My Inquiry
My Account
Analog Devices Inc./Maxim Integrated DS31256
- Part No.:
- DS31256
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Category:
- Telecom
- Package:
- 256-BGA
- Datasheet:
-
DS31256.pdf
- Description:
- IC TELECOM INTERFACE 256BGA
- Quantity:
- Payment:
- Shipping:
Inventory:1,677
Please send an inquiry. Send us your inquiry, and we will respond immediately.
Product details
Overview
The DS31256 from Maxim Integrated is a 256-channel, high-throughput HDLC controller IC designed for telecom line interface cards and multichannel T1/E1/T3 access equipment. It supports up to 60 T1 or 64 E1 data streams, delivers 132Mbps full-duplex throughput, features 16 physical ports with independent channelized/unchannelized configuration, and integrates three 52Mbps fast HDLC engines on Ports 0–2 - enabling dense frame-relay and multilink PPP routing in carrier-grade infrastructure.
For engineers reviewing the DS31256 datasheet, DS31256 pinout, DS31256 application, or DS31256 equivalent, key selection considerations include per-port HDLC engine speed grading (52Mbps vs. 10Mbps), PCI v2.1 interface compatibility, 256-pin PBGA package thermal and layout constraints, BERT assignment flexibility across channels, and backward compatibility with DS3134 in legacy system upgrades.
Technical Context
The DS31256 implements a layered architecture with dedicated Layer 1 circuitry for T1/E1/T3 physical layer framing, 16 independent HDLC processing engines (13 standard + 3 fast), dual-directional 16kB FIFOs, scatter/gather DMA controllers, and dual-bus connectivity via 33MHz 32-bit PCI and configurable local bus (Intel/Motorola signaling). Its port-level over-subscription capability enables dynamic bandwidth allocation across mixed T1/E1 line densities.
Each HDLC engine supports transparent mode, per-channel DS0 loopbacks in both directions, V.54 loopback code detection, and time-stamped receive packet handling. The integrated BERT can be assigned to any HDLC channel or port and supports automatic error insertion - critical for production line testing and field diagnostics in DSLAMs and routers.
Key Specifications
| Parameter | Value and Actual Design Meaning |
|---|---|
| HDLC Channels | 256 independent bidirectional channels - enables full DS0-level granularity for high-density T1/E1 aggregation. |
| Max Throughput | 132Mbps full-duplex - sustains line-rate processing for 60× T1 (1.544Mbps) or 64× E1 (2.048Mbps) streams simultaneously. |
| Port Count & Speed | 16 physical ports; Ports 0–2 support 52Mbps unchannelized operation; remaining ports support up to 10Mbps unchannelized or 8.192Mbps channelized. |
| FIFO Size | 16kB transmit + 16kB receive FIFO - buffers bursty traffic across multiple ports without host CPU intervention. |
| PCI Interface | 33MHz, 32-bit, PCI v2.1 compliant - ensures interoperability with standard x86-based control planes and legacy telecom host systems. |
| Power Supply | 3.3V core with 5V-tolerant I/O - simplifies level-shifting design and supports mixed-voltage backplane environments. |
| Package | 256-pin plastic BGA (27mm × 27mm) - optimized for thermal dissipation at 3.0W under natural convection in telecom line cards. |
Pinout & Package
DS31256 is housed in a 256-ball plastic ball grid array (PBGA) package measuring 27mm × 27mm with 1.27mm ball pitch. The package supports JEDEC-standard thermal and mechanical mounting for telecom line card applications.
