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Renesas 72V8985J
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- Part No.:
- 72V8985J
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
72V8985J.pdf
- Description:
- IC MULTIPLEXER 1 X 8:8 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:1,002
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Product details
Overview
IDT72V8985J from Integrated Device Technology is a 3.3 V, 256 × 256 non-blocking time slot interchange (TSI) digital switch supporting ST-BUS® and GCI protocols. It features eight 2.048 Mb/s RX inputs and eight TX outputs, each carrying 32 × 64 Kbit/s channels, with per-channel variable or constant throughput delay modes and microprocessor-controlled channel mapping for voice/data switching in TDM networks.
For engineers reviewing the IDT72V8985J datasheet, IDT72V8985J pinout, IDT72V8985J application, or IDT72V8985J equivalent, this device serves as a core TSI element in ISDN trunk interfaces, digital PBX systems, and multi-protocol backplane switching where frame integrity, low-latency voice routing, and 3.3 V/5 V-tolerant I/O are required.
Technical Context
The IDT72V8985J implements dual-mode TSI operation-Variable Delay (min. 3 time slots, ideal for voice) and Constant Delay (32–94 time slots, preserving frame alignment for data)-via programmable Connection Memory High bits. Its internal timing unit auto-detects ST-BUS® (active-low frame sync) or GCI (active-high frame sync) formats using the F0i input and aligns sampling edges accordingly.
It integrates serial-to-parallel and parallel-to-serial conversion for all 16 streams, uses a non-multiplexed 8-bit microprocessor interface (A0–A5, D0–D7, CS, DS, R/W, DTA), and supports split-memory access to Data Memory (read-only), Connection Memory Low (source mapping), and Connection Memory High (per-channel control).
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Capacity | 256 × 256 non-blocking TDM channel matrix, enabling full crosspoint routing between 8 RX and 8 TX serial streams. |
| Data Rate per Stream | 2.048 Mb/s serial rate, supporting 32 × 64 Kbit/s PCM/time slots per RX/TX line. |
| Delay Modes | Per-channel selection: Variable Delay (3–34 time slots) for minimal voice latency; Constant Delay (32–94 time slots) for frame-aligned data integrity. |
| Microprocessor Interface | 8-bit non-multiplexed bus with A0–A5 addressing, CS/DS/R/W control, and open-drain DTA acknowledgment (max. 1220 ns for Data Memory reads). |
| Supply & I/O | 3.3 V core supply (3.0–3.6 V); 3.3 V I/O with 5 V tolerant digital inputs (VI up to 5.25 V). |
| Operating Temperature | −40°C to +85°C industrial range, validated for embedded telecom infrastructure deployment. |
| Package | 44-pin PLCC (J44-1, order code J), 0.65 in × 0.65 in, leaded ceramic carrier with standard surface-mount footprint. |
Pinout & Package
Package: 44-pin Plastic Leaded Chip Carrier (PLCC), J44-1 footprint, 0.05 in pitch, 0.65 in × 0.65 in body size.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND (Pins 11, 30) | Ground reference | Primary power return path; two dedicated pins reduce ground bounce in high-speed TDM switching. |
| VCC (Pins 12, 29) | +3.3 V supply | Dual power pins ensure stable core voltage delivery across the die during simultaneous 16-stream data transfer. |
| RX0–RX7 (Pins 21–28, 2, 4) | Serial input streams | Eight differential-capable inputs accepting 2.048 Mb/s ST-BUS®/GCI frames; each carries 32 time slots. |
| TX0–TX7 (Pins 3–10) | Three-state serial outputs | Eight programmable outputs; ODE pin (Pin 27) enables global high-impedance control independent of software state. |
| F0i (Pin 22) | Frame synchronization input | Auto-identifies ST-BUS® (active-low) or GCI (active-high) format and resets internal 8 kHz framing counter. |
| C4i (Pin 23) | Serial clock input | 4.096 MHz master clock; defines bit boundaries and drives internal shift registers for all RX/TX streams. |
| A0–A5 (Pins 37–42, 13) | Address bus | Six-bit address for accessing Control Register, Connection Memory Low/High, or Data Memory locations. |
| D0–D7 (Pins 31, 32, 33, 34, 35, 36, 38, 39) | Data bus I/O | 8-bit bidirectional path for register reads/writes; supports split-memory mode for concurrent CPU read/write operations. |
| CS, DS, R/W (Pins 14, 15, 16) | Microprocessor control | Chip Select, Data Strobe, and Read/Write signals enable cycle-accurate access to internal memories without external glue logic. |
