AT1780 AIMTRON | Alldatasheet

Document overview

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Technical content

Features

  • 1.6A,0.21Ω,14V Power MOSFET
  • Operating input voltage:+2.6V to +5.5V
  • Adjustable Output from VIN to 12V
  • 640kHz /1.2MHz pin selectable switching Frequency
  • 0.1μA shutdown Current
  • Built-in Soft-Start function
  • Small 8-Pin MSOP Package

Applications

  • LCD Displays
  • Digital Cameras
  • Portable Applications
  • Hand-Held Devices General Description The AT1780 is a current-mode step-up DC/DC converter with a 1.6A, 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. *Protected by U.S. Patent # 6,791,368 Block Diagram FB CURRENT SENSE COMP SHDN GND LX SS VIN SOFT- START Oscillator Ramp Generator FSLC 1.24V Error Amplifier Comparator Enable BIAS Clock N 4uA gm R S Q Power ON/OFF Reference 1.24V Aimtron reserves the right without notice to change this circuitry and specifications.

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Pin Configuration 1780

Ordering Information

AT1780M_GRE MSOP8,Green 1780,data code with one bottom line *For more marking information, contact our sales representative directly Pin Description Pin No. Symbol I/O

Description

Compensation network connection. FB I Output voltage feedback input /SHDN I Shutdown control input, active low GND Ground LX O Switch Pin. VIN Power supply pin. FSLC I Frequency select input. Ground=640KHz, VIN=1.2MHz SS Soft-Start control pin.

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Absolute Maximum Ratings Rated Value Parameter Condition Min. Max. Unit LX to GND -0.3 +14 V IN, /SHDN, FREG, FB to GND -0.3 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℃） 330 mW 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. Recommended Operating Conditions (Ta=+250C) Values Parameter Symbol Min. Typ. Max. Unit Power supply voltage VIN 2.6 5.5 Ｖ SS pin capacitance CPE 0.033 μＦ Phase compensation capacitance CCOMP1 470 pＦ Phase compensation capacitance CCOMP2 pＦ Phase compensation resistance RCOMP KΩ fOSC1 540 640 740 kHz Oscillation frequency fOSC2 1000 1220 1500 kHz Operating temperature TOP -30 +25 +85

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw

Electrical Characteristics

(VIN = SHDN = 3V, FREQ = GND, TA =0℃ to +85℃, unless otherwise noted. Typical values are at TA = +25℃.) Values Parameter Symbol Condition Min. Typ. Max. Unit Input Supply Range VIN 2.6 5.5 V VIN Undervoltage Lockout UVLO VIN rising, typical hysteresis is 40mV,LX remains off below this level 2.1 2.3 2.5 V VFB = 1.3V, not switching 0.218 0.35 Quiescent Current IIN VFB = 1.0V, switching 2.045 mA Entire device Shutdown Supply Current IIN /SHDN = GND 0.1 μA Feedback Voltage VFB Level to produce VCOMP = 1.24V 1.222 1.24 1.258 V FB Input Bias Current IFB VFB = 1.25V nA Feedback-Voltage Line Regulation Level to produce VCOMP = 1.24V, 2.6V < VIN < 5.5V 0.05 0.15 %/V Transconductance gm ΔI = 5µA 140 μmhos Error amplifier Voltage Gain Av 500 V/V FSLC = GND 540 640 740 Frequency fosc FSLC = IN 1050 1200 1350 kHz FSLC = GND 91.3 Sawtooth wave oscillator (OSC) Maximum Duty Cycle DC FSLC = IN 82.1 Current Limit ILIM VFB = 1V, duty cycle = 65% 1.2 1.6 2.3 A On-Resistance RON ILX = 1.2A 0.21 0.5 Ω Leakage Current ILXOFF VLX = 12V 0.01 μA N-CHANNEL SWITCH Current-Sense Transresistance RCS 0.3 0.45 0.65 V/A Reset Switch Resistance 100 Ω SOFT-START Charge Current VSS = 1.2V 1.5 μA Input Low Voltage VIL /SHDN, FREQ; VIN = 2.6V to 5.5V 0.4 V Input High Voltage VIH /SHDN, FREQ; VIN = 2.6V to 5.5V 1.6 V Hysteresis SHDN, FREQ 100 mV FSLC Pull-Down Current IFSLC 1.5 μA CONTROL INPUTS /SHDN Input Current ISHDN 0.001 μA

