TLV3501

TLV3502

SBOS321D − MARCH 2005 − REVISED JULY 2005

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8

RELAXATION OSCILLATOR

The TLV350x can easily be configured as a simple and

inexpensive relaxation oscillator. In Figure 4, the R2

network sets the trip threshold at 1/3 and 2/3 of the supply.

Since this is a high-speed circuit, the resistor values are

rather low in order to minimize the effect of parasitic

capacitance. The positive input alternates between 1/3 of

V+ and 2/3 of V+ depending on whether the output is low

shown in Figure 4, the output is calculated to be 10.9MHz.

An implementation of this circuit oscillated at 9.6MHz.

Parasitic capacitance and component tolerances explain

the difference between theory and actual performance.

V+

f=10MHz

V

2/3 (V+)

1/3 (V+)

R

1

1k

Ω

R

2

5k

Ω

R

2

5k

Ω

R

2

5k

Ω

V

OUT

V

C

V+

t

C

62pF

1.38R

t

Figure 4. Relaxation Oscillator

HIGH-SPEED WINDOW COMPARATOR

A window comparator circuit is used to determine when a

signal is between two voltages. The TLV3502 can readily

output in Figure 5 is high. Figure 6 shows a simple means

of obtaining an active low output. Note that the reference

levels are connected differently between Figure 5 and

Figure 6. The operating voltage range of either circuit is

2.7V to 5.5V.

TLV3502b

TLV3502a

V

OUT

V

HI

V

LO

V

IN

SN74LVC1G02

V

HI

V

LO

V

IN

V

OUT

V

Time

Figure 5. Window Comparator—Active High

TLV3502b

TLV3502a

V

OUT

V

HI

V

LO

V

IN

SN74AHC00

V

HI

V

LO

V

IN

V

OUT

V

Time

Figure 6. Window Comparator—Active Low