AAT1109A

Advanced Analog Technology, Inc. AAT1109A Preliminary and Provisional ONE-CHANNEL BOOST SWITCHING REGULATOR Features Under-voltage lockout protection Totem pole output Output short circuit protection Incorporates soft start function Wide operating frequency： 10kHz to 1MHz Shut down control Low dissipation current : Typical 1.6mA in operation Sop-8 & Tssop-8 package available General Description The AAT1109A is a one-channel switching regulator control IC incorporating a soft start function and a short circuit protection function. Each device consists of an on-chip voltage reference, error amplifier, pulse width modulation controller, under-voltage protection, soft start and short circuit protection circuits. Switching frequencies up to 1MHz are set by an external resistor and capacitor. Soft-start time can be implemented by the SCP capacitor. Additionally, a chip enable feature is provided to power down reducing the supply current to 10uA. With a minimum number of external components, the AAT1109A offers a simple and cost effective solution. Pin Configuration TOP VIEW -IN SCP Vcc CE 1 2 3 4 8 7 6 5 FB OSC GND OUT (SOP-8 PACKAGE) (TSSOP-8 PACKAGE) – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Pin Description Pin # 1 2 3 4 5 6 7 8 Name -IN SCP Vcc CE OUT GND OSC FB I/O Description I Error amplifier inverting input pin I Soft start and SCP capacitor connection pin Power supply I Chip enable input pin（internal pull "H"） O Totem-type output pin Ground O Capacitor and resistor connection pin for setting the oscillation frequency O Error amplifier output pin Absolute Maximum Ratings CHARACTERISTICS Supply voltage SYMBOL VDD VALUE 7 UNIT V Output current Operating free-air temperature range Storage temperature range Power dissipation IO Tope Tstg -120/+120 -20 to 85 -65 to 150 500 mA o o C C Pd mW Recommended Operating Conditions Supply voltage, VDD Error amplifier input voltage OSC capacitor OSC resistor Oscillator frequency Output current Operating free-air temperature Symbol VDD VI CT RT f OSC Min 2.6 0.5 100 1.0 Max 6.5 1.6 10000 10 Unit V V pF kΩ 10 -20 1000 +30/-30 85 kHz mA o IO Tope C – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Electrical Characteristics, VDD = 3.3V (Unless Otherwise Specified) (See Note 1) Oscillator Parameter Test Condition Min Typ Oscillation frequency Frequency variation with temperature Frequency input stability f OSC C T = 270pF, R T = 4.2kΩ 400 500 5 Max Unit 600 KHz f dT f dV VDD = 2.6V to 6.5V % % 1 Under-voltage Protection Parameter Test Condition Min Typ Max Unit Upper threshold voltage Lower threshold voltage Hysteresis ( VUPH – VUPL ) VUPH VUPL VHYS TA = 25 C TA = 25 oC TA = 25 C TA =25 C. o o 2.12 2.47 1.96 2.28 0.3 2.85 2.63 V V V o Note1 : Typical values of all parameters are specified at Short Circuit Protection Control Parameter Test Condition Min Typ Max Unit Input threshold voltage Short-circuit detect threshold voltage Charging current Vr1 1.16 1.262 1.16 1.262 Vscp=0v -1.0 -1.5 1.36 1.36 -2.15 V V µA Vr 2 I SCP Soft start Parameter Test Condition Min Typ Max Unit Charging current Voltage at soft start completion Ics Vts Vscp=0v -1.0 -1.5 -2.15 1.36 µA V 1.16 1.262 Shun Down Control Parameter Test Condition Min Typ Max Unit Shut down release voltage Shut down enable voltage Vsdh Vsdl 2.0 0.5 V V – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Electrical Characteristics, VDD = 3.3V (Unless Otherwise Specified) (See Note 1) Idle period adjustment section Parameter Test Conditions Min Typ Max Unit Maximum duty cycle tDUTY C T = 270pF, R T = 4.2kΩ VFB = 1.12v 75 85 93 % EA (Error Amplifier) Parameter Test Condition Input threshold voltage VT input stability VT variation with temperature Input bias current Output voltage swing Output sink current Output source current Open-loop