DS26518GN+ Maxim Integrated Products, DS26518GN+ Datasheet - Page 31

• Manufacturer Part Number: DS26518GN+
• Description: IC TXRX T1/E1/J1 8PORT 256-CSBGA
• Manufacturer: Maxim Integrated Products
• Type: Transceiverr

Specifications of DS26518GN+

• Number Of Drivers/receivers: 8/8
• Protocol: T1/E1/J1
• Voltage - Supply: 3.135 V ~ 3.465 V
• Mounting Type: Surface Mount
• Package / Case: 256-CSBGA
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

9.2
The user should provide a system clock to the MCLK input of 2.048MHz, 1.544MHz, or a multiple of up to 8x the T1
and E1 frequencies. To meet many specifications, the MCLK source should have ±50ppm accuracy.
9.2.1 Backplane Clock Generation
The DS26518 provides facility for provision of BPCLK1 at 2.048MHz, 4.096MHz, 8.192MHz, 16.384MHz (see
Figure
generation. This register is also used to program REFCLKIO as an input or output. REFCLKIO can be an output
sourcing MCLKT1 or MCLKE1 as shown in
This backplane clock and frame pulse (TSSYNCIOn) can be used by the DS26518 and other IBO-equipped
devices as an “IBO Bus Master.” Hence, the DS26518 provides the 8kHz sync pulse and 4MHz, 8MHz, and 16MHz
clock. This can be used by the link layer devices and frames connected to the IBO bus.
Figure 9-9. Backplane Clock Generation
The reference clock for the backplane clock generator can be as follows:
•
•
•
•
•
9-9). The Global Transceiver Clock Control Register 1 (GTCCR1) is used to control the backplane clock
Clock Structure
External Master Clock. A prescaler can be used to generate T1 or E1 frequency.
External Reference Clock REFCLKIO. This allows for multiple DS26518s to use the backplane clock from
a common reference.
Internal LIU recovered RCLKs 1 to 8.
The clock generator can be used to generate BPCLK1 of 2.048MHz, 4.096MHz, 8.192MHz, or 16.384MHz
for the IBO.
If MCLK or RCLKn is used as a reference, REFCLKIO can be used to provide a 2.048MHz or 1.544MHz
clock for external use.
MCLK
Scaler
PLL
Pre
REFCLKIO
MCLKT1
MCLKE1
RCLK7
RCLK1
RCLK2
RCLK3
RCLK4
RCLK5
RCLK6
RCLK8
Figure
BPREFSEL3:0
9-9.
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BFREQSEL
BPCLK1:0
GEN
CLK
TSSYNCIO
REFCLKIO
BPCLK