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Evaluates: MAX77650/MAX77651

MAX77650/MAX77651 Evaluation Kit

EV Kit Features

On-Key Options

For applications that require the IC to enable with a user-

interactable switch, the EV kit comes with two common

types: the push-button (momentary) and the slide-switch

(persistent). The active-low enable pin (nEN) has an

external pullup resistor R2. Select which type of switch to

use with jumper J5. Refer to the MAX77650/MAX77651

data sheet for more information on configuring the IC for

momentary or persistent switches.

Temperature Monitoring

Jumper J7 allows selection between the following tem-

perature monitoring options:

1) Potentiometer R12 (Connect pins 1 and 2)

2) Fixed resistor divider R13 (Connect pins 1 and 4)

3) 3380K negative temperature coefficient thermistor

(NTC) RT1 (Connect pins 1 and 3)

Use the potentiometer setting (pin 1 and 2) to simulate

changing temperature to evaluate the charger’s JEITA

safe charging response. Turn the potentiometer knob

counterclockwise to simulate increasing battery tem-

perature. Turn the knob clockwise to simulate decreasing

temperature. Use the resistor setting (pin 1 and 4) to set

a static temperature (25°C). Use the thermistor setting

(pin 1 and 3) to evaluate the charger’s response to actual

EVK temperature. The NTC beta parameter is 3380K.

Temperature thresholds corresponding to this NTC beta

are listed in Table 2.

The MAX77650/MAX77651 automatically biases the tem-

perature monitoring circuit whenever CHGIN is valid

and the thermistor is enabled (THM_EN = 1), or the

MUX_SEL[3:0] bitfield is connecting the THM or TBIAS

pins to the AMUX output (MUX_SEL = 0b0111 or 0b1000).

Refer to the Adjustable Thermistor Temperature Monitors

section of the MAX77650/MAX77651 data sheet for more

information.

Battery Ammeter

The EV kit comes with an on-board ammeter for users to

measure battery current with selectable 6mA or 600mA

range. The battery current sense resistor voltage is ampli-

fied with an op-amp and then converted with an ADC. The

GUI reads the ADC value and displays the corresponding

current measurement. There is a removable jumper J208

(default installed, near the Li+ battery connector J9) that

shorts the negative terminal of the battery to GND. To

use the on-board battery ammeter, remove jumper J208

and select the desirable ammeter range (6mA or 600mA)

in the AMUX/ADC tab of the GUI. Reinstall jumper J208

when not using the on-board battery ammeter. See the

Software section for where to read the current value on

the GUI.

Table 2. Trip Thresholds for 3380K Beta

Thermistor

TRIP VOLTAGE (V)

TRIP TEMPERATURES (°C)

1.024

-10

0.976

-5

0.923

0.867

0.807

0.747

0.511

0.459

0.411

0.367

0.327

0.291

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