TDA8798HL Philips Semiconductors, TDA8798HL Datasheet - Page 4

• Manufacturer Part Number: TDA8798HL
• Description: Dual 8-bit/ 100 Msps A/D converter with DPGA
• Manufacturer: Philips Semiconductors

Philips Semiconductors
2001 Feb 14
handbook, full pagewidth
Dual 8-bit, 100 Msps A/D converter with optional DPGA
External filtering may be used between DPGA and ADC to limit the noise bandwidth.
The external filter has a low-pass cut-off frequency of
and a high-pass cut-off frequency of
Other types of filter may be used if DC biasing is correct.
Fig.2 DPGA input to filter output with ADC connected as a function of analog input frequency.
I OUT
I OUT
C o(DPGA)
C o(DPGA)
f
handbook, halfpage
h 3dB
–
DPGA
TDA8798
(dB)
R o(DPGA)
R o(DPGA)
10
20
30
40
50
------ -
2
0
1
0
----------------------------- -
R
i ADC
f
l 3dB
–
1
10
DPGA
DPGAN
Fig.3 External filter.
C
------ -
2
1
(1)
(3)
R 2
------------------------------------------
20
10 H
10 H
L
L
+
4
R
L
o DPGA
30
100 nF
100 nF
R
1 k
C
C
BUFN
BUF
40
(1) DPGA1/DPGA2.
(2) BUF1/BUF2.
(3) DPGA1N/DPGA2N.
(4) BUF1N/BUF2N.
f i (MHz)
(2)
(4)
FCE645
R i(ADC)
R i(ADC)
50
TDA8798
C i(ADC)
C i(ADC)
FCE267
Product specification
TDA8798