ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 Advanced Product Information – All Information Subject to Change 1.5A, PWM Step-Down DC/DCs in TDFN FEATURES GENERAL DESCRIPTION • • • • • The patent-pending ACT8309/ACT8310/ACT8311 are current-mode, fixed-frequency PWM, synchronous step-down DC/DC converters that are capable of delivering 1.5A with efficiency of up to 95%. These devices operate with a fixed frequency of 1.35MHz, minimizing noise in sensitive equipment as well as optimizing both efficiency and component size and cost. • • • • • • Multiple Patents Pending Up to 95% High Efficiency Up to 1.5A Guaranteed Output Current (ACT8311) 1.35MHz Constant Frequency Operation Internal Synchronous Rectifier Eliminates Schottky Diode ACT8309: Up to 900mA ACT8310: Up to 1.2A ACT8311: Up to 1.5A 100% Duty Cycle Low-Dropout Operation 0.1µA Shutdown Current Small TDFN33-8 Package − RoHS-Compliant These devices feature very low-resistance power MOSFET and 100% duty cycle operation, making them ideal choices for portable applications requiring a 3.0V or 3.3V rail to be generated from a Li+ battery. The ACT8311 is capable of supplying up to 1.5A of output current, while the ACT8309 and ACT8310 are capable of supplying up to 900mA and 1.2A, respectively. All three devices have adjustable output voltages that are programmable down to 1.2V. Contact Active-Semi for custom fixed output voltage availability. • Independent Enable/Disable Control • Minimal External Components APPLICATIONS • Wireless Handhelds • Portable Devices • GPS/PND equipment SYSTEM BLOCK DIAGRAM 2.7V to 5.0V ON OFF Power-OK Output Innovative Products. Active Solutions. IN Active-Semi SW VOUT Up to 1.5A ACT8311 EN FB Pb-free POK GP G -1- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 ORDERING INFORMATION PART NUMBER OUTPUT CURRENT OUTPUT VOLTAGE PACKAGE PINS TEMPERATURE RANGE ACT8309NHADJ-T 0.9A Adjustable TDFN33-8 8 -40°C to +85°C ACT8309NHxyz-T 0.9A 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, 3.3Vc TDFN33-8 8 -40°C to +85°C ACT8310NHADJ-T 1.2A Adjustable TDFN33-8 8 -40°C to +85°C ACT8310NHxyz-T 1.2A 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, 3.3Vc TDFN33-8 8 -40°C to +85°C ACT8311NHADJ-T 1.5A Adjustable TDFN33-8 8 -40°C to +85°C ACT8311NHxyz-T 1.5A 1.2V, 1.5V, 1.8V, 2.5V, 3.0V, 3.3Vc TDFN33-8 8 -40°C to +85°C c: Fixed output voltage options are available for production subject to minimum order quantities. Contact Active-Semi for more information regarding fixed output voltage options. PIN CONFIGURATION IN 1 GP 2 IN 3 G 4 ACT8309 ACT8310 ACT8311 8 SW 7 EN 6 POK 5 FB TDFN33-8 PIN DESCRIPTIONS PIN NAME DESCRIPTION 1, 3 IN Power Input. Bypass to GP close to IC with a high quality ceramic capacitor. 2 GP Power Ground. Connect to G with a short trace. 4 G Analog Ground. Connect to GP with a short trace. 5 FB Feedback Node. For fixed output voltage versions, connect this pin directly to the output. For the adjustable output versions the voltage at this pin is regulated to 0.8V, connect to this pin to the center of the output feedback resistor divider for voltage setting. 6 POK Open-Drain Power-OK Status Output. POK is an open-drain output which sinks current when the output voltage is less than 95% of the normal value. When the IC is disabled, POK is high impedance. 