DS5117 Issue 2.1 October 1999

SL2035

High Performance Broadband Downconverter

Preliminary Information

Ordering Information

SL2035/IG/MP1S (Tubes)

SL2035/IG/MP1T (Tape and Reel)

Features

Cat.1 (Normal ESD handling procedures should be

observed)

Applications

The SL2035 is a bipolar, broadband wide dynamic range

mixer oscillator, optimised for applications as the

downconverter in double conversion tuner systems. It also

has application in any system where a wide dynamic range

broadband frequency converter is required.

The SL2035 is a single chip containing all necessary active

circuitry and simply requires an external tuneable resonant

network for the local oscillator. The block diagram is shown

in Figure 1 and pin connections are shown in Figure 2.

In normal application the signal from the high IF output is

connected to the RFIN and RFIN inputs. The RF input

preamplifier of the device is designed for low noise figure

within the operating region and for high intermodulation

distortion intercept so offering good signal to noise plus

composite distortion spurious performance.

The preamplifier also provides gain to the mixer section

and back isolation from the local oscillator section. The

approximate model of the RF input is shown in Figure 3.

Absolute Maximum Ratings

RF differential input voltage

All I/O port DC offset

Storage temperature

Junction temperature

Package thermal resistance

Chip to ambient,

Chip to case,

20·3V to 17V

2·5V

255

°C to 1150°C

1150

°C

20

°C/W

80

°C/W

The output of the preamplifier is fed to the mixer section

which is optimised for low radiation application. In this stage

the RF signal is mixed with the local oscillator frequency,

which is generated by an on-chip oscillator. The oscillator

block uses an external tuneable network and is optimised

for low phase noise. A typical application is shown in

Figure 5. This block also contains a buffer-amplifier to

interface with an external PLL to allow for frequency

synthesis of the local oscillator.

The IF output can be loaded either differentially or single-

ended. It is recommended that the differential load as in

Figure 5 is applied as this gives best noise performance. If

the output is loaded single-ended the noise figure will be

degraded. The approximate model of the IF output is shown

in Figure 4.

In application care should be taken to achieve symmetric

balance to the IF outputs to maximise intermodulation

performance.

Figure 1 SL2035 block diagram

RFIN

RFIN

LO2

LO1

IF1

IF2

PRSC1