Datasheet AT1743 Datasheet (AIM)

AT1743

2-Channel PWM Controller for LCD Display

Features

• High-accuracy reference voltage circuit (±1%).

• Built-in short-circuit protection circuit.

• Built-in Undervoltage Lockout protection.

• Internal 2.5V Reference supply.

• Variable Dead time provides control over total
Range.

Applications

• LCD Display

• Portable equipment

Block Diagram

General Description

The AT1743 is 2-channel PWM switching
regulator controllers that contains an on-chip 2.5V
reference, two error amplifier, an adjustable
oscillator, two dead-time comparators, under­voltage lockout circuitry and 2 common-emitter
output. It is idea for step-up, step-down, and
inverting converter.

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]

1

AT1743

2-Channel PWM Controller for LCD Display

Pin Configuration

Ordering Information

Part number Package Marking

AT1743 TSSOP16 AT1743P

---

Pin Description

Pin No. Symbol I/O Description

1 CT -- External timing capacitor
2 RT -- External timing resistor
3 NON1 I Positive input for error amplifier 1
4 INV1 I Negative input for error amplifier 1
5 FB1 O Error amplifier 1 output
6 DT1 I Output 1 dead time / soft start setting
7 OUT1 O Output 1
8 GND -- Ground

9 Vcc -- Power supply
10 OUT2 O Output 2
11 DT2 I Output 2 dead time / soft start setting
12 FB2 O Error amplifier 2 output
13 INV2 I Negative input for error amplifier 2
14 NON2 I Positive input for error amplifier 2
15 SCP -- Time latch setting
16 Vref O

Reference voltage output（2.5V）

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]

2

AT1743

2-Channel PWM Controller for LCD Display

Absolute Maximum Ratings

(Ta=+250C)

Parameter Symbol

Power supply voltage Vcc 30 V
Power dissipation Pd 450*
Operating temperture Topr -30~+85

Storage temperture Tstg -55~+125
Output current Io 120*

Output voltage Vo 30

＊1 When mounted on 70mm×70mm×1.6mm glass epoxy board. Reduced by 6.5mw for each increase in Ta of 1℃ over 25℃.
＊2 Should not exceed Pd and values.

Limits

Unit

1

mW

℃
℃

2

mA

V

Recommended Operating Conditions

(Ta=+250C)

Va lu esParameter Symbol

Min. Typ. Max.

Power supply voltage V

CC

3.6 6.0 25

Output current Io -- -- 100 mA
Output voltage Vo -- -- 25 V
Error amplifier input voltage V
Timing capacitor C
Timing resistor
Oscillator frequency F

OM

CT

R

RT

OSC

0.3 -- 1.6 V

100 -- 15000 pF

5.1 -- 50
10 -- 800 kHz

Unit

Ｖ

kΩ

Timing chart

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]

3

AT1743

2-Channel PWM Controller for LCD Display

Electrical Characteristics (unless otherwise noted, Ta=25℃, and Vcc=6V )

Va lu esParameter Symbol Condition

Min. Typ. Max.

Reference voltage
block

Triangular wave
oscillator

Protection circuit

Rest period
adjustment circuit

Low-voltage input
miss-operation
prevention circuit

Error amplifier

PWM comparator

Output block

Total device

Output voltage Vref
Input stability V

Load stability V
Oscillation frequency Fosc
Frequency deviation F
Threshold voltage V
Standby voltage V
Latch voltage V
Source current I
Comparator threshold

voltage

V

Input threshold voltage
（fosc=10kHz）

V

On duty cycle D

Input bias current I
Latch mode source

current
Latch input voltage V

Threshold voltage V

Input offset voltage V
Input offset current I
Input bias current I
Open circuit gain AV -- 70 85 -- dB
Common-mode input

voltage range
Common-mode

rejection ratio
Maximum output

voltage

V

CMRR -- 60 80 -- dB

V

Minimum input voltage V
Output sink current I
Output source current I
Input threshold voltage

