ULN2003LV

IN3

IN4

OUT1

OUT2

OUT3

OUT4

IN5

IN6

IN7

GND

OUT5

OUT6

OUT7

COM

IN1

IN2

Logic Inputs

(1.8V to 5V)

VSUP_MAX

VSUP1

VSUP2

VSUP3

VSUP _MAX

VSUP_MAX = Max of {VSUP1, VSUP2, VSUP3} – VF

VF = Diode forward drop@ Total ground-pin current

ULN2003LV

www.ti.com

SLRS059A – APRIL 2012 – REVISED APRIL 2012

Max Supply Selector

The Figure 4 implements a max supply selector along with a 4-channel logic level shifter using a single

ULN20003LV. This setup configures ULN2003LV’s channel clamp diodes OUT5 – OUT7 in a diode-OR

configuration and thus the maximum supply among VSUP1, VSUP2 and VSUP3 becomes available at the COM

pin. The maximum supply is then used as a pull-up voltage for level shifters. Limit the net GND pin current to

less than 100mA DC to ensure reliability of the conducting diode. The unconnected inputs IN5-IN7 are pulled to

GND potential through 300k

Ω internal pull-down resistor.

Figure 4. ULN2003LV as Max Supply Selector

Copyright © 2012, Texas Instruments Incorporated

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Product Folder Link(s): ULN2003LV