January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

FEATURES

Power supply from 5 V (200 mW) to 8 V source also an
alternative 12 V source (12 V not for TDA3845T)

Gain controlled wideband IF amplifier (AC coupled with
three stages)

High precision internal 90

phase shifter for quadrature

demodulator

Amplitude detector for gain control which operates as a
peak detector for FM sound and as a mean level
detector for AM sound (switchable)

In-phase wideband synchronous demodulator for AM
detection

Stabilizer circuit for ripple rejection and constant output
signals

ESD protection for all pins

Suitable for all FM standards and L as well as L-accent
standard

NICAM compatible.

GENERAL DESCRIPTION

The TDA3845 is a quasi split-sound IF circuit which is
designed to provide high performance television FM/AM
sound.

QUICK REFERENCE DATA

ORDERING INFORMATION

Note

1. SOT38-1; 1996 November 28.

2. SOT109-1; 1996 November 28.

SYMBOL

PARAMETER

MIN.

TYP.

MAX.

UNIT

positive supply voltage

pin 14

4.5

5.0

8.8

pin 11 (not for TDA3845T)

10.8

12.0

13.2

supply current

1-16(RMS)

minimum IF input voltage (RMS value)

100

IF control range

12-13(RMS)

intercarrier output voltage 5.5 MHz (RMS value)

100

(S +W)/W

signal-to-weighted-noise ratio
(relative to 1 kHz; 50 kHz deviation)

at 5.5 MHz for 2T/20T

at 5.742 MHz for 2T/20T

6-13(RMS)

AF output voltage AM (RMS value)

440

550

660

(S +W)/W

signal-to-weighted-noise ratio; AM mode

THD

total harmonic distortion; AM mode

amb

operating ambient temperature

+70

EXTENDED

TYPE NUMBER

PACKAGE

PINS

PIN POSITION

MATERIAL

CODE

TDA3845

DIL

plastic

SOT38

(1)

TDA3845T

SO16

plastic

SOT109A

(2)

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

Fig.2 Pin configuration.

(1) not for TDA3845T, pin 11 not connected.

PINNING

Note to Pinning

1. Not for TDA3845T, pin 11 not connected.

SYMBOL

PIN

DESCRIPTION

IF2

IF amplifier input 2

n.c.

not connected

AGC

AGC control capacitor

OPT

optional capacitor (see note 10 to
the characteristics)

PMD

peak/mean detector capacitor

AM output

FM/AM switch

REF

LC reference circuit for the picture
carrier

REF

LC reference circuit for the picture
carrier

n.c.

not connected

positive supply voltage 2
(+12 V); note 1

ICO

intercarrier output

GND

ground (0 V)

positive supply voltage 1 (+5 V)

n.c.

not connected

IF1

IF amplifier input 1

LIMITING VALUES

In accordance with the Absolute Maximum Rating System (IEC134)

SYMBOL

PARAMETER

MIN.

MAX.

UNIT

supply voltage

pin 14

4.5

8.8

pin 11 (not for TDA3845T)

10.8

13.2

amb

operating ambient temperature

+70

stg

storage temperature

+125

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

CHARACTERISTICS

= 5 V (note 11); T

amb

= 25

C; all measurements are referenced to ground (pin 13); unless otherwise specified.

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

Supply

supply voltage

pin 14

4.5

5.0

8.8

pin 11 (not for TDA3845T)

10.8

12.0

13.2

tot

total supply current

IF amplifier

1-16

input resistance

1-16

input capacitance

2.5

1-16(RMS)

minimum IF input voltage
(RMS value)

note 1

100

1-16(RMS)

maximum IF input voltage
(RMS value)

note 2

100

gain control range

v3-16

gain control voltage range

1.5

3.0

IF bandwidth

3 dB

MHz

1-16

DC potential

1.7

Intercarrier mode (FM mode; standard B/G) notes 3, 4 and 5

Reference amplifier

8-9(p-p)

picture carrier amplitude
(peak-to-peak value)

