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LED Driving

Hi,

I have a tech. question about the Nrf24z1. I have one chip on the transmitter board and other chip on the receiver side. I am planning to toggle the transmitter side chips pin 7 and pin 8 (DD[1] and DD[0]) bits. Now, in response the receiver side chip's DD[1] and DD[0] will toggle too.

I need to drive one LED from DD[0] and the other LED from DD[1]. I am not a hardware guy, So, I thinking that may be somebody can advise me a LED driving circuitry for this problem. I do not know the exact current driving capability of these pins.

I am planning to use panel mount LEDS. But I do not have their part numbers yet. Please advice.

Thanks Regards, Raza

THE DATA SHEET OF THE CHIP IS AS FOLLOWS

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Reply to
john
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The way I'm reading it, DO[1] and DO[0] will toggle.

These can drive 10mA, it appears, which is more than enough to drive an LED directly. Just hook up, e.g., DO[0] to a 330ohm resistor and then the LED -- you'll probably get some 3-4mA through the LED (it depends on the voltage drop of the LED, which these days varies a lot depending on the color and efficiency of the LED you choose), which should be a good start.

---Joel

Reply to
Joel Koltner

Thanks. Will it be good idea to use a buffer IC or transistor to drive the LED? If yes that can you suggest some parts.

Reply to
john

It's not really necessary, but if it makes you feel better, sure, it's a fine idea.

If you're doing this as a prototype: Almost anything would work... if you want more current drive than you'll know what to do with, a 74AC244 (or 74AC125 or most others) can drive 24mA -- oodles or current. If you want something a little tamer, a 74HC244 (or many others) can drive 6mA.

If you're doing this as a product but don't have to shave off every last penny: NC7SZ57/58

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are great... they're "universal" 2-input, 1-output logic gates -- keep a bunch in a drawer and you'll never need to stock a plethora of different logic functions. They can also drive far more current than you'll need for an LED. (The only downsides are that these are rather small surface-mount parts and cost around a quarter each in small quantities.)

---Joel

Reply to
Joel Koltner

Use a 2n7000 fet, with a suitable resistor in the drain, but there's no reason not to drive the led directly, via a small resistor of 100 ohms or so. the value will depend on the Vcc of the RF chip, and the type of led. eg, 3V3 and a blue led won't work as the led needs ~4V. A red led and 100 ohms would give you about 10mA @3V3

Reply to
TTman

.

LED=20

LED -- =20

voltage drop=20

Joel, that IC runs from a 1.5 V supply. It often takes more voltage to get the LED to emit (visible) light. Some kind of buffer is likely necessary to get LED drive to high enough voltage. Though 2 equal channels at an combined 2 Mb/s is cool.

Reply to
JosephKK

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