DS2148/DS21Q48
5V E1/T1/J1 Line Interface
www.maxim-ic.com
FEATURES
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Complete E1, T1, or J1 line interface unit
(LIU)
Supports both long- and short-haul trunks
Internal software-selectable receive-side
termination for 75Ω/100Ω/120W
5V power supply
32-bit or 128-bit crystal-less jitter attenuator
requires only a 2.048MHz master clock for
both E1 and T1 with option to use 1.544MHz
for T1
Generates the appropriate line build outs,
with and without return loss, for E1 and
DSX-1 and CSU line build outs for T1
AMI, HDB3, and B8ZS, encoding/decoding
16.384MHz, 8.192MHz, 4.096MHz, or
2.048MHz clock output synthesized to
recovered clock
Programmable monitor mode for receiver
Loopbacks and PRBS pattern generation/
detection with output for received errors
Generates/detects in-band loop codes, 1 to 16
bits including CSU loop codes
8-bit parallel or serial interface with optional
hardware mode
Multiplexed and nonmultiplexed parallel bus
supports Intel or Motorola
Detects/generates blue (AIS) alarms
NRZ/bipolar interface for TX/RX data I/O
Transmit open-circuit detection
Receive Carrier Loss (RCL) indication
(G.775)
High-Z State for TTIP and TRING
50mA (rms) current limiter
PIN DESCRIPTION
44
1
44 TQFP
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7mm
CABGA
ORDERING INFORMATION
Single-Channel Devices:
DS2148TN 44-Pin TQFP
DS2148T
44-Pin TQFP
DS2148GN 7mm CABGA
DS2148G
7mm CABGA
Four-Channel Devices:
DS21Q48N (Quad) BGA
DS21Q48
(Quad) BGA
(-40°C to +85°C)
(0
o
C to +70
o
C)
(-40°C to +85°C)
(0
o
C to +70
o
C)
(-40°C to +85°C)
(0
o
C to +70
o
C)
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REV: 082504
DS2148/Q48
DESCRIPTION
The DS2148 is a complete selectable E1 or T1 Line Interface Unit (LIU) for short- and long-haul
applications. Throughout the data sheet, J1 is represented wherever T1 exists. Receive sensitivity adjusts
automatically to the incoming signal and can be programmed for 0dB to 12dB or 0dB to 43dB for E1
applications and 0dB to 30dB or 0dB to 36dB for T1 applications. The device can generate the necessary
G.703 E1 waveshapes in 75Ω or 120Ω applications and DSX-1 line build outs or CSU line build outs of
0dB, -7.5dB, -15dB, and -22.5dB for T1 applications. The crystal-less onboard jitter attenuator requires
only a 2.048MHz MCLK for both E1 and T1 applications (with the option of using a 1.544MHz MCLK
in T1 applications). The jitter attenuator FIFO is selectable to either 32 bits or 128 bits in depth and can
be placed in either the transmit or receive data paths. An X 2.048MHz output clock synthesized to RCLK
is available for use as a backplane system clock (where n = 1, 2, 4, or 8). The DS2148 has diagnostic
capabilities such as loopbacks and PRBS pattern generation/detection. 16-bit loop-up and loop-down
codes can be generated and detected. The device can be controlled via an 8-bit parallel muxed or
nonmuxed port, serial port or used in hardware mode. The device fully meets all of the latest E1 and T1
specifications including ANSI T1.403-1999, ANSI T1.408, AT&T TR 62411, ITU G.703, G.704, G.706,
G.736, G.775, G.823, I.431, O.151, O.161, ETSI ETS 300 166, JTG.703, JTI.431, JJ-20.1, TBR12,
TBR13, and CTR4.
