STV9553

14/24

10.4

Video response optimization: schematics in DC-coupling mode

The dynamic video response is optimized by carefully designing the supply decoupling of the video board

(see Section 10.7), the tracks (see Section 10.7), then by adjusting the input/output component network

(see Section 10.5).

For dynamic measurements such as rise/fall time and bandwidth, a 8pF load is used (total load including

the parasitic capacitance of the PC board and CRT Socket).

When used in kit with the STV921x preamplifier from ST, the preamplifier bandwidth register (BW, register

Figure 17. Video response optimization for one channel - DC coupling application

C11

4.7

µF

R10

L1

R11

CRT

OUT

STV9553

IN

150

Ω

150

Ω

0.33

µH

C10(*)

100nF

-

+

R1(**)

51

Ω

C1

1.5nF

Reference

OUT

C2

10pF

R1

82

Ω

L1

0.33

µH

Input Network #2

C2

10pF

R1

33

Ω

Input Network #3

IN

IN

C24

4.7

µF

C12(*)

100nF

R19(***)

33-40

Ω

2 other Input Networks (Network #2 and #3 below) can be used in replacement of the reference Input Network #1.

C2

15pF

Caution: For Application with Tr/Tf> 5.5ns, the PreAmplifier bandwidth register (BW, Register 13)

must be set to minimum value (0 dec)

(***): R19 must be mandatorily used

See Application note AN1510 for complete description.

Input Network #1

GNDP

GNDS

GNDA