MITEL SL1710 Datasheet

SL1710

Quadrature Downconverter

Preliminary Information

Supersedes October 1996 version in Media IC Handbook HB4599-1.0 DS3842 - 4.1 March 1997

The SL1710 is a quadrature downconverter, intended for
use with both Professional and Consumer Digital Satellite
Applications.

The device contains high linearity, low noise amplifiers,
quadrature mixers, plus an on-chip oscillator, operating
between 350MHz and 500MHz, which may be synthesised via
the differential prescaler outputs.

An AGC with 18dB gain control is provided to cope with a
wide range of input signal levels.

I and Q outputs are via low impedance single ended
amplifiers. These may be connected to a dual channel analog
to digital converter such as the PCA916, VP216, VP215 or
VP213, via a suitable anti-alias filter.

AGC
IOUT

VEEA

IFINB

IFIN
VCCA
QOUT

VEEC

1

16

SL1710

VCCB
VCODIS

VCO B
VCO A

VEEB
PSCAL
PSCALB
VCCC

MP16

FEATURES

■ Wide input frequency range (350-500MHz)

■ On chip oscillator with varactor tuning or SAW

resonator operation capability

■ Nominal 40dB conversion gain from IF input to I
and Q outputs

■ AGC amplifier with 18dB gain control range

■ I to Q phase match 90°C to ± 2°, gain match

better than 1dB

■ Low impedance I and Q single ended outputs,
with 15MHz ± 1dB BW

■ Divide by 32 prescaler outputs

■ Suitable for QPSK and up to 64QAM systems

AGC

IFIN
IFINB

Fig. 1 Pin allocation top view

ORDERING INFORMATION

SL1710/KG/MPAS
SL1710/KG/MPAD (Tape and Reel)

ABSOLUTE MAXIMUM RATINGS

Storage temperature -55°C to +150°C
Junction temperature -29°C to +150°C
Supply voltage -0.3 to 7.0V
Voltage at any other pin -0.3 to +7.0V

APPLICATIONS

■ Consumer digital satellite decoders

■ Professional digital satellite decoders

■ Communication systems

AGC

I OUT

VCODIS

VCOA
VCOB

LO

0 deg 90 deg

Quadrature
generator

Fig.2. SL1710 block diagram

AGC

÷32

Q OUT

PSCAL
PSCALB

SL1710

ELECTRICAL CHARACTERISTICS

T

= 0oC to +80oC, Vee= 0V, Vcc = 4.75 to 5.25 V, Fif = 479.5 MHz, IF bandwidth ± 15 MHz, output amplitude -11dBV

amb

These characteristics are guaranteed by either production test or design. They apply within the specified ambient temperature

and supply voltage unless otherwise stated.

Value

Characteristic Pin Min Typ Max Units Conditions

Supply voltage 6,9,16 4.75 5.25 V
Supply current 6,9,16 94 110 mA

RF Input

RF freq range 4, 5 350 500 MHz
Impedance 4, 5 75 ohm @ 480MHz. Fig. 4
VSWR 4, 5 1.7 @ 480MHz. Fig. 4
Noise Figure 4, 5 19 dB AGC at maximum gain
Noise Figure variation with 4, 5 0.5 1 dB/dB
gain

VCO

VCO freq (fo) control range 13, 14 350 500 MHz External tank circuit with varicap
Phase noise 13, 14 -85 dBc/Hz @ 10kHz from fo. but measured in

I or Q output. Note

Fo sensitivity to V

CC

13, 14 2 MHz/Volt Fixed external components and no

control loop
Fo sensitivity to temperature 13, 14 40 KHz/°C Uncompensation
Prescaler output, VOH 10, 11 V

VOL 10, 11 V

-0.96 Volt At 25°C

CC

-1.65 Volt

CC

Prescaler output duty cycle 10, 11 40 60 %Under maximum load conditions

Fig. 5

AGC

Gain, Vagc = +2.5V 40 dB
Temp stability of gain 1 ±2 dB For any gain setting 0V to 5V
Gain, Vagc = +0.5V 1 44 dB See Fig.6
Gain, Vagc = + V

