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| Advanced Analog Technology, Inc. AAT1102 (BIN2) Product information presented is current as of publication date. Details are subject to change without notice ADVANCED PWM DC-DC CONVERTER WITH INTERNAL SWITCH AND SOFT-START FEATURES 1.6A, 0.23, Internal Switch High Efficiency: 90% Adjustable Output: VDD to 15V Adjustable Frequency: 640kHz or 1.3MHz Wide Input Range: +2.6V to +5.5V Low Shutdown Current: 0.1A GENERAL DESCRIPTION The AAT1102 is a step-up DC-DC converter with a 1.6A, 0.23 internal switch. Equipped with an external compensation pin, this device offers user flexibility in determining loop dynamic and adjusting operating frequency. AAT1102 also allows the use of small, low equivalent resistance (ESR) ceramic output capacitor, and it's capable of converting a standard input of 3.3V to multiple outputs of 8V, - 8V , and 23V. Furthermore, filtering and loop performance are facilitated and enhanced by a high switching frequency of either 640 kHz or1.3MHz. The AAT1102's versatility comes with a power-smart design. A soft-start programmed with an external capacitor that sets the input current ramp rate, reduces the current consumption to 0.1A in shutdown mode. When operating, a mere 2.6V input yields an impressive output voltage as high as 15V. High switching frequency and economical design allow AAT1102 to be less than 1.1mm high. Its compact 8-pin MSOP package and superior performance make it an ideal part for biasing TFT displays. Programmable Soft-Start Small 8-Pin MSOP Package PIN CONFIGURATION TOP VIEW EO 1 2 AAT1102 3 4 8-Pin MSOP 8 7 6 5 SS IN FREQ SHDN VDD GND SW - - - Advanced Analog Technology, Inc. - Page 1 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) PIN DESCRIPTIONS PIN NAME FUNCTION 1 2 EO IN Compensation Pin for Error Amplifier Feedback Pin with a Typical Reference Voltage of 1.24V, VOUT = IN(1+ R1 ) R2 3 4 5 6 7 8 SHDN GND SW VDD FREQ SS Shutdown Control Pin. The Device Will Turn Off When SHDN is Low Ground Switch Pin Power Supply Pin Frequency Select Pin. Switch Oscillator Frequency to 640kHz When FREQ is Low, and 1.3MHz When FREQ is High Soft-Start Control Pin. No Soft-Start When the Pin is Left Open ABSOLUTE MAXIMUM RATINGS PARAMETER SW to GND IN, SHDN, VDD , FREQ to GND SS, EO to GND SYMBOL VALUE - 0.3 to +18 - 0.3 to +6 - 0.3 V to ( VDD + 0.3V) UNIT V V V A mW RMS SW Pin Current Continuous Power Dissipation ( TC = + 70 ) 8-Pin MSOP (De-Rate 4.1 mW / above +70) Operation Temperature Range Storage Temperature Range I SW Pd TC 1.2 330 - 30 to +85 - 45 to +125 Tstorage TJ TL Junction Temperature Range Lead Temperature (Soldering for 10 seconds) +150 +300 Note: 1. Absolute Maximum Ratings are threshold limit values that must not be exceeded. 2. Operation above these absolute maximum ratings may cause degradation or permanent damage to the device. 3. These are stress ratings only and do not necessarily imply functional operation below these limits. - - - Advanced Analog Technology, Inc. - Page 2 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) ELECTRICAL CHARACTERISTICS ( VDD = SHDN = 3V , FREQ = GND, TC =0 o C to 85 o C , unless otherwise specified. Typical values are at TC = +25o C ) PARAMETER SYMBOL VDD CONDITIONS MIN TYP MAX UNITS Input Supply Voltage Range VDD Under Voltage Lockout 2.6 When VDD is rising, typical hysteresis is 40mV; SW 2.25 remains off below this level VIN = 1.3V, not switching VIN = 1.0V, switching SHDN = 5.5 2.38 0.21 1.2 0.1 2.52 0.35 5.0 10.0 V V mA A