Copyright © 2016, Texas Instruments Incorporated

SW

BATTERY

LDO

Analog

supply

voltage

LP55281

Digital

supply

voltage

LBoost

CVDDA

1 PF

CVDD

100 nF

CIN

10 PF

VDDA

VDD2

VDD1

2.8V

Copyright © 2016, Texas Instruments Incorporated

SW

BATTERY

VDD1

LBoost

VDDA

LDO

Analog

supply

voltage

2.8V

LP55281

Digital

supply

voltage

LDO

2.8V

VDD2

CIN

10 PF

CVDDA

1 PF

CVDD

100 nF

22

LP55281

SNVS458D – JUNE 2007 – REVISED OCTOBER 2016

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Product Folder Links: LP55281

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Copyright © 2007–2016, Texas Instruments Incorporated

7.3.5 7-V Shielding

To shield the LP55281 device from high-input voltages (6 V to 7.2 V), the use of an external 2.8-V LDO is

required. This 2.8-V voltage protects internally the device against high voltage condition. The recommended

connection is shown in the picture below. Internally both logic and analog circuitry works at 2.8-V supply voltage.

Both supply voltage pins should have separate filtering capacitors. TI recommends pulling down the external

LDO voltage when it is disabled in order to minimize the leakage current of the LED outputs.

Figure 16. LP55281 With 7-V Shielding

In cases where high voltage is not an issue, the alternative connection is shown below.

Figure 17. LP55281 Without 7-V Shielding