Low voltage PIC's

[ajrussell]

Hi all,

This is my first post.
Im interested in using PIC's on single 1.5v battery, so I guess the PIC would have to operate over a range of ~1.2 to 1.5v.
As far as I know there are no pics that will operate in this range, but does anybody know of any DC-DC converter circuits/chips that would be suitable? Ideal characteristics would be:- low price, small size and low power consumption.

Thanks
AJ

 

[justDIY]

Texas Instruments and Maxim both have some boost converters that operate below 1 volt, providing various fixed and adjustable outputs.

National and Linear may have something too, although most of National's parts are Vin > 2.7

try searching for "single cell nimh"

 

[mvs sarma]

Hi all,

This is my first post.
Im interested in using PIC's on single 1.5v battery, so I guess the PIC would have to operate over a range of ~1.2 to 1.5v.
As far as I know there are no pics that will operate in this range, but does anybody know of any DC-DC converter circuits/chips that would be suitable? Ideal characteristics would be:- low price, small size and low power consumption.

Thanks
AJ

Hi Ajrussell,

try MAX 1722, this sotchip starts at 0.8V to near Vcc and gives you the low power required. Datasheet you can form www.alldatasheet.com

 

[ajrussell]

Thanks guys,

Sarma, that Maxim part is perfect, I chose the MAX1724EZK50-T, just 1 inductor and 2 cap's needed for 5v at 150mA, 1.5µA quiescent supply current and up to 90% efficiency and around $3, all good

 

[Hero999]

Why aren't there any low voltage PICs around?

If a digital watch and calculator can run of 1.5V and they rely on 1980s technology then why can't a PIC do this?

 

[Sceadwian]

PIC's were designed around a higher voltage, there are plenty of ASIC's that will work natively on 1.5 volts but PICS are a general purpose chip. Modern battery boost switchers can be tacked on without much of a second look and are incredibly efficient. There's really no need to have a PIC that can nativly run off a single cell. Not to mention rechargeables are only 1.2 volts. Even then if the clock rate is slow enough you may be able to run a pic at those voltages, though I'm not so sure about startup.

 

[eng1]

Why aren't there any low voltage PICs around?

If a digital watch and calculator can run of 1.5V and they rely on 1980s technology then why can't a PIC do this?

The supply voltage itself is not an issue. For low-power applications, a PIC with nanoWatt Technology requires 50 nanoamperes in standby and a few hundreds microamperes when running. The PIC can run of 3 V (a small lithium battery), as watches and calculators do.