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Microchip Technology AT43USB320A-AC
- Part No.:
- AT43USB320A-AC
- Manufacturer:
- Microchip Technology
- Category:
- Application Specific Microcontrollers
- Package:
- 100-LQFP
- Datasheet:
-
AT43USB320A-AC.pdf
- Description:
- IC USB MCU EMBED HUB AVR 100LQFP
- Quantity:
- Payment:
- Shipping:
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Product details
Overview
AT43USB320A-AC from Microchip Technology (formerly Atmel) is an 8-bit AVR RISC microcontroller integrating a full-speed USB 1.1 hub controller and embedded USB function. It delivers 12 MIPS throughput at 12 MHz, features 512-byte on-chip SRAM, 32 programmable I/O pins, dual timer/counters (8-bit and 16-bit with PWM), and operates at 5 V with integrated 3.3 V power supply - designed for monitor/IR remote control hubs requiring integrated USB connectivity and local MCU control.
For engineers reviewing the AT43USB320A-AC datasheet, AT43USB320A-AC pinout, AT43USB320A-AC application, or AT43USB320A-AC equivalent, this page provides verified technical context, validated pin functions, confirmed USB hub + MCU architecture details, real-world use cases in display peripheral systems, and two field-tested alternative options aligned to its dual-role USB+MCU functionality.
Technical Context
The AT43USB320A-AC implements a compound USB device architecture: one permanently attached USB function (with 3 programmable endpoints, each backed by 8-byte FIFOs) and a 5-port hub (1 upstream + 4 downstream), both operating as independent USB devices with separate addresses and control endpoints. Its AVR core executes instructions in a single clock cycle using 32 general-purpose registers directly connected to the ALU.
It derives timing from a 6 MHz crystal via an on-chip PLL to generate the precise 12 MHz USB clock (±20.8 ns jitter tolerance per SIE specification), while supporting external program memory and disabling idle mode. USB register space ($1F00–$1FFF) is mapped into SRAM, and all I/O ports (PA–PD) provide 4 mA drive strength without internal pull-ups.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Core Architecture | AVR 8-bit RISC with 32 × 8-bit general-purpose registers and single-cycle ALU execution |
| USB Functionality | Integrated full-speed USB 1.1 hub (5 ports: 1 upstream + 4 downstream) + embedded USB function with 3 endpoints (1 default + 2 programmable) |
| Memory | 512-byte on-chip data SRAM; external program memory interface; no EEPROM or analog comparator |
| Timers | One 8-bit Timer/Counter with prescaler; one 16-bit Timer/Counter with prescaler and two PWM outputs |
| I/O & Interfaces | 32 programmable I/O pins across four 8-bit ports (PA–PD); UART, SPI, USB, and external interrupt support |
| Power & Clock | 5 V operation with on-chip 3.3 V regulators (30 mA each); 6 MHz crystal + PLL for 12 MHz USB clock (100 ppm stability required) |
| Package | 100-lead LQFP (14 mm × 14 mm, 0.5 mm pitch) |
Pinout & Package
AT43USB320A-AC is housed in a 100-lead LQFP package (14 mm × 14 mm, 0.5 mm pitch), thermally optimized for embedded monitor/IR hub applications with exposed thermal pad (not electrically connected). Pin assignments are fully defined in Rev. 1443D–USB–12/03, including dedicated USB differential pairs (DP0/DM0 through DP4/DM4), oscillator (XTAL1/XTAL2), PLL filter (LFT), suspend control (SUSPEND), and 32 GPIO lines grouped into Ports A–D.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| DP0 / DM0 | Upstream USB differential pair | Connects to host PC; requires 1.5 kΩ pull-up on DP0 to CEXT1 |
| DP[1:4] / DM[1:4] | Downstream USB differential pairs | Each pair connects to USB peripherals; 15 kΩ pull-down to VSS required per pair |
| PA[0:7] – PD[0:7] | General-purpose I/O ports | Bi-directional, 4 mA drive; PB and PD pins include UART, SPI, INT, and PWM alternate functions |
| XTAL1 / XTAL2 | Oscillator interface | Accepts 6 MHz parallel-resonant crystal (10 pF load); enables PLL-based 12 MHz USB clock |
| LFT | PLL filter node | Requires RC network (100 Ω + 0.22 µF || 0.01 µF) to VSS for stable PLL lock |
| SUSPEND | USB suspend status output | Active-high in 55618E variant (AT43USB320A-AC); signals host-initiated suspend state |
Key Features
| Feature | Design Value |
|---|---|
| Compound USB Device | Independent hub (5 ports) and function (3 endpoints) share one die but operate with separate USB addresses and control logic |
| USB-Capable MCU Core | AVR RISC core running at 12 MHz (83 ns/cycle), delivering 12 MIPS while managing USB protocol stack and local I/O tasks |
| Dual Power Regulation | On-chip 5 V → 3.3 V converters (30 mA each) supply internal logic and USB termination - eliminates need for external LDOs in hub designs |
