8.2.2 Optical Receiver

The TLV360x 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 comparators will then output the proper output signal according to the

threshold set (VREF).

+

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(E). 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(E), 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(E) 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(E) latched status is cleared and the TLV3603(E) output can continue to track the status of the input

pins.

+

+

LE/HYS

TLV3603

VREF

System

IS

RS

MCU

RESET

ALERT

Figure 8-10. Over-Current Latched Output Circuit

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TLV3601, TLV3602, TLV3603, TLV3603E

SNOSDB1E – JUNE 2021 – REVISED APRIL 2023

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