ds2149qt-r Maxim Integrated Products, Inc., ds2149qt-r Datasheet - Page 8

• Manufacturer Part Number: ds2149qt-r
• Description: Ds2149 5v T1/j1 Line Interface Unit
• Manufacturer: Maxim Integrated Products, Inc.

PIN
Note 1: G.703 requires an accuracy of ±50ppm for T1. TR62411 and ANSI specifications require an accuracy of ±32ppm for T1 interfaces.
Note 2: Input pins have three operating modes.
19/
17
18
20
21
22
23
24
25
26
27
28
NLOOP
RRING
NAME
SCLK
CLKE
QRSS
RTIP/
VDD
TAIS
SDO
RLB
NLB
VSS
LLB
INT
SDI
CS
L3
L0
L1
L2
I/O
I/O
—
—
O
O
I
I
I
I
I
I
2
2
2
LBO3. LBO0 through LBO3 are used to select transmitter output pulse, and receiver
gain.
Network Loopback Active. Output high when RLB is activated by in-band loop-up
command present for 5 seconds. Output is reset when RLP is deactivated by in-band
loop-down command present for 5 seconds. Activation of remote loopback through
hardware pin 26 or control bit RLB releases the NLOOP output.
Receive Tip and Ring. Analog inputs for clock recovery circuitry. These pins connect
through a 1:1 transformer to the line (Section 6).
Positive Supply. 5V ±5%. See also VSM pin 10.
Signal Ground
LBO0. LBO0 through LBO3 are used to select transmitter output pulse, and receiver
gain.
INT. Used to alert the host when one or more bits are set in the status register.
LBO1. LBO0 through LBO3 are used to select transmitter output pulse, and receiver
gain.
Serial Data Input. Input for serial address and data stream. Sampled on rising of
SCLK.
LBO2. LBO0 through LBO3 are used to select transmitter output pulse, and receiver
gain.
Serial Data Output. Updated on falling edge of SCLK if CLKE is connected high.
Updated on rising edge of SCLK if CLKE is connected low. SDO is high-Z during
write cycle or when CS is high.
Remote Loopback. Used to invoke remote loopback. When held high, the transmitter
inputs are ignored and inbound data received at RTIP and RRING is routed to the
transmitter outputs, TTIP and TRING and transmitted at the inbound recovered clock
rate.
Network Loopback. Enables network loopback detection when RLB floats.
Chip Select. Must be low to read or write to the device. CS is an active-low signal.
Local Loopback. Used to invoke local loopback. When held high, digital inputs
TPOS and TNEG are looped back to RPOS and RNEG, through the jitter attenuator
if enabled. Floating this input invokes analog loopback. The analog output signal at
TTIP and TRING is routed to the receive inputs RTIP and RRING.
Serial Clock Input. Input clock to operate serial port. Max clock rate, 2.048MHz.
Transmit AIS. Input high forces transmitter to output unframed all ones. Unavailable
in remote loopback.
QRSS. Floating this pin enables QRSS pattern generator and detector. Input low
enables normal transmission of data.
Clock Edge Select
0 = Update RNEG/RPOS on falling edge of RCLK, SDO updated on rising edge of
SCLK.
1 = Update RNEG/RPOS on rising edge of RCLK, SDO updated on falling edge of
SCLK.
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FUNCTION