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Renesas 728981JG
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- Part No.:
- 728981JG
- Manufacturer:
- Renesas
- Category:
- Signal Switches, Multiplexers, Decoders
- Package:
- 44-LCC (J-Lead)
- Datasheet:
-
728981JG.pdf
- Description:
- IC MULTIPLEXER 1 X 4:4 44PLCC
- Quantity:
- Payment:
- Shipping:
Inventory:2,625
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Product details
Overview
IDT728981JG from Integrated Device Technology (IDT) is a 128 × 128 non-blocking time slot interchange (TSI) digital switch for ST-BUS®-compliant telecom systems. It supports four 2.048 Mb/s serial input streams (RX0–RX3), four 2.048 Mb/s output streams (TX0–TX3), microprocessor-controlled routing via an 8-bit parallel bus, and operates at 5 V over –40°C to +85°C. It enables dynamic channel switching in PCM-based voice/data multiplexing equipment.
For engineers reviewing the IDT728981JG datasheet, IDT728981JG pinout, IDT728981JG application, or IDT728981JG equivalent, key selection criteria include ST-BUS® timing compliance (4.096 MHz C4i clock, 8 kHz F0i frame sync), per-channel software-configurable processor/connection modes, three-state TX outputs with ODE control, and PLCC-44 package compatibility with legacy telecom board layouts.
Technical Context
The IDT728981JG implements a dual-memory architecture: 128-location Data Memory stores incoming serial data after internal serial-to-parallel conversion, while 32-location Connection Memory (split HIGH/LOW) defines routing paths. Frame-aligned 125 µs slots with 32 × 8-bit channels are synchronized by F0i and shifted using C4i at 4.096 MHz.
Routing operates in two mutually exclusive modes: Connection Mode reads Data Memory addresses from Connection Memory LOW to forward input channel data to output channels; Processor Mode directly outputs Connection Memory LOW contents on TX streams. Output enable is controlled per-channel via Connection Memory HIGH bits and globally via the ODE pin.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| Switch Capacity | 128 × 128 non-blocking TSI matrix for full-time-slot reassignment across all 128 channels |
| Serial Interface | ST-BUS®-compliant: 4 RX + 4 TX streams, each 2.048 Mb/s (32 × 64 kbit/s channels) |
| Timing Reference | 4.096 MHz C4i clock and 8 kHz F0i frame pulse ensure strict E1/T1 frame alignment |
| Microprocessor Bus | 8-bit parallel interface with CS, DS, R/W, A0–A5, D0–D7, and DTA handshake for register/memory access |
| Supply & Temp | 5 V ±5% operation; industrial temperature range –40°C to +85°C for telecom infrastructure deployment |
| Output Control | Three-state TX outputs with global ODE pin and per-channel OE bit in Connection Memory HIGH |
| Delay Profile | Minimum 2-channel delay between RX and TX streams; exact latency depends on stream pairing (e.g., RX0→TX1 allowed, RX0→TX0 not) |
Pinout & Package
Package: 44-pin Plastic Leaded Chip Carrier (PLCC), 0.05″ pitch, 0.65″ × 0.65″ footprint (order code J). Pin 1 index corner marked; DNC pins must remain unconnected.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| GND | Ground reference | Primary ground rail for analog/digital sections; multiple pins (11, 30) reduce impedance |
| VCC | Power supply | +5.0 V supply; four dedicated pins (21, 22, 23, 24) ensure stable core voltage under switching load |
| RX0–RX3 | Serial input | Four 2.048 Mb/s ST-BUS® data inputs; each carries 32 time slots of 64 kbit/s PCM data |
| TX0–TX3 | Serial output | Four three-state 2.048 Mb/s outputs; ODE and CMH bits control per-channel driver state |
| F0i | Frame sync input | 8 kHz active-HIGH pulse marking start of 125 µs E1 frame; used for internal address counter reset |
| C4i | Serial clock input | 4.096 MHz clock driving serial shift registers; determines maximum throughput and timing margins |
| A0–A5 | Address bus | 6-bit address for Control Register (A5=0) or 32-channel memory location (A5=1, A4–A0) |
| D0–D7 | Data bus | 8-bit bidirectional path for reading/writing Control Register, Data Memory, or Connection Memory |
