AAT1150 1MHz 1A Step-Down DC/DC Converter General Description Features The AAT1150 SwitchReg™ is a step-down switching converter ideal for applications where high efficiency, small size, and low ripple are critical. Able to deliver 1A with internal power MOSFETs, the current-mode controlled IC provides high efficiency using synchronous rectification. Fully internally compensated, the AAT1150 simplifies system design and lowers external parts count. • • • • • • • • • • • • • • • • • The AAT1150 is available in a Pb-free MSOP-8 package and is rated over the -40°C to +85°C temperature range. SwitchReg™ VIN Range: 2.7V to 5.5V Up to 95% Efficiency 110mΩ RDS(ON) MOSFET Switch <1.0μA of Shutdown Current 1MHz Switching Frequency Fixed or Adjustable VOUT: 1.0V to 4.2V High Initial Accuracy: ±1% 1.0A Peak Current Integrated Power Switches Synchronous Rectification Internally Compensated Current Mode Control Constant PWM Mode for Low Output Ripple Internal Soft Start Current Limit Protection Over-Temperature Protection MSOP-8 package -40°C to +85°C Temperature Range Applications • • • • • Cable/DSL Modems Computer Peripherals High Efficiency Conversion From 5V or 3.3V Supply Network Cards Set-Top Boxes Typical Application INPUT VP 10μF FB AAT1150 4.1μH LX ENABLE 100Ω VCC OUTPUT SGND PGND 3x 22μF 0.1μF 1150.2006.09.1.5 1 AAT1150 1MHz 1A Step-Down DC/DC Converter Pin Descriptions Pin # Symbol Function 1 FB 2 SGND 3 EN 4 VCC 5 VP Input supply voltage for converter power stage. 6, 7 LX Inductor connection pins. These pins should be connected to the output inductor. Internally, Pins 6 and 7 are connected to the drains of the P-channel switch and N-channel synchronous rectifier. 8 PGND Feedback input pin. This pin must be connected to the converter’s output. It is used to set the output of the converter to regulate to the desired value. Signal ground. Enable input pin. When connected high, the AAT1150 is in normal operation. When connected low, it is powered down. This pin should not be left floating. Power supply. It supplies power for the internal circuitry. Power ground return for the output stage. Pin Configuration MSOP-8 (Top View) PGND 7 LX 3 6 LX 4 5 VP SGND 2 EN VCC 2 1 1 2 8 FB 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Absolute Maximum Ratings1 TA = 25°C, unless otherwise noted. Symbol VCC, VP VLX VFB VEN TJ VESD Description VCC, VP to GND LX to GND FB to GND EN to GND Operating Junction Temperature Range ESD Rating2 - HBM Value Units 6 -0.3 to VP + 0.3 -0.3 to VCC + 0.3 -0.3 to 6 -40 to 150 3000 V V V V °C V Value Units 150 667 °C/W mW Rating Units -40 to +85 °C Thermal Characteristics3 Symbol ΘJA PD Description Maximum Thermal Resistance (MSOP-8) Maximum Power Dissipation (MSOP-8, TA = 25°C)4 Recommended Operating Conditions Symbol T Description Ambient Temperature Range 1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions specified is not implied. Only one Absolute Maximum Rating should be applied at any one time. 2. Human body model is a 100pF capacitor discharged through a 1.5kΩ resistor into each pin. 3. Mounted on a demo board. 