Table of Contents
Advertisement
Circuit Description
BANANA JACK
J9
J10
J11
J12
J13
J14
J15
J16
J17
J20
74
73
72
71
70
69
68
9.97
19.94
3.2.3
Analog Inputs
The EVM can be configured to provide the ADC with either transformer-coupled or differential amplifier
inputs from a single-ended source. The inputs are provided via SMA connector J3 for transformer-coupled
input or SMA connector J1 for differential amplifier input. To set up for one of these options, the EVM must
be configured as follows:
1. For a 1:1 transformer-coupled input to the ADC, a single-ended source is connected to J3. Confirm
that SJP4 has pins 2 and 3 shorted, and that SJP5 has pins 2 and 3 shorted. The transformer used,
the Mini-Circuits TC4-1W, forms an inherent band-pass filter with a pass band from 3 MHz to 800 MHz.
This is the default configuration for the EVM.
2. One can use a TI THS4509 amplifier to drive the ADC by applying an input to J1. Reconfigure SJP4
and SJP5 such that both have pins 1 and 2 shorted. A 5-VDC supply must be connected to the board
to provide power to U3 for this configuration.
The THS4509 amplifier path converts a single-ended signal presented on J1 into a differential signal.
8
Table 2. EVM Power Options
NAME
VOLTAGE
Device AGND
GND
AGND
GND
Device AVDD
Amplifier negative
rail
Amplifier positive rail
Auxiliary power
Device DVDD
DGND
GND
DGND
GND
30.13
40.33
50.13
f
IN
Figure 1. ADS5547 SNR Performance vs Decoupling
3.3
Device analog supply
–5
THS4509 Vs– supply
5
THS4509 Vs+ supply
5
Supplies power to all peripheral circuitry including the FPGA
and PROM. Voltages rails are created by using TI's TPS75003
voltage regulator.
3.3
Device internal digital output supply
If TP11, TP12, and TP13 are tied low, the TPS75003 is
disabled. In this case, one can supply 3.3 V to pin 1, 1.2 V to
pin 2, and 2.2 V to pin 3 of J20 while connecting the ground to
J17.
Baseline-All Decoupling Caps
60.13
69.59
79.87
− Input Frequency − MHz
SLWU028B – January 2006 – Revised November 2006
www.ti.com
DESCRIPTION
1 Decoupling Cap
89.75
100.33
130.13
170.13
Submit Documentation Feedback
G001
Advertisement
Table of Contents