| CS / DS / R/W | Bus control | Chip Select, Data Strobe, and Read/Write signals implement standard 8080-style microprocessor interface |
| DTA | Acknowledgment | Open-drain active-LOW signal confirming completion of bus transaction; requires external pull-up |
| ODE | Output enable | Global three-state control for TX0–TX3; overrides per-channel OE bits when pulled LOW |
Key Features
| Feature | Design Value |
|---|---|
| ST-BUS® Compliance | Hardware-level support for Mitel's ST-BUS® physical layer ensures plug-in interoperability with legacy telecom line cards and framers |
| Dual Routing Modes | Software-selectable Connection Mode (hardware-switched TSI) or Processor Mode (CPU-driven data injection) per output channel |
| Per-Channel Output Control | Connection Memory HIGH provides independent OE and CS bits for each of 128 output channels, enabling sparse matrix construction |
| Robust Initialization | ODE pin held LOW at power-up prevents bus contention; allows safe CMH programming before releasing outputs |
| Low-Latency Switching | Fixed 2-channel minimum delay (e.g., RX0→TX1) enables real-time voice path reconfiguration without buffer overflow risk |
Applications
| PCM Multiplexer | Digital Cross-Connect System |
|---|---|
Use Scenario: Aggregating 32 E1 lines into a single high-speed backplane interface in central office equipment. IC Role / Device Role / Timing Role: Time slot interchange performing dynamic channel mapping between input and output E1 streams under CPU supervision. Use Value: Enables flexible grooming of voice/data traffic without requiring frame alignment across multiple E1 sources due to internal F0i-synchronized buffering. | Use Scenario: Reconfiguring DS0-level connections between tributary ports in a carrier-grade digital loop carrier system. IC Role / Device Role / Timing Role: Non-blocking 128×128 switch fabric providing per-DS0 path control with sub-frame latency. Use Value: Supports hitless reconfiguration of voice circuits during maintenance via Processor Mode writes to Connection Memory LOW. |
| ISDN PRI Interface Card | VoIP Gateway Media Plane |
Use Scenario: Implementing B-channel switching and D-channel monitoring on a 30-B+D ISDN Primary Rate Interface card. IC Role / Device Role / Timing Role: ST-BUS®-native TSI handling 30 B-channels (64 kbit/s each) plus signaling channel routing within a single IC. Use Value: Eliminates need for external framing logic; direct connection to MT9075 or similar ST-BUS® transceivers reduces component count and board area. | Use Scenario: Bridging TDM voice streams from legacy PBX systems to packetized VoIP media gateways. IC Role / Device Role / Timing Role: Channelized TSI aligning and repackaging 64 kbit/s PCM samples into RTP payloads with deterministic jitter profile. Use Value: Provides precise 125 µs frame boundary control required for low-jitter transcoding; ODE pin enables clean mute/unmute of output streams during codec handover. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar time slot interchange applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| IDT728981PG | Same die, 40-pin PDIP package; larger footprint, through-hole mounting, no PLCC thermal pad | Suitable for prototyping or low-volume boards where socketing or manual assembly is preferred | Select IDT728981PG only if PLCC-44 layout constraints or reflow compatibility are not required |
| IDT728981DB | Same die, 44-pin PQFP (DB44-1); 10 mm × 10 mm body, 0.8 mm pitch, no leaded package | Better suited for high-density SMT production; requires different land pattern and reflow profile than PLCC | Choose IDT728981DB when board space is constrained and automated assembly is used |
Compared with IDT728981JG, IDT728981PG offers easier manual handling but higher parasitic inductance on serial lines, while IDT728981DB improves thermal dissipation and board density but demands tighter PCB layout control for signal integrity on 2.048 Mb/s streams.
Availability
IDT728981JG is available at Aetrix Electronics and suitable for PCM multiplexing, digital cross-connect systems, ISDN PRI interface cards, and VoIP gateway media planes requiring stable component supply across extended product lifecycles.