4. Derate 6.7mW/°C above 25°C. 1150.2006.09.1.5 3 AAT1150 1MHz 1A Step-Down DC/DC Converter Electrical Characteristics VIN = VCC = VP = 5V, TA = -40°C to +85°C, unless otherwise noted. Typical values are at TA = 25°C. Symbol VIN VOUT Description Input Voltage Range Output Voltage Tolerance ΔVOUT (VOUT*ΔVIN) Load Regulation ΔVOUT/VOUT Line Regulation VUVLO VUVLO(HYS) IQ ISHDN ILIM RDS(ON)H RDS(ON)L η VEN(L) VEN(H) IEN FOSC TSD THYS 4 Conditions Under-Voltage Lockout Under-Voltage Lockout Hysteresis Quiescent Supply Current Shutdown Current Current Limit High Side Switch On Resistance Low Side Switch On Resistance Efficiency Enable Low Voltage Enable High Voltage Enable Pin Leakage Current Oscillator Frequency Over-Temperature Shutdown Threshold Over-Temperature Shutdown Hysteresis VIN = VOUT + 0.3 to 5.5V, IOUT = 0 to 1A VIN = 4.2V, ILOAD = 0 to 1A VIN = 2.7V to 5.5V VIN Rising VIN Falling No Load, VFB = 0 VEN = 0V, VIN = 5.5V TA = 25°C TA = 25°C TA = 25°C VIN = 5V, VOUT = 3.3V, IOUT = 600mA VIN = 2.7V to 5.5V VIN = 2.7V to 5.5V VEN = 5.5V TA = 25°C Min Typ Max Units 2.7 5.5 V -4.0 4.0 % 3.0 0.2 % %/V 2.5 1.2 250 160 300 1.0 1.2 110 100 150 150 93 0.6 1000 mV μA μA A mΩ mΩ % 1.4 700 V 1.0 1200 V V μA kHz 140 °C 15 °C 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Typical Characteristics Efficiency vs. Output Current Efficiency vs. Output Current (VOUT = 1.5V) (VOUT = 3.3V) 100 100 60 4.2V 40 VIN = 5.0V 80 Efficiency (%) Efficiency (%) 90 2.7V 80 3.6V 20 70 60 50 40 30 20 10 0 0 10 100 1000 10 100 Output Current (mA) Output Current (mA) Low Side RDS(ON) vs. Temperature High Side RDS(ON) vs. Temperature 170 170 3.6V 150 150 RDS(ON) (mΩ) RDS(ON) (mΩ) 2.7V 130 110 5.5V 4.2V 90 70 -20 0 20 40 130 3.6V 2.7V 110 5.5V 90 60 80 100 4.2V 70 -20 120 0 20 40 60 80 100 120 Temperature (°C) Temperature (°C) Enable Threshold vs. Input Voltage RDS(ON) vs. Input Voltage 1.2 130 Enable Threshold (V) 120 High Side RDS(ON) (mΩ) 1000 110 100 Low Side 90 80 1.1 VEN(H) 1 0.9 VEN(L) 0.8 0.7 2.5 3 3.5 4 4.5 Input Voltage (V) 1150.2006.09.1.5 5 5.5 2.5 3 3.5 4 4.5 5 5.5 Input Voltage (V) 5 AAT1150 1MHz 1A Step-Down DC/DC Converter Typical Characteristics Oscillator Frequency Variation vs. Temperature (VIN = 3.6V) 3.5 10 2.5 6 Variation (%) Variation (%) Oscillator Frequency Variation vs. Supply Voltage 1.5 0.5 -0.5 2 -2 -6 -1.5 2.5 3 3.5 4 4.5 5 -10 -20 5.5 0 20 Supply Voltage (V) 0.6 0.15 Accuracy (%) Output Voltage Error (%) 0.25 VIN = 2.7V VIN = 3.6V -0.6 IOUT = 1.0A 0.05 IOUT = 0.4A -0.05 -0.15 -0.25 0 20 40 60 80 2.5 100 3 3.5 4 4.5 5 5.5 Input Voltage (V) Temperature (°C) Load Regulation Load Regulation (VOUT = 3.3V; VIN = 5.0V) (VOUT = 1.5V; VIN = 3.6V) 0 0 -1 -1 VOUT Error (%) Error (%) 100 (VOUT = 1.5V) 1.0 -1.0 -20 80 Line Regulation (IOUT = 900mA; VOUT = 1.5V) -0.2 60 Temperature (°C) Output Voltage vs. Temperature 0.2 40 -2 -3 -4 -2 -3 -4 -5 -5 0 0 150 300 450 IOUT (mA) 6 600 750 900 150 300 450 600 750 900 1050 Output Current (mA) 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Typical Characteristics Efficiency vs. Input Voltage AAT1150 Loop Gain and Phase (CO = 22μ μF; VO = 1.5V; VIN = 3.6V; IO = 1A) (VOUT = 1.5V) 100 IO = 1A 200 160 12 Gain (dB) IO = 0.4A 80 70 40 0 0 -4 Gain -8 2.5 3 3.5 4 4.5 5 VCC = 5.0V Operating Current (μA) Input Current (mA) (FB = 0V; VP = VCC) VCC = 5.5V 10 8 6 VCC = 3.6V VCC = 2.7V 2 0 200 190 180 VCC = 5.5V VCC = 5.0V 170 160 150 140 130 VCC = 4.2V VCC = 2.7V 120 110 100 -20 -20 -5 10 25 40 55 70 -5 85 10 25 VCC = 3.6V 40 55 70 85 Temperature (°C) Temperature (°C) Switching Waveform Transient Response (VIN = 3.6V; VOUT = 1.5V; IOUT = 1.2A) (VIN = 3.6V; VOUT = 1.5V; ILOAD = 0.25 to 1.2A) VOUT 50mV/div V(LX) 2V/div Inductor Current 500mA/div IL 500mA/div Time (500ns/div) 1150.2006.09.1.5 -200 1000 Non-Switching IQ vs. Temperature (VCC = VP) VCC = 4.2V -160 Frequency (kHz) No Load Input Current vs. Temperature 4 -120 100 Input Voltage (V) 12 -80 5 x 22μF -20 10 5.5 -40 3 x 22μF 4 x 22μF -16 50 80 4 -12 60 120 Phase 8 Phase (degrees) 90 Efficiency (%) 20 16 Time (20µs/div) 