Datasheet AD8233 (Analog Devices)

50 μA, 2 mm × 1.7 mm WLCSP, Low Noise, Heart Rate Monitor for Wearable Products Data Sheet AD8233 FEATURES FUNCTIONAL BLOCK DIAGRAM Fully integrated, single-lead electrocardiogram (ECG) front end A4 B4 A3 A2 A1 HPSENSE Low quiescent supply current: 50 μA (typical) IAOUT REFIN +VS GND HPDRIVE Leads on/off detection while in shutdown (<1 μA) A5 FR S1 10kΩ B3 A3 Common-mode rejection ratio: 80 dB (dc to 60 Hz) +IN 2 or 3 electrode configurations B5 –IN AC/DC IA B2 High signal gain (G = 100) with dc blocking capabilities C5 2-pole adjustable high-pass filter SDN 150kΩ B1 Accepts up to ±300 mV of half cell potential AD8233 C4 Fast restore feature improves filter settling RLDFB Uncommitted op amp RLD SDN C2 3-pole adjustable low-pass filter with adjustable gain D5 A2 RLD LOD LEADS OFF Integrated right leg drive (RLD) amplifier with shutdown DETECTION C C1 Single-supply operation: 1.7 V to 3.5 V S2 Integrated reference buffer generates virtual ground 10kΩ A1
01
Rail-to-rail output
0
SW OPAMP+ REFOUT OPAMP– OUT
37-
Internal RFI filter D4 D3 C3 D2 D1
137
8 kV human body model (HBM) ESD rating
Figure 1.
Shutdown pin 2 mm × 1.7 mm WLCSP APPLICATIONS Fitness and activity heart rate monitors Portable ECG Wearable and remote health monitors Gaming peripherals Biopotential signal acquisition, such as EMG GENERAL DESCRIPTION
includes an amplifier for driven lead applications, RLD. The AD8233 is an integrated signal conditioning block for ECG The AD8233 includes a fast restore function that reduces the and other biopotential measurement applications. It is designed duration of the otherwise long settling tails of the high-pass to extract, amplify, and filter small biopotential signals in the filters. After an abrupt signal change that rails the amplifier presence of noisy conditions, such as those created by motion or (such as a leads off condition), the AD8233 automatically remote electrode placement. This design allows an ultralow adjusts to a higher filter cutoff. This feature allows the AD8233 power analog-to-digital converter (ADC) or an embedded to recover quickly, and therefore, to take valid measurements microcontroller to easily acquire the output signal. soon after connecting the electrodes to the subject. The AD8233 implements a two-pole high-pass filter for The AD8233 is available in a 2 mm × 1.7 mm, 20-ball WLCSP eliminating motion artifacts and the electrode half cell potential. package. Performance is specified from 0°C to 70°C and is This filter is tightly coupled with the instrumentation architec- operational from −40°C to +85°C. ture of the amplifier to allow both large gain and high-pass
Table 1. AD8232 vs . AD8233 Comparison
filtering in a single stage, thereby saving space and cost.
Parameter AD8232 AD8233
Supply Current 170 μA 50 μA An uncommitted operational amplifier enables the AD8233 to Peak-to-Peak Voltage Noise 14 μV p-p 8.5 μV create a three-pole, low-pass filter to remove additional noise. (f = 0.5 Hz to 40 Hz) The user can select the frequency cutoff of all filters to suit Leads On/Off Detection in Not included Included different types of applications. Shutdown Right Leg Drive Shutdown Not included Included To improve the common-mode rejection of the line frequencies Package Size 4 mm × 4 mm × 2 mm × 1.7 mm × in the system and other undesired interferences, the AD8233 0.75 mm 0.5 mm
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Document Outline FEATURES APPLICATIONS FUNCTIONAL BLOCK DIAGRAM GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS INSTRUMENTATION AMPLIFIER PERFORMANCE CHARACTERISTICS OPERATIONAL AMPLIFIER PERFORMANCE CHARACTERISTICS RIGHT LEG DRIVE (RLD) AMPLIFIER PERFORMANCE CHARACTERISTICS REFERENCE BUFFER PERFORMANCE CHARACTERISTICS SYSTEM PERFORMANCE CHARACTERISTICS THEORY OF OPERATION ARCHITECTURE OVERVIEW INSTRUMENTATION AMPLIFIER OPERATIONAL AMPLIFIER RIGHT LEG DRIVE AMPLIFIER REFERENCE BUFFER FAST RESTORE CIRCUIT LEADS ON/OFF DETECTION DC Leads On/Off Detection AC Leads On/Off Detection STANDBY OPERATION INPUT PROTECTION RADIO FREQUENCY INTERFERENCE (RFI) POWER SUPPLY REGULATION AND BYPASSING INPUT REFERRED OFFSETS LAYOUT RECOMMENDATIONS APPLICATIONS INFORMATION ELIMINATING ELECTRODE OFFSETS HIGH-PASS FILTERING Two-Pole High-Pass Filter Additional High-Pass Filtering Options LOW-PASS FILTERING AND GAIN Driving ADCs DRIVEN ELECTRODE APPLICATION CIRCUITS HEART RATE MEASUREMENT (HRM) NEXT TO THE HEART EXERCISE APPLICATION—HEART RATE MEASURED AT THE HANDS HOLTER MONITOR CONFIGURATION SYNCHRONIZED ECG AND PPG MEASUREMENT PACKAGING AND ORDERING INFORMATION OUTLINE DIMENSIONS ORDERING GUIDE