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Pin 5 is an ENABLE/PWM DIMMING pin. If you don't want to dim it with PWM you tie it to Vdd and LD as per pg 3 of the spec sheet. "Vdd" is a poor choice of name for that pin, it is not a power input but rather the output of the internal 7.5v reg. The power in is connected to Vin.
The 300nS RC filter is:
1. Replace the wire between R10 and CS (pin 2) with a resistor.
2. Add a capacitor from pin 2 to ground.
Resistance times capacitance must be greater than 300 x 10^-9. For example, 91pF and 3.3K. It can be a bit greater than 300x10^-9 but don't make it wildly greater. The resistor you choose should not be really high, stay under 50k, maybe even 30k. A cheap ceramic disk cap will do fine.
I got that recommendation on the RC from Supertex directly. It's an obvious problem with the principle of the circuit and fixed all my probs. I love their part but find their negligence in documenting this fundamental requirement rather unfortunate!
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