（fosc=10kHz）

V
Saturation voltage V
Leak current I

REAK

Standby current I
Average current
consumption

I

Iref=1mA

Vcc=3.6~25V -- 1 10 mV

DL1

Iref=0~5mA

DLO

R

=10kΩ, CCT=220pF

RT

Vcc=3.6~25V -- 1 -- %

DV

IT

No pull up -- 50 100 mV

STB

No pull up -- 30 100 mV

LT

SCP

Pin 5, Pin 12 0.9 1.05 1.2 V

CT

Duty cycle=0%

V

t0

Duty cycle=100% 1.32 1.48 1.64 V

t100

-- 1.48 1.64 1.80 V

--

Divide Vref using 13

ON

kΩ and 27 kΩ
DT1, DT2=2.0V

BDT

DT1, DT2=0V 200 560 --

I

DT

IDT=40μA

DT

UT

IO

IO

IB

Vcc=3.6~25V 0.3 -- 1.6 V

OM

OH

OL

FB=1.25V 3 20 -- mA

OI

FB=1.25V

OO

V

Duty cycle=0% 1.79 1.97 2.15 V

t0

Duty cycle=100%

t100

Io=75mA -- 0.8 1.2 V

SAT

-- -- 2.53 -- V

-- -- -- 6 mV

-- -- -- 30 nA

-- -- 15 100 nA

-- 2.3 2.5 -- V

-- -- 0.7 0.9 V

Vo=25V
When output is off -- 1.3 1.8 mA

CCS

RRT=10 kΩ

CCA

2.48 2.5 2.53 V

-- 1 10 mV

320 400 480 kHz

1.5 2.5 3.5

1.79 1.97 2.15 V

45 55 65 %

-- 0.1 1

2.28 2.48 -- V

45 75 --

1.32 1.48 1.64 V

-- 0 5

-- 1.6 2.3 mA

Unit

μA

μA

μA

μA

μA

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]

4

2-Channel PWM Controller for LCD Display

Timing Curve

AT1743

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]

5

2-Channel PWM Controller for LCD Display

AT1743

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]

6

2-Channel PWM Controller for LCD Display

Application Circuit: Step-Down converter

AT1743

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]

7

AT1743

2-Channel PWM Controller for LCD Display

Package Outline 16-pin TSSOP

SYMBOL

MILLIMETERS INCHES

MIN TYP MAX MIN TYP MAX

A 1.05 1.10 1.20 0.041 0.043 0.047
A1 0.05 0.10 0.15 0.002 0.004 0.006
A2 - 1.00 1.05 - 0.039 0.041

b 0.20 0.25 0.28 0.008 0.010 0.011
C - 0.127 - - 0.005 ­D 4.90 5.075 5.10 0.193 0.1998 0.200
E 6.20 6.40 6.60 0.244 0.252 0.260

E1 4.30 4.40 4.50 0.170 0.173 0.177

L 0.50 0.60 0.70 0.020 0.024 0.028

e - 0.65 - - 0.026 -

y - - 0.076 - - 0.003

θ 0° 8° 0° 8°

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]

8

C

AT1743

2-Channel PWM Controller for LCD Display

Reflow Condition (IR/Convection or VPR Reflow)

Reference JEDEC Standard J-STD-020A

Classification Reflow Profiles

Convection or

IR/Convction

Average Heating Rate(180°C to peak) 5°C/second max. 10°C/second max.
Preheat Temperature(125±20°C)
Temperature maintained above 180°C
Time within 5°C of actual Peak

Temperature
Peak Temperature Range(Note 1)

Cooling Rate
Time 25°C to Peak Temperature

*1 The maximum peak temperatures for IR and VP reflow are depending on package dimensions.

120 seconds max.
10~150 seconds
10~20 seconds 60 seconds

219~225°C or
235~240°C
6°C /second max. 10°C/second max.
6 minutes max.

219~225°C or
235~240°C

Package Reflow Conditions

Pkg. Thickness ≥2.5mm
and all bags

Convection 219~225
VPR 219~225

°C

IR/Convection 219~225

°C

°C

Pkg. Thickness <2.5mm
and

Pkg. Volume ≥350 mm

Pkg. Thickness <2.5mm
and

3

Pkg. Volume <350 mm

Convection 235~240
VPR 235~240
IR/Convection 235~240

VPR

3

°C

°C

°

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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