7 AAT1150 1MHz 1A Step-Down DC/DC Converter Typical Characteristics Output Ripple Output Ripple (VIN = 3.6V; VOUT = 1.5V; IOUT = 1A) (VIN = 3.6V; VOUT = 1.5V; IOUT = 0A) VOUT 5mV/div BW = 20MHz VOUT 5mV/div BW = 20MHz LX 2V/div LX 2V/div Time (500ns/div) Time (500ns/div) Output Ripple Output Ripple (VIN = 5.0V; VOUT = 3.3V; IOUT = 1A) (VIN = 5.0V; VOUT = 3.3V; IOUT = 0A) VOUT 5mV/div BW = 20MHz VOUT 5mV/div BW = 20MHz LX 2V/div LX 2V/div Time (500nsec/div) Time (500ns/div) Inrush Limit (VIN = 3.6V; VOUT = 1.5V; IL = 1A) Enable 2V/div VOUT 1V/div IL 0.5A/div Time (200µs/div) 8 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Functional Block Diagram VCC VP = 2.7V- 5.5V 1.0V REF FB OP. AMP CMP DH LOGIC 1MΩ LX DL Temp. Sensing OSC SGND Applications Information Control Loop The AAT1150 is a peak current mode buck converter. The inner wide bandwidth loop controls the peak current of the output inductor. The output inductor current is sensed through the P-channel MOSFET (high side) and is also used for short-circuit and overload protection. A fixed slope compensation signal is added to the sensed current to maintain stability. The loop appears as a voltageprogrammed current source in parallel with the output capacitor. The voltage error amplifier output programs the current loop for the necessary inductor current to force a constant output voltage for all load and line conditions. The feedback resistive divider is inter- 1150.2006.09.1.5 EN PGND nal, dividing the output voltage to the error amplifier reference voltage of 1.0V. The error amplifier does not have a large DC gain typical of most error amplifiers. This eliminates the need for external compensation components while still providing sufficient DC loop gain for load regulation. The crossover frequency and phase margin are set by the output capacitor value only. Soft Start/Enable Soft start increases the inductor current limit point in discrete steps when the input voltage or enable input is applied. It limits the current surge seen at the input and eliminates output voltage overshoot. The enable input, when pulled low, forces the AAT1150 into a low power, non-switching state. The total input current during shutdown is less than 1μA. 9 AAT1150 1MHz 1A Step-Down DC/DC Converter Power and Signal Source Separate small signal ground and power supply pins isolate the internal control circuitry from the noise associated with the output MOSFET switching. The low pass filter R1 and C3 in schematic Figures 1 and 2 filters the noise associated with the power switching. Current Limit and Over-Temperature Protection For overload conditions, the peak input current is limited. Figure 3 displays the current limit characteristics. As load impedance decreases and the output voltage falls closer to zero, more power is dissipated internally, raising the device temperature. Thermal protection completely disables switching when internal dissipation becomes excessive, protecting the device from damage. The junction over-temperature threshold is 140°C with 15°C of hysteresis. Efficiency vs. Output Current AAT1150-1.5 R1 100 R2 C1 10μF 100k C7 0.1μF VP FB VCC LX EN LX (VOUT = 1.5V) V OUT 1.5V 1A L1 4.1μH SGND PGND 100 2.7V 80 C2, C3, C4 3x 22μF 6.3V RTN Efficiency (%) 2.7V-5.5V C1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3 C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L 0805 X5R L1 Sumida CDRH5D18-4R1μH 60 4.2V 40 3.6V 20 0 10 100 1000 Output Current (mA) Figure 1: Lithium-Ion to 1.5V Converter. Efficiency vs. Output Current (VOUT = 3.3V) AAT1150-3.3 R1 100 R2 C1 10μF 100k C7 0.1μF VP FB VCC LX EN LX SGND PGND V OUT 3.3V 1A 100 90 VIN = 5.0V 80 L1 4.1μH C2, C3, C4 3x 22μF 6.3V RTN C1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3 C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805 L1 Sumida CDRH5D18-4R1μH Efficiency (%) 3.5V-5.5V 70 60 50 40 30 20 10 0 10 100 1000 Output Current (mA) Figure 2: 5V Input to 3.3V Output Converter. 