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Typical Characteristics (VIN = 3.3V, FREQ = GND, TA=25℃, unless otherwise noted.) Output current Iout (mA) Efficiency Eff (%) Efficiency vs. Output current AT1780 100 1000 Vin=3.3V Vout=10V fosc=640kHz L=10uH Output current Iout (mA) Efficiency Eff (%) Efficiency vs. Output current AT1780 100 1000 Vin=3.3V Vout=10V fosc=1.2MHz L=4.7uH 120 160 200 9.90 10.00 10.10 Output current Iout (mA) Output voltage Vout (V) Output voltage vs. Output current 240 AT1780 10.05 9.95 9.85 9.80 9.75 9.70 9.65 Vin=3.3V Vout=10V fosc=640kHz L=10uH 120 160 200 9.90 10.00 10.10 Output current Iout (mA) Output voltage Vout (V) Output voltage vs. Output current 240 AT1780 10.05 9.95 9.85 9.80 9.75 9.70 9.65 Vin=3.3V Vout=10V fosc=1.2MHz L=4.7uH CH1:Output voltage,100mV/div/AC CH1:Output voltage,100mV/div/AC CH4:Output current,100mA/div/DC CH4:Output current,100mA/div/DC Vout=10V,fosc=640kHz,L=10uH Vout=10V,fosc=1.2MHz,L=4.7uH R1=100k,C1=470PF,C2=18PF R1=100k,C1=470PF,C2=18PF

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Typical Characteristics (continuted) CH1:LX voltage,5V/div/DC CH1:LX voltage,5V/div/DC CH4:Inductor current,500mA/div/DC CH4:Inductor current,500mA/div/DC Vout=10V,fosc=640kHz,L=10uH Vout=10V,fosc=1.2MHz,L=4.7uH CH1:LX voltage,5V/div/DC CH1:LX voltage,5V/div/DC CH2:Vin and /SHDN voltage,2V/div/DC CH2:Vin and /SHDN voltage,2V/div/DC CH3:SS voltage,2V/div/DC CH1:SS voltage,2V/div/DC CH4:Iin current,500mA/div/DC CH4:Iin current,500mA/div/DC Vout=10V,Iout=100mA, Vout=10V,Iout=100mA, fosc=640kHz,L=10uH fosc=1.2MHz,L=4.7uH

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Small Outline 8-pin Plastic µMAX B A e C L α E H D S INCHES MILLIMETERS SYMBOL MIN MAX MIN MAX NOTES A 0.037 0.043 0.94 1.10 0.002 0.006 0.05 0.15 B 0.010 0.014 0.25 0.36 C 0.005 0.007 0.13 0.18 D 0.116 0.120 2.95 3.05 e

0.0256 BSC

0.65 BSC

E 0.116 0.120 2.95 3.05 H 0.188 0.198 4.78 5.03 L 0.016 0.026 0.41 0.66 α S

0.207 BSC

0.525 BSC

Preliminary Product Information 640kHz/1.2MHz,Low-Noise Step-Up Current-Mode PWM Controller 7F, No.9, PARK AVENUE II, Science-Based Industrial Park, Hsinchu 300,Taiwan, R.O.C. Tel: 886-3-563-0878 Fax: 886-3-563-0879 WWW: http://www.aimtron.com.tw 3/24/06 REV 1.1 Email: service@aimtron.com.tw Reflow Profiles Sn-Pb Eutectic Assembly Pb-Free Assembly Profile Feature Large Body Pkg. thickness ≥2.5mm or Pkg. volume ≥350mm3 Small Body Pkg. thickness <2.5mm or Pkg. volume <350mm3 Large Body Pkg. thickness ≥2.5mm or Pkg. volume ≥350mm3 Small Body Pkg. thickness ≥2.5mm or Pkg. volume ≥350mm3 Average ramp-up rate (TL to TP) 3°C/second max. 3°C/second max. Preheat -Temperature Min(Tsmin) -Temperature Max (Tsmax) -Time (min to max)(ts) 100°C 150°C 60-120 seconds 150°C 200°C 60-180 seconds Tsmax to TL -Ramp-up Rate 3°C/second max. Time maintained above: -Temperature (TL) -Time (tL) 183°C 60-150 seconds 217°C 60-150 seconds Peak Temperature(TP) 225+0/-5°C 240+0/-5°C 245+0/-5°C 250+0/-5°C Time within 5°C of actual Peak Temperature (tP) 10-30 seconds 10-30 seconds 10-30 seconds 20-40 seconds Ramp-down Rate 6°C/second max. 3°C/second max. Time 25°C to Peak Temperature 6 minutes max. 8 minutes max. *All temperatures refer to topside of the package, measured on the package body surface.