LT1170 View Datasheet(PDF) - Linear Technology

Part Name

Description

View to exact match

LT1170

100kHz, 5A, 2.5A and 1.25A High Efficiency Switching Regulators

Linear Technology 

LT1170/LT1171/LT1172

TYPICAL APPLICATIO S (Note that maximum output currents are divided by 2 for LT1171, by 4 for LT1172.)

Driving High Voltage FET

(for Off-Line Applications, See AN25)

+

10V TO

20V

VIN

VSW

LT1170

G

D

Q1

D1

GND

1170/1/2 TA05

Negative-to-Positive Buck-Boost Converter†

External Current Limit

VX

R2

R1

500Ω

≈ 2V

D1

LT1170

GND

VC

1170/1/2 TA06

External Current Limit

L1**

50µH

L2

OPTIONAL

C3

OUTPUT

FILTER

+

C4*

100µF

OPTIONAL

INPUT FILTER

L3

VIN

VSW

LT1170

FB

GND

VC

R3

2.2k

D1

+

C2

1000µF

VOUT

12V

R1 2A

11.3k

Q1

R2

1.24k

VIN

–20V

C1

0.22µF

* REQUIRED IF INPUT LEADS ≥ 2"

** PULSE ENGINEERING 92114, COILTRONICS 50-2-52

† THIS CIRCUIT IS OFTEN USED TO CONVERT –48V TO 5V. TO GUARANTEE

FULL SHORT-CIRCUIT PROTECTION, THE CURRENT LIMIT CIRCUIT SHOWN

IN AN19, FIGURE 39, SHOULD BE ADDED WITH C1 REDUCED TO 200pF.

1170/1/2 TA07

Negative Buck Converter

VIN

VSW

+

– VIN

LT1170

FB

GND

VC

R1

1k

Q1

C1

1000pF

RS

NOTE THAT THE LT1170

GND PIN IS NO LONGER

COMMON TO VIN–.

R2

C2

1170/1/2 TA08

* REQUIRED IF INPUT LEADS ≥ 2"

** PULSE ENGINEERING 92114

COILTRONICS 50-2-52

+

C3*

100µF

OPTIONAL

INPUT FILTER

L3

VIN

–20V

VIN

VSW

LT1170

FB

GND

VC

C1

R3

+

D1

L1**

50µH

C2

1000µF

R1

4.64k

R4

Q1

12k

2N3906

LOAD

–5.2V

4.5A

R2

1.24k

OPTIONAL +

OUTPUT

FILTER

C4

200µF

L2

4µH

1170/1/2 TA09

11

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