10 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Output Voltage (V) 3.5 VCC = VP = 5.0V VO = 3.3V Figure 2 Schematic 3 2.5 2 1.5 VCC = VP = 3.6V VO = 1.5V Figure 1 Schematic 1 0.5 0 0 0.5 1 1.5 2 2.5 Output Current (A) Figure 3: Current Limit Characteristics. Inductor The output inductor is selected to limit the ripple current to some predetermined value, typically 20% to 40% of the full load current at the maximum input voltage. Manufacturer's specifications list both the inductor DC current rating, which is a thermal limitation, and the peak current rating, which is determined by the saturation characteristics. The inductor should not show any appreciable saturation under normal load conditions. During overload and short-circuit conditions, the average current in the inductor can meet or exceed the ILIMIT point of the AAT1150 without affecting converter performance. Some inductors may have sufficient peak and average current ratings yet result in excessive losses due to a high DCR. Always consider the losses associated with the DCR and its effect on the total converter efficiency when selecting an inductor. For a 1.0A load and the ripple set to 30% at the maximum input voltage, the maximum peak-topeak ripple current is 300mA. The inductance value required is 3.9μH. L= ⎛ V ⎞ VOUT ⋅ 1 - OUT IO ⋅ k ⋅ FS ⎝ VIN ⎠ L= 1.5V ⎛ 1.5V ⎞ ⋅11.0A ⋅ 0.3 ⋅ 830kHz ⎝ 4.2V⎠ The factor "k" is the fraction of full load selected for the ripple current at the maximum input voltage. The corresponding inductor RMS current is: IRMS = ⎛ 2 ΔI2⎞ ≈ Io = 1.0A I + ⎝o 12⎠ ΔI is the peak-to-peak ripple current which is fixed by the inductor selection above. For a peak-to-peak current of 30% of the full load current, the peak current at full load will be 115% of the full load. The 4.1μH inductor selected from the Sumida CDRH5D18 series has a 57mΩ DCR and a 1.95A DC current rating. At full load, the inductor DC loss is 57mW which amounts to a 3.8% loss in efficiency. Input Capacitor The primary function of the input capacitor is to provide a low impedance loop for the edges of pulsed current drawn by the AAT1150. A low ESR/ESL ceramic capacitor is ideal for this function. To minimize stray inductance, the capacitor should be placed as closely as possible to the IC. This keeps the high frequency content of the input current localized, minimizing radiated and conducted EMI while facilitating optimum performance of the AAT1150. Ceramic X5R or X7R capacitors are ideal for this function. The size required will vary depending on the load, output voltage, and input voltage source impedance characteristics. A typical value is around 10μF. The input capacitor RMS L = 3.9μH 1150.2006.09.1.5 11 AAT1150 1MHz 1A Step-Down DC/DC Converter current varies with the input voltage and the output voltage. The equation for the RMS current in the input capacitor is: VO ⎛ VO ⎞ ⋅ 1VIN ⎠ VIN ⎝ IRMS = IO ⋅ The input capacitor RMS ripple current reaches a maximum when VIN is two times the output voltage where it is approximately one half of the load current. Losses associated with the input ceramic capacitor are typically minimal and are not an issue. Proper placement of the input capacitor can be seen in