LTC3535 Datasheet, PDF(7/16 Page) Linear Technology – Dual Channel 550mA 1MHz Synchronous Step-Up DC/DC Converter

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LTC3535 Datasheet, PDF (7/16 Pages) Linear Technology – Dual Channel 550mA 1MHz Synchronous Step-Up DC/DC Converter

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LTC3535

PIN FUNCTIONS

VOUT1 (Pin 1): Output Voltage Sense and Drain of the

Internal Synchronous Rectiï¬er for Channel 1. PCB trace

length from VOUT1 to the output ï¬lter capacitor (4.7Î¼F

minimum) should be as short and wide as possible.

SW1 (Pin 2): Switch Pin for Channel 1. Connect inductor

between SW1 and VIN1. Keep PCB trace lengths as short

and wide as possible to reduce EMI. If the inductor current

falls to zero, or SHDN1 is low, an internal anti-ringing switch

is connected from SW1 to VIN1 to minimize EMI.

GND (Pins 3, 6): Signal and Power Ground. Provide a

short direct PCB path between GND and the (-) side of

the input and output capacitors.

VOUT2 (Pin 4): Output Voltage Sense and Drain of the

Internal Synchronous Rectiï¬er for Channel 2. PCB trace

length from VOUT2 to the output ï¬lter capacitor (4.7Î¼F

minimum) should be as short and wide as possible.

SW2 (Pin 5): Switch Pin for Channel 2. Connect inductor

between SW2 and VIN2. Keep PCB trace lengths as short

and wide as possible to reduce EMI. If the inductor current

falls to zero, or SHDN2 is low, an internal anti-ringing switch

is connected from SW2 to VIN2 to minimize EMI.

VIN2 (Pin 7): Battery Input Voltage for Channel 2. Connect

a minimum of 1Î¼F ceramic decoupling capacitor from this

pin to ground.

SHDN2 (Pin 8): Logic Controlled Shutdown Input for Chan-

nel 2. There is an internal 4MegÎ© pull-down on this pin.

SHDN = High: Normal operation.

SHDN = Low: Shutdown, quiescent current < 1Î¼A.

FB2 (Pin 9): Feedback Input to the gm Error Ampliï¬er of

Channel 2. Connect resistor divider tap to this pin. The

output voltage can be adjusted from 1.5V to 5.25V by:

VOUT = 1.195V Ã [1 + (R4/R3)]

VIN1 (Pin 10): Battery Input Voltage for Channel 1. Connect

a minimum of 1Î¼F ceramic decoupling capacitor from this

pin to ground.

SHDN1 (Pin 11): Logic Controlled Shutdown Input for Chan-

SHDN = High: Normal operation.

SHDN = Low: Shutdown, quiescent current < 1Î¼A.

FB1 (Pin 12): Feedback Input to the gm Error Ampliï¬er

of Channel 1. Connect resistor divider tap to this pin. The

output voltage can be adjusted from 1.5V to 5.25V by:

VOUT = 1.195V Ã [1 + (R2/R1)]

Exposed Pad (Pin 13): The Exposed Pad must be soldered

to the PCB ground plane. It serves as another ground

connection and as a means of conducting heat away

from the die.

3535f

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