Datasheet

ADC1212D_SER All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 2 — 4 March 2011 19 of 42
NXP Semiconductors
ADC1212D series
Dual 12-bit ADC: CMOS or LVDS DDR digital outputs
The component values are determined by the input frequency and should be selected so
as not to affect the input bandwidth.
11.2.3 Transformer
The configuration of the transformer circuit is determined by the input frequency. The
configuration shown in Figure 18
would be suitable for a baseband application.
The configuration shown in Figure 19 is recommended for high frequency applications. In
both cases, the choice of transformer is a compromise between cost and performance.
Fig 17. Anti-kickback circuit
Table 11. RC coupling versus input frequency, typical values
Input frequency (MHz) R () C (pF)
32512
70 12 8
170 12 8
001aan679
R
R
C
INAP/
INBP
INAM/
INBM
Fig 18. Single transformer configuration suitable for baseband applications
005aaa094
100 nF100 nF
100 nF
100 nF
25 Ω
25 Ω
25 Ω
25 Ω
12 pF
INAP/INBP
INAM/INBM
VCMA/VCMB
100 nF
Analog
input
ADT1-1WT
100 nF