| DTA (Pin 20) | Data Acknowledgment | Open-drain output signaling completion of microprocessor bus transaction; requires external pull-up for level translation. |
| ODE (Pin 27) | Output Drive Enable | Hardware-level master enable for all TX outputs; overrides per-channel OE bits in Connection Memory High when asserted low. |
| CCO (Pin 26) | Control Channel Output | 2.048 Mb/s serial output carrying 256 programmable bits (one per channel), synchronized to TX streams for sideband control. |
Key Features
| Feature | Design Value |
|---|---|
| Automatic protocol detection | Internal circuitry identifies ST-BUS® vs. GCI frame polarity and configures timing edges without firmware intervention. |
| Per-channel delay mode selection | V/C bit in Connection Memory High allows mixing Variable (voice-optimized) and Constant (data-secure) delay on same device. |
| Frame integrity assurance | Constant Delay mode guarantees fixed 2-frame latency (N → N+2) via multi-buffer memory architecture, preventing inter-frame skew. |
| 3.3 V / 5 V mixed-signal compatibility | 5 V tolerant inputs simplify integration with legacy 5 V microcontrollers while maintaining low-power 3.3 V core operation. |
| Programmable output drive control | ODE pin + per-channel OE bits enable hierarchical output management-global disable for safe initialization, fine-grained channel isolation for matrix construction. |
Applications
| ISDN Trunk Interface | Digital PBX Switching Matrix |
|---|---|
Use Scenario: Aggregating 30 B-channels from multiple E1 lines into a centralized switching fabric for call routing and conferencing. IC Role / Device Role / Timing Role: Time slot interchange engine performing dynamic cross-connection between incoming and outgoing TDM streams under microprocessor control. Use Value: Enables real-time, low-latency voice path setup with guaranteed ≤34-slot delay in Variable Mode, meeting ITU-T G.712 echo performance requirements. |
Use Scenario: Building scalable, modular PBX systems where multiple IDT72V8985J devices interconnect via backplane to form large-scale non-blocking switches. IC Role / Device Role / Timing Role: Core TSI node providing per-channel source/destination mapping and frame-aligned data forwarding across distributed modules. Use Value: Supports Constant Delay mode (32–94 slots) to preserve signaling channel alignment across multi-stage switching, critical for D-channel transparency. |
| Multi-Protocol Backplane | TDM-over-Packet Gateway |
Use Scenario: Interfacing legacy ST-BUS®-based voice cards with newer GCI-compliant DSP resources in hybrid telecom platforms. IC Role / Device Role / Timing Role: Protocol-agnostic TSI bridge that auto-negotiates frame format and adapts sampling edge timing per stream. Use Value: Eliminates need for external level-shifting or format-conversion ASICs; reduces BOM count and board space in migration-ready designs. |
Use Scenario: Extracting individual 64 Kbit/s voice channels from E1/T1 streams for encapsulation into VoIP packets in media gateways. IC Role / Device Role / Timing Role: Channel demultiplexer and re-sequencer, isolating specific time slots and presenting them to packet-processing engines via parallel interface. Use Value: Microprocessor port allows CPU to dynamically assign RX time slots to TX channels, enabling flexible channel-to-packet mapping per call leg. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar time slot interchange applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT72V8984J | 128 × 128 capacity; identical pinout, timing, and feature set except reduced channel count and memory depth. | Suitable only for smaller-scale TDM systems requiring ≤128 channels; not scalable to full 256 × 256 topologies. | Select IDT72V8984J when system channel count is capped below 128 and PCB layout reuse is prioritized. |
| PMC432-256 | 256 × 256 TSI with integrated PLL, JTAG debug, and wider temperature range (−40°C to +105°C); different pinout and 100-pin TQFP package. | Targets high-reliability industrial/military deployments; lacks automatic ST-BUS®/GCI detection and requires external clock synthesis. | Choose PMC432-256 for extended temperature or debug-critical applications where board redesign is acceptable. |
Compared with IDT72V8984J and PMC432-256, the IDT72V8985J uniquely balances full 256 × 256 switching capacity, automatic multi-protocol frame recognition, and PLCC packaging for drop-in replacement in legacy telecom hardware-without requiring clock generation or layout changes.
