LTM8062EVPBF datasheet(10/20 Pages) LINER

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LTM8062

8062f

APPLICATIONS INFORMATION

Figure 3. Resistive Divider Sets Minimum VIN

Reverse Protection Diode

The LTM8062 integrates a high voltage power Schottky

diode to provide input reverse voltage protection. The

anode of this diode is connected to VINA, and the cathode

is connected to VIN. There is a small mount of capacitance

at each end; please see the Block Diagram.

Input Supply Voltage Regulation

The LTM8062 contains a voltage monitor pin that enables

programming a minimum operational voltage. Connect-

ing a resistor divider from VIN to the VINREG pin enables

programming of minimum input supply voltage, typically

used to program the peak power voltage for a solar panel.

Maximum charge current is reduced when the VINREG pin

is below the regulation threshold of 2.7V.

If the VINREG function is not used, and if the input supply

cannot provide enough power to satisfy the requirements

of an LTM8062 charger, the input supply voltage will col-

lapse. A minimum operating supply voltage can thus be

programmed by monitoring the supply through a resistor

divider, such that the desired minimum voltage corresponds

to 2.7V at the VINREG pin. The LTM8062 servos the maxi-

mum output charge current to maintain the voltage on

VINREG at or above 2.7V.

Programming of the desired minimum voltage is ac-

complished by connecting a resistor divider as shown in

Figure 3. The ratio of RIN1/RIN2 for a desired minimum

voltage (VIN(MIN)) is:

RIN1/RIN2 = (VIN(MIN)/2.7) – 1

If the voltage regulation feature is not used, connect the

VINREG pin to VIN.

VIN

VINREG

8062 F03

LTM8062

INPUT SUPPLY

RIN1

RIN2

For most applications, the design process is straight

forward, summarized as follows:

1. Look at Table 1 and find the row that has the desired

input voltage range and battery float voltage.

2. Apply the recommended CIN and RADJ values.

3. Connect BIAS as indicated.

While these component combinations have been tested

for proper operation, it is incumbent upon the user to

verify proper operation over the intended system’s line,

load and environmental conditions. Bear in mind that the

maximum output current is limited by junction tempera-

ture, the relationship between the input and output voltage

magnitude and polarity and other factors. Please refer to

the graphs in the Typical Performance Characteristics

section for guidance.

Table 1. Recommended Component Values and Configuration

(TA = 25°C)

VIN RANGE (V)* VBAT (V)

CIN

RADJ1

TOP

(kΩ)

RADJ2

BOTTOM

(kΩ)

6 to 32

3.6

4.7μF 1206 X7R 50V

274

2870

6 to 32

4.1

4.7μF 1206 X7R 50V

312

1260

6 to 32

4.2

4.7μF 1206 X7R 50V

320

1150

6.25 to 32

4.7

4.7μF 1206 X7R 50V

357

835

9.5 to 32

7.05

4.7μF 1206 X7R 50V

530

464

9.75 to 32

7.2

4.7μF 1206 X7R 50V

549

459

11 to 32

8.2

4.7μF 1206 X7R 50V

626

417

11.5 to 32

8.4

4.7μF 1206 X7R 50V

642

412

12.75 to 32

9.4

4.7μF 1206 X7R 50V

715

383

16.5 to 32

12.3

4.7μF 1206 X7R 50V

942

344

17 to 32

12.6

4.7μF 1206 X7R 50V

965

340

18.25 to 32

13.5

4.7μF 1206 X7R 50V

1020

328

19 to 32

14.08

4.7μF 1206 X7R 50V

1090

332

19.5 to 32

14.42

4.7μF 1206 X7R 50V

1110

328

* Input bulk capacitance is required.

VIN Input Supply

The LTM8062 is biased directly from the charger input sup-

ply through the VIN pin. This pin provides large switched

currents, so a high quality low ESR decoupling capacitor is

recommended to minimize voltage glitches on VIN. 4.7μF

is typically adequate for most charger applications.

BIAS Pin Considerations

The BIAS pin is used to provide drive power for the in-

ternal power switching stage and operate other internal

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