ZLR964222L
Line Module User Guide
35
Microsemi Corporation Confidential and Proprietary
6.5 Shared Buck-Boost ABS Switching Regulator Performance
6.6 Thermal Performance
The
Le9642
device has a thermal ePAD which must be soldered to a large copper area for heat dissipation and tied
to a ground plane. For best thermal performance, a four layer PCB is recommended. Even with multi-layer boards it
is recommended that multiple copper pours be used for thermal relief. The ZLR964222L module is designed with a
2 layer PCB to demonstrate functionality in a cost optimized system. In this case it is highly recommended that all
components be placed on the top side of the PCB. The bottom side should be a solid ground plane with minimal
voids that would disrupt heat dissipation.
The
Le9642
has a recommended maximum operating junction temperature of 145°C. The device will indicate a
thermal
fault
at
a
junction
temperature
of
165°C.
Depending
on
the
setting
of
the
VP_DEVICE_OPTION_ID_CRITICAL_FLT function in the
VP-API-II
, the device may either go to the Disconnect
state or temporarily shut down the tip and ring drivers and turn them back on when the die temp is reduced. Note
that the device will alternately cycle in and out of the temporary shutdown condition if a high power dissipation
condition is present.
Le9642
JA
= 29°C/W
- using a 4-layer PCB with ground pours on both inner layers. Via array is a 7x7 array of
0.33
mm/13
mil vias.
Le9642
JA
= 35°C/W
- using a 2-layer PCB with all components mounted top side. Bottom side is a solid copper
pour with minimal routing voids. Via array is a 7x7 array of 0.33
mm/13
mil vias.
Actual device thermal performance is dependent on factors such as copper area and weight, EPAD solder
coverage, proximity of other heat producing devices, airflow, etc. Refer to Chapter 7 for PCB layout references for
footprint recommendations.
6.7 Adaptive Ringing
The ZLR964222L design includes an adaptive ringing feature that allows the device to adapt to heavier ringing
loads in order to limit maximum input power. The ZLR964222L is designed to ring a maximum of 5REN at 60Vrms,
but this does increase the VSW input current. If the customer wishes to limit the maximum power drawn by the
FXS, the adaptive ringing feature can be enabled. In the event that a heavy REN load is applied, the ringing power
can be reduced to a lower level to support the heavier load. This typically means that the ringing voltage will be
reduced to 50Vrms (based on the command line below) when a REN load greater then the threshold is detected.
Input Range:
10 to 14 V
DC
Supply Efficiency:
The efficiency will vary with load and input voltage. For a nominal 12 V
DC
input, the efficiency range
is typically 50% to 75%
Maximum Output
Voltage
-95 V
DC
, limited by output capacitor rating.
Ringing Voltage
Up to 85 V
PK
Ringing Drive
5 REN maximum at 60 V
RMS
single line
VBATL Output
Regulation:
2.0 % with 12 V
DC
input and -30 V
DC
output load varied from 0 to 30 mA
Output Accuracy:
-4 V
DC
to +4 V
DC
from the fixed ringing voltage setting
Operating Frequency:
24 kHz LPM, 128 kHz MPM and HPM states
