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ADAS1000/ADAS1000-1/ADAS1000-2

Data Sheet

Rev. A | Page 28 of 80

ECG INPUTS—ELECTRODES/LEADS

The ADAS1000/ADAS1000-1/ADAS1000-2 ECG product

consists of 5 ECG inputs and a reference drive, RLD (right leg

drive). In a typical 5-lead/vector application, four of the ECG

inputs (ECG3_RA, ECG1_LA, ECG2_LL, ECG4_V1) would

be used in addition to the RLD path. This leaves one spare

ECG path (which could be used for other purposes, such as

calibration or temperature measurement). Both V1 and V2

input channels can be used for alternative measurements if

desired. When used in this way, the negative terminal of the

input stage can be switched to the fixed internal VCM_REF =

1.3 V; see details in Table 48.

In a 5-lead system, the ADAS1000/ADAS1000-1/ADAS1000-2

can provide Lead I, Lead II, and Lead III data or electrode data

directly via the serial interface at all frame rates. The other ECG

leads can be calculated by the user’s software from either the

lead data or the electrode data provided by the ADAS1000/

ADAS1000-1/ADAS1000-2. Note that in 128 kHz data rate, lead

data is only available when configured in analog lead mode as

shown in Figure 57. Digital lead mode is not available for this

data rate.

A 12-lead (10-electrode) system can be achieved using one

ADAS1000 or ADAS1000-1 device ganged together with one

ADAS1000-2 slave device as described in the Gang Mode

Operation section. Here, 9 ECG electrodes and one RLD

electrode achieve the 10 electrode system, again leaving one

spare ECG channel that could be used for alternate purposes as

suggested previously. In such a system, having nine dedicated

electrodes benefits the user by delivering lead information

based on electrode measurements and calculations rather

than deriving leads from other lead measurements.

Table 10 outlines the calculation of the leads (vector) from the

individual electrode measurements.

Table 10. Lead Composition1

Lead Name

Composition

Equivalent

ADAS1000 or ADAS1000-1

LA – RA

LL – RA

III

LL – LA

aVR2

RA – 0.5 × (LA + LL)

−0.5 × (I + II)

aVL2

LA – 0.5 × (LL + RA)

0.5 × (I − III)

aVF2

LL – 0.5 × (LA + RA)

0.5 × (II + III)

V1’

V1 – 0.333 × (LA + RA + LL)

V2’

V2 – 0.333 × (LA + RA + LL)

12 Leads Achieved by Adding ADAS1000-2 Slave

V3’

V3 – 0.333 × (LA + RA + LL)

V4’

V4 – 0.333 × (LA + RA + LL)

V5’

V5 – 0.333 × (LA + RA + LL)

V6’

V6 – 0.333 × (LA + RA + LL)

These lead compositions apply when the master ADAS1000 device is configured into lead mode (analog lead mode or digital lead mode) with VCM = WCT = (RA + LA

+ LL)/3. When configured for 12-lead operation with a master and slave device, the VCM signal derived on the master device (CM_OUT) is applied to the CM_IN of the

slave device. For correct operation of the slave device, the device must be configured in electrode mode (see the FRMCTL register in Table 35).

These augmented leads are not calculated within the ADAS1000, but can be derived in the host DSP/microcontroller/FPGA.

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