2

LT1270A/LT1270

SYMBOL

PARAMETER

CONDITIONS

MIN

TYP

MAX

UNITS

Reference Voltage

Measured at Feedback Pin

1.224

1.244

1.264

V

q

1.214

1.244

1.274

V

Feedback Input Current

350

750

nA

1100

nA

gm

Error Amplifier

3000

4400

6000

µmho

Transconductance

q

2400

7000

µmho

Error Amplifier Source of

150

200

350

µA

Sink Current

q

120

400

µA

Error Amplifier Clamp Voltage

1.80

2.30

V

0.25

0.38

0.52

V

Reference Voltage Line Regulation

3V

q

0.03

%/V

Error Amplifier Voltage Gain

0.9V

500

800

V/V

Minimum Input Voltage

q

2.8

3.0

V

Supply Current

3V

7

10

mA

Control Pin Threshold

Duty Cycle = 0

0.80

0.90

1.08

V

q

0.60

1.25

V

Normal/Flyback Threshold

0.40

0.45

0.54

V

on Feedback Pin

Flyback Reference Voltage

15.0

16.3

17.6

V

q

14.0

18.0

V

Change in Flyback Reference

0.05

4.5

6.8

8.5

V

Voltage

Flyback Reference Voltage

0.01

0.03

%/V

Line Regulation

3V

Flyback Amplifier

150

300

650

µmho

Transconductance (gm)

Flyback Amplifier Source

q

15

32

70

µA

and Sink Current

q

25

40

70

µA

BV

Output Switch Breakdown

3V

q

60

75

V

Voltage

Output Switch ON

0.12

0.18

Ω

Resistance (Note 1, 3)

0.22

Ω

Control Voltage to Switch

12

A/V

Current Transconductance

A

G

A

U

A

R

BSOLUTEXI

TI

S

Supply Voltage ....................................................... 30V

Switch Output Voltage ............................................ 60V

Feedback Pin Voltage (Transient, 1ms) ................

±15V

Operating Junction Temperature Range

LT1270AC/LT1270C (Oper.)................ 0

°C to 125°C

LT1270AC/LT1270C (Short-Ckt) ......... 0

°C to 140°C

Storage Temperature Range ................ – 65

°c to 150°C

Lead Temperature (Soldering, 10 sec)................ 300

°C

PACKAGE/ORDER I FOR ATIO

ORDER PART

NUMBER

LT1270CT

LT1270ACT

T PACKAGE

5-LEAD TO-220

GND

FB

FRONT VIEW

5

4

3

2

1