Selection Guide for Surface-mount Devices
Step 1. Determine the circuit’s operating parameters.
Fill in the following information about the circuit:
Maximum ambient operating temperature
Normal operating current
Maximum operating voltage
(i.e. miniSMDC014 is 60VDC max.)
Maximum interrupt current
Step 2. Select the PolySwitch device that will accommodate the
circuit’s maximum ambient temperature and normal
operating current.
Look across the top of Table S2 to find the temperature that most
closely matches the circuit’s maximum operating temperature. Look
down that column to find the value equal to or greater than the circuit’s
normal operating current. Now look to the far left of that row to find the
part number for the PolySwitch surface-mount device that will best
accommodate the circuit. Devices in this section are grouped by device
dimensions, so your operating-current requirement may be found in
more then one grouping.
4
The thermal derating curves located in Figure S1 are the normalized
representations of the data in Table S2.
Step 3. Compare the selected device’s maximum electrical rat-
ings with the circuit’s maximum operating voltage and
interrupt current.
Look down the first column of Table S3 to find the part number you
selected in Step 2. Look to the right in that row to find the device’s
maximum operating voltage (VMAX) and maximum interrupt current
(IMAX). Ensure that VMAX and IMAX are greater than or equal to the circuit’s
maximum operating voltage and maximum interrupt current.
188 PolySwitch Surface-mount Resettable Devices
Raychem Circuit Protection
RAYTHEON [ RAYTHEON COMPANY ]
