Sony CXA3556N Datasheet

IF Down Converter for Digital Broadcast

Description

The CXA3556N is a one-chip integrated IC that
processes IF signals of a digital broadcast tuner and
includes an AGC amplifier circuit, a mixer circuit, a
local oscillator circuit and an output amplifier circuit.

The package utilizes a 24-pin SSOP suitable for
surface mounting.

Features

• AGC control width that has a 56dB variable range

• Low noise characteristics

• Low distortion characteristics (in par ticular, during

AGC gain reduction)

• Includes switching function between down

converter mode and linear amplifier mode

• Variable output amplifier gain by changing external

resistance

• Includes RF AGC output pin

• Variable RF AGC settings

• AGC control curve characteristics with excellent

linearity

Absolute Maximum Rating (Ta = 25°C)

• Supply voltage Vcc –0.3 to +12 V

• Operating temperature Topr –55 to +150 °C

Operating Conditions

• Supply voltage Vcc 4.75 to 5.25 V

• Operating temperature Topr –25 to +75 °C

CXA3556N

24 pin SSOP (Plastic)

Applications

Digital broadcast tuners

Structure

Bipolar silicon monolithic IC

Sony reserves the right to change products and specifications without prior notice. This information does not convey any license by
any implication or otherwise under any patents or other right. Application circuits shown, if any, are typical examples illustrating the
operation of the devices. Sony cannot assume responsibility for any problems arising out of the use of these circuits.

– 1 –

E02426-PS

Block Diagram and Pin Configuration

CXA3556N

IFIN1

IFIN2

RFAGC

IREG

VREG

LOB1

LOC1

LOC2

1

2

3

4

5

6

7

8

Comparator

REG

OSC

AGC
Amp.

Mixer

Output
Amp.

AGCIN

24

MODESEL

23

AGCGND

22

AO2

21

AO1

20

GND

19

AGCREF

18

17

E2

LOB2

CC

V

MO1

MO2

9

10

1

11

12

16

15

14

13

E1

AIN2

AIN1

CC

V

2

– 2 –

Pin Description and Equivalent Circuit

CXA3556N

Pin

No.

Symbol

Pin
voltage

1 IFIN1 1.4V

2 IFIN2 1.4V

3 RFAGC —

10

22

Equivalent circuit Pin description

CC

1

V

1
2

5k

3

5k

AGCGND

IF inputs.

RF AGC voltage output.
Comparator output.

Low level: 0.4V or less
High level: 8V or more

10

22

AGCGND

V

CC1

4 IREG 2.6V

5VREG 3.3V

6 LOB1 2.9V

7 LOC1 3.7V

8 LOC2 3.7V

10

10

22

Connects external resistance
27kΩ.

22

AGCGND

4

V

CC

1

Connects external capacitance

5

AGCGND

6

978

1µF.

V

CC

1

Connects external capacitance
and crystal oscillator.

9 LOB2 2.9V

19

GND

– 3 –

CXA3556N

Pin

No.

Symbol

10 VCC15V

Pin
voltage

Equivalent circuit Pin description

Power supply.

V

CC

10

1

11 MO1 2.3V

11

12

Mixer output pin.

12 MO2 2.3V

19

GND

13 VCC2 5V Power supply.

CC

1

14 AIN1 1.3V

15 AIN2 1.3V

16 E1 0.6V

10

14

15

200

200

10k

10k

V

Output amplifier circuit inputs.
Gain of output amplifier circuit
can be changed by connecting
external resistance between
Pins 16 and 17.

17 E2 0.6V

18 AGCREF —

19

10

17 16

V

90µA

CC1

18

GND

RF AGC setting voltage
adjustment pin.
Connect external resistance
between Pin 18 and GND and
change the value to change
RF AGC output voltage.

22

AGCGND

19 GND 0V GND

CC

1

V

20 21

Output amplifier output.

20 AO1 2.7V

10

21 AO2 2.7V

19

GND

– 4 –