AIM AT1780 Datasheet

AT1780

640kHz/1.2MHz,Low-Noise Step-Up

Current-Mode PWM Controller

Preliminary

Features

• 1.8A,0.21Ω,14V Power MOSFET

• Operating input voltage:2.6V to 12V
to 14V

• Adjustable Output from V

• 640kHz /1.2MHz pin selectable switching

Frequency

• 0.1μA shutdown Current

• Built-in Soft-Start function

• Small 8-Pin μMax Package

IN

Applications

• LCD Displays

• Digital Cameras

•

Portable Applications

• Hand-Held Devices

Block Diagram

General Description

The AT1780 is a current-mode step-up DC/DC
converter with a 1.8A, 0.21Ω power MOSFET.

The soft-start function is programmed with an
external capacitor, which sets the input current
ramp rate. It is ideal for generating bias voltages
for LCD panels. Pin selectable frequency 640KHz
or 1.2MHz operation results in a low noise output
that is easy to filter and faster loop performance.
An external compensation pin provides the user
flexibility in determining loop dynamics, allowing
the use of small, low equivalent series resistance
(ESR) ceramic output capacitors.

.

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

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AT1780

640kHz/1.2MHz,Low-Noise Step-Up

Current-Mode PWM Controller

Pin Configuration

Preliminary

Ordering Information

Part number Package Marking

AT1780 8µMAX

Pin Description

Pin No. Symbol I/O Description

1 COMP - Compensation network connection.
2 FB I Output voltage feedback input
3 /SHDN I Shutdown control input, active low
4GND
5 LX O Switch Pin.
6VIN
7 FSLC I Frequency select input. Ground=640KHz, VIN=1.2MHz
8 SS — Soft-Start control pin.

Ground

-

Power supply pin.

-

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

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AT1780

640kHz/1.2MHz,Low-Noise Step-Up

Current-Mode PWM Controller

Absolute Maximum Ratings

Preliminary

Rated ValueParameter Condition

Unit

Min. Max.

LX to GND — -0.3 +14 V
IN, /SHDN, FREG, FB to GND — -0.3 +8 V
SS, COMP to GND — -0.3 VIN+0.3 V
RMS LX pin current — — 1.2 A

Continuous power dissipation

8pin μMAX（TA=+70℃）

Operating temperature — -30 +85
Junction temperature — — +150
Storage temperature — -40 +150
Lead temperature — — +300

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are

stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the

operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended

periods may affect device reliability.

—330 mW

0

C

0

C

0

C

0

C

Recommended Operating Conditions

(Ta=+250C)

Power supply voltage V
SS pin capacitance C
Phase compensation capacitance C
Phase compensation capacitance C
Phase compensation resistance R

Oscillation frequency

f
f

Operating temperature T

CC

PE

COMP1

COMP2

COMP

OSC1

OSC2

OP

Va lu esParameter Symbol

Min. Typ. Max.

2.5 -- 7

-- 0.033 --

-- 680 --

-- 20 --

-- 180 -- KΩ

540 708 740 kHz

1000 1220 1500 kHz

-30 +25 +85 °C

Unit

Ｖ

μＦ

pＦ
pＦ

2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C.
Tel: [phone] WWW: http://www.aimtron.com.tw
Fax: [phone] Email: [e-mail]

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