8.2.2 Optical Receiver

The TLV3601 and TLV3603 can be used in conjunction with a high speed amplifier such as the OPA858 to

create an optical receiver as shown in the figure below. The photodiode is connected to a bias voltage and is

being driven with a pulsed laser. The OPA858 takes the current conducting through the diode and translates

it into a voltage for a high speed comparator to detect. The TLV3601 and TLV3603 will then output the proper

+

TDC

V

BIAS

+

LE/HYST

TLV3603

OPA858

V

REF

Figure 8-9. Optical Receiver

8.2.3 Over-Current Latch Condition

When it is important for a system to detect a brief over-current condition, it is advisable to utilize the latching

feature of the TLV3603. By latching the comparator output, the MCU is reassured not to miss the over-current

occurrence. The circuit below shows one way to implement the latching function.

When an over-current condition is detected by the TLV3603, the output will go high. The occurrence of the

output going high coupled with a logic high from the RESET signal from the MCU will create a logic low signal at

the output of the 2-channel NAND gate. This will cause the output of the TLV3603 to be held in a logic high state

(latched), thus allowing the MCU to detect the fault condition regardless of how narrow the over-current condition

persists. The addition of the NAND gate also provides a means of clearing the latch state of the comparator once

the MCU is done processing the event. This is accomplished by the MCU passing a logic low state to the NAND

input causing the LE/HYS pin of the comparator to be returned to a logic high state. The TLV3603 latched status

is cleared and the TLV3603 output can continue to track the status of the input pins.

+

+

LE/HYS

TLV3603

System

MCU

RESET

ALERT

Figure 8-10. Over-Current Latched Output Circuit

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TLV3601, TLV3603

SNOSDB1B – JUNE 2021 – REVISED NOVEMBER 2021

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