Renesas IDT7290820J8

Overview

IDT7290820J8 from Integrated Device Technology, Inc. is a 5V, 2,048 × 2,048 non-blocking time slot interchange (TSI) digital switch optimized for PCM voice and N×64 kbit/s data routing in ST-BUS®/GCI telecommunication systems. It supports serial bit rates of 2.048 Mb/s, 4.096 Mb/s, or 8.192 Mb/s with per-channel variable or constant throughput delay, JTAG boundary scan (IEEE-1149.1), and microprocessor interface compatibility with Intel/Motorola buses. It is deployed in TDM-based central office switches and multi-chip TSI fabric interconnects.

For engineers reviewing the IDT7290820J8 datasheet, IDT7290820J8 pinout, IDT7290820J8 application, or IDT7290820J8 equivalent, key selection considerations include frame alignment mode (ST-BUS®/GCI vs. WFP), per-stream input offset calibration, ODE-controlled TX output enable, CCO control bit mapping, and IMS register DR0/DR1 data rate configuration.

Technical Context

The IDT7290820J8 implements a dual-mode TSI architecture with separate data memory (up to 2,048 bytes) and connection memory (16 streams × 128 channels = 2,048 locations), enabling both Connection Mode (source-addressed switching) and Processor Mode (direct data write). Its timing unit synchronizes to F0i (8 kHz frame pulse) and CLK (4.096–16.384 MHz), with automatic ST-BUS®/GCI format detection based on FE/HCLK edge polarity.

Per-channel control is implemented via 5-bit fields in each connection memory location: PC (Processor/Connection Mode), V/C (Variable/Constant delay), OE (output enable), LPBK (loopback), and CCO (control output bit). Frame offset calibration uses the FOR register (±4.5 CLK periods resolution) and FE-driven measurement cycle, disabled only when WFPS = HIGH.

Key Specifications

Pinout & Package

Package: 84-pin Plastic Leaded Chip Carrier (PLCC), 0.05-inch pitch, 1.15-inch × 1.15-inch footprint (order code J). Pin 1 marked by index notch; IC pin tied to GND for IEEE-1149.1 compliance.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar time slot interchange applications.

Compared with IDT7290815J8 and CY7C9252V-10JC, the IDT7290820J8 uniquely integrates WFP mode, per-stream frame offset calibration, and CCO control output in a PLCC-84 package - making it the only option supporting scalable multi-chip TSI fabrics with deterministic inter-stream skew management.

Availability

IDT7290820J8 is available at Aetrix Electronics and suitable for central office switches, PCM multiplexers, distributed TSI fabric nodes, and telecom protocol analyzers requiring stable component supply and long-term lifecycle support.

Supply support for IDT7290820J8 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

Integrated Device Technology, Inc. (IDT) was a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance interconnect solutions before its acquisition by Renesas Electronics in 2019.

The IDT7290820J8 belongs to IDT's legacy TSI digital switch product line, designed specifically for carrier-grade TDM infrastructure requiring non-blocking, low-jitter, frame-aligned PCM channel routing in E1/T1 and ST-BUS® environments.

FAQ

What is the maximum serial data rate supported by the IDT7290820J8?

The IDT7290820J8 supports a maximum serial data rate of 8.192 Mb/s, achieved when DR0=0 and DR1=1 in the IMS register. At this rate, it delivers full 2,048 × 2,048 non-blocking switching capacity with 128 channels per 125 µs frame and requires a 16.384 MHz master clock (CLK) input. Lower rates of 4.096 Mb/s and 2.048 Mb/s are also supported with corresponding scaling of channel count and clock frequency.

How does the IDT7290820J8 handle frame synchronization for ST-BUS® and GCI interfaces?

The IDT7290820J8 automatically detects and configures for ST-BUS® or GCI frame formats when WFPS = LOW. In ST-BUS® mode, it aligns to the falling edge of F0i and samples data on the rising edge of CLK; in GCI mode, it aligns to the rising edge of F0i and samples on the falling edge of CLK. This hardware-level detection eliminates manual register configuration and ensures interoperability across mixed-interface systems.

Can the IDT7290820J8 perform per-channel output disable independently of the ODE pin?

Yes. The IDT7290820J8 supports per-channel output disable via the OE bit in each location of the connection memory. When ODE = HIGH, individual TX outputs are enabled or disabled based solely on their respective OE bits. When ODE = LOW, all TX0–TX15 outputs are forced into high-impedance regardless of OE bit values - providing both granular and global output control.

What is the function of the CCO pin on the IDT7290820J8?

The CCO (Control Output) pin on the IDT7290820J8 is a serial output that transmits the CCO bit from each connection memory location once per frame, synchronized with the TX data streams but advanced by one channel. At 2.048 Mb/s, it outputs 512 bits/frame at 4.096 Mb/s; at 8.192 Mb/s, it outputs 2,048 bits/frame at 16.384 Mb/s - enabling external logic to monitor or act on per-channel control state in real time.

Does the IDT7290820J8 support JTAG boundary scan, and how is it initialized?

Yes, the IDT7290820J8 fully complies with IEEE-1149.1 JTAG boundary scan. Initialization requires pulsing TRST LOW at power-up to place the TAP controller in Test-Logic-Reset state. Once released, the device enters functional mode. TMS, TDI, TDO, and TCK operate with internal pull-ups, allowing reliable scan chain operation without external biasing components.