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

AF

LPF

HPF1

Det.

Pulse

Det.(2)

AGC

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.

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

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

HA12181FP

Test Circuit

IF-IN
PULSE-IN

50

AM-SG

AF-IN

50

AF-SG

C501

1000p

+

C513

1µ

R500

100k

VCC (8.2V)

Det.Out

C504

R505

0.22µ

47k

16

12345678

+

C502

3.3µ

B

15 14 13 12 11 10 9

C500

0.033µ

C503

0.01µ

R506

12k

+

A

+

C506
100µ

R502

15k

C512

0.068µ

R503

180k

C511

0.033µ

C507

2200p

C509

0.033µ

0.033µ

C510

R504

4.7k
C508

+

1µ

C

OUT

Note: 1. Resistors tolerance are within ±5%.

2. Capacitors tolerance (C509 to C512) are within ±5%, other capacitor are within ±10%.

Operation Principle

Noise

Detector

9

D

ANT.

16

IF

1st IFT

B

A

RF

CONV.

IF

DET

3

Processing

Waveform Circuit

C

AM-IC

HA12181FP

Figure 2 System Block Diagram of AM Radio

Unit R : Ω
C : F

Out

Rev.2, Jun. 1997, page 8 of 21

HA12181FP

A system block diagram of AM Radio using the HA12181FP is shown in Figure 2 and waveforms at each
point in the system are illustrated in Figur e 3. Fo r AM wave with im pulse noise from ANT, the pulse
spreads its width each time when the AM wave passes through a selection filter.

The pulse width becomes the order of several hundred microseconds at detector output (Point C).

A radio without a noise canceller produces large noise to the audience. This IC perfectly detects every
noise by using the signals from 1st IFT (Poin t B) in front of the narrow band filter.

The wave process circuit approximates the voltage linearly at the pulse to reduce the noise in the output.

The principle for wave processing follows. Further investigation make it clear that the pulse width of
impulse noise is constant (several handred microseconds) and independent of the waveform or waveheight.

Therefore the former and later voltage (VA, VB) of the pulse can be found at the same time (T1) by means
of the wave and the delayed one for this time, as shown in the right figure.

Each Point
in the Figure

A

B

C

D

Waveform including Noise

Narrower Pulse Width

and Higher Wave Height

Wider Pulse
Width and Lower Wave Height

Noiseless

Figure 3 Waveforms at Each Point in the System

Point D

Point C

V

B

V

A

T

T

1

2

In an actual circuit, the differential voltage between input and output of phase shif t circuit is changed to the
capacitor C511 at pin 6.

At the time of T1, when the switch turns to the noise processing mode (the switch positions in Figure 4 are
inverted), the voltage difference (VA – VB) is held in C511.

C509 at pin 10 is changed by the differential voltage between the held voltage and the output voltage at pin
9 (VA): VA – (VA – VB) = VB.

Rev.2, Jun. 1997, page 9 of 21

HA12181FP

As the initial voltage of C509 is equal to th e ou tput v oltage (VA) before the switch change, the voltage
between terminals of C509 is changed from VA to VB.

The waveform which change up to C509 becomes the output, because the voltage of C509 appears at pin 9
through the buffer.

The changed up waveform of C509 is almost linearly approximated because of the constant current change
by the feedback from the output at pin 9.

At the time of T2 when the awitches change to the normal mode (the switch position in Figure 4), the
output recovers smoothly as the voltage of C509 is VB.

However the unmatch of the wave delay time due to the pulse width or the phase circuit and the offset of
circuit make a slight step difference on the waverform at the moment of switch change.

LPF, consisting of R1 and C509 make it smooth.

The frequency characteristics, which is detriorated by LPF in the normalmode, is compensated so that it
might become flat. C509 and C510 should have the same capacity, and the tolerance must be within ±5%.

3

Phase
Circuit

5

C512

+

Subtraction

–

Circuit

HPFAmp.

6 8

C511

+

Constant Current

Circuit(Subtraction

–

Circuit)

C510

R1

R2

10

Buffer

C509

9

Out

Figure 4 Waveform Processing Circuit

Rev.2, Jun. 1997, page 10 of 21

Evaluation Circuit for Noise Reduction Effect

HA12181FP

R502

R505

47 k

C504

C503

0.01µ

+

R500

100 k

22 k

12

AF AGC

0.22µ

Det.

