AT1780 AT1780M - Datasheet Archive

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Features General Description ·

AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Features General Description · 1.8A,0.21,14V Power MOSFET · Operating input voltage:2.6V to 12V · Adjustable Output from VIN to 14V · 640kHz /1.2MHz pin selectable switching Frequency · 0.1A shutdown Current · Built-in Soft-Start function · Small 8-Pin MSOP Package The AT1780 AT1780 is a current-mode step-up DC/DC converter with a 1.8A, 0.21 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. Applications · LCD Displays · Digital Cameras · Portable Applications · Hand-Held Devices . Block Diagram Aimtron reserves the right without notice to change this circuitry and specifications. 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Pin Configuration Ordering Information Part number AT1780M AT1780M AT1780M AT1780M_PBF AT1780M AT1780M_GRE Package MSOP-8 MSOP-8, PB-Free MSOP-8, Green Marking AT1780M AT1780M AT1780M AT1780M, date code with one bottom line AT1780M AT1780M, date code with two bottom line Pin Description Pin No. Symbol I/O 1 2 3 4 5 6 7 8 COMP FB /SHDN GND LX VIN FSLC SS I I O I - Description Compensation network connection. Output voltage feedback input Shutdown control input, active low Ground Switch Pin. Power supply pin. Frequency select input. Ground=640KHz, VIN=1.2MHz Soft-Start control pin. 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Absolute Maximum Ratings Parameter Condition LX to GND IN, /SHDN, FREG, FB to GND SS, COMP to GND RMS LX pin current Continuous power dissipation Operating temperature Junction temperature Storage temperature Lead temperature - - - - 8pin MAXTA=+70 - - - - Rated Value Min. Max. -0.3 +14 -0.3 +6 -0.3 VIN+0.3 - 1.2 - 330 -30 +85 - +150 -40 +150 - +300 Unit V V V A mW 0 C 0 C 0 C 0 C 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. Recommended Operating Conditions (Ta=+250C) Parameter Power supply voltage SS pin capacitance Phase compensation capacitance Phase compensation capacitance Phase compensation resistance Oscillation frequency Operating temperature Symbol VIN CPE CCOMP1 CCOMP2 RCOMP fOSC1 fOSC2 TOP Values Min. 2.5 -540 1000 -30 Typ. -0.033 680 20 180 708 1220 +25 Unit Max. 5.5 -740 1500 +85 p p K kHz kHz °C 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Electrical Characteristics (VIN = SHDN = 3V, FREQ = GND, TA =-20 to +85, unless otherwise noted. Typical values are at TA = +25.) Parameter Symbol Condition Values Unit Min. Typ. Max. Input Supply Range VIN VIN Undervoltage UVLO Lockout Entire device Quiescent Current Shutdown Supply Current IIN Feedback Voltage VFB FB Input Bias Current Error amplifier IIN IFB Feedback-Voltage Line Regulation Transconductance Voltage Gain N-CHANNEL SWITCH SOFT-START Frequency fosc Maximum Duty Cycle DC Current Limit Sawtooth wave oscillator (OSC) gm Av ILIM On-Resistance RON Leakage Current Current-Sense Transresistance Reset Switch Resistance Charge Current ILXOFF - 5.5 VIN rising, typical hysteresis is 40mV,LX 2.25 2.46 2.52 remains off below this level VFB = 1.3V, not 0.218 0.35 switching VFB = 1.0V, switching 2.045 5 /SHDN = GND 16 Level to produce 1.245 VCOMP = 1.24V VFB = 1.25V Level to produce VCOMP = 1.24V, 2.6V < VIN < 5.5V I = 5µA -FSLC = GND 540 FSLC = IN 1050 FSLC = GND 79 FSLC = IN VFB = 1V, duty cycle = 1.7 65% ILX = 1.2A V V mA A 1.25 1.255 0 40 V nA 0.05 0.15 %/V 280 - mhos 500 V/V 640 740 kHz 1200 1350 91.3 92 % 82.1 0.3 - 2.3 A 0.21 0.3 0.01 VLX = 12V RCS 20 A 0.45 0.65 V/A 100 Input Low Voltage VIL Input High Voltage VIH CONTROL INPUTS Hysteresis FSLC Pull-Down Current /SHDN Input Current 2.5 IFSLC ISHDN VSS = 1.2V /SHDN, FREQ; VIN = 2.6V to 5.5V /SHDN, FREQ; VIN = 2.6V to 5.5V SHDN, FREQ 1.5 1.5 2.55 0.51× VIN 0.57× VIN 0.07× VIN 7 A 5 9 A 0.001 1 A V V V 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Typical Curve (see Application circuit) CH1:LX CH2:Vout CH4:Inductor Current Fig 1. Switching Waveform CH1:/SHDN CH2:Vout CH3:SS CH4:Inductor Current Fig 2. Start-up Waveform with Soft-Start (Iout=200mA) 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller CH1:/SHDN CH2:Vout CH3:SS CH4:Inductor Current Fig 3. Start-up Waveform with Soft-Start (Iout=10mA) CH1:/SHDN CH2:Vout CH3:SS CH4:Inductor Current Fig 4. Start-up Waveform without Soft-Start (Iout=10mA) 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Typical Application Circuit 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Small Outline 8-pin Plastic MSOP SYMBOL A A1 B C D e E H L S INCHES MIN MAX 0.037 0.043 0.002 0.006 0.010 0.014 0.005 0.007 0.116 0.120 0.0256 BSC 0.116 0.120 0.188 0.198 0.016 0.026 0° 6° 0.207 BSC MILLIMETERS MIN MAX 0.94 1.10 0.05 0.15 0.25 0.36 0.13 0.18 2.95 3.05 0.65 BSC 2.95 3.05 4.78 5.03 0.41 0.66 0° 6° 0.525 BSC NOTES - 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 AT1780 AT1780 Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller Reflow Condition 1.Infrared-Ray Reflow 2.Infrared-Ray Reflow(Pb-free) 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