-0.5V 1 32 dB See Fig.6

CC

AGC range 18 dB
I Q outputs 480MHz local oscillator, 481 to

495MHz RF input @ -51dBV

Gain set to give -11dBV,

1-15MHz baseband output into

maximum load. Fig. 7
Output impedance 2, 7 8 ohm Fig. 8
Output clipping level 2, 7 1.5 V p-p
I phase lag with respect to Q 2, 7 88 90 92 degs 1 -15MHz
IQ crosstalk 20 dB
Output amplitude match 2, 7 1 dB I releative to Q, 1 -15MHz
Baseband flatness 2, 7 ±1 dB 1-15MHz, 1kΩ 15pF load
Two tone 3rd order intercept 2, 7 +3 dBV Referred to output. @ 1MHz
point Output load 1kohm, 15pF, all

AGC settings, 0.7V pk-pk output
Im3 2, 7 28 dBc
LO, and Sputii in IQ outputs 2, 7 -30 dBV 1-100MHz

(1, 2)

2

SL1710

ELECTRICAL CHARACTERISTICS (continued)

T

= 0oC to 80oC, Vee= 0V, Vcc = 4.75 to 5.25 V, These characteristics are guaranteed by either production test or design.

amb

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

Value

Characteristic Pin Min Typ Max Units Conditions

Prescaler sidebands 2, 7 -50 -47 dBV Measured in IQ outputs
Power supply rejection 2, 7 25 30 dB Attenuation VCC to IQ outputs,

over 0-500kHz

Notes:

1. The choice of L will have an effect on phase noise of the VCO

2. Target value at fo=500MHz, L (tank)=10nH, Q (tank, unloaded)=50, SSB

DESCRIPTION

The SL1710 is a quadrature downconverter, intended for
high linearity, low noise digital satellite applications. It contains
all the elements necessary, with the exception of the VCO
tuning components, to extract baseband I and Q signals from
a QPSK or QAM IF input signal.

A block diagram for the SL1710 is shown in Fig. 2.

In normal consumer digital satellite applications, the device
is fed via a SAW filter, centred at the standard IF of 479.5MHz.
A filtered single channel is therefore presented to the device,
at a typical level of -51dBV. An AGC is included with 18dB of
gain control, which is guaranteed to provide an overall conver­sion gain between 30 and 45dB from the RF input to the I and
Q outputs.

The quadrature mixers are fed from an on-chip oscillator
which is centred on the incoming IF. The oscillator external
tuning network should be fully symmetric, to ensure optimum
gain and phase match.

Single ended I and Q amplifiers are provided, which output
a 760mV (p/p) signal, assuming a nominal -51dBV input signal
and 40dB gain, suitable for driving a dual channel ADC such as
the PCA 869, PCA 913 and PCA 916 via an anti-alias filter (see
application notes). The ADC is normally AC coupled via two
capacitors (typically 4.7µF).

The SL1710 also includes divide by 32 prescaler output.
These may be fed to an external PLL circuit which can be used
to drive the on-chip oscillator, thus forming a complete control
loop.

The VCO can be disabled by applying 0V to pin 15.

3

SL1710

CH PUMP

1

XTAL1

2

XTAL2

3

SDA

4

SCL

5

P76P67P5

8

P4

9

P310NC11Vcc12RF I/P13RF I/P14Vee

15

DRV

16

IC2 SP5611

AGC

1

IOUT

2

VEEA

3

IFINB

4

IFIN

5

VCCA

6

QOUT

7

VEEC

8

VCCC

9

PSCALB

10

PSCAL

11

VEEB

12

VCOA

13

VCOB

14

VCODIS

15

VCCB

16

/32

Oscillator

I Mixer

Q Mixer

IC1 SL1710

L1

12nH

C12

3p9

D1

BB811

C13

3p3

1

42

3

LK2

T2

BCW31

5V

R4

110R

SK4

Q CH O/P

C11

220nF

SW1

VCO DISABLE

R2

4K7

5V

SK1

RF IN

C1

100nF

C2

100nF

R1

75R

L5

4u7

L6

4u7

C3

100nF

C4

100pF

C5

100nF

C6

100pF

C7

100nF

C8

100pF

+

C9

47uF

5V

5V

5V 5V

VR1

1K

R5

680R

R6

4K7

R7

680R

T1

BCW31

1

42

3

LK1

R3

110R

SK3

I CH O/P

C10

220nF

C14

10nF

C15

10nF

C19

220nF

C20

47nF

R8

22K

R9

22K

R10

4K7

T3

BCW31

R11

10K

C21

10nF

30V

C18

18pF

X1

4 MHz

C16

10nF

C17

100pF

1

2

3

CN1

DC POWER

30V

5V

SDA5

3

5V04GND5SCL5

6

SK4

I2C

5V

Fig. 3 Demonstration board circuit diagram

4