SPT5140

CONVERT CLOCK

For best performance, the clock should be ECL driven,

driving the clock this way, clock noise and power supply/

output intermodulation will be minimized. The rising edge

of the clock synchronizes the data and control inputs to

the SPT5140. Since the actual switching threshold of

switching threshold of CONV is set by this bias voltage.

ANALOG OUTPUTS

The SPT5140 has two analog outputs that are high im-

pedance, complementary current sinks. The outputs vary

in proportion to the input data, controls and reference cur-

rent values so that the full-scale output can be changed

In video applications, the outputs can drive a doubly ter-

minated 50 or 75 ohm load to standard video levels. In

the standard configuration of figure 6, the output voltage

is the product of the output current and load impedance

and is between 0 and –1.07 V. The Out– output (figure 4)

will provide a video output waveform with the Sync pulse

bottom at the –1.07 V level. The Out+ is inverted with

Sync up.

OUT +

Video Monitor

Inverse

Video

OUT –

75

Ω

75

Ω COAX

75

Ω

75

Ω

75

Ω COAX

75

Ω

SPT5140

Video Out

0 to –1 Volt

OUT +

OUT –

37.5

Ω

<5 pF

CONV

1 k

Ω

100

Ω

6.5

Ω

–1.2 V

(Max 1.5 mA)

1 k

Ω

24-Pin DIP

All Resistors Are 5% 1/4 W cc

Clock = –0.9 to –1.7 V, 100 kHz

CONV

1 k

Ω

Clock

(Max 60

µA)

–5.9 V

(Max 200 mA)

(Max 50 mA)

Out–

Ref In

Out+

–1.3 V

(Max 60

µA)

1 k

Ω

6.5

Ω

100

Ω

(Max 50 mA)

(Max 1.5 mA)

0.0 V

–1.3 V

CONV

CONV

Figure 5 – CONVert, CONVert Switching Levels

Figure 6A – Standard Load

Figure 6B – Test Load

Figure 7 – Burn-In Circuit

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