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Relay on MSP430

Petar Aladrovic
Prodigy 110 points
Other Parts Discussed in Thread: SN75372

Hello,

I have a following situation and would need some help.

MSP430xyz would send a signal "high" to relay. I am finding for example SN75372. I need 24V +- 10% but much higher temperature area

of some -40°C to aprox. 80°C. The selection of such relays is limited at TI, or I am doing something wrong ?

Is there possibility that somebody in this community reccomends relay for 24V and better temperature area.

Current of 150mA would be enough for my application.

 

Thank You.

 

 

  • 0
    Guru 227245 points

    We are using the ULN2003 for driving all kind of equipment. It has 7 independent channels, (more or less) TTL compatible controls (actually the maximum output current depends on the base voltage and C-E voltage), up to 500mA driver strength (2.5A max total), up to 50V and included clamp diode. It has to be used as low-side switch, however. That means it drives the bottom side of the relay to a common GND pin. It cannot be used to 'power' the high-side of a device. Good enough anyway for most uses.
    Drawbacks are the relatively high propagation time (1microsecond) and the high switching time (also up to 1 microsecond). Maximum frequency is therefore 0.5MHz. But this is way good enough for a relay. And you can even control the relay by a PWM pin, giving 100% at start to make it switch, then reduce to 70% or even 50% duty cycle, which will not make the relay switch but will be enough to hold its state once switched, reducing power consumption.

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