the reference design layout shown in Figures 4 and 5. Output Capacitor Since there are no external compensation components, the output capacitor has a strong effect on loop stability. Larger output capacitance will reduce the crossover frequency with greater phase margin. For the 1.5V 1.0A design using the 4.1μH inductor, three 22μF 6.3V X5R capacitors provide a stable output. In addition to assisting stability, the output capacitor limits the output ripple and provides holdup during large load transitions. The output capacitor RMS ripple current is given by: IRMS = 1 2⋅ 3 ⋅ For applications requiring an output other than the fixed outputs available, the 1V version can be programmed externally (see Figure 6). Resistors R3 and R4 force the output to regulate higher than 1V. R4 should be 100 times less than the internal 1mΩ resistance of the FB pin. Once R4 is selected, R3 can be calculated. For a 1.25V output with R4 set to 10kΩ, R3 is 2.55kΩ. R3 = (VO - 1) ⋅ R4 = 0.25 ⋅ 10.0kΩ = 2.55kΩ Layout Considerations Figures 4 and 5 display the suggested PCB layout for the AAT1150. The most critical aspect of the layout is the placement of the input capacitor C1. For proper operation, C1 must be placed as closely as possible to the AAT1150. Thermal Calculations There are two types of losses associated with the AAT1150 output switching MOSFET: switching losses and conduction losses. Conduction losses are associated with the RDS(ON) characteristics of the output switching device. At full load, assuming continuous conduction mode (CCM), a simplified form of the total losses is: VOUT ⋅ (VIN - VOUT) L ⋅ FS ⋅ VIN For a ceramic capacitor, the dissipation due to the RMS current of the capacitor is not a concern. Tantalum capacitors, with sufficiently low ESR to meet output voltage ripple requirements, also have an RMS current rating much greater than that actually seen in this application. 12 Adjustable Output PLOSS = IO2 ⋅ (RDS(ON)H ⋅ VO + RDS(ON)L ⋅ (VIN - VO)) VIN + tsw ⋅ FS ⋅ IO ⋅ VIN + IQ ⋅ VIN Once the total losses have been determined, the junction temperature can be derived from the ΘJA for the MSOP-8 package. 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter Figure 4: AAT1150 Evaluation Board Layout Top Layer. Figure 5: AAT1150 Evaluation Board Layout Bottom Layer. AAT1150-1.0 VIN+ 3.3V VP R1 100 R2 C1 10μF 100k C7 0.1μF EN R3 2.55k 1% V O + 1.25V 1A FB R4 10k 1% VCC EN LX SGND PGND LX L1 2.7μH C2, C3, C4 3x 22μF 6.3V VC1 Murata 10μF 6.3V X5R GRM42-6X 5R106K6.3 C2, C3, C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805 L1 Sumida CDRH4D28-2R7μH Figure 6: 3.3V to 1.25V Converter (Adjustable Output). 1150.2006.09.1.5 13 AAT1150 1MHz 1A Step-Down DC/DC Converter Design Example Specifications = 1.0A IOUT IRIPPLE = 30% of Full Load at Max VIN VOUT = 1.5V VIN = 2.7V to 4.2V (3.6V nominal) Fs = 830kHz Maximum Input Capacitor Ripple IRMS = IO ⋅ VO ⎛ VO ⎞ IO ⋅ 1= = 0.5ARMS, VIN = 2 ⋅ VO VIN ⎝ VIN⎠ 2 P = ESRCOUT ⋅ IRMS2 = 5mΩ ⋅ 0.52 A = 1.25mW Inductor Selection L= ⎛ VOUT V ⎞ 1.5V 1.5V⎞ ⎛ ⋅ 1 - OUT = ⋅ 1= 3.9μH IO ⋅ k ⋅ FS ⎝ VIN ⎠ 1.0A ⋅ 0.3 ⋅ 830kHz ⎝ 4.2V⎠ Select Sumida inductor CDRH5D18, 4.1μH, 57mΩ, 2.0mm height. ΔI = ⎛ 1.5V ⎞ VO 1.5V ⎛ V ⎞ ⋅ 1- O = ⋅ 1= 280mA 4.1μH ⋅ 830kHz ⎝ 4.2V⎠ L ⋅ FS ⎝ VIN ⎠ IPK = IOUT + ΔI = 1.0A + 0.14A = 1.14A 2 P = IO2 ⋅ DCR = 57mW Output Capacitor Dissipation IRMS = VOUT ⋅ (VIN - VOUT) 1.5V ⋅ (4.2V - 1.5V) 1 1 ⋅ ⋅ = = 82mARMS L ⋅ FS ⋅ VIN 2⋅ 3 2 ⋅ 3 4.1μH ⋅ 830kHz ⋅ 4.2V PESR = ESRCOUT ⋅ IRMS2 = 5mΩ ⋅ 0.0822A = 33μW 14 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter AAT1150 Dissipation