7 EN Enable Input. When higher than 1.4V, this pin turns the IC on. When lower than 0.4V, this pin turn the IC off. 8 SW Switch Output. Connect this pin to the switching end of the inductor. Innovative Products. Active Solutions. -2- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT IN, SW to GP -0.3 to +5.5 V FB, EN, POK to G -0.3 to +5.5 V -0.3 to VIN + 0.3 V -0.3 to +0.3 V Internally limited A 61 °C/W 1.63 W Operating Junction Temperature -40 to 150 °C Storage Temperature -55 to 150 °C 300 °C FB, EN, SW Voltage GP to G Continuous SW Current Junction to Ambient Thermal Resistance (θJA) Maximum Power Dissipation (derate 5.3mW/°C above TA = 50°C) Lead Temperature (Soldering, 10 sec) c: Do not exceed these limits to prevent damage to the device. Exposure to absolute maximum rating conditions for long periods may affect device reliability. Innovative Products. Active Solutions. -3- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 ELECTRICAL CHARACTERISTICS (VIN = VEN = 3.6V, TA = 25˚C, unless otherwise specified.) PARAMETER Input Voltage Range Under Voltage Lockout Threshold SYMBOL TEST CONDITIONS VIN VUVLO MIN TYP MAX UNIT 5.0 V 2.5 2.6 V 2.7 VIN rising, hysteresis = 80mV 2.35 Standby Supply Current VFB = 103%VFB,TYP, IOUT = 0 150 310 µA Shutdown Supply Current EN = G, VIN = 4.2V 0.1 1 µA TA = 25°C 0.786 0.80 0.814 -40°C < TA < 85°C 0.776 0.80 0.824 TA = 25°C -2% VNOM +2% -40°C < TA < 85°C -3% VNOM +3% Output Voltage Line Regulation 0.06 0.4 Output Voltage Load Regulation 0.6 FB Voltage VFB Output Voltage Accuracy Current Limit Max Output Current Oscillator Frequency PMOS On-Resistance NMOS On-Resistance fSW RONP RONN 1.1 1.3 1.8 ACT8310NH 1.4 1.7 2.2 ACT8311NH 1.75 2.1 2.8 ACT8309NH 0.9 ACT8310NH 1.2 ACT8311NH 1.5 1.35 1.6 VFB = 0.1V 450 ACT8309, ISW = -100mA 0.15 0.234 ACT8310, ISW = -100mA 0.12 0.192 ACT8311, ISW = -100mA 0.10 0.165 ISW = 100mA 0.15 0.26 EN Logic High Threshold VIH VIN = 2.7V to 5.0V EN Logic Low Threshold VIL VIN = 2.7V to 5.0V EN Input Bias Current IEN VIN = 5.0V, EN = G or IN POK Threshold 1.05 V %/V % ACT8309NH VOUT = 80% of VOUT,NOM V A A MHz kHz 1.4 Ω Ω V 0.01 % of VOUT,NOM 95 0.4 V 0.1 µA % POK Output Low Voltage VOL IPOK = 100µA 0.008 0.012 V POK Leakage Current IPOK VPOK = 5.0V 0.01 0.1 µA Innovative Products. Active Solutions. -4- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 Figure1: Functional Block Diagram Active-Semi ACT8309 ACT8310 ACT8311 IN EN IN SW GATE DRIVER PWM CONTROL OUT OUT GP POK FB G Figure 2: Typical Application Circuit 2.7V to 5.0V IN 10µF IN Active-Semi 3.3µH SW OUT EN ACT8311 549k? 549kΩ OUT 3.0V Up to 1.5A 22µF FB 100k? 100kΩ 200k? 200kΩ POK GP Innovative Products. Active Solutions. G -5- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 FUNCTIONAL DESCRIPTION For most applications, a 22µF ceramic output capacitor is recommended. Although the these regulators were designed to take advantage of the benefits of ceramic capacitors, namely small size and very-low ESR, low-ESR tantalum capacitors can provide acceptable results as well. The patent-pending ACT8309/ACT8310/ACT8311 are current-mode, fixed-frequency PWM, synchronous step-down DC/DC converters that are capable of delivering up to 1.5A (ACT8311) with efficiency of up to 95%. These devices feature very lowresistance power MOSFETs and 100% duty cycle operation, making them ideal choices for portable applications requiring a 3.0V or 3.3V rail to be generated form a Li+ battery. These device operate with a fixed frequency of 1.35MHz, minimizing noise in sensitive equipment as well as optimizing both efficiency and component size and cost. Inductor Selection These devices were optimized for operation with 3.3µH inductors, although inductors in the 1.5µH to 4.7µH range may be used. Choose an inductors with a low DC-resistance, and avoid inductor saturation by choosing inductors with DC ratings that exceed the maximum output current of the application by at least 30%. 