C502

3.3µ
114 15

IF AGC

Pulse

OR

IF

Gate pulse

Det.(1)

AGC

IF Input

Gen.

Pulse

AGC

Noise

AF

AGC

AF

Amp.

LPF

HPF1

Det.

LPF

IF

Amp.

16

Det.(2)

C501

1000 p

VCC(8.2 V)

13

(2)

(1)

HPF

Det.

Pulse

Volt.

Stabi.

4

R506

+

C506

100µ

Buffer

Amp.

Gate pulse (1)

Gate pulse (2)

SW4

Hight-pass Amp.

(waveform

Phase

Circuit

SW2

3

7

+

12 k

AF Input

SW5

Stabilized

Current Circuit

(waveform

compensation)

SW3

Level Diff.

Det.

Circuit

SW1

Stabilized

Voltage

C513

1µ

C507

Gate Time

Constant

119

R503

180 k

AF Output

+

0.033µ

C509

108652

Capacitor

for By-pass

compensation)

Capacitor

for Hold

Capacitor

for Pahse

Circuit

C500

0.033µ

2200 p

R504

4.7 k

C508

1µ

Capacitor

for waveform

C510

0.033µ

C511

0.033µ

C512

0.068µ

Noise

Meter

Unit R : Ω

compensation

C : F

2nd IFT

1st IFT

Two signals

dummy ANT.

Det.

IF

MIX

RF

50

Pulse SG.

AM-IC

OSC

50

AM SG.

Rev.2, Jun. 1997, page 11 of 21

HA12181FP

Example of Noise Reduction Effect

20

10

0

–10

–20

Output (dB)

–30

–40

Pulse : No input

–50

–60

0 10 20 30 40 50 60 70 80 90 100 110

AM SG : fc=999kHz, m=30%, fm=1kHz

Pulse : No input

Two Signals dummy ANT.

50Ω

NRoff

Pulse SG.

AM SG.

50Ω

NRon

AM SG Output (EMF) (dBµ)

VCC=8.2V

Vout

16Ω

16Ω

30Ω

16Ω

Noise

15p

To
ANT

65p

Pulse SG Output (EMF)

10µs

100mV

2µs

Figure.2

P-P

AM SG : fc=999kHz,
no mod.
Pulse SG :
Refer to Figure.2

120

20

VCC=8.2V

Pulse : No input

Two Signals dummy ANT.

50Ω

16Ω

16Ω

50Ω

16Ω

Noise

Vout

15p

To
ANT

30Ω

65p

AM SG : fc=999kHz,
no mod.
Pulse SG :
Refer to Figure.2

10

0

–10

–20

Output (dB)

–30

–40

NRon

AM SG : fc=999kHz, m=30%, fm=1kHz

Pulse SG.

NRoff

AM SG.

–50

–60

0 10 20 30 40 50 60 70 80 90 100 110

AM SG Output (EMF) (dBµ)

Pulse SG Output (EMF)

10µs

100mV

10µs

Figure.3

P-P

120

Rev.2, Jun. 1997, page 12 of 21

PC Board Layout Pattern

HA12181FP

IF in

AF in

V

CC

FN-8648

C502

C505

R501

R506

R500

+

+

C504

C503
C501
C513

C506

+

(Top view)

C507

R503
R502

R504

C508

+

C509

Vout

16

C510
C511
C512

HA12181FP

(Bottom view)

HA12181FP

Rev.2, Jun. 1997, page 13 of 21

HA12181FP

Main Characteristics

10

Vout (dB)

0

Vin max (Vrms)

-2

2.0

-4

1.5

-6

1.0

-8

0.5

-10

Vout : Vin = 100 mVrms const

Vout
(0 dB = 96 mVrms)

Vin Max
(THD ≥ 1.0%)

-12

0

40

0.5

0.4

0.3

THD (%)

0.2

0.1

100

0

40

100

400 1 k 2 k

200

200

f (Hz)

Vin = 100 mVrms

400 1 k 2 k

f (Hz)