UVLO I DD Quiescent Current Shutdown Current ERROR AMPLIFIER PARAMETER I SC GND SYMBOL CONDITIONS MIN TYP MAX UNITS Feedback Voltage VDD Input Bias Current VIN I IN Feedback-Voltage Line Regulation Transconductance Voltage Gain OSCILLATOR PARAMETER SYMBOL f OSC gm Level to produce VEO = 1.228 1.240 1.24V VIN= 1.24V 0 Level to produce VEO = 1.24V, 0.05 2.6V < VDD < 5.5V I = 5 A 70 105 1,500 1.254 40 0.15 240 V nA %/V A AV /V V/V CONDITIONS MIN TYP MAX UNITS Frequency Maximum Duty Cycle D MAX FREQ = GND FREQ = VDD FREQ = GND FREQ = VDD 540 640 1,100 1,320 79 85 85 740 1,600 92 kHz % - - - Advanced Analog Technology, Inc. - Page 3 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) ELECTRICAL CHARACTERISTICS ( VDD = SHDN = 3V , FREQ = GND, TC =0 C to 85 C , unless otherwise specified. Typical values are at TC = +25o C ) o o N-CHANNEL SWITCH PARAMETER SYMBOL I LIM R ON CONDITIONS VDD = 1V, Duty Cycle = 65% I SW = 1.2A MIN TYP MAX UNITS Current Limit On-Resistance Leakage Current SOFT-START PARAMETER 1.2 1.6 0.23 0.01 2.3 0.50 20.00 A A I SWOFF VSW = 15V SYMBOL CONDITIONS MIN TYP MAX UNITS Reset Switch Resistance Charge Current CONTROL INPUTS PARAMETER SYMBOL VIL VIH VSS = 1.2V 1.5 4.0 300 7.0 A CONDITIONS MIN TYP MAX UNITS Input Low Voltage Input High Voltage Hysteresis FREQ Pull-Down Current SHDN Input Current SHDN, FREQ; VDD = 2.6V to 5.5V SHDN, FREQ; VDD = 2.6V to 5.5V SHDN, FREQ 0.3 VDD 0.7 VDD 0.1 VDD 1.8 5.0 0.001 9.0 1.000 V V V A A I FREQ I SHDN - - - Advanced Analog Technology, Inc. - Page 4 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Typical Operating Characteristics 95 90 95 90 EFFICIENCY (%) 80 75 70 65 60 55 50 1 3 5 7 9 20 40 60 80 100 150 200 EFFICIENCY (%) 85 85 80 75 70 65 60 55 50 1 3 5 7 9 20 40 60 80 100 150 200 STEP-UP REGULATOR OUTPUT VOLTAGE vs.LOAD CURRENT(VMAIN=8.3V) 8.4 8.4 8.3 8.3 8.2 8.2 8.1 1 3 5 7 9 20 40 60 80 100 150 200 8.1 1 3 5 7 9 20 40 60 80 100 150 200 LOAD CURRENT(mA) 950 850 1.4 INDUCTOR CURRENT(mA) 2.6 2.8 3 3.3 3.8 3.9 4.2 4.5 4.8 5 750 650 550 450 350 250 150 50 1.2 1 0.8 0.6 0.4 0.2 0 2.7 3 3.5 4 4.5 - - - Advanced Analog Technology, Inc. - Page 5 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Fig. 1 TYPICAL APPLICATION CIRCUIT VDD 2.6V TO 5V ON/ OFF - - - Advanced Analog Technology, Inc. - Page 6 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Fig. 2 BLOCK DIAGRAM - - - Advanced Analog Technology, Inc. - Page 7 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Fig. 3 AAT1102 IN A SEPIC CONFIGURATION VDD 2.6V TO 5V - - - Advanced Analog Technology, Inc. - Page 8 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Fig. 4 MULTIPLE-OUTPUT TFT LCD POWER SUPPLY - - - Advanced Analog Technology, Inc. - Page 9 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Inductor selection VD I L ( peak ) = I IN + IN , where D is duty cycle 2 Lf s I V And I IN = o , D = 1 - IN , 1- D Vo The inductor current rating must be greater than Power Stage Transfer Functions The duty to output voltage transfer function T p is: ( s + w )( s - w z 2 ) vo = T p 0 2 esr 2 d s + 2wn s + wn - rc 1 , wesr = (1 - D )(RL + rc ) Crc T p ( s) = I L(peak) . Loop Compensation Design Where T p 0 = VO And (1 - D )2 RL + r LC (RL + rc ) 2 C[r (RL + rc ) + RL rc (1 - D ) ] + L = , 2 2 LC (RL + rc )[r + (1 - D ) RL ] wz 2 = RL (1 - D ) - r , wn = L 2 r = rL + DrDS + (1 - D) RF rL is the inductor equivalent series resistance, rc is capacitor ESR, RL is the converter load resistance, C is output filter capacitor, rDS is the Fig.1. Closed-current