L6221 STMicroelectronics, L6221 Datasheet - Page 9

• Manufacturer Part Number: L6221
• Description: QUAD DARLINGTON SWITCH
• Manufacturer: STMicroelectronics

APPLICATION INFORMATION
When inductive loads are driven by L6221A/N, a
zener diode in series with the integral free-wheeling
diodes increases the voltage across which energy
stored in the load is discharged and therefore
speeds the current decay (fig. 18).
For reliability it is suggested that the zener is chosen
so that V
The reasons for this are two fold :
1) The zener voltage changes in temperature and
2) The instantaneous power must be limited to avoid
Figure 19 : Driver for Solenoids up to 3A.
Some care must be taken to ensure that the collec-
tors are placed close together to avoid different cur-
rent partitioning at turn-off.
We suggest to put in parallel channel 1 and 4 and
channel 2 and 3 as shown in figure 19 for the similar
current.
the reverse second breakdown.
p
+ V
z
< 35 V.
electrical characteristics of the logic section (turn-on
and turn-off delay time) and the power stages (col-
lector saturation voltage, free-wheeling diode for-
ward voltage).
Figure 18.
L6221AS - L6221AD - L6221N
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