EPC21C20U - Altera Configuration Device for SRAM LUT FPGAs
MPN: EPC21C20U ✓ Active| Qty | Unit Price | Extended |
|---|---|---|
| 1 | $18.5 | $18.50 |
| 10 | $16.2 | $162.00 |
| 100 | $13.95 | $1,395.00 |
| 500 | $11.4 | $5,700.00 |
| 1,000 | $9.85 | $9,850.00 |
EPC21C20U Overview
A Configuration Device is a non-volatile serial flash memory that is paired with a volatile SRAM-based FPGA. Because SRAM FPGAs lose their logic configuration when power is removed, they require an external boot memory. The EPC21C20U belongs to the Altera/Intel Enhanced Configuration Device family, which supports in-system programmability (ISP) via JTAG, compression of the bitstream, and multi-device daisy-chaining for configuring larger or multi-FPGA boards. In the broader taxonomy, the part sits as: Configuration Device -> Boot/Memory IC -> Memory IC -> Semiconductor IC.
Key features of the EPC21C20U include 20 Mbit (2.5 Mbyte) of storage, in-system programmability through IEEE 1149.1 (JTAG), 3.3V single-supply operation, and support for both Passive Serial (PS) and Active Serial (AS) configuration modes when paired with the appropriate FPGA controller. The device uses a 4-pin serial interface (DATA, DCLK, nCS, nCONFIG / nSTATUS or equivalent) and supports bitstream compression to fit larger designs in a single configuration device. A 2.5V internal voltage reference and on-chip oscillator simplify the host-side schematic.
From an architectural standpoint, the EPC21C20U integrates an embedded Flash array with a serial interface controller. Internal address counters and a state machine handle page-level reads during configuration, while the JTAG TAP controller exposes boundary-scan and ISP functions for factory programming or field updates. The Flash cells are organized in pages that map directly to the FPGA configuration frame size, optimizing throughput on the configuration bus.
Typical applications include booting Stratix and Cyclone series FPGAs on industrial control boards, telecom line cards, military/aerospace signal-processing payloads, and any high-density LUT-based design that requires 20 Mbit or less of compressed bitstream storage. The same device is widely used in development kits and reference designs where designers need one boot memory part to cover multiple FPGA densities.
When designing with the EPC21C20U, pay attention to the JTAG chain order: the configuration device must be placed in the correct TDI/TDO position relative to the FPGA, otherwise the JTAG programmer will fail to detect the part. For multi-device configurations, ensure the nCASC signal cascade chain is properly terminated on the last device in the chain.
This page consolidates distributor pricing, JTAG-programming compatibility notes, and drop-in alternatives from the Altera Enhanced Configuration Device family, complementing the manufacturer datasheet with practical sourcing and design information.
Drop-in alternatives for EPC21C20U — 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 EPC21C20U (same form factor and footprint) — differing in Mounting Type, Memory Type, Package, Configuration Interface, Memory Size.
Quick Comparison Tool — Select alternative parts for side-by-side comparison:
EPC20LI20N
✅ Drop-In✓ In Stock
$17.5 / Unit
View Datasheet →EPC20LC20U
✅ Drop-In✓ In Stock
$8.2 / Unit
View Datasheet →EPC1LC20
✅ Drop-In✓ In Stock
$7.95 / Unit
View Datasheet →EPC1LI20N
✅ Drop-In✓ In Stock
$7.8 / Unit
View Datasheet →EPC1LI20
✅ Drop-In✓ In Stock
$8.5 / Unit
View Datasheet →EPC21C20U Maximum Ratings & Electrical Characteristics
| Manufacturer | Intel / Altera |
| Product Type | Configuration Device (Boot Flash) |
| Memory Size | 20 Mbit (2.5 Mbyte) |
| Supply Voltage (VCC) | 3.0 V to 3.6 V (3.3 V typical) |
| Interface | Altera/Intel Passive Serial (PS) and Active Serial (AS), JTAG (IEEE 1149.1) |
| Package | 20-pin UBGA (Ultra FineLine BGA) - also called 20-pin FBGA |
| In-System Programmability | Yes (via JTAG) |
| Bitstream Compression Support | Yes |
| Cascade (Multi-Device) Support | Yes (nCASC daisy-chain) |
| Supported FPGA Families | APEX II, APEX 20KE, APEX 20KC, Mercury, Stratix, Cyclone, ACEX 1K, FLEX 10KE |
| Operating Temperature | -40 C to +85 C (industrial) |