P= = IO2 ⋅ (RDS(ON)H ⋅ VO + RDS(ON)L ⋅ (VIN -VO)) VIN (0.14Ω ⋅ 1.5V + 0.145Ω ⋅ (3.6V - 1.5V)) 3.6V + (tsw ⋅ FS ⋅ IO + IQ) ⋅ VIN + (20nsec ⋅ 830kHz ⋅ 1.0A + 0.3mA) ⋅ 3.6V = 0.203W TJ(MAX) = TAMB + ΘJA ⋅ PLOSS = 85°C + 150°C/W ⋅ 0.203W = 115°C Manufacturer Part Number Value Max DC Current DCR TaiyoYuden Toko Sumida Sumida MuRata MuRata NPO5DB4R7M A914BYW-3R5M-D52LC CDRH5D28-4R2 CDRH5D18-4R1 LQH55DN4R7M03 LQH66SN4R7M03 4.7μH 3.5μH 4.2μH 4.1μH 4.7μH 4.7μH 1.4A 1.34A 2.2A 1.95A 2.7A 2.2A 0.038 0.073 0.031 0.057 0.041 0.025 Size (mm) L×W×H Type 5.9 × 6.1 × 2.8 Shielded 5.0 × 5.0 × 2.0 Shielded 5.7 × 5.7 × 3.0 Shielded 5.7 × 5.7 × 2.0 Shielded 5.0 × 5.0 × 4.7 Non-Shielded 6.3 × 6.3 × 4.7 Shielded Table 1: Surface Mount Inductors. Manufacturer Part Number MuRata MuRata MuRata MuRata GRM40 X5R 106K 6.3 GRM42-6 X5R 106K 6.3 GRM21BR60J226ME39L GRM21BR60J106ME39L Value Voltage Temp. Co. Case 10μF 10μF 22μF 10μF 6.3V 6.3V 6.3V 6.3V X5R X5R X5R X5R 0805 1206 0805 0805 Table 2: Surface Mount Capacitors. 1150.2006.09.1.5 15 AAT1150 1MHz 1A Step-Down DC/DC Converter Ordering Information Output Voltage1 Package Marking2 Part Number (Tape and Reel)3 1.0V (Adj VOUT ≥ 1.0V) 1.5V 1.8V 2.5V 3.3V MSOP-8 MSOP-8 MSOP-8 MSOP-8 MSOP-8 JZXYY HYXYY KAXYY KCXYY HZXYY AAT1150IKS-1.0-T1 AAT1150IKS-1.5-T1 AAT1150IKS-1.8-T1 AAT1150IKS-2.5-T1 AAT1150IKS-3.3-T1 All AnalogicTech products are offered in Pb-free packaging. The term “Pb-free” means semiconductor products that are in compliance with current RoHS standards, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. For more information, please visit our website at http://www.analogictech.com/pbfree. Package Information MSOP-8 4° ± 4° 4.90 ± 0.10 3.00 ± 0.10 1.95 BSC 0.95 REF 0.60 ± 0.20 PIN 1 3.00 ± 0.10 0.85 ± 0.10 0.95 ± 0.15 10° ± 5° GAUGE PLANE 0.254 BSC 0.155 ± 0.075 0.075 ± 0.075 0.65 BSC 0.30 ± 0.08 All dimensions in millimeters. 1. Contact sales for custom voltage options. 2. XYY = assembly and date code. 3. Sample stock is held on part numbers listed in BOLD. 16 1150.2006.09.1.5 AAT1150 1MHz 1A Step-Down DC/DC Converter © Advanced Analogic Technologies, Inc. AnalogicTech cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in an AnalogicTech product. No circuit patent licenses, copyrights, mask work rights, or other intellectual property rights are implied. AnalogicTech reserves the right to make changes to their products or specifications or to discontinue any product or service without notice. Customers are advised to obtain the latest version of relevant information to verify, before placing orders, that information being relied on is current and complete. All products are sold subject to the terms and conditions of sale supplied at the time of order acknowledgement, including those pertaining to warranty, patent infringement, and limitation of liability. AnalogicTech warrants performance of its semiconductor products to the specifications applicable at the time of sale in accordance with AnalogicTech’s standard warranty. Testing and other quality control techniques are utilized to the extent AnalogicTech deems necessary to support this warranty. Specific testing of all parameters of each device is not necessarily performed. AnalogicTech and the AnalogicTech logo are trademarks of Advanced Analogic Technologies Incorporated. All other brand and product names appearing in this document are registered trademarks or trademarks of their respective holders. Advanced Analogic Technologies, Inc. 830 E. Arques Avenue, Sunnyvale, CA 94085 Phone (408) 737-4600 Fax (408) 737-4611 1150.2006.09.1.5 17