DS21Q55 Maxim Integrated Products, DS21Q55 Datasheet - Page 194

• Manufacturer Part Number: DS21Q55
• Description: IC TXRX QUAD T1/E1/J1 SCT 256BGA
• Manufacturer: Maxim Integrated Products

Specifications of DS21Q55

• Function: Transceiver
• Interface: E1, J1, T1
• Number Of Circuits: 4
• Voltage - Supply: 3.14 V ~ 3.47 V
• Current - Supply: 75mA
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 256-BGA
• Includes: BERT Generator and Detector, Dual HDLC Controllers
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Power (watts): -

28.
The DS21Q55 contains an on-chip clock synthesizer that generates a user-selectable clock output on the
BPCLK pin, referenced to the recovered receive clock (RCLK). The synthesizer uses a phase-locked loop
to generate low-jitter clocks. Common applications include generation of port and backplane system
clocks. The CCR2 register is used to enable (CCR2.0) and select (CCR2.1 and CCR2.2) the clock
frequency of the BPCLK pin.
Register Name:
Register Description:
Register Address:
Bit #
Name
Default
Bit 0/Backplane Clock Enable (BPEN)
Bits 1, 2/Backplane Clock Selects (BPCS0, BPCS1)
Bits 3 to 7/ Unused, must be set to 0 for proper operation
BPCS1
0
0
1
1
PROGRAMMABLE BACKPLANE CLOCK SYNTHESIZER
0 = disable BPCLK pin (pin held at logic 0)
1 = enable BPCLK pin
TRPA4
7
0
BPCS0
0
1
0
1
TRPA3
CCR2
Common Control Register 2
71h
6
0
BPCLK Frequency (MHz)
TRPA2
5
0
16.384
8.192
4.096
2.048
TRPA1
4
0
194 of 237
TRPA0
0
3
BPCS1
2
0
BPCS0
1
0
BPEN
0
0