L6997S

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5

APPLICATION INFORMATION

5.1 5A Demo board description

for the conversion) so replacing the input capacitors the power input voltage could be also 35V. When instead

Ω resistor in order to filter the

device input voltage. On the topside demo there are two different jumpers: one jumper, near the OVP and POW-

ER GOOD test points, is used to shut down the device; when the jumper is present the device is in SHUTDOWN

PSK mode. When the jumper is present, at light load, the system will go in PFM mode; if there is not the jumper,

at light load, the system will remain in PWM mode. In the demo bottom side there are two others different jump-

ers. They are used to set or remove the INTEGRATOR configuration. When the jumpers named with INT label

are closed AND the jumpers named with the NOINT label are open the integrator configuration is set. Some-

times the integrator configuration needs a low frequency filter the to reduce the noise interaction. In this case

instead close the INT jumpers put there a resistor and after a capacitor to ground (as in the schematic diagram);

the pole value is around 500Khz but it should be higher enough than the switching frequency (ten times). On

the opposite when the jumpers named with the NOINT are closed and the jumpers named with INT are open

the NON INTEGRATOR configuration is selected. Refer to the Table 1 and 2 for the jumpers connection.

Figure 10. Demoboard Schematic Diagram

C14,C15

R3

R10

TP1

TP2

C10

R6

Q1

D2

TP3

C2

C6

R8

C12

C9

R9

R1

D1

R2

R5

SD

NS

L1

R7

C7,C13

C11

C4

R4

Rn

C3

C1

Q2

Cn

INT

INT

NOINT

NOINT

C5

C8

Vcc

SHDN

VREF

OSC

NOSKIP

INT

VFB

GNDSENSE

SS

BOOT

ILIM

HGATE

PHASE

LGATE

PGND

GND

VSENSE

OVP

PGOOD

VOUT

GNDOUT

GNDin

VIin

L6997S

J1