MAX77751

3.15A USB-C Autonomous Charger

for 1-Cell Li+ Batteries

www.maximintegrated.com

Maxim Integrated | 37

Inductor Selection

The MAX77751's control scheme requires an external inductor from 0.47μH to 1μH for proper operation.

Table 6. Recommended Inductors

MANUFACTURER

PART NUMBER

INDUCTANCE

(μH)

(A)

(A)

DCR(TYP)

(mΩ)

SIZE (L x W x T)

(mm)

SEMCO

CIGT252008LMR47MNE

0.47

5.5

4.5

24

2.5 x 2.0 x 0.8

SEMCO

CIGT252010LMR47MNE

0.47

6

4.5

24

2.5 x 2.0 x 1.0

SEMCO

CIGT201610EHR47MNE

0.47

5.9

5

18

2.0 x 1.6 x 1.0

CYNTEC

HTGH25201T-R47MSR-68

0.47

6.6

5.6

16.5

2.5 x 2.0 x 1.0

Charger Status Outputs

Input Status (INOKB)

INOKB is an open-drain and active low output that indicates the input status. If a valid input source is inserted and the

buck converter starts switching, INOKB pulls low. When the reverse boost is enabled, INOKB pulls low to indicate 5V

output from CHGIN.

INOKB can be used as a logic output for the system processor by adding a 200kΩ pullup resistor to the system IO voltage.

INOKB can also be used as an LED indicator driver by adding a current limit resistor and an LED to SYS.

Charging Status Output (STAT)

STAT is an open-drain and active low output that indicates charge status. Table 7 shows the STAT status changes.

Table 7. STAT Output Per Charging Status

CHARGING STATUS

STAT

LOGIC STATE

CHARGE STATUS LED

No input

High impedance

High

Off

Trickle, precharge, fast

charge

Repeat low and high impedance

with 1Hz, 50% duty cycle

After an external diode and a

capacitor rectifier, high

Blinking with 1Hz, 50% duty

cycle.

Top-off and done

Low

Low

Solid on

Faults

High impedance

High

Off

STAT can be used as a logic output for the system processor by adding a

200kΩ pullup resistor to the system IO voltage

and a rectifier (a diode and a capacitor).

STAT also can be used as an LED indicator driver by adding a current limit resistor and an LED to SYS.