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LT1680

High Power DC/DC

Step-Up Controller

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High Voltage: Operation Up to 60V Max

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High Current: N-Channel Drive Handles Up to

10,000pF Gate Capacitance

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Programmable Average Current Limiting

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5V Reference Output with 10mA External

Loading Capability

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Fixed Frequency Current Mode Operation

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Oscillator Synchronizable Up to 200kHz

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Undervoltage Lockout with Hysteresis

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Programmable Start Inhibit for Power Supply

Sequencing and Protection

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User Adjustable Slope Compensation

FEATURES

The LT

power supply controller optimized for boost topologies.

The IC drives N-channel MOSFET switches for DC/DC

converters in applications up to 60V input. A high current

gate drive output handles up to 10,000pF gate capaci-

tance, enabling the construction of high power DC/DC

converters. Current sense common mode range up to 60V

allows current sensing to be referenced to the input

supply, eliminating the need for sense blanking circuits.

The LT1680 incorporates programmable average current

limiting allowing accurate limiting of DC current in the

magnetics, independent of ripple current . User adjustable

slope compensation provides stable operation at duty

cycles up to 90%.

The LT1680 operating frequency is programmable and

can be synchronized up to 200kHz. Minimum off-time

operation provides switch protection. The IC also incorpo-

rates a soft start feature that is gated by both shutdown

and undervoltage lockout conditions.

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High Power Single Board Systems

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Distributed Power Converters

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Industrial Control Systems

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Lead-Acid Battery Back-Up Systems

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Automotive and Heavy Equipment

, LTC and LT are registered trademarks of Linear Technology Corporation.

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3

4

5

6

7

8

16

15

14

13

12

11

10

9

SL/ADJ

SS

SGND

SYNC

GATE

PGND

RUN/SHDN

+

LT1680

MBR0520

15k

R7

2k

1N914

1nF

C3 2.2nF

C4 0.22

µF

C2

1

µF

C11 1nF

1680 TA01

C6 0.1

µF

R6

75k

R9

100k

C12

1

µF

M1

IRFZ44

×3

D1

MBR20100CT

×2

+

680

µF

25V

×4

680

µF

63V

×3

48V

5.2A

L1

25

µH

0.005

Ω

10V TO 15V

24A (DC)

+

L1: Kool M

Kool M

µ IS A REGISTERED TRADEMARK OF MAGNETICS, INC.

12V to 48V, 250W Boost

OUTPUT POWER (W)

0

90

95

100

200

1680 TA02

85

80

75

50

100

150

250

Efficiency vs Output Power