TSH122 STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

Features

■ Very low consumption: 1.7 mA ■ Ultra low power-down mode: 4 nA typ., 500 nA max. ■ Internal 6th order reconstruction filter ■ Internal gain of 6 dB ■ Rail-to-rail output buffer for 75 Ω video line ■ Excellent video performance – Differential gain 0.5% – Differential phase 0.10° – Group delay of 10 ns ■ SAG correction ■ Bottom of video signal close to 0 V ■ Tested with 2.5 V and 3.3 V single supply ■ Data min. and max. are physically tested and guaranteed during production (consumption, gain, filtering, and other parameters are guaranteed)

Applications

■ Mobile phones ■ Digital still camera ■ Digital video camera ■ Portable DVD players

Description

The TSH122 is a video buffer that uses a voltage feedback amplifier, with an internal gain of 6 dB, an output rail-to-rail, an internal input DC-shift and a SAG correction. A power-down function allows switching to a sleep mode with an ultra-low consumption. The TSH122 features a 6th-order internal reconstruction filter to attenuate the parasitic frequency of 27 MHz from the clock of the video DAC. The TSH122 operates from 2.25 to 5 V single power supplies and is tested at 2.5 V and 3.3 V. The TSH122 is a single operator available in a tiny SC70 plastic package for space saving. OUTSAG IN GND Vcc EN (enable) Top view OUTSAG IN GND Vcc EN (enable) Top view SC70

1 Absolute maximum ratings and operating conditions

Table 1. Absolute maximum ratings

  1. All voltage values, except differential volt age, are with respect to network terminal.
  2. Charged device model: all pins and the package are charged together to the specified voltage and then

discharged directly to the ground through only one pin. This is done for all pins.

  1. Human body model: a 100 pF capacit or is charged to the specified voltage, then discharged through a

while the other pins are floating.

  1. Machine model: a 200 pF capacitor is charged to the specified voltage, then discharged directly between
  2. An output current limitation protects the circuit from transient currents. Short-circuits can cause excessive

heating. Destructive dissipation can result from short-circuits on amplifiers. Table 2. Operating conditions

  1. Tested in full production at 0 V/2.5 V and 0 V/3.3 V single power supply.

2 Electrical characteristics

Table 3. V CC = +2.5V, +3.3V, Tamb = 25°C (unless otherwise specified)

7.2 MHz

Table 3. V CC = +2.5V, +3.3V, Tamb = 25°C (unless otherwise specified) (continued)

3 Application information

3.1 Power supply considerations

capacitor, also placed as close as possible to the IC pins. Figure 23. Circuit for power supply bypassing Figure 24. Supply noise rejection

3.2 Implementation considerations

3.2.1 Input

3.2.2 Filter

flatness along the video band. Figure 25. Internal schematic

3.2.3 Output

the power consumption by removing the DC component included in the signal. remains at 6 dB (see Figure 27).

2.25 V to 5 V

5 Power-down

Figure 26. Schematic diagram with output capacitor Figure 27. Schematic diagram without output capacitor

7 CABLE7

7 CABLE

3.3 Using the TSH122 to drive a Cvbs signal

Figure 28. Details on Cvbs (NTSC color bar 100%) as 0 V (bottom of the synchronization tip at 0 V - see Figure 14).

0 IRE

4 Package information

Figure 29. SC70-6 (or SOT323-6) package footprint (in millimeters)

Figure 30. SC70-6 (or SOT323-6) package mechanical data

5 Ordering information

6 Revision history

Table 4. Order codes Table 5. Document revision history 04-Aug-2008 1 Initial release.