Microchip Technology AT18F040-30XU

Overview

AT18F040-30XU from Atmel is a 4-Mbit JTAG In-System Programmable (ISP) configuration PROM designed to store and serially load bitstream data into Xilinx Virtex-II, Virtex-E, Spartan-3, and Spartan-II FPGAs. It operates with 3.3V internal supply (VCCINT), supports 1.8V/2.5V/3.3V I/O (VCCO), delivers up to 33 MHz configuration clock speed, and features IEEE 1532-compliant ISP via JTAG interface.

For engineers reviewing the AT18F040-30XU datasheet, AT18F040-30XU pinout, AT18F040-30XU application, or AT18F040-30XU equivalent, key selection criteria include JTAG boundary-scan testability (IEEE 1149.1), cascading support via CEO/CE daisy-chain, low-power standby current (<1 mA), open-collector DATA output with 20 kΩ pull-up, and compatibility with Xilinx FPGA master/slave serial configuration modes.

Technical Context

The AT18F040-30XU implements a serial flash memory architecture with dedicated download interface logic for direct FPGA configuration control. Its internal address counter is synchronized to external CLK or JTAG TCK, and it supports both FPGA-initiated (master serial) and externally clocked (slave serial) configuration flows.

Boundary-scan testing uses IEEE 1149.1-compliant TAP controller with TMS/TCK/TDI/TDO pins and BSDL-defined scan cells on all I/Os. The device integrates separate power domains: VCCINT (3.3V core), VCCO (1.8–3.3V I/O), and VCCJ (1.8–3.3V JTAG), enabling mixed-voltage system integration without level shifters.

Key Specifications

Pinout & Package

Package: 20-lead TSSOP (20A2), 4.4 mm × 6.5 mm body, 0.65 mm pitch, RoHS-compliant, green (Pb/halide-free).

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar FPGA configuration memory applications.

Compared with XCF04SVO20C and AT17LV040-10JU, the AT18F040-30XU provides broader voltage flexibility (1.8–3.3 V I/O), integrated cascade capability, and full IEEE 1532/JTAG support - making it optimal for new industrial and telecom designs requiring field programmability and mixed-voltage FPGA integration.

Availability

AT18F040-30XU is available at Aetrix Electronics and suitable for high-reliability FPGA configuration in industrial automation, telecom infrastructure, and defense electronics requiring stable component supply across extended product lifecycles.

Supply support for AT18F040-30XU 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

Atmel Corporation (now part of Microchip Technology) is a semiconductor manufacturer specializing in microcontrollers, nonvolatile memory, and programmable logic devices for embedded systems.

The AT18F series was developed specifically to deliver cost-effective, JTAG-programmable configuration memory for Xilinx and Atmel FPGAs - emphasizing in-system update capability, low-power operation, and seamless integration into master/slave serial configuration topologies.

FAQ

What is the maximum configuration clock frequency supported by the AT18F040-30XU?

The AT18F040-30XU supports a maximum configuration clock frequency of 33 MHz, as specified in its AC characteristics table. This enables rapid FPGA bitstream loading - for example, a full 4 Mbit configuration completes in under 120 ms. The device maintains timing compliance across its full industrial temperature range (−40°C to +85°C) and supply voltage range (VCCINT = 3.0–3.6 V). This performance is achieved using optimized internal flash access logic and low-latency serial interface control within the AT18F040-30XU.

Does the AT18F040-30XU support cascading with other configuration PROMs?

Yes, the AT18F040-30XU supports hardware cascading via its CEO (Chip Enable Output) pin. When the internal address counter reaches its maximum value, CEO goes low to signal end-of-data and can be connected directly to the CE (Chip Enable) input of a downstream AT18F-series device. This enables daisy-chained configurations for higher-density FPGAs or multi-FPGA systems. The AT18F040-30XU's AC characteristics specify TOCE (CE to CEO delay) and TOCK (CLK to CEO delay) to ensure reliable timing in cascaded setups - a feature not present in legacy alternatives like the AT17LV040-10JU.

Can the AT18F040-30XU configure both Xilinx and Atmel FPGAs?

Yes, the AT18F040-30XU is explicitly qualified to configure multiple Xilinx FPGA families including Virtex-II, Virtex-E, Spartan-3, and Spartan-II, as documented in Table 4-1 of its datasheet. It is also functionally compatible with Atmel's own AT40KAL series FPGAs. This dual compatibility stems from its adherence to standard FPGA serial configuration protocols and pinout alignment with Xilinx XCFxxS PROMs. The AT18F040-30XU achieves this through configurable I/O voltage (VCCO = 1.8–3.3 V) and flexible clocking modes (master/slave serial), making it suitable for heterogeneous FPGA development environments.

What are the power supply requirements for the AT18F040-30XU?

The AT18F040-30XU requires three independent supply connections: VCCINT (3.0–3.6 V, typ. 3.3 V) for internal logic, VCCO (1.7–3.6 V) for DATA, RESET/OE, and CE I/O drivers, and VCCJ (1.7–3.6 V) for JTAG pins (TMS/TCK/TDI/TDO). This triple-supply architecture allows interfacing with FPGAs operating at different I/O voltages while maintaining clean JTAG signaling. Decoupling capacitors (0.1 µF ceramic) are required on each supply rail per the layout guidelines in the AT18F040-30XU datasheet to ensure stable operation during high-speed configuration bursts.

Is the AT18F040-30XU RoHS compliant and lead-free?

Yes, the AT18F040-30XU is RoHS compliant and manufactured in a green (Pb/halide-free) package, as confirmed in its Features section and Packaging Information. The 20-lead TSSOP (20A2) package meets JEDEC MO-153 standards and carries explicit "Green Package: Yes" designation in the device offering table. This compliance applies to both material composition and manufacturing process - verified per EU Directive 2011/65/EU. No exemptions are claimed, and the device is suitable for use in environmentally regulated markets including the EU, China, and South Korea.