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DS2148/Q48
TABLE OF CONTENTS
LIST OF FIGURES............................................................................................................................... 4
LIST OF TABLES ................................................................................................................................ 5
INTRODUCTION................................................................................................................................. 6
3.1 DOCUMENT REVISION HISTORY ............................................................................................ 6
4. PIN DESCRIPTION ............................................................................................................................. 9
5. HARDWARE MODE ......................................................................................................................... 22
5.1 REGISTER MAP .......................................................................................................................... 23
5.2 PARALLEL PORT OPERATION................................................................................................ 24
5.3 SERIAL PORT OPERATION ...................................................................................................... 24
6. CONTROL REGISTERS.................................................................................................................... 28
6.1 DEVICE POWER-UP AND RESET ............................................................................................ 31
7 STATUS REGISTERS ....................................................................................................................... 34
8. DIAGNOSTICS .................................................................................................................................. 39
8.1 IN-BAND LOOP CODE GENERATION AND DETECTION ................................................... 39
8.2 LOOPBACKS ............................................................................................................................... 43
8.2.1 Remote Loopback (RLB)......................................................................................................... 43
8.2.2 Local Loopback (LLB)............................................................................................................ 43
8.2.3 Analog Loopback (LLB) ......................................................................................................... 44
8.2.4 Dual Loopback (DLB) ............................................................................................................ 44
8.3 PRBS GENERATION AND DETECTION ................................................................................. 44
8.4 ERROR COUNTER...................................................................................................................... 44
8.4.1 Error Counter Update ............................................................................................................ 45
8.5 ERROR INSERTION.................................................................................................................... 45
9. ANALOG INTERFACE ..................................................................................................................... 46
9.1 RECEIVER .................................................................................................................................... 46
9.2 TRANSMITTER ........................................................................................................................... 47
9.3 JITTER ATTENUATOR .............................................................................................................. 47
9.4 G.703 SYNCHRONIZATION SIGNAL ...................................................................................... 48
10. DS21Q48 QUAD LIU......................................................................................................................... 56
11. DC CHARACTERISTICS.................................................................................................................. 60
12. AC CHARACTERISTICS.................................................................................................................. 62
13. MECHANICAL DIMENSIONS......................................................................................................... 71
13.1 MECHANICAL DIMENSIONS—QUAD VERSION................................................................. 73
1.
2.
3.
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DS2148/Q48
1. LIST OF FIGURES
Figure 3-1 DS2148 BLOCK DIAGRAM..................................................................................................... 7
Figure 3-2 RECEIVE LOGIC ...................................................................................................................... 8
Figure 3-3 TRANSMIT LOGIC ................................................................................................................... 9
Figure 4-1 PARALLEL PORT MODE PINOUT (BIS1 = 0, BIS0 = 1 or 0) ............................................ 21
Figure 4-2 SERIAL PORT MODE PINOUT (BIS1 = 1, BIS0 = 0) .......................................................... 21
Figure 4-3 HARDWARE MODE PINOUT (BIS1 = 1, BIS0 = 1) ............................................................ 22
Figure 5-1 SERIAL PORT OPERATION FOR READ ACCESS (R=1) MODE 1.................................. 25
Figure 5-2 SERIAL PORT OPERATION FOR READ ACCESS MODE 2 ............................................. 25
Figure 5-3 SERIAL PORT OPERATION FOR READ ACCESS MODE 3 ............................................. 26
Figure 5-4 SERIAL PORT OPERATION FOR READ ACCESS MODE 4 ............................................. 26
Figure 5-5 SERIAL PORT OPERATION FOR WRITE ACCESS (R=0) MODES 1&2 ...……………27
Figure 5-6 SERIAL PORT OPERATION FOR WRITE ACCESS MODES 3&4 …………...…………27
