MAX8743 Ver la hoja de datos (PDF) - Maxim Integrated

Número de pieza

componentes Descripción

Fabricante

MAX8743

Dual, High-Efficiency, Step-Down Controller with High Impedance in Shutdown

Maxim Integrated 

Dual, High-Efficiency, Step-Down

Controller with High Impedance in Shutdown

Typical Operating Characteristics (continued)

(Circuit of Figure 1, components from Table 1, VIN = 15V, SKIP = GND, TON = unconnected, TA = +25°C, unless otherwise noted.)

LOAD-TRANSIENT RESPONSE

(8A COMPONENTS, PWM MODE, VOUT1 = 1.8V)

MAX8743 toc12

STARTUP WAVEFORM (VOUT2)

MAX8743 toc13

2.5V ROUT2 = 2.5Ω

VOUT2

1V/div

2.5V

20µs/div

VOUT1

100mV/div 0V

0A

IOUT1

5A/div

0V

0V

400µs/div

ILX2

0V

1A/div

0V

ON2

5V/div

PGOOD 0V

5V/div

0V

SHUTDOWN WAVEFORM (VOUT2)

MAX8743 toc14

ROUT2 = 2.5Ω

VOUT2

1V/div

400µs/div

DL2

5V/div

ON2

5V/div

PGOOD

5V/div

Pin Description

PIN

QSOP TQFN

1

32

2

33

3

34

4

35

5

1

6

2

NAME

FUNCTION

OUT1

FB1

ILIM1

V+

TON

SKIP

Output Voltage Connection for the OUT1 PWM. Connect directly to the junction of the external

inductor and output filter capacitors. OUT1 senses the output voltage to determine the on-time

and also serves as the feedback input in fixed-output modes.

Feedback Input for OUT1. Connect to GND for 1.8V fixed output or to VCC for 1.5V fixed output, or

connect to a resistor-divider network from OUT1 for an adjustable output between 1V and 5.5V.

Current-Limit Threshold Adjustment for OUT1. The current-limit threshold at CS1 is 0.1 times the

voltage at ILIM1. Connect a resistor-divider network from REF to set the current-limit threshold

between 25mV and 250mV (with 0.25V to 2.5V at ILIM). Connect to VCC to assert 50mV default

current-limit threshold.

Battery Voltage-Sense Connection. Connect to input power source. V+ is only used to adjust the

DH_ on-time for pseudofixed-frequency operation.

On-Time Selection Control Input. This four-level input pin sets the DH_ on-time to determine the

operating frequency.

TON

FREQUENCY (OUT1) (kHz)

FREQUENCY (OUT2) (kHz)

AGND

620

460

REF

485

355

Open

345

255

VCC

235

170

Pulse-Skipping Control Input. Connect to VCC for low-noise forced-PWM mode. Connect to AGND

to enable pulse-skipping operation.

8 _______________________________________________________________________________________

Share Link: