TDA8769 Datasheet, PDF (14/28 Pages) NXP Semiconductors – 12-bit, 60/80/105 Msps Analog-to-Digital Converter (ADC) Nyquist/high IF sampling

Philips Semiconductors
12-bit, 60/80/105 Msps Analog-to-Digital Converter
(ADC) Nyquist/high IF sampling
Objective specification
TDA8769
11 APPLICATION INFORMATION
11.1 Output coding and control signals
Table 1 Output coding with differential inputs (typical values to AGND); V_IN(p−p) − V_{INN(p−p)} = 1.9 V − 0.5 dBFS;
V_VREF = V_CCA3 − 1.75 V
CODE
V_IN(p-p)
V_INN(p-p)
IR
BINARY OUTPUTS
(D11 TO D0)
TWO’S COMPLEMENT
OUTPUTS (D11 TO D0)
Underflow
<2.925
>3.875
0
000000000000
100000000000
0
2.925
3.875
1
000000000000
100000000000
1
−
−
000000000001
100000000001
:
:
:
:
:
2 047
3.4
3.4
0111 1111 1111
1111 1111 1111
:
:
:
:
:
4 094
−
−
1111 1111 1110
0111 1111 1110
4 095
3.875
2.925
1111 1111 1111
0111 1111 1111
Overflow
>3.875
<2.925
0
1111 1111 1111
0111 1111 1111
Table 2 Mode selection
CONTROL INPUT TWO’S
COMPLEMENT OUTPUT
(OTC)
0
1
don’t care
CHIP ENABLE NOT
(CEN)
0
0
1
OUTPUT DATA (D0 TO D11 AND IR)
binary; active
two’s complement; active
high impedance
Table 3 Track-and-hold selection
CONTROL INPUT TRACK-AND-HOLD (TH)
1
0
active
inactive; tracking
MODE
Table 4 Complete conversion signal selection
DEL1
0
0
1
1
DEL0
0
1
0
1
OUTPUT SIGNAL
inactive
active (for timing values, see Chapter 10)
11.2 TDA8769 in 3G radio receivers
TDA8769 has been proven in many 3G receivers with various operating conditions regarding input frequency, signal
input frequency bandwidth and sampling frequency. TDA8769 provides a maximum analog input frequency of 250 MHz.
It allows a significant cost reduction of the RF front-end, from two mixers to only one, even in multicarrier architecture.
Table 5 shows possible applications with the TDA8769 in High IF sampling mode.
2003 Dec 09
14