AD9613 Analog Devices, AD9613 Datasheet - Page 27

• Manufacturer Part Number: AD9613
• Description: 12-bit, 170/210/250 MSPS, 1.8 V Dual Analog-to-Digital Converter (ADC)
• Manufacturer: Analog Devices

Specifications of AD9613

• Resolution (bits): 12bit
• # Chan: 2
• Sample Rate: 250MSPS
• Interface: LVDS,Par
• Analog Input Type: Diff-Bip
• Ain Range: 1.75 V p-p
• Adc Architecture: Pipelined
• Pkg Type: CSP

Data Sheet
POWER DISSIPATION AND STANDBY MODE
As shown in Figure 57, the power dissipated by the AD9613 is
proportional to its sample rate. The data in Figure 57 was taken
using the same operating conditions as those used for the Typical
Performance Characteristics section.
By asserting PDWN (either through the SPI port or by asserting
the PDWN pin high), the AD9613 is placed in power-down mode.
In this state, the ADC typically dissipates 10 mW. During power-
down, the output drivers are placed in a high impedance state.
Asserting the PDWN pin low returns the AD9613 to its normal
operating mode. Note that PDWN is referenced to the digital
output driver supply (DRVDD) and should not exceed that
supply voltage.
Low power dissipation in power-down mode is achieved by
shutting down the reference, reference buffer, biasing networks,
and clock. Internal capacitors are discharged when entering
power-down mode and then must be recharged when returning
to normal operation. As a result, wake-up time is related to the
time spent in power-down mode, and shorter power-down
cycles result in proportionally shorter wake-up times.
When using the SPI port interface, the user can place the ADC
in power-down mode or standby mode. Standby mode allows
the user to keep the internal reference circuitry powered when
faster wake-up times are required. See the Memory Map Register
Description section and the
Interfacing to High Speed ADCs via SPI, for additional details.
Table 11. Output Data Format
Input (V)
VIN+ − VIN–
VIN+ − VIN–
VIN+ − VIN–
VIN+ − VIN–
VIN+ − VIN–
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
40
Figure 57. AD9613-250 Power and Current vs. Sample Rate
60
80
VIN+ − VIN−,
Input Span = 1.75 V p-p (V)
Less than –0.875
–0.875
0
+0.875
Greater than +0.875
ENCODE FREQUENCY (MSPS)
100
120
TOTAL POWER
AN-877
I
140
DRVDD
I
AVDD
160
Application Note,
180
200
220
240
Offset Binary Output Mode
0000 0000 0000
0000 0000 0000
1000 0000 0000
1111 1111 1111
1111 1111 1111
0.5
0.4
0.3
0.2
0.1
0
Rev. B | Page 27 of 36
DIGITAL OUTPUTS
The AD9613 output drivers can be configured for either ANSI
LVDS or reduced drive LVDS using a 1.8 V DRVDD supply.
As detailed in Application Note AN-877, Interfacing to High
Speed ADCs via SPI, the data format can be selected for offset
binary, twos complement, or gray code when using the SPI
control.
Digital Output Enable Function (OEB)
The AD9613 has a flexible three-state ability for the digital output
pins. The three-state mode is enabled using the OEB pin or
through the SPI interface. If the OEB pin is low, the output data
drivers are enabled. If the OEB pin is high, the output data drivers
are placed in a high impedance state. This OEB function is not
intended for rapid access to the data bus. Note that OEB is
referenced to the digital output driver supply (DRVDD) and
should not exceed that supply voltage.
When using the SPI interface, the data outputs of each channel
can be independently three-stated by using the output enable bar
bit (Bit 4) in Register 0x14. Because the output data is interleaved,
if only one of the two channels is disabled, the output data of
the remaining channel is repeated in both the rising and falling
output clock cycles.
Timing
The AD9613 provides latched data with a pipeline delay of 10 input
sample clock cycles. Data outputs are available one propagation
delay (t
Minimize the length of the output data lines and loads placed
on them to reduce transients within the AD9613. These
transients can degrade converter dynamic performance.
The lowest typical conversion rate of the AD9613 is 40 MSPS. At
clock rates below 40 MSPS, dynamic performance can degrade.
Data Clock Output (DCO)
The AD9613 also provides data clock output (DCO) intended for
capturing the data in an external register. Figure 2 shows a timing
diagram of the AD9613 output modes.
ADC OVERRANGE (OR)
The ADC overrange indicator is asserted when an overrange is
detected on the input of the ADC. The overrange condition is
determined at the output of the ADC pipeline and, therefore, is
subject to a latency of 10 ADC clock. An overrange at the input is
indicated by this bit 10 clock cycles after it.
PD
) after the rising edge of the clock signal.
Twos Complement Mode (Default)
1000 0000 0000
1000 0000 0000
0000 0000 0000
0111 1111 1111
0111 1111 1111
AD9613
OR
1
0
0
0
1