Texas Instruments LM3402HV Evaluation Board LM3402HVEVAL/NOPB LM3402HVEVAL/NOPB Datenbogen
Produktcode
LM3402HVEVAL/NOPB
SW
LM3402
GND
CS
8V
V
TRANSIENT
~ 0.67
5
Module
Connector
Module
Connector
1 k
5
SW
LM3402
GND
CS
8V
V
TRANSIENT
~ 0.67
5
Module
Connector
Module
Connector
SNVS450E – SEPTEMBER 2006 – REVISED MAY 2013
Figure 24. CS Pin, Transient Path
Figure 25. CS Pin, Transient Path with Protection
Adding a resistor in series with the CS pin causes the observed output LED current to shift very slightly. The
reason for this is twofold: (1) the CS pin has about 20pF of inherent capacitance inside it which causes a slight
delay (20ns for a 1k
reason for this is twofold: (1) the CS pin has about 20pF of inherent capacitance inside it which causes a slight
delay (20ns for a 1k
Ω
series resistor), and (2) the comparator that is watching the voltage at the CS pin uses a
pnp bipolar transistor at its input. The base current of this pnp transistor is approximately 100nA which will cause
a 0.1mV change in the 200mV threshold. These are both very minor changes and are well understood. The shift
in current can either be neglected or taken into consideration by changing the current sense resistance slightly.
a 0.1mV change in the 200mV threshold. These are both very minor changes and are well understood. The shift
in current can either be neglected or taken into consideration by changing the current sense resistance slightly.
Copyright © 2006–2013, Texas Instruments Incorporated
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