5

AGND

I

Analog Ground. The analog ground ties to all of the noise sensitive

signals. Provide a clean ground for the analog control circuitry and should

not be in the path of large currents.

Return for output voltage set resistor divider.

Connect this pin to PGND.

6

FB

I

Feedback Input.

Feedback Input to the gm Error Amplifier. Connect resistor divider tap to

this pin.

The output voltage can be adjusted from 2.5V to 5.5V by:

The feedback networks should be connected directly to a dedicated

analog ground plane and this ground plane must connect to the AGND

pin. If no analog ground plane is available, then the ground connection of

the feedback network must tie directly to the AGND pin. Connecting the

network to the PGND can inject noise into the system and effect

performance.

The feedback network, resistors R1 and R2 must be connected to FB pin

directly as closely as possible. And FB is a sensitive signal node, trace

area at FB pin should be small.

Please keep FB away from the inductor and SW switching node on the

PCB layout to minimize copper trace connections that can inject noise into

the system.

7,8

O

DC-DC Power Output, IC Supply Voltage and Output Voltage Sense

Input (Drain of the Internal Synchronous Rectifier P-MOSFET). PCB trace

wide as possible. Care should be taken to minimize the loop area formed

PGND pin. The minimum recommended output filter capacitance is

22 Fx2 ceramic with a X5R or X7R dielectric and the optimum placement

feature.

9

PGND

P

Power Ground. Ground connection for high-current power converter

node. High current return for the low-side driver and power main switch

N-MOSFET. Connect PGND with large copper areas directly to the input

and output supply returns and negative terminals of the input and output

filter capacitor(s).

Tie this pin to the ground island/plane through the lowest impedance

connection available.

Connect this pin to AGND.

(1) I = input; O = output; P = power

LESHAN RADIO COMPANY, LTD.

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