| Pin/Terminal | Circuit Role | Design Meaning |
|---|---|---|
| CLKIN | PCI Clock Input | Accepts 33MHz reference clock for PCI interface timing; requires stable low-jitter source for reliable bus arbitration. |
| AD[31:0] | PCI Address/Data Multiplexed Bus | Carries address during Phase 1 and data during Phase 2 of PCI cycles; shared with C/BE[3:0] for command encoding. |
| C/BE[3:0] | PCI Command/Byte Enable | Defines transaction type (I/O read/write, memory read/write) and active byte lanes - essential for proper register and FIFO access. |
| FRAME# | PCI Frame Start Signal | Indicates start of PCI transaction; asserted by initiator to begin address phase - required for synchronous host-to-DS31256 command flow. |
| TRDY# | PCI Target Ready | Asserted by DS31256 to signal readiness to complete current data phase - governs throughput in burst-mode DMA transfers. |
| TxD[7:0], RxD[7:0] | Local Bus Data | 8-bit bidirectional data path for local bus mode (PCI bridge or direct microcontroller access); supports Intel/Motorola timing modes. |
| TMS, TCK, TDI, TDO | JTAG Test Access Port | IEEE 1149.1-compliant boundary-scan interface for production test, debug, and in-system programming of configuration registers. |
Key Features
| Feature | Design Value |
|---|---|
| Per-port HDLC engine speed grading | Ports 0–2 support 52Mbps unchannelized operation; other ports support ≤10Mbps - enables cost-optimized port allocation for mixed-speed T1/E1/T3 line cards. |
| On-chip BERT with channel/port assignment | BERT function assignable to any HDLC channel or port - eliminates need for external test equipment during manufacturing and field maintenance. |
| Time-stamped receive packets | Hardware timestamping at packet ingress - enables precise latency measurement and synchronization-critical applications like SONET/SDH EOC termination. |
| Transmit packet priority setting | Per-packet priority control in transmit DMA engine - allows QoS enforcement for real-time protocols such as VoIP or control-plane signaling. |
| Scatter/gather DMA | Reduces host memory fragmentation overhead and CPU load - improves system efficiency in Linux-based router platforms with large buffer pools. |
Applications
| DSLAM Line Card | High-Density Router |
|---|---|
|
Use Scenario: Aggregating 64 E1 lines from copper access networks into IP backbone via multilink PPP. IC Role / Device Role / Timing Role: HDLC controller performing frame assembly/disassembly, CRC generation/verification, and bit stuffing for each DS0 channel. Use Value: 256-channel capacity and 132Mbps throughput enable single-IC replacement of multiple lower-density controllers - reducing BOM count and board area in compact DSLAM chassis. |
Use Scenario: Supporting 60 T1 interfaces in a service provider edge router with frame-relay switching and QoS-aware packet forwarding. IC Role / Device Role / Timing Role: High-throughput HDLC processor handling channelized T1 framing, LMI signaling, and per-VC statistics collection. Use Value: Three 52Mbps fast ports handle high-bandwidth control links (e.g., T3 management channels), while standard ports manage individual T1s - optimizing performance-per-watt in power-constrained rack units. |
| T3/E3 Termination | SONET/SDH EOC System |
|
Use Scenario: Dual T3 termination in a transport demarcation device, converting T3 payloads to Ethernet/IP for metro aggregation. IC Role / Device Role / Timing Role: HDLC controller extracting and reinserting T3 framing bits, managing payload mapping, and supporting clear-channel operation. Use Value: Supports two simultaneous T3 streams (each requiring 44.736Mbps) with full HDLC processing - eliminating need for external framer/FIFO combinations in T3 interface modules. |
Use Scenario: Embedded EOC (Embedded Operations Channel) termination in SONET ADMs, carrying OAM&P traffic over SDH section overhead. IC Role / Device Role / Timing Role: HDLC link-layer processor handling EOC framing, error detection, and transparent transport of management messages. Use Value: On-chip BERT and V.54 loopback detection provide built-in diagnostic capability for remote EOC link validation - reducing truck rolls and improving SLA compliance. |
Equivalent & Alternatives
The following parts are listed as comparable options for similar HDLC controller applications.
| Alternative Part | Technical Difference | Application Difference | Selection Advice |
|---|---|---|---|
| DS3134 | 128-channel HDLC controller; no 52Mbps fast ports; supports only up to 30 T1 or 32 E1 streams; lacks integrated BERT. | Targeted at mid-density access nodes where full 256-channel scale is unnecessary; suitable for cost-sensitive T1/E1 concentrators. | Select DS3134 when system requirements fit within half the channel count and BERT is handled externally or omitted. |
| PMC-Sierra PM5352 | 256-channel HDLC controller with integrated T1/E1 line interface (LIU); supports JESD-204B-like serial backplane interface instead of PCI; higher power consumption. | Used in newer-generation modular line cards with integrated analog front-end and serial fabric interconnect - not drop-in compatible with DS31256's parallel PCI/local bus architecture. | Choose PM5352 only when redesigning for serial backplane architecture and requiring integrated LIU functionality. |
Compared with DS3134, the DS31256 doubles channel density and adds BERT and fast ports; compared with PM5352, it retains legacy PCI compatibility and lower power but requires external line interface components - making DS31256 optimal for incremental upgrades of existing PCI-based telecom platforms.