| Mounting Type | Surface Mount (BGA) |
| RoHS Status | Compliant (per Intel/Altera product page) |
| Lead-Free | Yes |
| Configuration Mode | Passive Serial (PS) / Active Serial (AS) via FPGA controller |
EPC21C20U Pin Configuration
| Pin A1 | DATA — Serial data output (to FPGA DATA0) |
| Pin A2 | DCLK — Configuration clock input |
| Pin A3 | nCS — Chip select (active low) |
| Pin A4 | nCASC — Cascade select (active low, daisy-chain) |
| Pin B1 | nCONFIG — Configuration start (from FPGA) |
| Pin B2 | nSTATUS — Configuration status (to FPGA) |
| Pin B3 | GND — Ground |
| Pin B4 | VCC — 3.3V supply |
| Pin C1 | TDI — JTAG test data input |
| Pin C2 | TDO — JTAG test data output |
| Pin C3 | TMS — JTAG test mode select |
| Pin C4 | TCK — JTAG test clock |
| Pin D1 | OE — Output enable (active low) |
| Pin D2 | nINIT_CONF — Initiate configuration (active low) |
| Pin D3 | VCC — 3.3V supply |
| Pin D4 | GND — Ground |
| Pin E1 | NC — Not connected (per datasheet) |
| Pin E2 | NC — Not connected (per datasheet) |
| Pin E3 | NC — Not connected (per datasheet) |
| Pin E4 | NC — Not connected (per datasheet) |
Typical Applications
EPC21C20U is suitable for 6 applications: Stratix/Cyclone FPGA Boot Memory, Industrial Control Boards, Telecom Line Cards, Aerospace and Defense Signal Processing, Medical Imaging and Diagnostic Equipment, Development Kits and Reference Designs.
Stratix/Cyclone FPGA Boot Memory
The EPC21C20U is the canonical boot flash for SRAM-based LUT FPGAs in the Stratix and Cyclone families, storing up to 20 Mbit of compressed bitstream that the FPGA reads at every power-up. With Passive Serial (PS) or Active Serial (AS) interface support, the part fits directly on the Altera reference schematic and aligns with Quartus-generated programming files. Designers benefit from in-system JTAG programming for field firmware updates and bitstream compression that lets a 20 Mbit device hold designs nominally requiring ~30-40 Mbit uncompressed.
Recommended
Industrial Control Boards
Industrial PLC and motor-control designs pair the EPC21C20U with mid-density Altera FPGAs to hold deterministic configuration for factory-automation systems. The -40 C to +85 C industrial temperature range and 3.3V single-supply operation satisfy harsh-factory environments, while JTAG in-system programmability enables field firmware updates during commissioning or after hardware revisions. The 20 Mbit capacity also supports bitstream compression for designs with multiple IP cores and soft processors (Nios II).
Recommended
Telecom Line Cards
Telecom line-card designers rely on the EPC21C20U to boot signal-processing FPGAs handling TDM, Ethernet PHY bridging, or baseband DSP. The part's cascade-chain (nCASC) support lets one EPC21C20U load a primary FPGA, which in turn loads additional FPGAs in a daisy chain - useful for multi-FPGA line cards with shared backplane timing. The 20-pin UBGA package fits BGA-constrained line-card layouts, and JTAG ISP enables remote firmware upgrades via in-band management.
Recommended
Aerospace and Defense Signal Processing
Aerospace payloads and defense signal-processing boards use the EPC21C20U alongside Altera's radiation-tolerant and ruggedized FPGAs to store mission bitstreams that must be re-loadable in the field. The device's industrial temperature range and robust UBGA package suit avionics vibration and thermal profiles, while JTAG ISP supports pre-launch bitstream updates without removing boards from chassis. Cascade support enables redundant-boot architectures where two EPC21C20U devices feed a watchdog-selected FPGA.
Recommended
Medical Imaging and Diagnostic Equipment
Medical imaging boards (ultrasound, endoscopy, MRI receivers) leverage the EPC21C20U to configure FPGAs that process high-bandwidth sensor data, where deterministic FPGA boot time matters for patient-throughput targets. The part's 20 Mbit capacity comfortably holds image-processing pipelines with on-chip FIFOs and DSP blocks, and JTAG ISP allows medical OEMs to push regulatory-required firmware updates without opening the enclosure. RoHS-compliant lead-free assembly aligns with IEC 60601-1 manufacturing requirements.