Availability
IDT72V8985J is available at Aetrix Electronics and suitable for ISDN trunk interfaces, digital PBX switching matrices, and multi-protocol backplane designs requiring stable component supply, long-term lifecycle support, and verified industrial-temperature operation.
Supply support for IDT72V8985J 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 (IDT) was a fabless semiconductor company specializing in timing, memory interface, RF, and high-performance interconnect solutions before its acquisition by Renesas in 2019.
The IDT72V8985J belongs to IDT's TSI digital switch product line, designed specifically for carrier-grade TDM infrastructure requiring deterministic latency, multi-protocol interoperability, and microprocessor-configurable channel routing.
FAQ
What is the minimum throughput delay achievable with the IDT72V8985J in Variable Delay mode?
The IDT72V8985J achieves a minimum throughput delay of three time slots in Variable Delay mode-occurring when an input channel is routed to the same or immediately succeeding output channel positions (e.g., input channel n to output channel n, n+1, or n+2). This low-latency behavior meets strict voice-path timing requirements in digital telephony systems and is enforced by internal pipeline architecture without software overhead.
Does the IDT72V8985J support both ST-BUS® and GCI protocols simultaneously?
Yes-the IDT72V8985J automatically detects and adapts to either ST-BUS® (active-low frame sync) or GCI (active-high frame sync) formats on power-up or frame transition using the F0i input. Its internal timing unit reconfigures sampling edges and bit boundaries accordingly, allowing mixed-protocol systems to operate without external mode selection logic or firmware reconfiguration.
How does the ODE pin interact with per-channel output enable settings in the IDT72V8985J?
The ODE pin acts as a hardware-level master override for all TX0–TX7 outputs in the IDT72V8985J: when ODE is LOW, all serial outputs enter high-impedance regardless of Connection Memory High OE bit states. When ODE is HIGH, individual channel output drivers are enabled or disabled solely based on their respective OE bits, enabling safe initialization sequences and dynamic channel isolation during runtime.
What is the function of the CCO pin on the IDT72V8985J, and how is it controlled?
The CCO (Control Channel Output) pin on the IDT72V8985J outputs a 2.048 Mb/s serial stream carrying 256 programmable bits-one per time slot-synchronized to the TX streams. Each bit is driven by the CCO bit (bit 1) in the corresponding Connection Memory High location, allowing sideband control signaling (e.g., channel status, encryption flags) to be embedded alongside voice/data payloads without consuming TDM bandwidth.
Can the IDT72V8985J operate with a 5 V microprocessor interface while using a 3.3 V supply?
Yes-the IDT72V8985J features 5 V tolerant digital inputs (VI up to 5.25 V), allowing direct connection to 5 V microprocessors or FPGAs without level shifters. Its core logic and I/O buffers operate from a 3.3 V supply (3.0–3.6 V), ensuring compatibility with modern low-voltage controllers while maintaining robust noise margins against legacy 5 V systems.
72V8985J Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- 72V
- Package/Case:
- 44-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Active
- Type:
- Multiplexer
- Circuit:
- 1 x 8:8
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 3V ~ 3.6V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 44-PLCC (16.59x16.59)
72V8985J FAQ
1.How can I place an order for 72V8985J through Aetrix?
Please submit a Request for Quotation (RFQ) for 72V8985J 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 72V8985J reliable?
The price and inventory of 72V8985J are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 72V8985J is usually 5 days.
3.What payment methods are accepted for 72V8985J?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 72V8985J transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 72V8985J?
72V8985J orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 72V8985J 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 72V8985J?
For technical support, including 72V8985J datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 72V8985J requirements.
6.How does Aetrix verify that 72V8985J is sourced from the original manufacturer or authorized distributors?
All 72V8985J 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 72V8985J meets industry standards.
7.What is the process for return or replacement of 72V8985J?
All 72V8985J units undergo pre-shipment inspection (PSI). If there is an issue with 72V8985J, 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 72V8985J part is unused and in its original packaging.
Return procedure for 72V8985J:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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