ADS1299EEG-FE Daughter Card Hardware Introduction
Table 2. Power Supply Test Points
Test Point
Voltage
TP7
+5.0V
TP9
+1.8V
TP10
+3.3V
TP5
+5.0V
TP13
+2.5V
TP6
–2.5V
TP8
GND
The front-end board must be properly configured in order to achieve the various power-supply schemes.
The default power-supply setting for the ADS1299EEG-FE is a unipolar analog supply of 5V and DVDD of
3V or +1.8V.
shows the board and component configurations for each analog power-
supply scheme;
shows the board configurations for the digital supply.
Table 3. Analog Supply Configurations
Unipolar Analog Supply
Bipolar Analog Supply
Power Supplies
5V
±2.5V
JP2 (AVDD)
2-3 (default)
1-2
JP20 (AVSS)
1-2 (default)
2-3
U8
Don’t Care
TPS72325
U9
Don’t Care
TPS73225
Table 4. Digital Supply Configurations
DVDD
+3.0V
+1.8V
JP24
2-3 (default)
1-2
4.2
Clock
The ADS1299 has an on-chip oscillator circuit that generates a 2.048MHz clock (nominal). This clock can
vary by ±5% over temperature. For applications that require higher accuracy, the ADS1299 can also
accept an external clock signal. The ADS1299EEG-FE provides an option to test both internal and
external clock configurations. It also provides an option to generate the external clock from either the
onboard oscillator or from an external clock source.
The onboard oscillator is powered by the DVDD supply of the ADS1299. Care must be taken to ensure
that the external oscillator can operate either with +1.8V or +3.0V, depending on the DVDD supply
configuration.
shows the jumper settings for the three options for the ADS1299 clocks.
Table 5. Clock Jumper Options
ADS1299 Clock
Internal Clock from the ADS1299
Clock from Oscillator on the EVM
External Clock Source
JP18
Not Installed
2-3 (default)
1-2
JP19
Don’t Care
1-2
Don’t Care
J3– pin 17
Don’t Care
Don’t Care
External Clock Source
15
SLAU443 – May 2012
EEG Front-End Performance Demonstration Kit
Copyright © 2012, Texas Instruments Incorporated