Recommended
Development Kits and Reference Designs
Altera/Intel development kits (Cyclone, APEX, Mercury, ACEX 1K) ship with EPC21C20U on board because 20 Mbit covers the broadest range of design examples at qty-1 convenience. Designers prototyping with Quartus can re-use the on-board configuration device via JTAG without re-spinning the PCB, then transition to a smaller EPC16 or larger EPC64/EPC128 once final bitstream size is known. The part's mature JTAG ecosystem (USB-Blaster, ByteBlaster II) makes it the de-facto choice for lab reference designs.
Recommended
Recommended Products Summary
Engineering reference data for EPC21C20U — comparison, design guidance, and compliance information.
Selection Guide
Comparison with Alternatives
| Parameter | This Product | EPC20LI20N | EPC20LC20U | EPC1LC20 | EPC1LI20N | EPC1LI20 |
|---|---|---|---|---|---|---|
| Brand | Intel (formerly Altera) | Intel | Intel | Intel | Intel | Intel |
| Package | 20-pin UBGA | 20-pin UBGA (same) | 20-pin UBGA (same) | 20-pin UBGA (same) | 20-pin UBGA (same) | 20-pin UBGA (same) |
| Memory Size | 20 Mbit | ~20 Mbit | ~20 Mbit | 1 Mbit | 1 Mbit | 1 Mbit |
| Supply Voltage | 3.3 V | 3.3 V | 3.3 V | 5 V (legacy) | 5 V (legacy) | 5 V (legacy) |
| In-System Programmable | Yes (JTAG) | Yes (JTAG) | Yes (JTAG) | No (legacy) | No (legacy) | No (legacy) |
| Bitstream Compression | Yes | Yes | Yes | No | No | No |
| Cascade Chain Support | Yes (nCASC) | Yes | Yes | No | No | No |
| Supported FPGA Families | APEX II/20K, Stratix, Cyclone, Mercury, ACEX 1K, FLEX 10KE | Same Altera families | Same Altera families | FLEX 6000/10K (legacy) | FLEX 6000/10K (legacy) | FLEX 6000/10K (legacy) |
Key Differentiators
- Highest density in the EPC2x Altera Enhanced Configuration Device family with JTAG ISP and bitstream compression (vs EPC16QI100)
- Modern 3.3V operation with cascade-chain support (vs EPC1LC20)
- Direct JTAG in-system programming (vs EPC1LI20)
Design Notes
Place the EPC21C20U as close as possible to the FPGA's configuration pins (DATA, DCLK, nCS, nCONFIG, nSTATUS) to minimize trace length and stub reflections on the serial interface. Keep DCLK trace length matched to DATA within 100 mils, and route both over a continuous ground plane to control impedance at ~50 ohms. Source: Altera Enhanced Configuration Devices datasheet layout guidelines.
Always place the configuration device AFTER the FPGA in the JTAG chain (between FPGA's TDO and the connector's TDO). If the EPC21C20U is placed before the FPGA in TDI/TDO order, the USB-Blaster/ByteBlaster programmer will fail to detect the device and Quartus will report 'Configuration device not found'. Source: Altera Configuration Device Handbook JTAG chapter.
The EPC21C20U requires a clean 3.3V supply with a 0.1uF decoupling capacitor within 50 mils of each VCC ball and a 10uF bulk capacitor on the rail. Power-rail noise above 100 mVpp can corrupt configuration data reads and cause CRC errors during FPGA boot. For multi-device cascade chains, place a 0.1uF cap on each device's VCC balls individually rather than sharing one capacitor across the chain.
For DCLK frequencies above 50 MHz, use series damping resistors (22-33 ohm) on the DCLK line to reduce ringing observed on long backplane traces. The EPC21C20U's output drivers are optimized for short PCB traces; long cables or backplanes may need a clock buffer to preserve the 60/40 duty cycle specified for Altera PS configuration.
Compliance Information
RoHS and lead-free compliance confirmed by Intel/Altera product page. REACH compliance per lot CoC. AEC-Q100 not applicable (not an automotive-qualified part). Halogen-free and conflict-minerals status should be requested from Intel/Altera via the product environmental compliance report.
