HMP8117_07 Datasheet, PDF (3/45 Pages) Intersil Corporation – NTSC/PAL Video Decoder

Analog Front End Block Diagram
(EXTERNAL) (INTERNAL CLAMP)
VAA
1.75V
INPUT
VIDEO
1.0μF
nmos
+
-
TO
MUX
#
13
75
PIN
50μA
VID1
VID2
1.0μF
1.0μF
CVBS1
7
CVBS2 ₆
Y_IN
1.0μF
CVBS3(Y) ₅
75 75 75
CLAMP
CLAMP
CLAMP
1.75V
REF
CHROMA
ATTEN
(BELOW)
M
13-STEP
U
VARIABLE
X
ATTENUATOR
1.75V
4 TO 13
DECODER
GAIN CONTROL
SET POINT
4
GAIN
11 ^CORRECTION
LOGIC
BACKPORCH
ENABLE
LOW-PASS
FILTER
(REMOVE Fsc)
CHROMA MULT.
(BELOW)
FINE ADJUST MULT. FACTOR
Y_OUT
Y_IN
EXTERNAL
2X
9
ANTI-ALIAS ⁸
BUF
FILTER
2.5V
10-BIT ¹⁰
ADC
1.5V
DIGITAL
ANTI-
ALIAS
FILTER
CHARGE PUMP
DISABLE
Y[7:0]
STORAGE
CAP
LCAP
76
0.1μF
CHROMA INPUT
C_IN
75
1.0μF
EXTERNAL
ANTI-ALIAS
FILTER
C
19
MUX
SELECT
(OFFSET LUMA SIGNAL TO LOWER ADC REF ~= 1.5V)
CHROMA
ATTEN
13-STEP
(SIGNAL BIAS ~ 2.0V)
VARIABLE
ATTENUATOR
2X
2.0V
100μA
100μA
A/D_TEST
17
CHARGE PUMP
DISCHARGE
LUMA
CHARGE ^DC-RESTORE
LOGIC
SYNC-TIP ENABLE
BUF
2.5V
10-BIT ¹⁰
ADC
1.5V
DIGITAL
ANTI-
ALIAS
FILTER
DISABLE
CHROMA
MULT.
C[7:0]
STORAGE
CAP
CCAP ₂₉
0.1μF
100μA
(OFFSET CHROMA SIGNAL TO ADC MID-SCALE ~= 2.0V)
100μA
DISCHARGE _CHROMA
CHARGE ^DC-RESTORE
LOGIC
SYNC-TIP ENABLE
PIN #
# DECODER PIN #
NOMINAL (NTSC) OPERATING CONDITION
PIN # NOMINAL (NTSC) OPERATING CONDITION
BIAS/
INTERNAL
REFERENCE
5 6 7 _{CVBSX. SIZE = INPUT. SYNC TIP CLAMPED AT ~= 1.75 VDC.}
76 _{LCAP. DC-SIGNAL OFFSET ~= 2.4 VDC.}
POWERDOWN
RSET
28
REF_CAP
78
1.0μF
9 8 _{YOUT/YIN. SIZE = ~1.0 VP-P, SYNC TIP OFFSET ~= 1.5 VDC.}
19 _{C. SIZE = INPUT SIZE. PORCH OFFSET ~= 2.0 VDC.}
29 _{CCAP. DC-SIGNAL OFFSET ~= 2.4 VDC.}
28 _{RSET. DC-SIGNAL OFFSET ~= 1.2 VDC.}
17 _{A/D_TEST. SIZE ~= F(LUMA AGC), PORCH OFFSET ~= 2.0VDC.}
78 _{REF_CAP. DC-SIGNAL OFFSET ~= 2.5 VDC.}