Datasheet

Vref
+Vs
+Vs
Vref
+Vs
Vref
+Vs
+Vs
RG1 6.1k
RG2 6.1k
R3 10k
R7 52k
C4 47n
R4 52k
C2 47n
Rprot1 100k
C5 33p
Rprot2 100k
C7 33p
R12 500k
C10 1u
+
-
+
U1 OPA333
Rprot3 100k
R5 10M
R6 10k
C11 1n
R_RLD 52k
C_RLD 47n
+
ECG_RA
+
ECG_LA
Vout
C6 1n
R1 1M
R9 1M
V1 5
-
+
+
U2 OPA2314
-
+
+
U3 OPA2314
ECGp
ECGn
+
+
-
Rg
Rg
Ref
U4 INA826
RA Electrode
LA Electrode
RL Electrode
INA826
www.ti.com SBOS562E –AUGUST 2011–REVISED APRIL 2013
Figure 67 is an example of a LEAD I ECG circuit. The input signals come from leads attached to the right arm
(RA) and left arm (LA). These signals are simulated with the circuitry in the corresponding boxes. Protection
resistors (R
PROT1
and R
PROT2
) and filtering are also provided. The OPA333 is used as an integrator to remove the
gained-up dc offsets and servo the INA826 outputs to V
REF
. Finally, the right leg drive is biased to a potential
(+V
S
/2) and it inverts and amplifies the average common-mode signal back into the patient's right leg. This
architecture reduces the 50-/60-Hz noise pickup. Click the following link to download the TINA-TI file: ECG
Circuit.
Figure 67. ECG Circuit
Copyright © 2011–2013, Texas Instruments Incorporated Submit Documentation Feedback 27
Product Folder Links: INA826