LA72912V

No.A1409-3/12

Video FM De-modulation Block (DEMOD) T6=0.4V,T17=2.0V

Ratings

Parameter

Symbol

In

OUT

Conditions

min

typ

max

Unit

Current dissipation

ICCP

Measure the currents into pin 2 (DEMOD mode)

26.0

32.0

38.0

mA

Video output level

VOUT

T5A

T3

Demodulation level, when the FM signal of 2.2MHz

deviation. Load impedance = 1k

Ω T3-GND.

2.09

2.2

2.31

Vp-p

Video output level B

VOUTB

T5A

T3

Demodulation level, when the FM signal of 2.0MHz

deviation. Load impedance = 1k

Ω T3-GND.

(In this case only, VCC make 4.5V to 5.5V.)

1.9

2.0

2.1

Vp-p

FM stop detection level

(DOC characteristic 1)

DOC1

T5A

T20

T18

T20

T5 = 11.5MHz, 300mVp-p. Measure T20 voltage

(V20). Set T20 V20 (AGC-Fix). T5 input level

when T5 amplitude is decrease gradually, and

T18 becomes "Low"

40

60

mVp-p

(Drop Delay Down)

DDD

T5A

T20

T18

T20

Shift time from T5 = 300mVp-p → 0mVp-p to

T18 ”Low”.

0.5

1.5

2.5

μs

FM return judgment

level

DOC2

T5A

T20

T18

T20

T5 = 11.5MHz, 300mVp-p, Measure T20 Voltage

(V20). Set T20 V20 (AGC-Fix). T5 inputs the level

when T5 amplitude is increase gradually, and T18

becomes "High"

60

90

mVp-p

Video DC level when

returning

DOC2B

T5A

T20

T23

Confirmation of output of Video signal from T3.

Measurement of DC level.

0.5

1.0

1.5

V

(Drop Delay Rise)

Return operation delay

time

DWR

T5A

T20

T18

T20

Shift time from T5 = 0mVp-p

→3 00mVp-p to

T18 ”High”

0.2

1.5

2.5

μsec

4V Regulator

VREG

T4

Measurement of T4 DC level.

3.9

4.0

4.3

V

Range of input

Dynamic range

ACIN5

T5A

T3

DEV = 2.0MHz. Input amplitude level of FM

signal. (T5A: 11.5MHz to 13.5MHz)

500

1000

mVp-p

DG

DG

T5A

T3

0

6

10

%

DP

DP

T5A

T3

0

6

10

deg

Output voltage at mute

MUV

T3

Mute level measurement of T3

0

10

20

IRE

FM demodulation

voltage

(11.0M)

VDEM11

VDEM12

VDEM13

T5A

T23

T5A = 11.0MHz, 100mVp-p, 200mVp-p and

400mVp-p.

Each T23 voltage measurement

0.3

0.8

1.3

V

FM demodulation

voltage

(12.5M)

VDEM21

VDEM22

VDEM23

T5A

T23

T5A = 12.5MHz, 100mVp-p, 200mVp-p and

400mVp-p.

Each T23 voltage measurement

0.7

1.2

1.7

V

FM demodulation

voltage

(14.0M)

VDEM31

VDEM32

VDEM33

T5A

T23

T5A = 14MHz, 100mVp-p, 200mVp-p and

400mVp-p

Each T23 voltage measurement

1.1

1.6

2.1

V

FM demodulation

linearity1,2,3

LDEM1

LDEM2

LDEM3

Calculate FM demodulation linearity

LDEM1 = {[VDEM21 - (VDEM11 + VDEM31) / 2]

/ (VDEM31 - VDEM11)}

×100

LDEM2 = {[VDEM22 - (VDEM12 + VDEM32) /2 ]

/ (VDEM32 - VDEM12)}

×100

LDEM3 = {[VDEM23 - (VDEM13 + VDEM33) / 2]

/ (VDEM33 - VDEM13)}

×100

-2

0

+2

%

FM demodulation

Sensitivity1,2,3

SDEM1

SDEM2

SDEM3

Calculate FM recovery Sensitivity with consider

pin 3 output level conversion ratio.

SDEM1 = (VDEM31-VDEM11)/3.0

SDEM2 = (VDEM32-VDEM12)/3.0

SDEM3 = (VDEM33-VDEM13)/3.0

0.28

0.33

0.38

V/MHz

Main linear de-emphasis

amplitude

GMED

T5A

T23

T5 = 200mVp-p FM signal

(fm = 10kHz, Center Carrier = 12.5MHz,

DEV = 2.0MHz) Signal level of T23

481

535

589

mVp-p

Main linear

de-emphasis

Characteristics(1)

GMED1

T5A

T23

T5 = 200mVp-p FM signal (fm = 500kHz, Center

Carrier = 12.5MHz, DEV = 2.0MHz). Signal level

of T23 versus GMRD (Ratio of GMED).

-3.5

-1.5

+0.5

dB

Main linear

de-emphasis

Characteristics(2)

GMED2

T5A

T23

T5 = 200mVp-p FM signal (fm = 2MHz, Center

Carrier = 9.25MHz, DEV = 2.0MHz). Signal level

of T23 versus GMRD (Ratio of GMED)

-6.5

-4.5

-2.5

dB