Datasheet

ADS4126 , ADS4129
ADS4146 , ADS4149
SBAS483G – NOVEMBER 2009–REVISED JANUARY 2011 www.ti.com
RECOMMENDED OPERATING CONDITIONS
Over operating free-air temperature range, unless otherwise noted.
ADS412x, ADS414x
MIN TYP MAX UNIT
SUPPLIES
AVDD Analog supply voltage 1.7 1.8 1.9 V
DRVDD Digital supply voltage 1.7 1.8 1.9 V
ANALOG INPUTS
Differential input voltage range
(1)
2 V
PP
Input common-mode voltage V
CM
± 0.05 V
Maximum analog input frequency with 2V
PP
input amplitude
(2)
400 MHz
Maximum analog input frequency with 1V
PP
input amplitude
(2)
800 MHz
CLOCK INPUT
Input clock sample rate
ADS4129/ADS4149
Low-speed mode enabled
(3)
20 80 MSPS
Low-speed mode disabled
(3)
> 80 250 MSPS
ADS4126/ADS4146
Low-speed mode enabled
(3)
20 80 MSPS
Low-speed mode disabled
(3)
> 80 160 MSPS
Input clock amplitude differential (V
CLKP
– V
CLKM
)
Sine wave, ac-coupled 0.2 1.5 V
PP
LVPECL, ac-coupled 1.6 V
PP
LVDS, ac-coupled 0.7 V
PP
LVCMOS, single-ended, ac-coupled 1.8 V
Input clock duty cycle
Low-speed mode enabled 40 50 60 %
Low-speed mode disabled 35 50 65 %
DIGITAL OUTPUTS
C
LOAD
Maximum external load capacitance from each output pin to DRGND 5 pF
Differential load resistance between the LVDS output pairs (LVDS
R
LOAD
100 Ω
mode)
T
A
Operating free-air temperature –40 +85 °C
HIGH PERFORMANCE MODES
(4)(5)(6)
Set the MODE 1 register bits to get best performance across sample
Mode 1 clock and input signal frequencies.
Register address = 03h, register data = 03h
Set the MODE 2 register bit to get best performance at high input
Mode 2 signal frequencies.
Register address = 4Ah, register data = 01h
(1) With 0dB gain. See the Fine Gain section in the Application Information for relation between input voltage range and gain.
(2) See the Theory of Operation section in the Application Information.
(3) See the Serial Interface section for details on low-speed mode.
(4) It is recommended to use these modes to get best performance. These modes can be set using the serial interface only.
(5) See the Serial Interface section for details on register programming.
(6) Note that these modes cannot be set when the serial interface is not used (when the RESET pin is tied high); see the Device
Configuration section.
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