9 Application and Implementation

Note

Information in the following applications sections is not part of the TI component specification,

and TI does not warrant its accuracy or completeness. TI’s customers are responsible for

determining suitability of components for their purposes, as well as validating and testing their design

implementation to confirm system functionality.

9.1 Application Information

The LSF0102-Q1 device is able to perform voltage translation for open-drain or push-pull interfaces such as I2C,

SPI, UART, MDIO, SDIO, and GPIO.

9.2 Typical Application

9.2.1 Bidirectional Translation

SW

SW

LSF0102-Q1

8

6

2

7

3

4

5

EN

B1

B2

A2

A1

Vref_A

Vref_B

1

GPIO1

GPIO2

VCC

Vref_A = 1.2 V

GPIO3

VCC

GPIO3

VCC

Vpu3 = 2.5 V

Vpu1 = 3.3 V

Rpu

Rpu

Rpu

200 NŸ

GND

GND

GND

VB_Pullup = 3.3 V

Figure 9-1. Bidirectional Translation to Multiple Voltage Levels

9.2.1.1 Design Requirements

9.2.1.1.1 Enable, Disable, and Reference Voltage Guidelines

The LSF0102-Q1 device has an EN input that is used to disable the device by setting EN LOW, which places

all I/Os in the high-impedance state. Since LSF family is switch-type voltage translator, the power consumption

is very low. It is recommended to always enable LSF0102-Q1 device for bidirectional applications by connecting

the EN pin to the Vref_B pin, as shown in Figure 9-1. For additional details on setting up the Vref_A, Vref_B, and EN

pins, see the Understanding the Bias Circuit for the LSF Family video.

Table 9-1. Application Operating Condition

PARAMETER

MIN

TYP

MAX

UNIT

Vref_A (1)

reference voltage (A)

0.95

5.5

V

Vref_B

reference voltage (B)

Vref_A + 0.8

5.5

V

VI(EN)

input voltage on EN pin

Vref_A + 0.8

Vref_B

5.5

V

VPU

pull-up supply voltage

0

Vref_B

V

(1)

Vref_A is required to be the lowest voltage level across all inputs and outputs.

The 200 kΩ, bias resistor is required to allow Vref_B to regulate the EN input. A filter capacitor on Vref_B is

recommended. Also Vref_B and VI(EN) are recommended to be 1.0 V higher than Vref_A for best signal integrity.

LSF0102-Q1

SDLS969B – MAY 2018 – REVISED MAY 2023

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