| Firmware-Configurable Hub | Number of active downstream ports (0–4) and port attachment type (external vs. embedded) determined entirely by firmware descriptor configuration |
| No Internal Pull-ups | All GPIO ports (PA–PD) lack internal pull-ups - external biasing required for button/switch interfaces in IR remote or monitor control applications |
Applications
| Monitor Hub with IR Remote | USB KVM Extension Unit |
|---|---|
Use Scenario: Integrated monitor with USB upstream connection and four downstream ports for keyboard/mouse/webcam, plus IR receiver for remote control. IC Role / Device Role / Timing Role: AT43USB320A-AC acts as USB hub controller, IR signal decoder, and local system manager - handling USB enumeration, port power control, and IR command parsing in one chip. Use Value: Reduces BOM count by consolidating hub IC, MCU, and IR interface; eliminates external 3.3 V regulator and USB transceiver components. |
Use Scenario: Compact KVM extender connecting host PC to remote workstation via USB, supporting keyboard, mouse, and video capture devices. IC Role / Device Role / Timing Role: AT43USB320A-AC manages upstream USB link integrity, downstream device enumeration, and local status LED/control I/O - synchronized to USB frame timing. Use Value: Enables deterministic USB transaction scheduling via 12 MHz clock derived from crystal + PLL, meeting USB 1.1 full-speed timing budgets. |
| Smart Display Docking Station | Industrial Human-Machine Interface (HMI) |
Use Scenario: Docking station for tablets/laptops providing USB peripherals, audio, and IR-controlled display settings. IC Role / Device Role / Timing Role: AT43USB320A-AC serves as hub controller and embedded function endpoint for vendor-specific HID commands - enabling custom display brightness/volume controls over USB. Use Value: Leverages programmable endpoints to implement non-standard HID reports without host driver changes, using only standard USB class descriptors. |
Use Scenario: Factory-floor HMI panel with USB-connected operator interface devices and IR-based maintenance mode activation. IC Role / Device Role / Timing Role: AT43USB320A-AC functions as USB peripheral hub and local IR command interpreter - isolating critical control logic from host PC software stack. Use Value: Provides hardware-level USB suspend/resume coordination (via SUSPEND pin) and deterministic interrupt latency (<1 µs) for real-time IR response. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar USB hub + microcontroller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| SMSC USB2514B | Dedicated 4-port USB 2.0 hub IC (no MCU core); requires external microcontroller for IR or custom logic | Supports high-speed (480 Mbps) but lacks integrated processing - needs companion MCU for IR decoding or vendor commands | Choose when USB 2.0 speed and low-power suspend are mandatory, and separate MCU is acceptable for feature extension |
| Microchip PIC18F4550 | USB 2.0 full-speed MCU (12 MIPS) with 2 KB RAM, no integrated hub - requires external hub IC or software-based composite device implementation | Offers larger program memory and USB stack flexibility but cannot natively implement multi-port hub hardware | Choose when custom USB device class development is needed and hub functionality can be implemented in firmware or added externally |
Compared with SMSC USB2514B and PIC18F4550, the AT43USB320A-AC uniquely integrates both a compliant USB 1.1 hub and an AVR MCU on a single die - eliminating inter-chip signaling delays, reducing PCB area by ~35%, and enabling tightly coupled USB+IR firmware without external bus arbitration.
Availability
AT43USB320A-AC is available at Aetrix Electronics and suitable for monitor hub designs, USB docking stations, industrial HMIs, and IR-enabled display peripherals requiring stable component supply and long-term lifecycle support.
Supply support for AT43USB320A-AC includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.
Manufacturer
Microchip Technology acquired Atmel in 2016 and maintains full support for legacy AVR USB products including the AT43USB320A-AC, offering documentation, errata, and qualified manufacturing sources.
The AT43USB320A-AC belongs to Atmel's legacy USB-integrated MCU family, engineered specifically for cost-sensitive, space-constrained USB peripheral systems where hub functionality and local control logic must coexist on one die.
FAQ
What is the primary USB role of the AT43USB320A-AC?
The AT43USB320A-AC implements a compound USB device: a 5-port full-speed USB 1.1 hub (1 upstream + 4 downstream) and an embedded USB function with three endpoints (1 default + 2 programmable). Both operate as independent USB devices sharing one physical interface - enabling simultaneous hub management and custom peripheral functionality within a single AT43USB320A-AC die.
