HIT HA12181FP Datasheet

HA12181FP

AM Radio Noise Reduction System

ADE-207-171A (Z)

2nd. Edition

June 1997

Functions

• Buffer amp. for audio

• Linear approximate circuit for noise reduction

• IF Amp., detector, audio amp. and AGC circuit for noise detection

• Gate pulse generator

Features

• High noise cancelling capacity: 46 dB typ.

• Less gain loss: G

• Low total harmonic destortion and high signal-to noise ratio: THD = 0.06% typ., S/N = 75 dB typ.

• Operation supply voltage range: 7.0 V to 10 V (8.2 V typ.)

• Less external parts count

= –0.5 dB typ.

V

HA12181FP

Block Diagram

R502

R505

47 k

C504

0.22µ

C503

0.01µ

C502

+

22 k

12

AF AGC

Det.

3.3µ 114 15

Pulse

OR

IF

AGC

Gen.

Gate pulse

Det.(1)

Noise

AF

LPF

HPF1

Det.

Pulse

Det.(2)

AGC

Amp.

VCC(8.2 V)

13

(2)

(1)

HPF

Det.

Pulse

+

C506

100µ

Buffer

Amp.

Gate pulse (1)

Gate pulse (2)

SW4

Hight-pass Amp.

(waveform

Phase

Circuit

SW2

SW5

Stabilized

Current Circuit

compensation)

(waveform

SW3

Level Diff.

Det.

Circuit

C507

Gate Time

Constant

119

R503

180 k

AF Output

+

C508

C509

0.033µ

108652

Capacitor

for By-pass

compensation)

Capacitor

for Hold

Capacitor

for Pahse

2200 p

R504

4.7 k

1µ

Capacitor

for waveform

C510

0.033µ

C511

0.033µ

C512

0.068µ

C : F

Unit R : Ω

compensation

R500

100 k

IF AGC

Rev.2, Jun. 1997, page 2 of 21

LPF

IF

Amp.

16

C501

IF Input

Volt.

Stabi.

4

1000 p

2nd IFT

1st IFT

ANT

R506

12 k

7

SW1

3

+

C513

AF Input

Det.

IF

MIX

RF

1µ

Stabilized

Voltage

AM-IC

OSC

Circuit

C500

0.033µ

HA12181FP

Table of Pin Description and External Parts

Influence of External

External parts

DC No. of pin Name Function

voltage

(V) (No

input) Equivalent circuit No.

recommended value

1 IF AGC Time 2.7 R500 100 K Longer Longer

constant

C502 3.3 µ time to for IF AGC.

C502

3.3µ

1

R500

100k

+

parts Larger

than recommended value

stabilize AGC.

Smaller than recommended value

distortion of recover.

2 Bias1 Bypass

for voltage Stabi.

3AF

input

Input of AF.

4 Bias2 Decide

the current of filter network.

5 Phase Phase

circuit

3.2

3.3

1.3

3.3

C500

0.033µ

AF IN

2

5

4

C512

0.068µ

20k

3

+

C513

C500 0.033 µ — Increased

noise.

C513 1 µ — —

R506 12 K Cut off

frequency of L·P·F and H·P·F shifted lower.

Cut off frequency of L·P·F and H·P·F shifted higher.

C512 0.068 µ Must be used on the

recommended value.

Rev.2, Jun. 1997, page 3 of 21

HA12181FP

Table of Pin Description and External Parts (cont)

Influence of External

External parts

DC No. of pin Name Function

6 Hold Hold of

voltage

(V) (No

input) Equivalent circuit No.

3.3

C511 0.033 µ Must be used on the

recommended value

level difference.

6

C511

0.033µ

7GNDGND — — — — — 8 High-

Pass.

HighPass

3.3

C510 0.033 µ Must be used on the

AMP. (Waveform Compensation)

8

C510

0.033µ

parts Larger

than recommended value

Smaller than recommended value

recommended value.

9 AF out Output of 3.3 C508 1 µ Output DC cut

AF

9

R504 4.7 K Output load

+

10 Wave

form

Waveform

C508

3.3

1µ

R504

4.7k

C509 0.033 µ Must be used on the

recommended value. Compensation

10

C509

0.033µ

Rev.2, Jun. 1997, page 4 of 21

HA12181FP

Table of Pin Description and External Parts (cont)

Influence of External

External parts

DC No. of pin Name Function

voltage

(V) (No

input) Equivalent circuit No.

recommended value

11 Gate Gate R503 180 K Gate Gate

pulse

4.5V

C507 2200 P pulse generation

0

11

parts Larger

than recommended value

width become wider.

Smaller than recommended value

pulse width become narrow.

R503 180k

R502 22 K Higher

noise detection sensitivity.

Lower noise detection sensitivity.

C503 0.01 µ — —

12 Vth Determi-

nation of noise detection sensitivit y

13 V

V

CC

14 IF Det. IF AGC

C507

2200p

1.1

12

R502 22k

8.2 — — — — —

3.3

detector

14 13

C503

0.01µ

15 AF Time 0 R505 47 K Longer Miss-

AGC constant

for AF AGC

C504 0.22 µ time to

stabilize AGC.

operaton in noise detector.

15

C504

0.22µ

R505 47k

Rev.2, Jun. 1997, page 5 of 21

HA12181FP

Table of Pin Description and External Parts (cont)

Influence of External

External parts

DC No. of pin Name Function

voltage

(V) (No

input) Equivalent circuit No.

recommended value

16 IF in IF input 1.3 IF Input Coupling

30k

16

C501 1000p

IF IN

Absolute Maximum Ratings (Ta = 25°C)

Item Symbol Rating Unit

Supply voltage V

CC

Power dissipation Pd 400* Operating temperature Topr –40 to +85 °C Storage temperature Tstg –55 to +125 °C Note: 1. Value at Ta = 85°C

16 V

1

parts Larger

than recommended value

Smaller than recommended value

— Instability

mW

Rev.2, Jun. 1997, page 6 of 21

HA12181FP

Electrical Characteristics (Tentative) (VCC = 8.2 V, Ta = 25°C, Pin 3 input: Vin = 100

mVrms, f = 1 KHz, Pin 16 input: Vin = 74 dBµ, fc = 450 KHz, fm = 1 KHz, m = 30%)

Item Symbol Min Typ Max Unit Test conditions

Supply current I Output voltage Vout 70 95 120 mVrms Pin 3 input only Total harmonic distortion THD1 — 0.06 0.3 % Signal-to-noise ratio S/N (1) 60 75 — dB Pin 3 input Vin = 100 mVrms

Strong input total harmonic distortion

Recovered output voltage VO (AF) 50 78 120 mVrms Pin 16 input only Recovered output signal-to-

noise-ratio Noise suppression ratio NSR 35 46 — dB Input the waveform below.

CC

THD2 — 1.0 2.5 % Pin 3 input Vin = 500 mVrms

S/N (2)3545—dB

— 11.0 — mA No input signal, IC only

(Reference), Rg = 10 KΩ

Pin 3 input Vin = 100 mVrms (Reference) no input sine wave

100mV

Pin 16 Input

2ms

10µs

Figure 1 Input Waveform at Measurement of Noise Suppression Ratio

Rev.2, Jun. 1997, page 7 of 21