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Product Specification
TS8388BFS
This is true so long as the out of phase analog input pin VINB is 50 ohms terminated very closely to one of the neighboring shield ground pins
(52, 53, 58, 59) which constitute the local ground reference for the inphase analog input pin (VIN).
Thus the differential analog input preamplifier will fully reject the local ground noise ( and any capacitively and inductively coupled noise) as
common mode effects.
In typical single–ended configuration, enter on the (VIN) input pin, with the inverted phase input pin (VINB) grounded through the 50 ohms
termination resistor.
In single–ended input configuration, the in-phase input amplitude is 0.5 Volt peak to peak,centered on 0V. (or -2 dBm into 50 ohms.)
The inverted phase input is at ground potential through the 50 ohms termination resistor.
However, dynamic performances can be somewhat improved by entering either analog or clock inputs in differential mode.
Typical Single ended analog input configuration
VIN or VINB
VIN or VINB double pad (pins 54, 55 or 56, 57)
50
(external)
50
reverse termination
1M
3 pF
-250
250
[mV]
500 mV
Full Scale
analog input
t
VINB
VIN
VINB = 0V
V
IN = +/- 250 mV 500 mV diff
7.4.
CLOCK INPUTS (CLK) (CLKB)
The TS8388BFS can be clocked at full speed without noticeable performance degradation in either differential or single ended configuration.
This is explained by the fact the ADC uses a differential preamplifier stage for the clock buffer, which has been designed in order to be entered
either in differential or single–ended mode.
Recommended sinewave generator characteristics are typically -120 dBc/Hz phase noise floor spectral density, @ 1 KHz from carrier ,
assuming a single tone 4 dBm input for the clock signal.
7.4.1.
SINGLE ENDED CLOCK INPUT (GROUND COMMON MODE)
Although the clock inputs were intended to be driven differentially with nominal -0.8V / -1.8V ECL levels, the TS8388BFS clock buffer can
manage a single–ended sinewave clock signal centered around 0 Volt. This is the most convenient clock input configuration as it does not
require the use of a power splitter.
No performance degradation ( e.g. : due to timing jitter) is observed in this particular single–ended configuration up to 1.2GSPS Nyquist
conditions ( Fin = 600 MHz ).
This is true so long as the inverted phase clock input pin is 50 ohms terminated very closely to one of the neighbouring shield ground pin, which
constitutes the local Ground reference for the inphase clock input.
Thus the TS8388BFS differential clock input buffer will fully reject the local ground noise ( and any capacitively and inductively coupled noise) as
common mode effects.
Moreover, a very low phase noise sinewave generator must be used for enhanced jitter performance.
The typical inphase clock input amplitude is 1 Volt peak to peak, centered on 0 Volt (ground) common mode.
This corresponds to a typical clock input power level of 4 dBm into the 50 ohms termination resistor.
Do not exceed 10 dBm to avoid saturation of the preamplifier input transistors.
The inverted phase clock input is grounded through the 50 ohms termination resistor.