Specifications

Cinterion
®
TX62-W/TX82-W Hardware Interface Description
2.1 Application Interface
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t TX62-W_TX62-W-x_TX82-W-x_HID_v01.200d 2022-09-08
Public / Preliminary
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If the FST_SHDN functionality is not used, the FST_SHDN line can be left open because of a
configured internal pull-up resistor.
If there is a reasonable probability for sudden power losses, Thales recommends to implement
a circuit using the FST_SHDN line with a capacitor to buffer sufficient energy to complete the
fast shutdown - see below for sample capacity calculation.
Please note that the normal software controlled shutdown via AT^SMSO can also be config-
ured as a fast shutdown, i.e., without network deregistration. For details see [1].
Sample Capacity Calculation:
The following formula is a guideline for a capacitor required in a fast shutdown circuit to buffer
enough energy to complete the fast shutdown process.
Depending on the application design and use case the factors may vary.
Capacitor energy:
E[J]= 0.5xC * (V^2max-V^2-min) * Aging factor
Example:
Aging factor e.g = 0.7
E[J]= 0.5 * 2500uF * ((4.5V)^2 - (3.0V)^2) * 0.7 = 0.0098J
Note: Vmax can be limited by the module supply and/or capacitor voltage. Same applies for
the Vmin which is mostly limited by VBATT min.
Module energy usage:
Vavg = Vmax + Vmin / 2
Aavg = See typical values in Section 3.4.1
E[W] = Vavg * Aavg * Efficiency
Example:
Power Circuit Efficiency factor, e.g = 0.8
E[W] = ((4.5V + 3.0V) / 2) * 0.2A * 0.8 = 0.6375W (assuming the Cat NB1/2 worst case)
Discharge time:
T[s] = E[J] / E[W]
Example:
T[s] = 0.0098J / 0.6375W = 0.015s