MITEL SL1461KG, SL1461MPAS, SL1461SA Datasheet

The SL1461SA is a wideband PLL FM demodulator,

intended primarily for application in satellite tuners.

The device contains all elements necessary, with the exception of external oscillator sustaining network and loop feedback components, to form a complete PLL system operating at frequencies up to 800MHz.

An AFC with window adjust is provided, whose output signal can be used to correct for any frequency drift at the head end local oscillator.

FEATURES

■ Single chip PLL system for wideband FM

demodulation

■ Simple low component count application

■ Allows for application of threshold extension

■ Fully balanced low radiation design

■ High operating input sensivity

■ Improved VCO stability with variations in supply or

temperature

■ AGC detect and bias adjust

■ 75Ω video output drive with low distortion levels

■ Dynamic self biasing analog AFC

■ Full ESD Protection*

* Normal ESD handling procedures should be observed

Wideband PLL FM Demodulator

Advance Information

DS4049 - 1.2 December 1994

AFC PUMP

AFC WINDOW ADJUST

V OSCILLATOR + OSCILLATOR –

AGC BIAS

AGC OUTPUT

RF INPUT

Fig.1 Pin connections - top view

APPLICATIONS

■ Satellite receiver systems

■ Data communications Systems

ORDERING INFORMATION

SL1461SA/KG/MPAS

16116

SL1461SA

11 10

7 89

SL1461SA

AFC OUTPUT

VIDEO FEEDBACK + VIDEO –

VIDEO + VIDEO FEEDBACK – VIDEO OUTPUT

RF INPUT

MP16

AGC BIAS

RF INPUTS

AGC OUTPUT

LOCAL

OSCILLATOR

AFC WINDOW

ADJUST

8 9

4 5

VIDEO FEEDBACK +

VIDEO +

VIDEO –

VIDEO FEEDBACK –

VIDEO OUTPUT

AFC PUMP

AFC OUTPUT

Fig.2 SL1461SA block diagram

SL1461SA

ELECTRICAL CHARACTERISTICS

= -20°C to +80°C, VCC = +4.5V to +5.5V. The electrical characteristics are guaranteed by either production test or design.

amb

They apply within the specified ambient temperature and supply voltage unless otherwise stated.

Characteristics

Supply current Operating frequency Input sensitivity Input overload VCO sensitivity (dF/dV) VCO linearity

VCO supply stability VCO temperature stability Phase detector gain

Loop amplifier input impedance Loop amplifier output impedance Loop amplifier open loop gain Loop amplifier gain bandwidth product Loop amplifier output swing Video drive output impedance Video drive: Luminance nonlinearity

- differential gain

- differential phase

- intermodulation

- signal/noise

- Tilt

- baseline distortion AGC output current AGC bias current AFC window current AFC charge pump current AFC leakage current AFC output saturation voltage

Value

Min. Typ. Max.

300

800

-40

2.0 20

0.5

0.25

450

570

700 25 38

240

1.2

1.9

0.5

1.0

2.5 3

-40

0 0

0.3

0.4

3 2

400 250 400

0.4

Units

mA MHz dBm dBm

MHz/V

KHz/°C

V/rad V/rad

Ω Ω

dB MHz Vp-p

Ω

% %

Degree

% %

µA

Conditions

Preamp limiting

Refer to application in Fig. 3 Refer to application in Fig. 3; with

13.5MHz p-p deviation See note 5 See note 5 Differential loop filter Single ended loop filter Single ended Single ended Single ended Single ended Single ended

1KΩ load, See note 3 and 4 75KΩ load, See note 3 and 4 75KΩ load, See note 3 and 4 See notes 1, 3 and 4 1KΩ load, See note 2 and 4 1KΩ load, See note 3 and 4 1KΩ load, See note 3 and 4 Maximum load voltage drop 2V

400µA gives 1.5V deadband window

With charge pump disabled AFC output enabled

Note 1. Product of input modulation f 1 at 4.43MHz, 13.5MHz p–p deviation and f 2 at 6MHz p–p deviation, (PAL chroma and sound

subcarriers).

Note 2. Ratio of output video signal with input modulation at 1MHz, 13.5MHz p–p deviation, to output rms noise in 6MHz bandwidth with

no input modulation. Note 3. Input test signal pre–emphasised video 13.5MHz p–p deviation. Output voltage 600mV pk–pk. Note 4. See page 3 Note 5. Assuming operating frequency of 479.5MHz set with V

shown in Fig. 3. also refer to Fig. 8.

