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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.
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.
Applications
* LCD Display * Portable equipment
Block Diagram
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 1
AT1743
2-Channel PWM Controller for LCD Display
Pin Configuration
Ordering Information
Part number AT1743 Package TSSOP16 Marking AT1743P -
Pin Description
Pin No. Symbol I/O Description
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16
CT RT NON1 INV1 FB1 DT1 OUT1 GND Vcc OUT2 DT2 FB2 INV2 NON2 SCP Vref
--I I O I O --O I O I I -O
External timing capacitor External timing resistor Positive input for error amplifier 1 Negative input for error amplifier 1 Error amplifier 1 output Output 1 dead time / soft start setting Output 1 Ground Power supply Output 2 Output 2 dead time / soft start setting Error amplifier 2 output Negative input for error amplifier 2 Positive input for error amplifier 2 Time latch setting Reference voltage output2.5V
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 2
AT1743
2-Channel PWM Controller for LCD Display
Absolute Maximum Ratings
(Ta=+250C)
Parameter Power supply voltage Power dissipation Operating temperture Storage temperture Output current Output voltage
2 Should not exceed Pd and values.
Symbol Vcc Pd Topr Tstg Io Vo
Limits 30 450*1 -30~+85 -55~+125 120*2 30
Unit V mW mA V
1 When mounted on 70mmx70mmx1.6mm glass epoxy board. Reduced by 6.5mw for each increase in Ta of 1 over 25.
Recommended Operating Conditions
(Ta=+250C)
Parameter Power supply voltage Output current Output voltage Error amplifier input voltage Timing capacitor Timing resistor Oscillator frequency
Symbol VCC Io Vo VOM CCT RRT FOSC Min. 3.6 --0.3 100 5.1 10
Values Typ. 6.0 ------Max. 25 100 25 1.6 15000 50 800
Unit mA V V pF k kHz
Timing chart
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 3
AT1743
2-Channel PWM Controller for LCD Display
Electrical Characteristics
Parameter Output voltage Input stability Load stability Oscillation frequency Frequency deviation Threshold voltage Standby voltage Latch voltage Source current Comparator threshold voltage Input threshold voltage fosc=10kHz On duty cycle Input bias current Latch mode source current Latch input voltage Threshold voltage Input offset voltage Input offset current Input bias current Open circuit gain Common-mode input voltage range Common-mode rejection ratio Maximum output voltage Minimum input voltage Output sink current Output source current Input threshold voltage fosc=10kHz Saturation voltage Leak current Standby current Average current consumption Symbol Vref VDL1 VDLO Fosc FDV VIT VSTB VLT ISCP VCT Vt0 Vt100 DON IBDT IDT VDT VUT VIO IIO IIB AV VOM CMRR VOH VOL IOI IOO Vt0 Vt100 VSAT IREAK ICCS ICCA
(unless otherwise noted, Ta=25, and Vcc=6V )
Condition
Values Max.
Unit 2.53 V 10 mV 10 mV 480 kHz -% 1.80 V 100 mV 100 mV 3.5 A 1.2 V V V % A A V V mV nA nA dB V dB V
Reference voltage block Triangular wave oscillator
Protection circuit
Min. Typ. Iref=1mA 2.48 2.5 Vcc=3.6~25V -1 Iref=0~5mA -1 RRT=10k, CCT=220pF 320 400 Vcc=3.6~25V -1 -1.48 1.64 No pull up -50 No pull up -30 -1.5 2.5 Pin 5, Pin 12 Duty cycle=0% Duty cycle=100% Divide Vref using 13 k and 27 k DT1, DT2=2.0V DT1, DT2=0V IDT=40A -----Vcc=3.6~25V ---FB=1.25V FB=1.25V Duty cycle=0% Duty cycle=100% Io=75mA Vo=25V When output is off RRT=10 k 0.9 1.05
1.79 1.97 2.15 1.32 1.48 1.64 45 -200 55 0.1 560 65 1 ---6 30 100 -1.6 ---
Rest period adjustment circuit
2.28 2.48 ----70 0.3 60 2.3 2.53 --15 85 -80 2.5
Low-voltage input miss-operation prevention circuit
Error amplifier
PWM comparator Output block Total device
-0.7 0.9 V 3 20 -mA 45 75 -- A 1.79 1.97 2.15 V 1.32 1.48 1.64 V -0.8 1.2 V A -0 5 -1.3 1.8 mA -1.6 2.3 mA
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 4
AT1743
2-Channel PWM Controller for LCD Display
Timing Curve
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 5
AT1743
2-Channel PWM Controller for LCD Display
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 6
AT1743
2-Channel PWM Controller for LCD Display
Application Circuit: Step-Down converter
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 7
AT1743
2-Channel PWM Controller for LCD Display
Package Outline 16-pin TSSOP
SYMBOL A A1 A2 b C D E E1 L e y
MILLIMETERS MIN TYP MAX 1.05 1.10 1.20 0.05 0.10 0.15 1.00 1.05 0.20 0.25 0.28 0.127 4.90 5.075 5.10 6.20 6.40 6.60 4.30 4.40 4.50 0.50 0.60 0.70 0.65 0.076 0 8
MIN 0.041 0.002 0.008 0.193 0.244 0.170 0.020 0
INCHES TYP 0.043 0.004 0.039 0.010 0.005 0.1998 0.252 0.173 0.024 0.026 -
MAX 0.047 0.006 0.041 0.011 0.200 0.260 0.177 0.028 0.003 8
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 8
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(180C to peak) 5C/second max. 120 seconds max. Preheat Temperature(12520C) 10~150 seconds Temperature maintained above 180C Time within 5C of actual Peak 10~20 seconds Temperature Peak Temperature Range(Note 1) 219~225C or 235~240C Cooling Rate 6C /second max. 6 minutes max. Time 25C to Peak Temperature
VPR
10C/second max.
60 seconds 219~225C or 235~240C 10C/second max.
*1 The maximum peak temperatures for IR and VP reflow are depending on package dimensions.
Package Reflow Conditions Pkg. Thickness 2.5mm Pkg. Thickness <2.5mm Pkg. Thickness <2.5mm and and and all bags Pkg. Volume 350 mm3 Pkg. Volume <350 mm3 Convection 219~225C VPR 219~225C IR/Convection 219~225C Convection 235~240C VPR 235~240C IR/Convection 235~240C
2F, No.10, Prosperity RD. II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 WWW: http://www.aimtron.com.tw Fax: 886-3-563-0879 Email: service@aimtron.com.tw 9

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