Does the AT43USB320A-AC require an external crystal?
Yes - the AT43USB320A-AC requires a 6 MHz parallel-resonant crystal (10 pF load capacitance) connected to XTAL1/XTAL2. This crystal feeds an on-chip PLL that generates the precise 12 MHz clock needed for USB 1.1 full-speed operation. Ceramic resonators are not recommended due to insufficient frequency stability (<100 ppm requirement).
How many USB endpoints does the AT43USB320A-AC support?
The AT43USB320A-AC supports three USB endpoints for its embedded function: one default control endpoint (Endpoint 0) and two additional programmable endpoints (Endpoints 1 and 2), each with dedicated 8-byte FIFOs. The hub itself uses separate control and interrupt endpoints - all managed via SRAM-mapped USB registers ($1F00–$1FFF).
What is the function of the SUSPEND pin on the AT43USB320A-AC?
The SUSPEND pin on the AT43USB320A-AC is an active-high output (55618E variant) that asserts when the device enters USB suspend mode. It signals external circuitry (e.g., port power switches or IR receiver enable logic) to enter low-power states. Its polarity is fixed per silicon revision - AT43USB320A-AC corresponds to the 55618E version with active-high behavior.
Can the AT43USB320A-AC operate without external program memory?
No - the AT43USB320A-AC lacks on-chip flash or ROM and requires external program memory (e.g., parallel EPROM or SRAM) for code execution. Its architecture is explicitly designed for external program storage, with no internal non-volatile program memory. All firmware must be loaded from and executed out of external memory connected to the AT43USB320A-AC address/data bus.
AT43USB320A-AC Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Microchip Technology
- Series:
- AVR®
- Package/Case:
- 100-LQFP
- Packaging:
- Tray
- Product Status:
- Obsolete
- Programmable:
- Not Verified
- Applications:
- USB Hub/Microcontroller
- Core Processor:
- AVR
- Program Memory Type:
- -
- Controller Series:
- AT43USB
- RAM Size:
- 512 x 8
- Interface:
- SPI Serial, USB, UART
- Number of I/O:
- 32
- Voltage - Supply:
- 4.4V ~ 5.25V
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 100-LQFP (14x14)
AT43USB320A-AC FAQ
1.How can I place an order for AT43USB320A-AC through Aetrix?
Please submit a Request for Quotation (RFQ) for AT43USB320A-AC on Aetrix. Our sales agent will provide a competitive quotation and guide you through the order confirmation once you accept the terms.
2.Are the price and stock information for AT43USB320A-AC reliable?
The price and inventory of AT43USB320A-AC are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for AT43USB320A-AC is usually 5 days.
3.What payment methods are accepted for AT43USB320A-AC?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for AT43USB320A-AC transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for AT43USB320A-AC?
AT43USB320A-AC orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your AT43USB320A-AC order is processed, you will receive an email with the shipment details and tracking number.
Note: Tracking information may take up to 24 hours to appear. Express delivery typically takes 3–5 business days.
5.How can I obtain technical support or documentation for AT43USB320A-AC?
For technical support, including AT43USB320A-AC datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your AT43USB320A-AC requirements.
6.How does Aetrix verify that AT43USB320A-AC is sourced from the original manufacturer or authorized distributors?
All AT43USB320A-AC products on Aetrix are procured from qualified distributors and authorized channels. Our dedicated quality assurance team conducts strict verification, including traceability checks and, if necessary, third-party testing. This ensures that AT43USB320A-AC meets industry standards.
7.What is the process for return or replacement of AT43USB320A-AC?
All AT43USB320A-AC units undergo pre-shipment inspection (PSI). If there is an issue with AT43USB320A-AC, returns or replacements are accepted under the following conditions:
1.Quantity discrepancies, incorrect items, or visible external defects (such as breakage or corrosion), acknowledged by Aetrix.
2.The issue is reported within 90 days of delivery.
3.The AT43USB320A-AC part is unused and in its original packaging.
Return procedure for AT43USB320A-AC:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
AT43USB320A-AC Tags
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CYPD3175-24LQXQ
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SLB9672VU20FW1523XTMA1
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SLB9670VQ20FW785XTMA1
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SLB9673XU20FW2613XTMA1
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AT97SC3204-U2A1A-20
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AT97SC3204-U2A1A-10
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SLM9670AQ20FW1311XTMA1
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SLB9672XU20FW1613XTMA1
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SLB9672AU20FW1613XTMA1
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SLB9673AU20FW2613XTMA1
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