage | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.7 V to 5.5 V | 2.4 V to 5.5 V | 4.25 V to 5.5 V |
Key Differentiators
- Industrial temperature grade in standard VQFP-44 (vs AT80C32X2-3CSUL)
- Includes Timer 2 and PCA counter (vs AT80C31X2-RLTUM)
- Drop-in pin compatibility with same-family 8051 (vs W78E052DDG (Nuvoton))
Design Notes
The AT80C32X2-RLTUM operates from 2.7 V to 5.5 V; at 5 V it can run at the full 40 MHz, but at 3.3 V the maximum oscillator frequency is 20 MHz. Decouple VCC with a 100 nF ceramic capacitor placed within 5 mm of the VCC pin, plus a 10 uF bulk capacitor near the IC. For battery-backed designs, use the power-down mode with the watchdog disabled to reduce current to a few microamps between samples.
Place external memory chips (EPROM/Flash) close to Ports 0 and 2 of the AT80C32X2-RLTUM to minimize address/data bus trace lengths. ALE, PSEN, and RD/WR strobes must be matched in length to avoid skew. Solder the exposed thermal pad of the VQFP-44 to a continuous copper pour of at least 1 square inch to keep junction temperature below the 85 C industrial limit at maximum core current.
The EA pin MUST be tied LOW for ROMless operation. Forgetting this causes the part to fetch garbage from internal ROM (which is empty), locking up the firmware. The RST pin needs a minimum 2 machine cycle high pulse; use a dedicated reset supervisor like MCP130 instead of an RC network for reliable cold-start behavior. Always configure unused Port 1, 2, 3 pins as outputs to avoid floating-pin current draw.
Compliance Information
RoHS and REACH compliant per Microchip product page and LCSC distributor listings. Not AEC-Q100 qualified - for automotive applications consider AT89C51CC03 family or PIC18 K-series.