270

8-9

operating resistance

8-9

DC potential

3.9

Intercarrier mixer and output stage

12(RMS)

output signal (RMS value)

at 5.5 MHz

100

at 5.74 MHz

intercarrier bandwidth

1 dB

MHz

3 dB

MHz

residual video AM on intercarrier
signal

note 6

output resistance

DC potential

1.8

12(peak)

permissible AC output current
(peak value)

note 7

0.7

permissible DC output current

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

AF signal performance (note 8)

(S +W)/W

black picture

60/58

68/64

(S +W)/W

2T/20T pulses with white bars

57/55

60/58

(S +W)/W

6 kHz sinewave
(black-to-white modulation)

53/51

57/55

(S +W)/W

250 kHz square wave
(black-to-white modulation)

50/44

56/50

AM mode (standard L) note 9

S/N weighted in accordance with CCIR 468-3

6(RMS)

AF output signal (RMS value)

440

550

660

AF bandwidth

3 dB; note 12

0.02

120

kHz

THD

total harmonic distortion

(S +W)/W

signal-to-weighted-noise ratio

note 10

output resistance

200

DC potential

1.8

6(peak)

permissible AC output current
(peak value)

note 7

0.3

permissible DC output current

Standard switch (note 4)

peak signal AGC (FM mode)

used

1.8

or switch open-circuit

used

1.8

5.5

mean signal AGC (AM mode)

0.8

switch current

at 0 V

200

at V

via a 2.2 k

series resistor

2.5

Ripple rejection (note 13)

AM/AF signal

voltage ripple on V

voltage ripple on output signal

FM phase noise

f(RMS)

intercarrier signal

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

AM mode (standard L) note 9

S/N weighted in accordance with CCIR 468-3

6(RMS)

AF output signal (RMS value)

440

550

660

AF bandwidth

3 dB; note 12

0.02

120

kHz

THD

total harmonic distortion

(S +W)/W

signal-to-weighted-noise ratio

note 10

output resistance

200

DC potential

1.8

6(peak)

permissible AC output current
(peak value)

note 7

0.3

permissible DC output current

Standard switch (note 4)

peak signal AGC (FM mode)

used

1.8

or switch open-circuit

used

1.8

5.5

mean signal AGC (AM mode)

0.8

switch current

at 0 V

200

at V

via a 2.2 k

series resistor

2.5

Ripple rejection (note 13)

AM/AF signal

voltage ripple on V

voltage ripple on output signal

FM phase noise

f(RMS)

intercarrier signal

SYMBOL

PARAMETER

CONDITIONS

MIN.

TYP.

MAX.

UNIT

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

Notes to the characteristics

1. Start of gain control (LOW IF input signal) at

3 dB intercarrier signal reduction at pin 12, AGC mode set to FM or

3 dB AF signal reduction at pin 6, AGC mode set to AM.

2. End of gain control (HIGH IF input signal) at +1 dB intercarrier signal expansion at pin 12, AGC mode set to FM or

1 dB AF signal expansion at pin 6, AGC mode set to AM.

3. Picture carrier (38.9 MHz) to sound carriers (33.4 MHz/33.158 MHz) ratio: 13/20 dB.

IF input signal (picture carrier at sync pulse); V

1-16

= 10 mV (RMS). Transmitter mode: DSB.

Reference for the (S + W)/W ratio (0 dB) corresponds to the sound modulation where f = 1 kHz and frequency
deviation

f =

50 kHz.

With reduced frequency deviation

f =

27 kHz and the (S + W)/W figures will decrease by 5.4 dB.

4. If the device is used only for the B/G standard (no AM), the capacitor at pin 5 can be omitted (pin 5 has to be

disconnected). In this event the AGC will always operate as a peak signal AGC and is independent of the voltage at
pin 7.
The AM mode can also be used for the B/G standard, consequently standard switching is not required. However, the
intercarrier level depends on the video modulation and the AF performance may decrease.
When the IC is operated from a 12 V power supply pin 7 can be connected to a 12 V logic level via a 2.2 k

resistor.

