Le78D11
Data Sheet
Pin Name
Type
Description
Line State Control
C11, C21, C31
C12, C22, C32
Output
Per channel outputs which control the Le77D11 device line states.
Sets a programmable current limit threshold for the DC feed in the Le77D11 device. Connects to
the corresponding RDC1 and RDC2 pins of the Le77D11 device through the RDCi resistors.
VDC1, VDC2
F1, F2
Output
Input*
Output
Fault detect pin for channels 1 and 2. A low indicates a fault for the respective channel, which can
be triggered by large longitudinal voltages or ground key.
Software programmable 256 or 85.3 kHz clock for the switching regulator in the Le77D11 device
(applicable to the Le77D11 device only).
CHCLK
Line Supervision Processing Inputs
IMT1, IMT2
Connects to the IMTi leads of the Le77D11 device. IIMT = ILOOP • KDC
Input
VA1, VA2,
VB1, VB2
Connects to the A and B leads of the Le77D11 through a 475 kΩ resistor.
Input
I
I
General purpose voltage sense inputs of the Le77D11 devices can connect to high voltage
supplies through a 475 kΩ resistor.
VS1, VS2
Input
Voice Data
These pins are the inputs for the analog transmit signals (VOUTi) from the Le77D11 device. The
Le78D11 VoSLAC device converts these signals to digital words and processes them. After
processing, they are multiplexed into serial time slots and sent out of the DXA pin.
VIN1, VIN2
Input
The Le78D11 VoSLAC device extracts and processes voice data from time slots on DRA serial
data port. After processing, the Le78D11 VoSLAC device converts the voice data to analog
signals and outputs it at these pins to the Le77D11 device.
VOUT1, VOUT2
Output
Band Gap Voltage Reference
A 69.8 k external resistor (RREF) connected between this pin and analog ground generates an
accurate, on-chip reference current for the A/D's and D/A's on the Le78D11 chip.
IREF
Input
This pin provides a 1.4 V, single ended reference to the Le77D11 device to which the Le78D11
VoSLAC device is connected.
VREF
Output
Note:
* 5 V tolerant pin.
12
Zarlink Semiconductor Inc.
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