Availability
DS31256 is available at Aetrix Electronics and suitable for DSLAM line cards, high-density routers, T3/E3 termination systems, and SONET/SDH EOC termination requiring stable component supply, long-term lifecycle support, and RoHS-compliant packaging.
Supply support for DS31256 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
Maxim Integrated (now part of Analog Devices) is a semiconductor company specializing in precision analog, mixed-signal, and high-speed communication ICs for industrial, telecom, and computing markets.
The DS31256 belongs to Maxim's Envoy family of high-density HDLC controllers, engineered specifically for carrier-class T1/E1/T3 access multiplexing and multilink PPP routing in space- and power-constrained line cards.
FAQ
What is the maximum number of T1/E1 data streams supported by the DS31256?
The DS31256 supports up to 60 T1 (1.544Mbps) or 64 E1 (2.048Mbps) data streams simultaneously. This capacity is achieved through its 16 physical ports, each configurable to handle one, two, or four T1/E1 lines in channelized mode - allowing flexible deployment in DSLAMs and routers where line density varies across service tiers. The DS31256 achieves this using 256 independent HDLC channels and efficient scatter/gather DMA.
Does the DS31256 include an integrated bit error-rate tester (BERT)?
Yes, the DS31256 includes an on-board BERT with automatic error insertion capability. Unlike external test gear, this BERT can be assigned to any HDLC channel or any of the 16 physical ports - enabling per-link diagnostics without host software intervention. The DS31256 BERT supports standard PRBS patterns and is accessible via dedicated BERT registers (5XX memory map range), making it integral to production test and field maintenance workflows.
What are the key differences between the DS31256 and the DS3134?
The DS31256 doubles the channel count (256 vs. 128), adds three 52Mbps fast HDLC engines on Ports 0–2, includes an integrated BERT, and supports higher aggregate throughput (132Mbps vs. ~66Mbps). The DS31256 also introduces port-level over-subscription and enhanced DMA prioritization. While both share PCI v2.1 and local bus interfaces, the DS31256 is not pin-compatible with DS3134 - requiring PCB redesign for migration, though firmware retains backward compatibility for register-level operations.
What package type and thermal characteristics does the DS31256 use?
The DS31256 uses a 256-pin plastic BGA package measuring 27mm × 27mm with 1.27mm ball pitch. Under natural convection at +70°C ambient, it dissipates up to 3.0W with a junction-to-air thermal resistance (θJA) of 28.5°C/W. The package includes internal 2oz copper planes for improved heat spreading and is rated for commercial temperature range (0°C to +70°C), making it suitable for conduction-cooled telecom line cards where airflow is constrained.
Can the DS31256 operate in both channelized and unchannelized modes?
Yes, the DS31256 supports both channelized and unchannelized operation on all 16 physical ports - configurable independently per port. In channelized mode, each port handles discrete DS0 channels (e.g., one T1 = 24 DS0s); in unchannelized mode, it processes full T1/E1/T3 payloads as continuous bitstreams. This dual-mode capability enables the DS31256 to serve diverse applications including frame-relay access, multilink PPP, and clear-channel T3 termination - all within a single IC footprint.
DS31256 Specifications
- Product attributes
- Attribute value
- Manufacturer:
- Analog Devices Inc./Maxim Integrated
- Series:
- -
- Package/Case:
- 256-BGA
- Packaging:
- Tray
- Product Status:
- Obsolete
- Function:
- -
- Interface:
- Serial
- Number of Circuits:
- -
- Voltage - Supply:
- 3V ~ 3.6V
- Current - Supply:
- 500mA
- Power (Watts):
- -
- Operating Temperature:
- 0°C ~ 70°C
- Grade:
- -
- Qualification:
- -
- Mounting Type:
- Surface Mount
- Supplier Device Package:
- 256-BGA (27x27)
DS31256 FAQ
1.How can I place an order for DS31256 through Aetrix?