100% Duty Cycle Operation These devices are capable of operating at up to 100% duty cycle operation. During 100% duty cycle operation, the high-side power MOSFET is held on continuously, providing a direct connection from the input to the output (through the inductor), ensuring the lowest possible dropout voltage in batterypowered applications. Output Voltage Setting Figure 3 shows the feedback network necessary to set the output voltage when using adjustable output voltage options. output voltage options. Select components as follows: Set RFB2 = 200kΩ, calculate RFB1 using the following equation: Synchronous Rectification ⎛V ⎞ RFB1 = RFB2 ⎜⎜ OUT − 1⎟⎟ ⎝ VFB ⎠ The ACT8309/ACT8310/ACT8311 each feature integrated n-channel synchronous rectifiers, maximizing efficiency and minimizing the total solution size and cost by eliminating the need for external rectifiers. Where VFB is 0.8V. Figure 3: Soft-Start Output Voltage Setting The ACT8309/ACT8310/ACT8311 each include integrated soft-start circuitry. When enabled, the output voltage track an internal 200µs soft-start ramp so that the output power up in a controlled, monotonic manner that is independent of loading. VOUT ACT8309/ ACT8310/ ACT8311 RFB1 FB RFB2 Compensation The ACT8309/ACT8310/ACT8311 each utilize current-mode control and a proprietary internal compensation scheme to simultaneously simplify external component selection and optimize transient performance over their full operating range. No compensation design is required, simply follow a few simple guidelines described below when choosing external components. Enable/Disable Control These devices may be enabled and disabled using the EN input. Drive EN to a logic-high to enable the regulator, drive EN to a logic-low to disable the regulator. When disabled, each regulator’s quiescent supply current drops to less than 1µA. Power-OK Output (POK) Capacitor Selection These devices feature an open-drain “Power-OK” indicator output. This output sinks current whenever the output voltage is (typically) 5% below the regulation voltage, and goes high-impedance when the output voltage is above this threshold. To generate The input capacitor reduces peak currents and noise induced upon the voltage source. A 10µF ceramic capacitor is recommended for most applications. Innovative Products. Active Solutions. -6- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 a logic-level “Power-OK” signal, simply connect a pullup resistor from POK to an appropriate output voltage. PCB Layout Considerations High switching frequencies and large peak current make PC board layout an important part of stepdown DC/DC converter design. A good design minimizes excessive EMI on the feedback paths and voltage gradients in the ground plane, both of which can result in instability or regulation errors. Step-down DC/DCs exhibit discontinuous input current, so the input capacitors should be placed as close as possible to the IC, and avoiding the use of vias if possible. The inductor, input filter capacitor, and output filter capacitor should be connected as close together as possible, with short, direct, and wide traces. The ground nodes for each regulator’s power loop should be connected at a single point in a star-ground configuration, and this point should be connected to the backside ground plane with multiple vias. For fixed output voltage options the output node for each regulator should be connected to its