LTC3633A-2/LTC3633A-3

1

3633a23f

Load Transient Response

Continuous Operation

TSSOP Packages

TYPICAL APPLICATION

DESCRIPTION

Dual Channel 3A, 20V

Monolithic Synchronous

Step-Down Regulator

lithicsynchronousbuckregulatorusingacontrolledon-time,

current mode architecture, with phase lockable switching

frequency. The two channels can run 180° out of phase to

relax the requirements for input and output capacitance. The

operating supply voltage range is from 3.6V to 20V, making

it suitable for lithium-ion battery stacks as well as point of

load power supply applications from a 12V or 5V supply.

The operating frequency is programmable from 500kHz to

4MHz with an external resistor and may be synchronized

to an external clock signal. The high frequency capabil-

ity allows the use of small surface mount inductors and

capacitors. The unique constant frequency/controlled on-

time architecture is ideal for high step-down ratio applica-

tions that operate at high frequency while demanding fast

transient response. An internal phase locked loop servos

the on-time of the internal one-shot timer to match the

frequency of the internal clock or an applied external clock.

The LTC3633A-2 can select between forced continuous

mode and high efficiency Burst Mode operation. The

LTC3633A-2 and LTC3633A-3 differ in their output volt-

age sense range (refer to Table 1 in the Operation section

for a description of the entire LTC3633A product family).

FEATURES

APPLICATIONS

Efficiency vs Load Current

L, LT, LTC, LTM, Burst Mode, Linear Technology and the Linear logo are registered trademarks of

Linear Technology Corporation. All other trademarks are the property of their respective owners.

Protected by U.S. Patents including 5481178, 5847554, 6580258, 6304066, 6476589, 6774611.

0.001

0

10

30

40

50

70

0.1

10

3633a23 TA01b

20

80

100

90

60

0.01

1

LOAD CURRENT (A)

Burst Mode

OPERATION

RUN1

RUN2

TRACKSS2

PGOOD2

LTC3633A-2

BOOST2

0.1μF

1.5μH

73.2k

10k

SW2

PGND

SGND

PHMODE

TRACKSS1

PGOOD1

BOOST1

SW1

22μF

5V AT 3A

0.1μF

1μH

45.3k

10k

22μF

3.3V AT 3A

6V TO 20V

47μF

x2

MODE/SYNC

RT

ITH1

ITH2

2.2μF

3633a23 TA01a