Philips FM1246 Datasheet

TUNERS

DATA SH EET

FM1246

Desktop video & FM radio module
system CCIR I

Preliminary specification
File under Tuners, DC03

1997 May 14

Philips Components Preliminary specification

Desktop video & FM radio module
system CCIR I

FEATURES

• System I and FM radio broadcast

• True 5 V device (low power dissipation)

• Full TV frequency range from channel A (45.75 MHz) to

channel 69 (855.25 MHz)

• FM radio band coverage from 87.50 to 108.00 MHz

• PLL controlled tuning

• Programmable PLL step size (31.25, 50 or 62.5 kHz)

• True-synchronous vision IF demodulator (PLL)

• Ultra-linear FM PLL demodulator for FM radio broadcast

• Demodulated video output, AF sound output, second

sound IF output

• I2C-bus control of tuning, address selection, AFC status
information

• Complies with European regulations on radiation, signal
handling and immunity

• Small horizontally mounted metal housing.

DESCRIPTION

The FM1246 front-end is designed to receive both TV and
FM stereo signals in the PC Multimedia environment. The
units are available with separate 75 Ω inputs for TV and
FM broadcast reception. The input connectors available
are either standard phono or IEC type (female for TV, male
for FM radio). The tuning, bandswitching and antenna
selection are made through the I

The front-end covers the TV bands from 45.75 MHz to

855.25 MHz. The FM band covers the standard

87.50 MHz to 108.00 MHz. An RDS decoder can be

connected to the AF-MPX output. The FM1246 meets the
input immunity and radiation requirements of CENELEC.

“CENELEC 55020, 55013’’

2

C-bus.

FM1246

In the FM radio mode, the level detector and AFT functions
are provide for the auto-search routines. The level detector
and AFT status can be read from the A/D bits in the
status-byte. The mute function is also provided to
suppress the audio output signal, if required.

The tuner AGC for both TV and FM radio operation, is
generated with a novel AGC detector which measures the
IF signal level directly at the tuner IF output pins. As
opposed to the conventional AGC detector, this new circuit
allows a higher take-over level and offers superior
immunity against tuner overload.

The demodulation of the TV sound and FM radio IF
(10.70 MHz) is done with a PLL demodulation circuit
contained in the IF IC. In the FM radio mode, the
multiplexed AF signal is then channelled to a stereo
decoder IC which extracts the left/right analog signals.
The multiplexed audio signal is also available at pin 25 to
support RDS implementations. The 2nd IF TV sound output
is provided to connect external (analog 2 carrier or digital)
stereo processing.

ORDERING INFORMATION

TYPE DESCRIPTION

FM1246/HM/PH standard phono 3139 147 13901
FM1246/HM/I IEC connector 3139 147 13911

CATALOGUE

NUMBERS

The FM1246 consists of a TV tuner, an FM radio tuner and
an IF section, all on a single PCB. The front-end is
assembled in a metal housing made of a rectangular
tin-plated steel frame, with front and rear covers, which
have soldered contacts to the frame. The two phono or
IEC antenna connectors (female for TV, male for FM
radio) are mounted on one side of the frame for the TV/FM
signal inputs. All other connections are made via pins at
the bottom.

The TV IF section uses an intercarrier SAW filter, followed
by a true-synchronous vision IF demodulator (PLL) IC. The
analog AFC voltage is fed to the 5-level A/D converter in
the PLL tuning IC, so that the AFC status can be read via
the I2C-bus.

1997 May 14 2

MARKING

The following items of information are printed on a sticker
that is on the top cover of the tuner:

• Type number

• Code number

• Origin letter of factory

• Change code

• Year and week code.

Philips Components Preliminary specification

Desktop video & FM radio module

FM1246

system CCIR I

INTERMEDIATE FREQUENCIES

SYSTEM

FREQUENCY

(MHz)

Picture carrier 38.90
Colour 34.47
Sound 32.90
NICAM 32.348
FM 10.70

PINNING

SYMBOL PIN DESCRIPTION

V

T

V

S(tuner)

11 tuning voltage (monitor)

12 supply voltage tuner section +5 V
SCL 13 I
SDA 14 I
AS 15 I
AF O/P right 20 FM radio right channel
AF O/P left 21 FM radio left channel

nd

2

IF O/P 22 second IF TV sound output
CVBS 23 Composite Video Baseband Signal (CVBS) output
V

S(IF)

24 supply voltage IF section +5 V

AF O/P 25 AF sound output

− TH1, TH2, TH3 and TH4 mounting tags (ground)

CHANNEL COVERAGE

BAND

FREQUENCY

(MHz)

FM radio band 87.50 to 108.00
Low band 45.75 to 170.00
Mid band 170.00 to 450.00
High band 450.00 to 855.25

2

C-bus serial clock

2

C-bus serial data

2

C-bus address select

1997 May 14 3

Philips Components Preliminary specification

Desktop video & FM radio module
system CCIR I

BLOCK DIAGRAM

2nd IF

FILTER

10.7 MHz

FILTER

AGC

DETECTOR

SAW

IF

V

VCO

PLL
VIF

DEMODULATOR

TRAP

FM

DEMODULATOR

FM-IF

10.7 MHz

DISCRIMINATOR

STEREO

DECODER

FILTER

10.7 MHz

FM1246

AF

(TV)

S(IF)

+5 V

V

CVBS

23

sound

output

2nd IF

AF-R AF-L

IF

MIXER - OSCILLATOR IC

HIGH BAND

OSC.

HIGH

MID

OSC.

MID BAND

LOW

OSC.

