Analog Devices MAX30001G Manual page 20

MAX30001G Evaluation Kit
Powering the EV Kit
The MAX30001G EV kit can be powered from an external
supply or directly from the MAX32630FTHR. To use an
external supply, install a shunt on jumper J_EXT_PWR in
the 1-2 position. This connects the EXT_PWR test point
to the board's 5V rail. Set the power supply's output to
+5V, disable the output, connect the positive lead to EXT_
PWR and the negative to AGND1, then enable the supply.
To power the EV kit with the MAX32630FTHR, install a
shunt on jumper J_SYS in the 1-2 position to connect the
SYS node to the 5V rail. SYS regulates the USB voltage
or directly connects to the battery if present.
The MAX30001G IC receives power from OVDD, AVDD,
and DVDD. These pins receive power either through
the MAX32630FTHR, externally through test points, or
through adjustable LDOs U2 and U3. To supply the IC
from the MAX32630FTHR's 1.8V and 3.3V rails, place
a shunt in the 1-2 position on the 1V8 and 3V3 jumpers.
To use the onboard LDOs, place the shunts in the 2-3
position. Two potentiometers are available to set the U2
and U3 voltages: R4 and R10.
To operate the EV kit without a connection to a host
PC or power supply, insert a microSD card into the
MAX32630FTHR. After saving a test configuration, disconnect
the board from the host PC and connect a Li+ battery
to the MAX32630FTHR. Refer to the MAX32630FTHR
documentation for details on connecting a Li+ battery.
Press SW2 to trigger the measurements saved to the SD
card. The J_SYS shunt must be in the 1-2 position for this
configuration.
Configuring the Board for Measurement
The MAX30001G EV kit offers several potential connec-
tion and component configurations to enable a variety of
tests. Both the ECG channel and BioZ channel allow for
user-defined line resistance with resistors R26 and R27
for BioZ, and R29 and R30 for ECG. By default, these resis-
tors are populated with 0Ω shunts but can be changed to
suit the application. The board also allows for the instal-
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Evaluates: MAX30001G
lation of external low-pass filtering capacitors on the ECG
and BioZ lines. Capacitors C8 and C25 can create an
external common mode filter for the ECG and BioZ lines,
respectively. C24, C29, C26, and C28 filter ECGP, ECGN,
BIP, and BIN. The cutoff frequency of the filters is set by
the value of these capacitors and the input resistors R26,
R27, R29, and R30. The board also allows the ECGN and
ECGP or BIN and BIP inputs to be shorted with jumpers
EP_EN and BP_BN, respectively.
Refer to the MAX30001G EV kit schematic and
MAX30001G EV kit PCB layout sections for component
connections and placements.
ECG Measurement
The EV kit ships configured to measure ECG with
balanced electrodes, R-to-R, and BioZ signals. The jumper
configurations required for these measurements are
shown in Figure 17. Connected jumpers are distinguished
with solid black nodes in the jumper box. To use the
electrode connectors on the EV kit, ensure the required
shunts are installed.
By default, the EV kit leaves the ECG channel balanced.
By removing the shunts on EN_UNBAL And EP_UNBAL,
the ECGN and ECGP lines each include a 51kΩ resistor
and 47nF capacitor in parallel.
BioZ Measurement
Additionally, the EV kit includes a 100Ω resistor to verify
the BioZ configuration. Attach shunts on RP and RN to
connect the resistor to the BioZ inputs and shunts on
DP_BP and DN_BN to route the drive signal to the BioZ
channel. Figure 18 illustrates these connections.
Refer to the MAX30001G data sheet for details on configur-
ing a BioZ measurement. Note that the default setting of
the current generator is FMSTR/64 (about 500Hz) and the
BioZ channel has an internal high-pass filter with a default
500Hz cutoff frequency. In order to correctly measure the
100Ω resistor, bypass or lower the filter cutoff frequency
or increase the current generator frequency.
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