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LT8390A

8390afa

For more information www.linear.com/LT8390A

TYPICAL PERFORMANCE CHARACTERISTICS T

A = 25°C, unless otherwise noted.

ISMON Voltage vs V(ISP-ISN)

SS Current vs Temperature

Oscillator Frequency

vs Temperature

V(ISP-ISN) (mV)

100

0.25

0.50

0.75

1.00

1.25

1.50

8390a G28

TEMPERATURE (°C)

–50 –25

0.0

10.0

12.5

7.5

5.0

2.5

15.0

125

100

150

8390a G29

PULL-UP

PULL-DOWN

RT = 59.0k

RT = 100k

RT = 226k

TEMPERATURE (°C)

–50 –25

75 100 125 150

0.5

1.0

1.5

2.0

2.5

8390a G30

PIN FUNCTIONS

BG1: Buck Side Bottom Gate Drive. Drives the gate of buck

side bottom N-channel MOSFET with a voltage swing from

ground to INTVCC.

BST1: Buck Side Bootstrap Floating Driver Supply. The

BST1 pin has an integrated bootstrap Schottky diode from

theINTVCCpinandrequiresanexternalbootstrapcapacitor

to the SW1 pin. The BST1 pin swings from a diode voltage

drop below INTVCC to (VIN + INTVCC).

SW1: Buck Side Switch Node. The SW1 pin swings from

a Schottky diode voltage drop below ground up to VIN.

TG1: Buck Side Top Gate Drive. Drives the gate of buck

side top N-channel MOSFET with a voltage swing from

SW1 to BST1.

LSP: Positive Terminal of the Buck Side Inductor Current

Sense Resistor (RSENSE). Ensure accurate current sense

with Kelvin connection.

LSN: Negative Terminal of the Buck Side Inductor Current

Sense Resistor (RSENSE). Ensure accurate current sense

with Kelvin connection.

VIN: Input Supply. The VIN pin must be tied to the power

inputtodeterminethebuck,buck-boost,orboostoperation

regions. Locally bypass this pin to ground with a minimum

1µF ceramic capacitor.

INTVCC: Internal 5V Linear Regulator Output. The INTVCC

linearregulatorissuppliedfromtheVINpin,andpowersthe

internal control circuitry and gate drivers. Locally bypass

thispintogroundwithaminimum 4.7µFceramiccapacitor.

EN/UVLO: Enable and Undervoltage Lockout. Force the

pin below 0.3V to shut down the part and reduce VIN qui-

escent current below 2µA. Force the pin above 1.233V for

normal operation. The accurate 1.220V falling threshold

can be used to program an undervoltage lockout (UVLO)

threshold with a resistor divider from VIN to ground. An

accurate2.5µApull-downcurrentallowstheprogramming

of VIN UVLO hysteresis. If neither function is used, tie this

pin directly to VIN.

TEST: Factory Test. This pin is used for testing purpose

only and must be directly connected to ground for the

part to operate properly.

LOADEN: Load Switch Enable Input. The LOADEN pin is

used to control the ON/OFF of the high side PMOS load

switch. If the load switch control is not used, tie this pin

to VREF or INTVCC. Forcing the pin low turns off TG1 and

TG2, turns on BG1 and BG2, disconnects the VC pin from

all internal loads, and turns off LOADTG.

VREF: Voltage Reference Output. The VREF pin provides

an accurate 2V reference capable of supplying 1mA

current. Locally bypass this pin to ground with a 0.47µF

ceramic capacitor.

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