Datasheet

ADAS1000-3/ADAS1000-4 Data Sheet
Rev. A | Page 30 of 76
DEFIBRILLATOR PROTECTION
The ADAS1000-3/ADAS1000-4 do not include defibrillation
protection on chip. Any defibrillation protection required by
the application requires external components. Figure 58 and
Figure 59 show examples of external defibrillator protection,
which is required on each ECG channel, in the RLD path, and
in the CM_IN path if using the CE input mode. Note that, in
both cases, the total ECG path resistance is assumed to be 5 kΩ.
The 22 MΩ resistors shown connected to RLD are optional and
used to provide a safe termination voltage for an open ECG
electrode; they may be larger in value. Note that, if using these
resistors, the dc lead-off feature works best with the highest
current setting.
ESIS FILTERING
The ADAS1000-3/ADAS1000-4 do not include electrosurgical
interference suppression (ESIS) protection on chip. Any ESIS
protection required by the application requires external
components.
ECG PATH INPUT MULTIPLEXING
As shown in Figure 60, signal paths for numerous functions are
provided on each ECG channel (except respiration, which only
connects to the ECG1_LA, ECG2_LL, and ECG3_RA pins).
Note that the channel enable switch occurs after the RLD
amplifier connection, thus allowing the RLD to be connected
(redirected into any one of the ECG paths). The CM_IN path is
treated the same as the ECG signals.
Figure 58. Possible Defibrillation Protection on ECG Paths Using Neon Bulbs
Figure 59. Possible Defibrillation Protection on ECG Paths Using Diode Protection
Figure 60. Typical ECG Channel Input Multiplexing
ELECTRODE
PATIENT
CABLE
4kΩ
ECG1
500Ω 500Ω
ELECTRODE
PATIENT
CABLE
4kΩ
ECG2
RLD
22MΩ
1
22MΩ
1
ARGON/NEON
BULB
ARGON/NEON
BULB
1
OPTIONAL.
SP724
AVDD
SP724
AVDD
500Ω 500Ω
ADAS1000-3/
ADAS1000-4
10997-018
ELECTRODE
PATIENT
CABLE
4.5kΩ
ADAS1000-3/
ADAS1000-4
500Ω
ELECTRODE
PATIENT
CABLE
4.5kΩ
500Ω
RLD
22MΩ
1
22MΩ
1
AVDD
AVDD
1
OPTIONAL.
2
TWO SP724 CHANNELS PER ELECTRODE MAY PROVIDE BEST PROTECTION.
SP724
2
SP724
2
ECG1
ECG2
10997-019
INPUT AMPLIFIER
RLD AMP
DCLO
CURRENT
ACLO
CURRENT
RESPIRATION
INPUT
CALIBRATION
DAC
CHANNEL
ENABLE
ECG PIN
1.3V VCM_REF
+
–
TO CM
AVERAGING
FROM CM
AVERAGING
TO
FILTERING
ADAS1000-3/
ADAS1000-4
VCM
MUX FOR LEAD CONFIG,
COMMON ELECTRODE
+
–
10997-020