Figure 9-1 BASIC INTERFACE ………………………………………………………………………..50
Figure 9-2 PROTECTED INTERFACE USING INTERNAL RECEIVE TERMINATION.................... 51
Figure 9-3 PROTECTED INTERFACE USING EXTERNAL RECEIVE TERMINATION .................. 52
Figure 9-4 E1 TRANSMIT PULSE TEMPLATE...................................................................................... 53
Figure 9-5 T1 TRANSMIT PULSE TEMPLATE...................................................................................... 54
Figure 9-6 JITTER TOLERANCE............................................................................................................. 55
Figure 9-7 JITTER ATTENUATION ........................................................................................................ 55
Figure 10-1 BGA 12 x 12 PIN LAYOUT .................................................................................................. 59
Figure 12-1 INTEL BUS READ TIMING (PBTS = 0, BIS1 = 0, BIS0 = 0) ............................................ 63
Figure 12-2 INTEL BUS WRITE TIMING (PBTS = 0, BIS1 = 0, BIS0 = 0)........................................... 63
Figure 12-3 MOTOROLA BUS TIMING (PBTS = 1, BIS1 = 0, BIS0 = 0) ............................................ 64
Figure 12-4 INTEL BUS READ TIMING (PBTS = 0, BIS1 = 0, BIS0 = 1) ............................................ 66
Figure 12-5 INTEL BUS WRITE TIMING (PBTS = 0, BIS1 = 0, BIS0 = 1)........................................... 66
Figure 12-6 MOTOROLA BUS READ TIMING (PBTS = 1, BIS1 = 0, BIS0 = 1) ................................. 67
Figure 12-7 MOTOROLA BUS WRITE TIMING (PBTS = 1, BIS1 = 0, BIS0 = 1)................................ 67
Figure 12-8 SERIAL BUS TIMING (BIS1 = 1, BIS0 = 0)........................................................................ 68
Figure 12-9 RECEIVE SIDE TIMING ...................................................................................................... 69
Figure 12-10 TRANSMIT SIDE TIMING................................................................................................. 70
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DS2148/Q48
2. LIST OF TABLES
Table 4-1 BUS INTERFACE SELECTION ................................................................................................ 9
Table 4-2a PIN ASSIGNMENT................................................................................................................. 10
Table 4-2b PIN DESCRIPTIONS (Sorted by Pin Name, DS2148T Pin Numbering) ............................... 11
Table 4-3a PIN ASSIGNMENT IN SERIAL PORT MODE..................................................................... 13
Table 4-3b PIN DESCRIPTIONS IN SERIAL PORT MODE (Sorted by Pin Name, DS2148T Pin
Numbering) .......................................................................................................................................... 14
Table 4-4a PIN ASSIGNMENT IN HARDWARE MODE....................................................................... 16
Table 4-4b PIN DESCRIPTIONS IN HARDWARE MODE (Sorted by Pin Name, DS2148T Pin
Numbering) .......................................................................................................................................... 16
Table 4-5 LOOPBACK CONTROL IN HARDWARE MODE ................................................................ 20
Table 4-6 TRANSMIT DATA CONTROL IN HARDWARE MODE ..................................................... 20
Table 4-7 RECEIVE SENSITIVITY SETTINGS...................................................................................... 20
Table 4-8 MONITOR GAIN SETTINGS .................................................................................................. 20
Table 4-9 INTERNAL RX TERMINATION SELECT............................................................................. 20
Table 4-10 MCLK SELECTION................................................................................................................ 20
Table 5-1 REGISTER MAP ....................................................................................................................... 23
Table 6-1 MCLK SELECTION.................................................................................................................. 29
Table 6-2 RECEIVE SENSITIVITY SETTINGS...................................................................................... 31
Table 6-3 BACK PLANE CLOCK SELECT............................................................................................. 32
Table 6-4 MONITOR GAIN SETTINGS .................................................................................................. 32
Table 6-5 INTERNAL RX TERMINATION SELECT............................................................................. 33
Table 7-1 RECEIVED ALARM CRITERIA ............................................................................................. 35
Table 7-2 RECEIVE LEVEL INDICATION............................................................................................. 38
Table 8-1 TRANSMIT CODE LENGTH................................................................................................... 40
Table 8-2 RECEIVE CODE LENGTH ...................................................................................................... 40
Table 8-3 DEFINITION OF RECEIVED ERRORS.................................................................................. 44
Table 8-4 FUNCTION OF ECRS BITS AND RNEG PIN ........................................................................ 45
Table 9-1 LINE BUILD OUT SELECT FOR E1 IN REGISTER CCR4 (ETS = 0) ................................. 48
Table 9-2 LINE BUILD OUT SELECT FOR T1 IN REGISTER CCR4 (ETS = 1) ................................. 48
Table 9-3 TRANSFORMER SPECIFICATIONS FOR 5V OPERATION ............................................... 49
Table 10-1 DS21Q48 PIN ASSIGNMENT................................................................................................ 56
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