ISL78208 Datasheet, PDF(3/25 Page) Intersil Corporation – Wide VIN Dual Standard Buck Regulator with 3A/3A Continuous Output Current

English

English German Russian Spanish Italian Polish Chinese Japanese Korean French Portuguese	Language :

ISL78208 Datasheet, PDF (3/25 Pages) Intersil Corporation – Wide VIN Dual Standard Buck Regulator with 3A/3A Continuous Output Current

◁

Pin Configuration

ISL78208

(32 LD WFQFN)

TOP VIEW

32 31 30 29 28 27 26 25

FB1 1

SS1 2

PGND1 3

NC1 4

BOOT1 5

PHASE1 6

PHASE1 7

NC2 8

24 FB2

23 SS2

22 PGND2

21 NC5

20 BOOT2

19 PHASE2

18 PHASE2

17 NC4

9 10 11 12 13 14 15 16

Pin Descriptions

PIN NUMBER

25, 32

1, 24

2, 23

3, 22

5, 20

6, 7, 18, 19

9, 10, 15, 16

11, 13

SYMBOL

COMP2, COMP1

FB1, FB2

SS1, SS2

PGND1, PGND2

BOOT1, BOOT2

PHASE1, PHASE2

VIN1, VIN2

EN1, EN2

PIN DESCRIPTION

COMP1/COMP2 is the output of the error amplifier.

Feedback pin for the regulator. FB is the negative input to the voltage loop error amplifier. COMP is the

output of the error amplifier. The output voltage is set by an external resistor divider connected to FB.

In addition, the PWM regulatorâs power-good and undervoltage protection circuits use FB1/2 to monitor the

regulator output voltage.

Soft-Start pins for each controller. The SS1/2 pins control the soft-start and sequence of their respective

outputs. A single capacitor from the SS pin to ground determines the output ramp rate. See the âOutput

Tracking and Sequencingâ on page 15 for soft-start and output tracking/sequencing details. If SS pins are

tied to VCC, an internal soft-start of 2ms will be used. Maximum CSS value is 50nF.

Power ground connections. Connect directly to the system GND plane.

Floating bootstrap supply pin for the power MOSFET gate driver. The bootstrap capacitor provides the

necessary charge to turn on the internal N-Channel MOSFET. Connect an external capacitor from this pin to

PHASE.

Switch node output. It connects the source of the internal power MOSFET with the external output inductor

and with the cathode of the external diode.

The input supply for the power stage of the PWM regulator and the source for the internal linear regulator

that provides bias for the IC. Place a minimum of 10ÂµF ceramic capacitance from each VIN to GND and

close to the IC for decoupling.

PWM controllerâs enable inputs. The PWM controllers are held off when the pin is pulled to ground. When

the voltage on this pin rises above 2V, the PWM controller is enabled. If EN1, EN2 pins are driven by an

external signal, the minimum off-time for EN1, EN2 should be:

EN_T_off (Î¼s) = 10Î¼s â¢ CSS â 2.2nF

where CSS is the soft-start pin capacitor (nF). ISL78208 does not have debouncing to EN1, EN2 external

signals.

FN8354.0

July 12, 2013

▷