5. LC reference circuit for the picture carrier (pins 8 and 9); 68 pF/0.247

H; in series with 27 pF:

Q loaded = 40 (Qo = 90); tuned to 38.9 MHz yields quadrature demodulation for the picture carrier which provides
optimum video suppression at the intercarrier output (e.g. black-to-white jump of the video modulation.The series
capacitor provides a notch at the sound carrier frequency in order to produce more attenuation for the sound carrier
in the PC reference channel. The ratio of parallel to series capacitance depends on the ratio of picture to sound
carrier frequency which has to be adapted to other TV transmission standards, if required, in accordance with the
formula:

Where:
C

= series capacitor

C = parallel capacitor
f

= picture carrier frequency

= sound carrier frequency

The result is an improved `intercarrier buzz' in the stereo system B/G, particularly with 250 kHz video modulation
(up to 10 dB improvement in sound Channel 2), or to suppress 350 kHz video modulated beat in the digitally
modulated NICAM subcarrier

In order to optimize the AF signal performance, fine tuning to the optimum S/W at the sound Channel 2 may be
achieved by a 250 kHz video modulated square wave.

6. Residual video AM is defined as:

m = (A

B)/A

A = intercarrier level at sync pulse

B = intercarrier level at 100% white video modulation

7. If higher AC output current is required an external resistor must be connected between the output pin and ground in

order to increase the bias current of the emitter follower. The permissible maximum DC output current must not be
exceeded.

(

)

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

8. For all S/N measurements the used vision IF modulator must conform to the following:

Incidental phase modulation for black-to-white jump should be less than 0.5 degrees. Intercarrier performance,
measured with the television demodulator AMF2 (intercarrier mode weighted S/N ratio) better than 60 dB for 6 kHz
sinewave black-to-white video modulation. Weighted S/N ratio of the demodulated intercarrier signals in accordance
with CCIR 468-3, measured with de-emphasis of 50

The indicated (S + W)/W ratio X/Y concerns the sound channels 1 and 2 that means demodulated intercarrier signals
of 5.5 and 5.74 MHz respectively.

9. Sound carrier frequency in the range of 30 to 40 MHz modulated with f = 1 kHz and a modulation depth of 80%.

IF input signal (sound carrier) V

1-16

= 10 mV (RMS).

10. The capacitor at pin 4 can be omitted, however, the (S + W)/W figure for the AM sound (standard L) will be up to

8 dB worse in the IF voltage range 1 mV to 100 mV.

11. When the supply at V

= 12 V the performance will be comparable with the performance when V

= 5 to 8 V.

The power supply pin that is not in use should be disconnected.

12. The maximum value given as minimum 120 kHz and typical 700 kHz.

13. Voltage ripple

200 mV (p-p) at 70 Hz.

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

PACKAGE OUTLINES

UNIT

max.

REFERENCES

OUTLINE

VERSION

EUROPEAN

PROJECTION

ISSUE DATE

IEC

JEDEC

EIAJ

inches

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

SOT38-1

92-10-02
95-01-19

min.

max.

1.40
1.14

0.055
0.045

0.53
0.38

0.32
0.23

21.8
21.4

0.86
0.84

6.48
6.20

0.26
0.24

3.9
3.4

0.15
0.13

0.254

2.54

7.62

0.30

8.25
7.80

0.32
0.31

9.5
8.3

0.37
0.33

2.2

0.087

4.7

0.51

3.7

0.15

0.021
0.015

0.013
0.009

0.01

0.10

0.020

0.19

050G09

MO-001AE

(e )

seating plane

pin 1 index

10 mm

scale

Note

1. Plastic or metal protrusions of 0.25 mm maximum per side are not included.

(1)

DIP16: plastic dual in-line package; 16 leads (300 mil); long body

SOT38-1

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

detail X

(A )

pin 1 index

UNIT

max.

(1)

REFERENCES

OUTLINE

VERSION

EUROPEAN

PROJECTION

ISSUE DATE

IEC

JEDEC

EIAJ

inches

1.75

0.25
0.10

1.45
1.25

0.25

0.49
0.36

0.25
0.19

10.0

9.8

4.0
3.8

1.27

6.2
5.8

0.7

0.6

0.7
0.3

8
0

0.25

0.1

DIMENSIONS (inch dimensions are derived from the original mm dimensions)

Note

1. Plastic or metal protrusions of 0.15 mm maximum per side are not included.

1.0
0.4

SOT109-1

91-08-13
95-01-23

076E07S

MS-012AC

0.069

0.0098
0.0039

0.057
0.049

0.01

0.019
0.014

0.0098
0.0075

0.39
0.38

0.16
0.15

0.050

1.05

0.041

0.24
0.23

0.028
0.020

0.028
0.012

0.01

0.25

0.01

0.004

0.039
0.016

2.5

5 mm

scale

SO16: plastic small outline package; 16 leads; body width 3.9 mm

SOT109-1

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

SOLDERING

Introduction

There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
situations reflow soldering is often used.

This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our

"IC Package Databook" (order code 9398 652 90011).

DIP

OLDERING BY DIPPING OR BY WAVE

The maximum permissible temperature of the solder is
260

C; solder at this temperature must not be in contact

with the joint for more than 5 seconds. The total contact
time of successive solder waves must not exceed
5 seconds.

The device may be mounted up to the seating plane, but
the temperature of the plastic body must not exceed the
specified maximum storage temperature (T

stg max

). If the

printed-circuit board has been pre-heated, forced cooling
may be necessary immediately after soldering to keep the
temperature within the permissible limit.

EPAIRING SOLDERED JOINTS

Apply a low voltage soldering iron (less than 24 V) to the
lead(s) of the package, below the seating plane or not
more than 2 mm above it. If the temperature of the
soldering iron bit is less than 300

C it may remain in

contact for up to 10 seconds. If the bit temperature is
between 300 and 400

C, contact may be up to 5 seconds.

EFLOW SOLDERING

Reflow soldering techniques are suitable for all SO
packages.

Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied

to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.

Several techniques exist for reflowing; for example,
thermal conduction by heated belt. Dwell times vary
between 50 and 300 seconds depending on heating
method. Typical reflow temperatures range from
215 to 250

Preheating is necessary to dry the paste and evaporate
the binding agent. Preheating duration: 45 minutes at
45

AVE SOLDERING

Wave soldering techniques can be used for all SO
packages if the following conditions are observed:

A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave) soldering
technique should be used.

The longitudinal axis of the package footprint must be
parallel to the solder flow.

The package footprint must incorporate solder thieves at
the downstream end.

During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.

Maximum permissible solder temperature is 260

C, and

maximum duration of package immersion in solder is
10 seconds, if cooled to less than 150

C within

6 seconds. Typical dwell time is 4 seconds at 250

A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.

EPAIRING SOLDERED JOINTS

Fix the component by first soldering two diagonally-
opposite end leads. Use only a low voltage soldering iron
(less than 24 V) applied to the flat part of the lead. Contact
time must be limited to 10 seconds at up to 300

C. When

using a dedicated tool, all other leads can be soldered in
one operation within 2 to 5 seconds between
270 and 320

January 1993

Philips Semiconductors

Objective specification

Quasi split-sound circuit and AM
demodulator

TDA3845; TDA3845T

DEFINITIONS

LIFE SUPPORT APPLICATIONS

These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.

Data sheet status

Objective specification

This data sheet contains target or goal specifications for product development.

Preliminary specification

This data sheet contains preliminary data; supplementary data may be published later.

Product specification

This data sheet contains final product specifications.

Limiting values

Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.

Application information

Where application information is given, it is advisory and does not form part of the specification.

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