loop for boost with PCM transistor on-resistance, and R F is the diode forward resistance. The duty to inductor current transfer function T pi is: T pi ( s) = il s + wzi = T pi 0 2 2 d s + 2wn s + wn VO (RL + 2rc ) 1 , wzi = C (RL / 2 + rc ) L(RL + rc ) Where Tpi 0 = Fig.2. Block diagram of boost converter with PCM - - - Advanced Analog Technology, Inc. - Page 10 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) Current Sampling Transfer Function Error voltage to duty transfer function Fm is: 2 f s s 2 + 2wn s + wn d Fm ( s ) = = vei T pi 0 Rcs s (s + wzi )(s + wsh ) 2 2 = g m Rc s + w c 12 f s T p 0 x s R cs T pi 0 2 ( ) (s + wz1 )(s - wz 2 ) (s + wzi )( s 2 + sws h + 12 f s 2 ) Where = V FB , Vo Where wsh = 3ws 1 - M - Ma , , = 2 1+ M1 + M a ws = 2 . f s The compensator transfer function Therefore, Fm depends on duty to inductor current T ( s ) = v c = g R s + wc , where w = 1 c mc c Rc C c s v fb transfer function T pi , and f s is the clock switching frequency; Rcs is the current-sense amplifier transresistance. For the boost converter M 1 = V IN / L and M 2 = ( VO - V IN )/ L For AAT1102 , Rcs = 0.275 V/A, M a is slope compensation, M a =0.8x106. The closed-current loop transfer function Ticl 12 f s s 2 + 2wn s + wn x Rcs T pi 0 (s + wzi )(s 2 + wsh s + 12 f s 2 2 2 O c _ + Comparator is: Ticl ( s ) = ( ) ) Fig.3. Voltage loop compensator Compensator design guide: 1 fs 2 The Voltage-Loop Gain With Current Loop Closed The control to output voltage transfer function Td is: v ( s) Td ( s ) = o = Ticl ( s )T p ( s ) vc ( s ) The voltage-loop gain with current loop closed is: Lvi ( s ) = Tc ( s )Td ( s ) 1. Crossover frequency f ci < 2. Gain margin>10dB 3. Phase margin>40 4. The Lvi ( s ) = 1 at crossover frequency, Therefore, the compensator resistance, Rc is determined by: - - - Advanced Analog Technology, Inc. - Page 11 of 18 V5.0 Advanced Analog Technology, Inc. Rc = (RL + 2rc ) Vo 2f ci CRcs VFB kg m r (1 - D )RL - (1 - D ) AAT1102 (BIN2) VFB is equal to reference voltage, V REF . V REF =1.24V, k is the correct factor, and k = (6 - 8) 5. The output filter capacitor is chosen so C . RL pole cancels Rc . C c zero Rc C c = Cc = C RL + rc , and (1 - 3) 2 Fig.5. Bode diagram using Matlab simulation C RL + rc (1 - 3)Rc 2 Example: VIN =5V, VO =9.6V, I O =250mA, f s =600 kHz, VFB =1.25V, L = 6.8uH , g m = 105uS , Rcs = 0.275 V/A, rL = 0.1 , rDS = 0.23 , rC = 50m , k =7 R F = 1.4 , f ci = 21.4 kHz, C c =1.3nF, Rc = 27k , C =4.7uF Fig.4. CH1: PWM waveform, CH2, v p - p for Vo - - - Advanced Analog Technology, Inc. - Page 12 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) PACKAGE DIMENSION MSOP-8 - - - Advanced Analog Technology, Inc. - Page 13 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) PACKAGE DIMENSION (CONT.) MSOP-8 - - - Advanced Analog Technology, Inc. - Page 14 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) TAPE AND REEL PACKING METHOD: 2,500PCS/REEL, 1 REEL/BOX - - - Advanced Analog Technology, Inc. - Page 15 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) TAPE AND REEL (CONT.) PACKING METHOD: 2,500PCS/REEL, 1 REEL/BOX - - - Advanced Analog Technology, Inc. - Page 16 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) PART MARKING MSOP8 TOP MARKING 1102 MAAC MSOP8 BACK MARKING YYWW - - - Advanced Analog Technology, Inc. - Page 17 of 18 V5.0 Advanced Analog Technology, Inc. AAT1102 (BIN2) ORDERING INFORMATION - - - Advanced Analog Technology, Inc. - Page 18 of 18 V5.0 |
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