Typical Applications

UNIVERSAL LOGIC LEVEL SHIFTER

The output of LMV7275 is an unconnected drain of an

NMOS device, which can be pulled up, through a resistor, to

any desired output level within the permitted power supply

range. Hence, the following simple circuit works as a univer-

sal logic level shifter, pulling up the signal to the desired

level.

POSITIVE PEAK DETECTOR

A positive peak detect circuit is basically a comparator oper-

ated in a unity gain follower configuration, with a capacitor as

a load to maintain the highest voltage. A diode is added at

the output to prevent the capacitor from discharging through

the pull-up resistor, and a 1M

Ω resistor added in parallel to

the capacitor to provide a high impedance discharge path.

When the input V

comparator follows it, thus charging the capacitor. When it

decreases, the cap discharges through the 1M

Ω resistor.

The decay time can be modified by changing the resistor.

The output should be accessed through a follower circuit to

prevent loading.

OR’ING THE OUTPUT

Since the output is an unconnected NMOS drain, many

drains can be tied together, pulled up to V

resistor to provide an output OR’ing function. If any of the

comparator outputs is pulled low the output V

20064052

FIGURE 6. Logic Level Shifter

20064054

FIGURE 7. Positive Peak Detector

20064053

FIGURE 8. OR’ing the Outputs

www.national.com

13