@ 5.0V and ambient temperature of +20°C. Only applies to Application

SL1461SA

TEST CONFIGURATION

VIDEO GENERATOR

ROHDE & SCHWARZ SGPF

PRE EMPHASISED BASE BAND VIDEO

DE EMPHASISED BASE BAND VIDEO 1V p–p

The video drive characteristics measurements were made using the above test configuration. The maximum figures recorded in the Electrical Characteristics Table coincide with high temperatures and extremes of supply voltage. No adjustment to the recorded figures has been made to compensate for the effects of temperature on the external components of the application test board, in particular the varactor diodes. If operation of the device at high ambient temperatures is envisaged then attention to temperature compensation of the external circuitry will result in performance figures closer to the stated typical figures.

BASE BAND VIDEO 1V p–p

ROHDE & SCHWARZ SFZ

RF CARRIER FREQ 479.5MHz

FM MODULATION 13.5MHz P–P

PRE–EMPHASISED VIDEO

MONTFORD TEST OVEN

SL1461 TEST APPLICATION BOARD

See Fig. 3 for details

DE EMPHASISED NETWORK

ROHDE & SCHWARZ UAF

TV SAT TEST TX

VIDEO AMPLIFIER/

VIDEO ANAL YSER

ABSOLUTE MAXIMUM RATINGS

All voltages are referred to VEE at 0V

Characteristics

Supply voltage RF input voltage RF input DC offset Oscillator ± DC offset Video ± DC offset Video feedback ± DC offset Video output DC offset AFC pump DC offset AFC disable DC offset AFC deadband DC offset AGC bias DC offset AGC output DC offset Storage temperature Junction temperature MP16 package thermal resistance,

chip to ambient

Fig.2 SL1461SA block diagram

Min. Typ. Max.

-0.3

-55

2.5

+0.3

VCC+0.3 V

+0.3

VCC+0.3 V

+0.3

125 150 111

Vp-p

V V V V V V V V V V

°C °C

°C/W

Conditions

SL1461SA

ABSOLUTE MAXIMUM RATINGS cont.

All voltages are referred to V

Characteristics

at 0V

Min. Typ. Max.

Conditions

MP16 package thermal resistance, chip to case

Power consumption at 5.5V ESD protection - pins 1 to 15 ESD protection - Pin 16

AGC BIAS AFC WINDOW ADJUST

RV1 RV2

BB515 BB515

470nF

TP3

4n7

1.7

50K

47nF 100nF

4K7

5K1

4K7

250

1nF

°C/W

kV kV

27K

C2C1

16116

SL1461SA

11 10

7 89

C8C7

Mil-std-883 method 3015 class 1 Mil-std-883 method 3015 class 1

1K2

1nF

TP4

100pF

100nF

C11

C10

TP1

TP2

100pF

VIDEO OUTPUT

+5V

1nF

C12

RF INPUT

Fig.3 Standard application circuit

FUNCTIONAL DESCRIPTION

The SL1461SA is a wideband PLL FM demodulator, optimised for application in satellite receiver systems and requiring a minimum external component count. It contains all the elements required for construction of a phase locked loop circuit, with the exception of tuning components for the local oscillator, and an AFC detector circuit for generation of error signal to correct for any frequency drift in the outdoor unit local oscillator. A block diagram is contained in Fig. 2 and the typical application in Fig. 3.

The internal pin connections are contained in Fig.6/6a

In normal applications the second satellite IF frequency of typically 402 or 479.5MHz is fed to the RF preamplifier, which has a working sensitivity of typically -40 dBm, depending on application and layout. The preamplifier contains an RF level detect circuit, which generates an AGC signal that can be used for controlling the gain of the IF amplifier stages, so maintaining a fixed level to the RF input of the SL1461SA, for optimum threshold performance. The bias point of the AGC circuit can be adjusted to cater for variation in AGC line voltage requirement and device input power. The typical AGC curves are shown in Fig. 9. It is recommended that the device is operated with an input signal between -30 and -35dBm. This

ensures optimum linearity and threshold performance, and gives a good safety margin over the typical sensitivity of

-40dBm. The output of the preamplifier is fed to the mixer section

which is of balanced design for low radiation. In this stage the RF signal is mixed with the local oscillator frequency, which is generatedby an on–board oscillator. The oscillator block uses an external varactor tuned sustaining network and is optimised for high linearity over the normal deviation range. A typical frequency versus voltage characteristic for the oscillator is contained in Fig. 7. The loop output is designed to compensate for first order temperature variation effects; the typical stability is shown in Fig. 8

The output of the mixer is then fed to the loop amplifier

around which feedback is applied to determine loop transfer characteristic . Feedback can be applied either in differential or single ended mode; if the appropriate phase detector gains are assumed in calculating loop filters, both modes should give the same loop response.

The loop amplifier drives a 75Ω output impedance buffer

amplifier, which can either be connected to a 75Ω load or used to drive a high input impedance stage giving greater linearity and approximately 6dB higher demodulated signal output level.

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