IDT82P2916
16-CHANNEL HIGH-DENSITY T1/E1/J1 LINE INTERFACE UNIT
Pin Description
18
April 24, 2010
REFA
Output
AB15
REFA: Reference Clock Output A
REFA can output three kinds of clocks: a recovered clock of one of the 16 channels, an exter-
nal clock input on CLKA or a free running clock. The clock frequency is programmable. Refer
The output on REFA can also be disabled, as determined by the REFA_EN bit (b6,
REFA).When the output is disabled, REFA is in High-Z state.
REFB
Output
W14
REFB: Reference Clock Output B
REFB can output a recovered clock of one of the 16 channels, an external clock input on
details.
The output on REFB can also be disabled, as determined by the REFB_EN bit (b6,
REFB).When the output is disabled, REFB is in High-Z state.
CLKA
Input
AA14
CLKA: External T1/E1 Clock Input A
External T1/J1 (1.544 MHz) or E1 (2.048 MHz) clock is input on this pin. The CKA_T1E1 bit
(b5,
REFA) should be set to match the clock frequency.
When not used, this pin should be connected to GNDD.
CLKB
Input
V14
CLKB: External T1/E1 Clock Input B
External T1/J1 (1.544 MHz) or E1 (2.048 MHz) clock is input on this pin. The CKB_T1E1 bit
(b5,
REFB) should be set to match the clock frequency.
When not used, this pin should be connected to GNDD.
Common Control
VCOM[0]
VCOM[1]
Output
M20
M19
VCOM: Voltage Common Mode [1:0]
These pins are used only when the receive line interface is in Receive Differential mode and
connected without a transformer (transformer-less).
To enable these pins, the VCOMEN pin must be connected high. Refer to
Figure-6 for the
connection.
When these pins are not used, they should be left open.
VCOMEN
Input
(Pull-Down)
L19
VCOMEN: Voltage Common Mode Enable
This pin should be connected high only when the receive line interface is in Receive Differen-
tial mode and connected without a transformer (transformer-less).
When not used, this pin should be left open.
REF
-
L20
REF: Reference Resistor
An external resistor (10 K
, ±1%) is used to connect this pin to ground to provide a standard
reference current for internal circuit. This resistor is required to ensure correct device opera-
tion.
RIM
Input
(Pull-Down)
AB11
RIM: Receive Impedance Matching
In Receive Differential mode, when RIM is low, all 16 receivers become High-Z and only exter-
nal impedance matching is supported. In this case, the per-channel impedance matching con-
figuration bits - the R_TERM[2:0] bits (b2~0,
RCF0,...) and the R120IN bit (b4,
RCF0,...) - are
ignored.
In Receive Differential mode, when RIM is high, impedance matching is configured on a per-
channel basis by the R_TERM[2:0] bits (b2~0,
RCF0,...) and the R120IN bit (b4,
RCF0,...).
This pin can be used to control the receive impedance state for Hitless Protection applica-
In Receive Single Ended mode, this pin should be left open.
Name
I / O
Pin No.
Description