voltage amplification VT VTdV VTdT VFB = 0.7v Vdd = 2.6 to 6.5v TA = -20 oC to 90 oC Min Typ Max Unit 1.249 1.262 1.275 V 2 8 mV 1 % IB VOM + VOM − I OM + I OM − A VD FB=0.7V FB=0.7V 3 -45 70 1.4 0.1 1.7 0.05 20 -75 85 1 0.2 µA V mA µA dB Output section Parameter Test Condition Typ Max Unit High-level output voltage Low-level output voltage Rise time Fall time VOH VOL Trise Tfall IO=-30mA IO=+30mA CL=1000pF CL=1000pF 1.9 2.3 0.8 100 100 1.2 V V nS nS Operating Current Parameter Test Condition Min Supply current I DD−OFF I DD−ON Output ”OFF”state RT =4.2k Typ 1.3 Max Unit mA 1.6 mA – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A How to set the time constant for soft start and short circuit protection 1.Soft start At power on, the AAT1109A operates in soft start mode. The capacitor Cscp connected to SCP pin starts charging at a constant current. In the soft start mode, the voltage at SCP pin (VSCP) is input to the PWM comparator, so that the ON duty of the OUT pin is controlled by the VSCP. On completion of soft start operation, the voltage at the SCP pin stays low, the input from soft start circuit to the PWM comparator stay high, and enter the short circuit protection waiting state. Soft start time Ts(sec) ~ 0.84 × CSCP (uF) 2.Short circuit protection If the switching regulator output suddenly drops due to loading effect , the error amplifier output is fixed at VOM+ and capacitor CSCP starts charging. When the voltage at the SCP pin reaches approximately 1.26V ,the output pin set low and SCP pin stays low. Once the protection circuit operates, the circuit can be recovered by setting the power supply. Short circuit detection time Tscp(sec) ~ 0.84 × CSCP (uF) – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Function Block Diagram VDD CE C h ip E n a b le IR E F GND V ref 1 .2 6 V SCP com p. LATCH SCP S o ft sta rt SCP UVC UVC CE O SC O SC CE UVLO VCC CE V re f 1 .2 6 v PW M C om p. FB VREF CE VCC D TC 0 .7 6 5 V E rr-A m p V ref 1 .2 6 V OUT UVC -IN CE – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Application Circuit 1 BOOST(step-up) VDD L1 D1 VOUT CE CE 4 1 -IN C4 R4 SCP VDD R1 -IN R2 Q1 C2 2 8 FB C1 VDD 3 7 OSC R3 C3 OUT 5 6 GND AAT1109A Application Circuit 2 (with charge pump) VDD L1 D1 VOUT C2 CE CE 4 1 -IN C4 R4 SCP VDD R1 -IN R2 Q1 2 8 FB C1 VDD 3 7 OSC R3 C3 OUT 5 6 GND VP ≅ 3*Vout D2 C6 D3 C7 D4 C5 D6 C8 C9 VN ≅ -Vout C10 AAT1109A D5 D7 – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Boost （Step-up）Timing Chart FB Reference input for short circuit ldle period setting voltage Soft start setting voltage OSC 1.262V OUTPU T SCP soft start output short circuit output short circuit Ts 2.47V Lockout free VDD Tscp – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Package Dimension (Unit: Mil) 8-pin SOP θ DIMENSIONS IN MILLIMETERS SYMBOLS A A1 A2 b C D E E1 e L y θ MIN 1.47 0.10 --0.33 0.19 4.80 5.80 3.80 --0.38 --0 NOM. 1.60 --1.45 0.41 0.20 4.85 6.00 3.90 1.27 0.71 ----MAX 1.73 0.22 --0.51 0.25 4.95 6.20 4.00 --1.27 0.076 0 DEMINSIONS IN INCHES MIN 0.058 0.004 --0.013 0.0075 0.189 0.228 0.150 --0.015 --0 NOM. 0.063 --0.057 0.016 0.008 0.191 0.236 0.154 0.050 0.028 ----MAX 0.068 0.008 --0.020 0.0098 0.195 0.244 0.157 --0.050 0.00. 0 – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1 Advanced Analog Technology, Inc. AAT1109A Package Dimension (Unit: Mil) 8-pin TSSOP θ D E1 E L C Dimension Millimeters Min Nom 1.10 0.10 0.22 0.127 3.00 6.40 4.40 0.65 0.60 3° Inches Max 1.20 0.175 -----------3.10 6.60 4.50 --0.75 8° A Min 0.039 0.002 ------------0.114 0.244 0.169 --0.020 0° Nom 0.043 0.004 0.008 0.005 0.118 0.252 0.173 0.026 0.024 3° Max 0.047 0.006 ------------0.122 0.260 0.177 --0.028 8° A A1 1.00 0.025 ----------2.90 6.20 4.30 --0.45 0° A1 b C D E E1 e L θ b e – – 台灣類比科技股份有限公司 – Advanced Analog Technology, Inc. – V 0.1