LTC4419

1

4419f

Typical applicaTion

FeaTures

DescripTion

18V Dual Input Micropower

PowerPath Prioritizer

The LTC®4419 is a dual input monolithic PowerPath™

prioritizerwithlowoperatingcurrent,thatprovidesbackup

switchover for keeping critical circuitry alive during brown

out and power loss conditions. Unlike diode-OR products,

little current is drawn from the inactive supply even if its

voltage is greater than the active supply.

Internal2Ω,currentlimitedPMOSswitchesprovidepower

path selection from a primary input (V1) or a backup input

(V2) to the output. An adjustable voltage monitor set via

an external resistive divider provides flexibility in setting

the V1 to V2 switchover threshold. When primary input V1

drops, the ADJ monitor input causes OUT to be switched

to V2. Fast non-overlap switchover circuitry prevents both

reverse and cross conduction while minimizing output

droop.

The LTC4419 has two auxiliary comparators with open-

drain outputs that provide flexible voltage monitoring. The

V2ON output indicates if V2 is powering OUT. Freshness

seal mode prevents V2 battery discharge during storage

or shipment.

applicaTions

n

Selects Highest Priority Valid Supply from Two Inputs

n

Wide 1.8V to 18V Operating Range

n

Internal Dual 2Ω, 0.5A Switches

n

Low 3.6µA Operating Current

n

Low 320nA V2 Current When V1 Connected to OUT

n

Blocks Reverse and Cross Conduction Currents

n

Reverse Supply Protection to –15V

n

V2 Freshness Seal/Ship Mode

n

±1.5% Accurate Adjustable Switchover Threshold

n

Two Auxiliary ±2.3% Accurate Voltage Comparators

n

Overcurrent and Thermal Protection

n

Thermally Enhanced 10-Pin 3mm

× 3mm DFN

and 12-Lead Exposed Pad MSOP Packages

n

Low Power Battery Backup

n

Portable Equipment

n

Point-of-Sale (POS) Equipment

L

, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks and

PowerPath and ThinSOT are trademarks of Linear Technology Corporation. All other trademarks

are the property of their respective owners.

+

1M

1M

V2ON

1M

5V

WALL

ADAPTER

237k

C1

10µF

121k

4.02M

7.4V

Li-Ion

280k

V1

OUT

OUT

V1UV

V2UV

CMPOUT1

CMPOUT2

V2ON

ADJ

CMP1

CMP2

4419 TA01a

SWITCHOVER

THRESHOLD: V1 < 4V (V1 FALLING)

GND

LTC4419

V2

V2UV THRESHOLD: V2 < 6V (V2 FALLING)

V1UV THRESHOLD: V1 < 4.4V (V1 FALLING)

Typical Switchover Waveforms

SWITCHOVER

THRESHOLD

OUT

50µs/DIV

V2

2V/DIV

V1

2V/DIV

4419 TA01b