LOW BAND

VT

AFT

PLL

DC-DC

11 12 13 14 15 20 21 22 2524

CCA505

AS

SDA

SCL

+5 V

VT

S( tuner)

V

monitor

Fig.1 Electrical block diagram.

handbook, full pagewidth

TV

antenna

FM

antenna

1997 May 14 4

Philips Components Preliminary specification

Desktop video & FM radio module

FM1246

system CCIR I

LIMITING VALUES
Limiting values under operational conditions

The tuner can be guaranteed to function properly under the following conditions.

SYMBOL PARAMETER PIN MIN. TYP. MAX. UNIT

V

S

V

S(ripple)

I

S(tuner)

V

SCL

V

SDA

I

SDA

V

AS

V

AFright(FM)

Z

AFright(FM)

V

AFleft(FM)

Z

AFleft(FM)

Z

IF

Z

CVBS

t

L

V

S(IF)

I

S(IF)

Z

AF

supply voltage
peak-to-peak ripple voltage susceptibility

(at5V±5%); note 1

20 Hz to 100 kHz −−5mV

12

>100 kHz to 500 kHz −−10 mV
supply current −−120 mA
SCL bus input voltage 13 −0.3 − +5.25 V
SDA bus input voltage
SDA bus current (open collector) −1 − +5 mA

14

address select voltage; note 2 15 −−+5.25 V
FM right channel DC voltage
FM right channel load impedance parallel connected:

resistive value − 50 − kΩ

20

capacitive value − 9 − pF
FM left channel DC voltage
FM left channel load impedance:

resistive value − 50 − kΩ

21

capacitive value − 9 − pF
2nd IF sound output load impedance 22 0.5 −−kΩ
Composite Video Baseband Signal load impedance
CVBS load time constant −−100 ns
IF supply voltage
IF supply current −−150 mA

23

24

AF sound output load impedance parallel connected:

25resistive value 5.0 −−kΩ

capacitive value −−4nF

4.75 5.00 5.25 V

−0.3 − +5.25 V

− 1.0 − V

− 1.0 − V

− 75 −Ω

4.75 5.0 5.25 V

Notes

1. Sinusoidal ripple voltage superimposed on the 5 V supply voltage in the frequency range of 20 Hz to 500 kHz.
Criteria for TV interference >57 dB.

2. For detailed information about the address decoding, refer to Chapter “Application information”.

1997 May 14 5

Philips Components Preliminary specification

Desktop video & FM radio module

FM1246

system CCIR I

Environmental conditions

SYMBOL PARAMETER CONDITIONS MIN. TYP. MAX. UNIT

Non-operational conditions

T

amb

RH relative humidity −−100 %
g

B

g

S

Operational conditions

T

amb

RH relative humidity −−95 %

OVERALL PERFORMANCE
Conditional data

Unless otherwise specified, all electrical values for Chapter “Overall performance” apply at the following conditions.

ambient temperature −25 − +85 °C

bump acceleration 25 g −−245 m/s
shock acceleration 50 g −−490 m/s
vibration amplitude 10 to 55 Hz − 0.35 − mm

ambient temperature −10 − +60 °C

2
2

SYMBOL PARAMETER VALUE UNIT

T

amb

ambient temperature 25 ±5 °C
RH relative humidity 60 ±15 %
V
Z
Z
Z
t

pr

Z

S
CVBS
IF
AF

S(AE)

supply voltage (tuner and IF section) 5 ±0.125 V

video output load impedance (DC) 75 Ω

2nd IF sound output load impedance (DC) 0.5 kΩ

AF sound output load impedance 100 kΩ

pre-heating time (+5 V at pin 24) 10 minutes

aerial source impedance (asymmetrical) 75 Ω

1997 May 14 6

Philips Components Preliminary specification

Desktop video & FM radio module

FM1246

system CCIR I

TUNER CHARACTERISTICS

For detailed information about the PLL programming, refer to Chapter “Application information”.
The desktop video tuner is guaranteed to function properly within the specified operational conditions, but a certain

deterioration of performance parameters may occur at the limits of the operational conditions.

Required data for test equipment to be used

EQUIPMENT PARAMETER VALUE UNIT

DC voltmeter input impedance >1 MΩ
Oscilloscope input impedance:

resistance >1 MΩ

capacitance <15 pF
Spectrum analyzer input impedance 50 Ω
FET probe input impedance:

resistance 1 MΩ

capacitance 3.5 pF

output impedance 50 Ω
voltage gain 0 dB

AC millivoltmeter input impedance >100 kΩ

1997 May 14 7

Philips Components Preliminary specification

Desktop video & FM radio module
system CCIR I

handbook, full pagewidth

IF

output

BU2

aerial

connector

V

T

V

S

SCL

SDA

IF

PROBE

OUT

11

1

/

TDA1308

2

12 13 14 15

240

kΩ

TP2 TP3

220

220

nF

nF

39
kΩ

563

2

240

kΩ

−

17

+

−

39
kΩ

+

84

1

/

TDA1308

2

+

+

µF

µF

FM1246

2120109 22 23 24 25

5 V

22
Ω

47

47

kΩ

47

1

kΩ

10

nF

kΩ

nF
3

1

33

µF

++

220

kΩ

47

µF

22

Ω

220

kΩ

47

µF

22

Ω

TEST JIG

CCA650

S1

15 kHz

LOW-PASS

FILTER

(1) BU4 loaded with 75 Ω.
(2) 50 µs de-emphasis.
SA = Spectrum Analyzer.
P = FET probe.
DA = Distortion Analyzer.
VAC = dual channel AC voltmeter (Zi= 600 Ω).
The minimum load impedance required at the CVBS output (pin 23) is 75 Ω (both AC and DC).

Fig.2 Typical test set up.

SA

BU6BU2BU4BU5BU8BU7

video

P

out

(1)

+5 V

10
nF

5

kΩ

(2)

DADA

1997 May 14 8