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ADS1x9xECG-FE Hardware Introduction
Leads
Lead Off Status
LL off
IN2P is red
RA off
IN2N and IN1N are red
LA off
IN1P is red
Monitoring lead-off information is achieved by polling the Status byte in the data-word after each
conversion. Within the ADS1x9xECG-FE software, there are two ways to view the Lead-Off Status. Within
the Live ECG\RESP tab, the information about the lead status is shown in the upper right corner of the
GUI. Within the Analysis tab, a pop-up window showing the status can be viewed by clicking on the
Show/Poll Lead-Off Status button.
5
ADS1x9xECG-FE Hardware Introduction
The key features of the ADS1x9x analog front end demonstration board are:
•
Based on MSP430F5529
•
ADS1192 and ADS1292 suitable for six leads of ECG: Lead I, Lead II, Lead III, Lead aVR, Lead aVL,
or Lead aVF
•
ADS1292R suitable for one lead of ECG (Lead I) and respiration channel
•
Low power consumption (350 Micro Watt/channel)
•
Data Rate ranges from 125 SPS to 8 kSPS
•
Unipolar Operation
•
Lead off detection circuitry
•
On chip oscillator and reference
•
On chip RLD amplifier
•
SPI data interface
•
8Gb NAND Flash support
The ADS1x9xECG-FE can be used as a demo board for standard six lead ECG and respiration channel
using four electrode inputs. Defibrillator protection and patient protection circuitry are not provided on the
ADS1x9xECG-FE board. The printed circuit board (PCB) and schematic are shown in
Appendix C
.
MSP430F5529 (U7) is the micro-controller used on the board. For more details of the MSP430F5529
please visit
http://focus.ti.com/docs/prod/folders/print/msp430f5529.html
The following sections explain the main hardware components available on the ADS1x9xECG-FE.
5.1
Power Supply
ADS1x9x can operate from 2.7 V to 5.25 V analog supply (AVDD/AVSS) and 1.65 to 3.6V (DVDD) digital
supply. In this design the ADS1x9x is operated at 3 V analog and 3.3 V digital.
The power for the board is derived from the USB input (P1) through a forward biased diode (D3) to avoid
reverse current flow. The USB data bus is ESD protected using TI’s ESD protection diode array
TPD4E004DRYR (U2). The USB VBUS is fed to the integrated Li-ion linear charger and system power-
path management module, BQ24032ARHLR (U8), which generates greater than 4.2V output (VCC_BAT).
This output is then fed to TI’s low-power linear voltage regulator, TPS73033 (U16), for generating
regulated 3.3V for digital section of the board. The 3V supply for the analog section is derived from
VCC_BAT using TI’s low dropout voltage regulator TPS73201 (U10).
The inductors L3, L4, L5 and L7 are used to minimize the power supply noise induced by the power
supply regulators.
The test points TP25, TP32 are provided to make sure the power supplied to the board is correct. The
corresponding voltages are given in the table below. The analog power supply (ADS_AVDD) is also
brought out on connector P3.
27
SLAU384A – December 2011 – Revised April 2012
ADS1x9xECG-FE Demonstration Kit
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