corresponding FB pin through the shortest possible route, while keeping sufficient distance from switching nodes to prevent noise injection. Adjustable output versions should follow the same guidelines, but additionally connect the feedback resistors to the FB pin as close to the IC as possible to minimize noise injection. Innovative Products. Active Solutions. -7- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = VEN = 3.6V, TA = 25°C, unless otherwise specified.) ACT8309 Dropout Voltage vs. Load Current ACT8309 Efficiency vs. Load Current VOUT = 3.0V 60 VOUT = 1.2V VOUT = 1.8V VOUT = 3.3V 50 40 180 Dropout Voltage (mV) Efficiency (%) 80 30 20 10 140 VOUT = 3.0V 120 100 80 60 40 0 10 1 VOUT = 3.3V 160 20 VIN = 3.6V 0 100 1000 0 10000 100 200 ACT8310 Efficiency vs. Load Current 40 180 Dropout Voltage (mV) Efficiency (%) VOUT = 1.2V VOUT = 3.3V 50 30 20 10 700 800 900 VOUT = 3.3V 160 140 VOUT = 3.0V 120 100 80 60 40 20 VIN = 3.6V 0 0 1 10 100 1000 0 10000 40 200 Dropout Voltage (mV) VOUT = 1.2V VOUT = 3.3V 50 30 20 10 0 VOUT = 3.3V 180 160 VOUT = 3.0V 140 120 100 80 60 40 20 VIN = 3.6V 1 1200 ACT8309/8310/8311-006 80 VOUT = 1.8V 1000 220 ACT8309/8310/8311-005 90 VOUT = 3.0V 800 ACT8311 Dropout Voltage vs. Load Current ACT8311 Efficiency vs. Load Current 60 600 Load Current (mA) 100 70 400 200 Load Current (mA) Efficiency (%) 600 ACT8309/8310/8311-004 80 VOUT = 1.8V 500 200 ACT8309/8310/8311-003 90 VOUT = 3.0V 400 ACT8310 Dropout Voltage vs. Load Current 100 70 300 Load Current (mA) Load Current (mA) 60 ACT8309/8310/8311-002 90 70 200 ACT8309/8310/8311-001 100 0 10 100 1000 0 10000 Load Current (mA) Innovative Products. Active Solutions. 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.5 Load Current (mA) -8- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 TYPICAL PERFORMANCE CHARACTERISTICS (VIN = VEN = 3.6V, TA = 25°C, unless otherwise specified.) Startup Waveform ACT8309/8310/8311-008 CH1 ACT8309/8310/8311-007 VIN = 4.2V VOUT = 3.3V IOUT = 1A Load Transient Response VVOUT = 3.3V IN = 4.2V VOUT = 3.3V CH1 CH2 CH2 CH1: VOUT, 100mV/div (AC COUPLED) CH2: Load Current (100mA to 1000mA) TIME: 100µs CH1: VOUT, 1.0V/div CH2: POK, 2.0V/div TIME: 100µs Innovative Products. Active Solutions. -9- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8309/8310/8311 Active-Semi Rev PrA, 24-Jan-08 PACKAGE OUTLINE TDFN33-8 PACKAGE OUTLINE AND DIMENSIONS SYMBOL DIMENSION IN MILLIMETERS DIMENSION IN INCHES MIN MAX MIN MAX A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.153 0.253 0.006 0.010 D 2.900 3.100 0.114 0.122 E 2.900 3.100 0.114 0.122 D2 2.200 2.400 0.087 0.094 E2 1.400 1.600 0.055 0.063 b 0.200 0.320 0.008 0.013 e L 0.650 TYP 0.375 0.575 0.026 TYP 0.015 0.023 Active-Semi, Inc. reserves the right to modify the circuitry or specifications without notice. Users should evaluate each product to make sure that it is suitable for their applications. Active-Semi products are not intended or authorized for use as critical components in lifesupport devices or systems. Active-Semi, Inc. does not assume any liability arising out of the use of any product or circuit described in this datasheet, nor does it convey any patent license. Active-Semi and its logo are trademarks of Active-Semi, Inc. For more information on this and other products, contact [email protected] or visit http://www.active-semi.com. For other inquiries, please send to: 1270 Oakmead Parkway, Suite 310, Sunnyvale, California 94085-4044, USA Innovative Products. Active Solutions. - 10 - www.active-semi.com Copyright © 2008 Active-Semi, Inc.