Please submit a Request for Quotation (RFQ) for DS31256 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 DS31256 reliable?
The price and inventory of DS31256 are updated periodically and may fluctuate due to market conditions. Stock and pricing data are typically refreshed every 24 hours. Quotation validity for DS31256 is usually 5 days.
3.What payment methods are accepted for DS31256?
We accept Wire Transfer, PayPal, Credit Card, Western Union, MoneyGram, and Escrow for DS31256 transactions.
Note: Certain payment methods may incur a processing fee.
4.How is shipping managed for DS31256?
DS31256 orders can be shipped via leading logistics carriers, including DHL, UPS, FedEx, TNT, or Registered Mail.
Once your DS31256 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 DS31256?
For technical support, including DS31256 datasheets, pinout diagrams, or application guidance, please contact our engineering support team. They can provide detailed documentation and assistance for your DS31256 requirements.
6.How does Aetrix verify that DS31256 is sourced from the original manufacturer or authorized distributors?
All DS31256 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 DS31256 meets industry standards.
7.What is the process for return or replacement of DS31256?
All DS31256 units undergo pre-shipment inspection (PSI). If there is an issue with DS31256, 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 DS31256 part is unused and in its original packaging.
Return procedure for DS31256:
1.Submit a request within 90 days.
2.Obtain a Return Material Authorization (RMA) from Aetrix.
DS31256 Tags
-
LMC567CMX/NOPB
Texas Instruments
-
LM567CMX/NOPB
Texas Instruments
-
LM567CM/NOPB
Texas Instruments
-
VSC8531XMW-02
Microchip Technology
-
VSC8531XMW-05
Microchip Technology
-
GPY115C0VI
MaxLinear, Inc.
-
SI32185-A-FMR
Skyworks Solutions Inc.
-
VSC8541XMV-05
Microchip Technology
-
SI32178-B-FM1R
Skyworks Solutions Inc.
-
GPY215C0VI
MaxLinear, Inc.
-
CPC7514ZTR
Littelfuse Inc.
-
VSC8502XML-03
Microchip Technology
Tech Hub
A practical engineering guide to 3.3V and 5V logic compatibility, input thresholds, resistor dividers, translator ICs, MOSFET level shifting, I2C pull-ups, timing limits and power-sequencing risks.
The 74HC595 uses push-pull logic outputs, while the TPIC6B595 uses 50 V open-drain DMOS sinks for higher-power loads. This guide compares timing, current limits, 3.3 V interfacing, load wiring, thermal…
The 74HC595 converts serial data into eight stable parallel outputs. This guide covers pin functions, shift and storage timing, OE and MR behavior, drive-current limits, cascading, voltage compatibilit…
A technical comparison of level-sensitive latches and edge-triggered flip-flops, covering timing windows, setup and hold limits, master–slave operation, time borrowing, race-through, HDL inference and…
A D latch stores one bit while Enable controls when data can pass. This reference covers gate-level operation, truth tables, transparency, setup and hold timing, LE versus OE, common ICs and practical …
An SR latch stores one bit through cross-coupled feedback. This engineering reference covers NOR and NAND implementations, truth tables, forbidden-state recovery, gated operation, switch debouncing, fa…
Latch circuits retain one bit through feedback. This technical reference covers SR and D latches, truth tables, transparency, timing limits, latch-versus-flip-flop behavior, applications and common log…
An engineering guide to LED driver operation, constant-current and constant-voltage outputs, linear and switching topologies, dimming, IC selection, calculations, replacement compatibility, and fault c…
Operational amplifier guide covering op amp basics, feedback, ideal vs real op amps, common configurations, buffer circuits, offset, bias current, gain-bandwidth, slew rate, rail-to-rail limits and sel…
Jumper cables guide covering safe connection order, red and black clamp placement, final ground connection, cable gauge, length, clamp quality, copper vs CCA cables, jump starter comparison and battery…