10 k4 k 20 k 50 k

10 k4 k

Rev.2, Jun. 1997, page 14 of 21

10

Vo (AF) : 0 dB = 76 mVrms

0

-10

-20
fc = 450 kHz, m = 30%, fm = 1kHz

-30

Vout (dB)

-40

Noise (no modulation)

-50

-60

-70

10 20 30 40 50 60 70 80 90 100 110

Vin (EMF) (dBµ)

HA12181FP

120

50

Pulse input at Gate ON

20

10

5

2

V pulse (mVp-p)

1

0.5

0.2
1 k

10µs

2ms

5 k 10 k

V pulse

100 k50 k

R (Ω)

Rev.2, Jun. 1997, page 15 of 21

HA12181FP

120

THD1 (%)

100

0.5

80

0.4

60

0.3

40

0.2

20

0.1

0

Vout (mVrms)

Vout

THD1

0

678910111213141516

120

THD2 (%)

1.0

100

0.8

0.6

0.4

0.2

0

V

(V)

CC

S/N1 (dB)

S : 100 mVrms = 0 dB
N : no-input

80

S/N1

60

40

20

THD2 (Vin = 500 mVrms, f = 1 kHz)

0

678910111213141516

V

(V)

CC

Rev.2, Jun. 1997, page 16 of 21

Vo (AF) (mVrms)

S/N2 (dB)

60

120

HA12181FP

50

40

30

20

10

60

50

40

100

80

60

40

20

0

0

678910111213141516

60

50

40

S/N2

Vo (AF)

V

(V)

CC

NSR (pulse input)

Vin = 74 dBµ
fc = 450 kHz
fm = 1 kHZ
m = 30%

30

20

10

30

20

ICC (no-input)

10

0

0

678910111213141516

V

(V)

CC

Rev.2, Jun. 1997, page 17 of 21

HA12181FP

V pulse (mVp-p)

1.0

0.8

0.6

0.4

0.2

0

678910111213141516

V pulse (Pulse input level at Gate on)

V

(V)

CC

Vout (AF) (mVrms)

THD1 (%)

0.5

100

0.4

80

0.3

60

0.2

40

0.1

20

0

0

-40 -20 0 20 40 60 80 100

Rev.2, Jun. 1997, page 18 of 21

Vout

VCC = 8.2 V
Vin = 100 mVrms, f = 1 kHz

THD1

Ta ( C)

NSR (dB)

60

50

(mA)

CC

I

60

50

HA12181FP

VCC = 8.2 V

40

30

20

10

40

30

20

10

0

0

-40 -20 0 20 40 60 80 100

NSR (pulse input)

ICC (no-input)

Ta ( C)

Rev.2, Jun. 1997, page 19 of 21

HA12181FP

Package Dimensions

16

Unit: mm

10.06

10.5 Max
9

5.5

1

0.80 Max

1.27

0.42 ± 0.08

0.40 ± 0.06

8

0.10 ± 0.10

0.15

0.12

2.20 Max

M

7.80

0.22 ± 0.05

0.20 ± 0.04

0.70 ± 0.20

Hitachi Code
JEDEC Code
EIAJ Code
Weight

+ 0.20
– 0.30

1.15

0 – 8˚

FP-16DA

—

SC-530-16C

0.24 g

Rev.2, Jun. 1997, page 20 of 21

HA12181FP

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1. Hitachi neither warrants nor grants licenses of any rights of Hitachi’s or any third party’s patent,
copyright, trademark, or other intellectual property rights for information contained in this document.
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intellectual property rights, in connection with u se of the information contained in this document.

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received the latest product standards or specifications before final design, purchase or use.

3. Hitachi makes every attempt to ensure that its products are of high quality and reliability. However,
contact Hitachi’s sales office before using the product in an application that demands especially high
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traffic, safety equipment or medical equipment for life support.

4. Design your application so that the product is used within the ranges guaranteed by Hitachi particularly
for maximum rating, operating supply voltage range, heat radiation characteristics, installation
conditions and other characteristics. Hitachi bears no responsibility for failure or damage when used
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failure rates or failure modes in semiconductor devices and employ systemic measures such as fail­safes, so that the equipment incorporating Hitachi product does not cause bodily injury, fire or other
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Colophon 2.0

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