Supply support for IDT728981JG 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 telecom ICs before its acquisition by Renesas Electronics in 2019.
The IDT728981JG belongs to IDT's legacy TSI switch family designed specifically for E1/T1 infrastructure equipment, emphasizing ST-BUS® interoperability, deterministic latency, and microprocessor configurability in carrier-class systems.
FAQ
What is the primary function of the IDT728981JG in a telecom system?
The IDT728981JG functions as a 128 × 128 time slot interchange digital switch that dynamically reroutes individual 64 kbit/s PCM channels between four 2.048 Mb/s input and output serial streams. It operates under microprocessor control to enable flexible circuit switching in E1-based infrastructure like multiplexers and cross-connect systems, maintaining strict ST-BUS® timing compliance with 4.096 MHz C4i and 8 kHz F0i synchronization.
How does the IDT728981JG handle timing synchronization for E1 frames?
The IDT728981JG uses the F0i input pin to receive an 8 kHz frame pulse that resets its internal address counter, ensuring alignment with 125 µs E1 frames. The C4i pin accepts a 4.096 MHz clock that drives serial-to-parallel and parallel-to-serial conversion, guaranteeing precise 8-bit time slot positioning. This dual-clock architecture maintains ST-BUS®-compliant timing without requiring external frame alignment logic.
Can the IDT728981JG operate in both hardware-switched and processor-driven modes simultaneously?
No - the IDT728981JG supports two mutually exclusive routing modes: Connection Mode (hardware-switched, using Connection Memory LOW as address pointers into Data Memory) and Processor Mode (CPU-driven, outputting Connection Memory LOW contents directly on TX streams). Mode selection is controlled globally via bit 6 (PE) of the Control Register; mixing modes per channel is not supported.
What is the role of the ODE pin on the IDT728981JG, and how does it interact with per-channel output control?
The ODE (Output Drive Enable) pin is a global three-state control for all TX0–TX3 outputs. When ODE is LOW, all serial outputs enter high-impedance regardless of Connection Memory HIGH settings. When ODE is HIGH, per-channel output state is determined by bit 0 (OE) in each Connection Memory HIGH location, allowing selective channel muting while maintaining bus integrity in matrix configurations.
What package type does the IDT728981JG use, and why is it significant for telecom board design?
The IDT728981JG uses a 44-pin Plastic Leaded Chip Carrier (PLCC) package (order code J), featuring a 0.05″ lead pitch and 0.65″ × 0.65″ body. Its gull-wing leads provide robust mechanical attachment and moderate thermal performance, making it suitable for legacy telecom backplanes where vibration resistance and socket compatibility are critical - unlike PQFP or PDIP variants which lack this specific mounting and thermal profile.
728981JG Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Renesas
- Series:
- 7200
- Package/Case:
- 44-LCC (J-Lead)
- Packaging:
- Tube
- Product Status:
- Obsolete
- Type:
- Multiplexer
- Circuit:
- 1 x 4:4
- Independent Circuits:
- 1
- Current - Output High, Low:
- -
- Voltage Supply Source:
- Single Supply
- Voltage - Supply:
- 4.75V ~ 5.25V
- Operating Temperature:
- -40°C ~ 85°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 44-PLCC (16.59x16.59)
728981JG FAQ
1.How can I place an order for 728981JG through Aetrix?
Please submit a Request for Quotation (RFQ) for 728981JG 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 728981JG reliable?
The price and inventory of 728981JG are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for 728981JG is usually 5 days.
3.What payment methods are accepted for 728981JG?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for 728981JG transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for 728981JG?
728981JG orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your 728981JG 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 728981JG?
For technical support, including 728981JG datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your 728981JG requirements.
6.How does Aetrix verify that 728981JG is sourced from the original manufacturer or authorized distributors?
All 728981JG 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 728981JG meets industry standards.
7.What is the process for return or replacement of 728981JG?
All 728981JG units undergo pre-shipment inspection (PSI). If there is an issue with 728981JG, 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 728981JG part is unused and in its original packaging.
Return procedure for 728981JG:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
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