/a>ECG” title=”ECG”>ECG” title=”ECG”>ECG analog front-end (ECG FE), integrating a 24-bit delta-sigma (ΔΣ) ADC and programmable gain amplifier (PGA) that can simultaneously sample , voltage reference and on-board oscillator. Power consumption per channel is only 335uW, input referred noise 8 μVPP (150-Hz BW, G = 6), input bias current 200pA, data rate from 125SPS to 8kSPS, CMMR is -105dB, programmable gain 1, 2, 3, 4, 6, 8 or 12, support single power supply and bipolar power supply, mainly used in portable low power medical electrocardiograph, sports and bodybuilding and other fields. This article introduces the main ADS1x9x Features, Functional Block Diagram, Single and Bipolar Supply Operation Circuit Diagram, ADS1x9xECG-FE Demo Board Key Features, Block Diagram, Circuit Diagram, Bill of Materials and PCB Component Layout.
Low-Power, 2-Channel, 24-Bit Analog Front-End for Biopotential Measurements
The ADS1291, ADS1292, and ADS1292R are multichannel, simultaneous sampling, 24-bit, delta-sigma (ΔΣ) analog-to-digital converters (ADCs) with a built-in programmable gain amplifier (PGA), internal reference, and an onboard oscillator.
The ADS1291, ADS1292, and ADS1292R incorporate all features commonly required in portable, low-power medical electrocardiogram (ECG), sports, and fitness applications. ADS1292R enables the creation of scalable medical instrumentation systems at significantly reduced size, power, and overall cost.
The ADS1291, ADS1292, and ADS1292R have a flexible input multiplexer per channel that can be independently connected to the internally-generated signals for test, temperature, and lead-off detection. Additionally, any configuration of input channels can be selected for derivation of the right leg drive (RLD) output signal.
The ADS1292R version includes a fully integrated respiration impedance measurement The devices are packaged in a 5-mm × 5-mm, 32-pin thin quad flat pack (TQFP). Operating temperature is specified from –40℃ to +85℃.
ADS1x9x main features:
• Two Low-Noise PGAs and Two High-Resolution ADCs (ADS1292 and ADS1292R)
• Low Power: 335 μW/channel
• Input-Referred Noise: 8 μVPP A(150-Hz BW, G = 6)
• Input Bias Current: 200 pA.
• Data Rate: 125 SPS to 8 kSPS
• CMRR: –105dB
• Programmable Gain: 1, 2, 3, 4, 6, 8, or 12
• Supplies: Unipolar or Bipolar
– Analog: 2.7V to 5.25V
– Digital: 1.7V to 3.6V
• Built-In Right Leg Drive Amplifier, Lead-Off Detection, Test Signals t
• Integrated Respiration Impedance Measurement (ADS1292R)
• Built-In Oscillator and Reference
• Flexible Power-Down, Standby Mode
• SPI™-Compatible Serial Interface.
• Operating Temperature Range: –40℃ to +85℃
• Medical Instrumentation (ECG) including:
– Patient monitoring: Holter, event, stress, and vital signs including ECG, AED, and Telemedicine
– Sports and fitness (heart rate, respiration, and ECG)
• High-Precision, Simultaneous, Multichannel Signal Acquisition
Figure 1. ADS1x9x functional block diagram
Figure 2. ADS1x9x single-supply operating circuit diagram
Figure 3. ADS1x9x dual power supply circuit diagram
ADS1x9xECG-FE Demo Board
This demonstration kit models the ADS1192, ADS1292 and ADS1292R. The family of devices are two-channel, 16/24-bit, low-power, integrated analog front-end (AFE) designed for portable electrocardiogram (ECG) and respiration applications. The ADS1x9xECG-FE is intended for prototyping and evaluation. This user’s guide includes a complete circuit description, schematic diagram, and Bill of Materials.
The ADS1x9xECG FE is a demonstration kit for the ADS1292R, a two channel, simultaneous sampling, 24-bit, delta-sigma (ΔΣ) analog-to-digital converter (ADC) with a built-in programmable gain amplifier (PGA), internal reference, and respiration measurement. The ADS1292R chip incorporates all of the features that are commonly required in medical electrocardiogram (EKG/ECG) and electroencephalogram (EEG) and respiratory monitoring applications. The ADS1x9xECG FE is equipped with a MSP430F5529 micro-controller giving the user all the circuitry needed to run the ADC. The board can be used with a variety of patient simulators and allows the user to take advantage of the flexible input multiplexer which can be independently connected to the internally-generated signals for test, temperature, and lead -off detection. Software is available from Texas Instruments to allow the evaluation platform to run with a PC user interface.
ADS1x9xECG-FE demo board main features:
Easy-to-use evaluation software for Microsoft™ Windows XP or Windows 7
Built-in analysis tools including oscilloscope, FFT, and histogram displays
Flexible input configurations
Integrated Respiration Impedance
Digital Low Pass, High Pass, and 50/60Hz notch filters for post processing
Real time data streaming from the demo board to the PC
Ability to export data in simple test files for post processing
Figure 4. ADS1x9xECG-FE Demo Board Outline Drawing
The board can be assembled with any of these chips. ADS1292, ADS1292R and ADS1192 demonstration kits are available. The MSP430 firmware and PC application are designed to automatically detect the installed part and configure to accommodate the part.
Features supported in this release:
1. Four electrode ECG cable support
2. View six ECG Leads: Lead I, Lead II, Lead III, Lead aVR, Lead aVL, Lead aVF and respiration channel (ADS1292R only) .
3. Two modes of operation: Evaluation and Live ECG / Respiration
4. Acquire data at up to 8 kHz in Evaluation mode
5. Current based Lead off detection
6. USB based power and PC application connectivity
7. Access to all ADS1x9x registers via an easy to use GUI.
8. Built-in time domain, histogram, FFT and ECG / Resp related analysis on the PC application
9. Live ECG with heart rate calculation.
10. Live Respiration wave with respiration rate calculation
11. USB based firmware upgrade option
12. MSP430 Firmware debugging using ez430 USB emu
ADS1x9xECG-FE demo board main features:
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
Figure 5. ADS1x9xECG-FE Demo Board Block Diagram
Figure 6. ADS1x9xECG-FE Demo Board Circuit Diagram (1)
Figure 7. ADS1x9xECG-FE Demo Board Circuit Diagram (2)
Figure 8. ADS1x9xECG-FE Demo Board Circuit Diagram (3)
Figure 9. ADS1x9xECG-FE Demo Board Circuit Diagram (4)
Figure 10. ADS1x9xECG-FE Demo Board Circuit Diagram (5)
Figure 11. ADS1x9xECG-FE Demo Board Circuit Diagram (6)
ADS1x9xECG-FE Demo Board Bill of Materials (BOM):
Figure 12. ADS1x9xECG-FE Demo Board Component Layout: Top Layer
Figure 13. ADS1x9xECG-FE Demo Board Component Layout: Bottom Layer
For details, see: