SM5301BS

SEIKO NPC CORPORATION —13

TYPICAL APPLICATION CIRCUITS

ATSC Digital TV Application

(*1) Pins without an input signal, set by NUXSEL, should be left open or tied to GND.

(*2) Connect 4

× 0.1µF capacitor between the supply pins close to the IC.

(*3) Connect a 47

µF capacitor between the supply pins close to the IC.

(*4) Connect a capacitor if an error occurs due to external noise for GSR1, GSG1, GSB1 pins. Also, if open-

circuit, the internal impedance and external capacitance (C) form an RC network. When power is applied,

the open-circuit potential rises with time constant

τ = C × 10k (sec).

(*5) Printed circuit board supply wiring

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If the supply is used for other digital circuits, there is a possibility that noise will be introduced. Accord-

ingly, these circuits should be connected to the application’s analog supply.

I

Ground-plane wiring should be performed, as much as possible, to provide low GND line impedance.

I

If ground-plane wiring up to the GND pins is difficult, the ground plane should be as close to the IC as

possible with a separate wire to each GND pin.

(*6) The tab (radiation fin) between 7 pin and 8 pin and between 21 pin and 22 pin should be connected to the

large ground plane as much as possible for radiation.

Input Capacitor and High Pass Filter Cutoff Frequency

forms a highpass filter (HPF) with the internal impedance.

The HPF cutoff frequency is given by the following equation.

(C: input capacitance, R: signal input impedance = 9.3k

Ω (typ))

Cut-off

control voltage

+5V

(*2)

(*3)

1.0

µF

(*1)

(*4)

GSB1

DISABLE

(*1)

(*2)

220

µF

B/V

+

75

Ω

220

µF

R/Y

+

75

Ω

(*4)

GSG1

(*4)

GSR1

1.0

µF

Filter through

switch

(*1)

(*2)

(*2)

220

µF

G/U

+

75

Ω

(*6)

(*6)

1.0

µF

fc =

1

2

πCR