TSH122 STMicroelectronics, TSH122 Datasheet - Page 10

• Manufacturer Part Number: TSH122
• Description: Ultra low power video buffer/filter with power-down
• Manufacturer: STMicroelectronics

Specifications of TSH122

• Very Low Consumption: 1.7 mA
• Ultra Low Power-down Mode: 4 nA typ., 500 nA max.

Application information
3.2
3.2.1
3.2.2
3.2.3
10/16
Implementation considerations
Input
The DC level shifter optimizes the position of the video signal with no clamping on the output
rails.
Filter
A reconstruction filter is used to attenuate the DAC’s sampling frequency because it
generates a parasitic signal in the video spectrum (typically at 27 MHz in the case of
standard video). This function is fulfilled while keeping a low group delay and a good gain
flatness along the video band.
Figure 25. Internal schematic
Output
In an AC-coupling configuration, the SAG correction allows use of two small low-cost
capacitors in place of one large capacitor (see
the power consumption by removing the DC component included in the signal.
Nevertheless, the output can be directly connected to the line without any capacitor. In this
case, the OUT and SAG pins are connected together and the equivalent gain of the buffer
remains at 6 dB (see
Input
Input
Figure
1
1
6
6
DC shifter
DC shifter
th
th
27).
LPF
LPF
order
order
2R
2R
+
+
2
2
+
+
-
-
GND
GND
6
6
+Vcc
+Vcc
2.25 V to 5 V
2.25 V to 5 V
R
R
Figure
5 Power-down
5 Power-down
2R
2R
26). The AC-coupling output reduces
2R
2R
SAG
SAG
4
4
3
3
Output
Output
TSH122