Guaranteed turn-on time

The TS3121 is tested in production for a guaranteed start-up time. Once the supply voltage crosses the minimum

value of VCC_min_operating = 1.7 V, the output voltage is settled in a stable condition within a maximum delay of

tturn-on = 15 µs. For low power applications, the supply voltage of the TS3121 can be disconnected when the

device is not in use. During shutdown (VCC = 0 V), because of its fail-safe structure, the input and output pins can

stay biased. In applications with switched Vcc, care should be taken to keep the Vcc ramp-up below 0.5 V/µs to

prevent false triggering of the integrated ESD protection circuit.

Figure 50. Turn-on timing diagram

VID

VCC

VOUT

1.5 V

turn-on time (tturn-on)

VOL

0V

-100mV

VCC_operating

VOH

0V

XXXX

50 %

Propagation delay

There is a delay between when the input crosses the reference voltage and the output responds. This is called

the propagation delay. Propagation delay can be different between high-to-low and low-to-high input transitions.

This is shown as tPLH and tPHL in Figure 51 and is measured from the mid-point of the input to the midpoint of the

output. Note that for open-drain comparators, the output rise time trise and tPLH strongly depend on the pull-up

circuit connected to the output pin.

Figure 51. Propagation delay

VIN :

Vref

Vref - 100mV

Vref + 100mV

VOUT :

VOL

VOH

tPLH

tPHL

trise

90%

10%

10%

90%

tfall

+

–

V+

V-

VIN

Vref

VOUT

50%

50%

TS3121, TS3121A

Application information

DS14484 - Rev 3

page 22/34