Datasheet

ADC1213D_SER All information provided in this document is subject to legal disclaimers. © NXP B.V. 2011. All rights reserved.
Product data sheet Rev. 7 — 9 June 2011 20 of 42
NXP Semiconductors
ADC1213D series
Dual 12-bit ADC; serial JESD204A interface
Single-ended or differential clock inputs can be selected via the SPI (see Table 20). If
single-ended is selected, the input pin (CLKM or CLKP) is selected via control bit
SE_SEL.
If single-ended is implemented without setting bit SE_SEL accordingly, the unused pin
should be connected to ground via a capacitor.
11.3.3 Clock input divider
The ADC1413D contains an input clock divider that divides the incoming clock by a factor
of 2 (when bit CLKDIV2_SEL = logic 1; see Table 20
). This feature allows the user to
deliver a higher clock frequency with better jitter performance, leading to a better SNR
result once acquisition has been performed.
11.3.4 Duty cycle stabilizer
The duty cycle stabilizer can improve the overall performance of the ADC by
compensating the input clock signal duty cycle. When the duty cycle stabilizer is active
(bit DCS_EN = logic 1; see Table 20
), the circuit can handle signals with duty cycles of
between 30 % and 70 % (typical). When the duty cycle stabilizer is disabled
(DCS_EN = logic 0), the input clock signal should have a duty cycle of between 45 % and
55 %.
11.4 Digital outputs
11.4.1 Serial output equivalent circuit
The JESD204A standard specifies that if the receiver and the transmitter are DC-coupled,
both must be fed from the same supply.
The output should be terminated when 100  (typical) is reached at the receiver side.
Table 12. Duty cycle stabilizer
Bit DCS_EN Description
0 duty cycle stabilizer disable
1 duty cycle stabilizer enable
Fig 19. CML output connection to the receiver (DC-coupled)
VDDD
CMLPA/CLMPB
CMLNA/CLMNB
AGND
005aaa082
12 mA to 26 mA
100 Ω
+
RECEIVER
50 Ω
−