DS21FF42, DS21FT42

4 x 4 16 Channel T1 Framer / 4 x 3 12 Channel T1 Framer

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Status Explanations for product status codes

Part Number Status
DS21FF42 Active: In Production. See Ordering Information for details.
DS21FT42 Active: In Production. See Ordering Information for details.


The 4 x 4 and 4 x 3 multichip modules (MCM) offer a high-density packaging arrangement for the DS21Q42 T1 Enhanced Quad Framer. Either three (DS21FT42) or four (DS21FF42) silicon die of these devices is packaged in an MCM with the electrical connections as shown in Figure 1-1.

All of the functions available on the DS21Q42 are also available in the MCM packaged version. However, in order to minimize package size, some signals have been deleted or combined. These differences are detailed in Table 1-1. In the 4 x 3 (FT) version, the fourth quad framer is not populated and hence all of the signals to and from this fourth framer are absent and should be treated as No Connects (NC). Table 2-1 lists all of the signals on the MCM and it also lists the absent signals for the 4 x 3.

The availability of both a 12-channel and a 16-channel version allow the maximum framer density with the lowest cost. For example, in a T3 application, two devices (one DS21FF42 and one DS21FT42) provide 28 framers without the additional cost and power consumption of any unused framers that appear in an octal approach.

Data Sheet

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Key Features

  • 16 or 12 completely independent T1 framers in one small 27mm x 27mm, 1.27mm pitch BGA package
  • Each multichip module (MCM) contains four (FF) or three (FT) DS21Q42 die
  • Each quad framer can be concatenated into a single 8.192MHz backplane data stream
  • IEEE 1149.1 JTAG-Boundary Scan Architecture
  • DS21FF42 and DS21FT42 are pin compatible with DS21FF44 and DS21FT44, respectively, to allow the same footprint to support T1 and E1 applications
  • 300-pin MCM 1.27mm pitch BGA package (27mm x 27mm)
  • Low-power 3.3V CMOS with 5V tolerant input and outputs


  • High-Density Line Cards
  • Multiplexers/Demultiplexers
  • Routers/Switches

Key Specifications:

T/E Carrier & Packetized Products
Part Number Transmission Standard Functions Channels VSUPPLY
See Notes
DS21FF42  T1/J1 Framer 16 3.3 $142.14 @1k
DS21FT42  12 $134.03 @1k
See All T/E Carrier & Packetized Products (88)

Pricing Notes:

This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.


DS21FF42, DS21FT42: Functional Diagram
Functional Diagram

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Information Index

Rev 1; 2002-08-09
This page last modified: 2009-10-22