ACT8325 Active-Semi Rev0, 13-May-08 Dual PWM Step-Down DC/DCs in TDFN33 FEATURES GENERAL DESCRIPTION • Multiple Patents Pending • Two Integrated Step-Down DC/DC Converters The patent-pending ACT8325 integrates two stepdown DC/DCs into a single, thin, space-saving package to provide a cost-effective, highly-efficient ActivePMUTM power management solution. This device is ideal for a wide range of portable handheld equipment that can benefit from the advantages of ActivePMU technology but do not require a high level of integration. − REG1: 350mA − REG2: 550mA • 180° Out-of-Phase Operation − Reduces Input Capacitor Requirements • • • • Fixed or Adjustable Output Voltage Options REG1 and REG2 are fixed-frequency, current-mode PWM step-down DC/DC converters that are optimized for high efficiency and are capable of supplying up to 350mA and 550mA, respectively. Both outputs are available in a wide range of factorypreset output voltage options, and an adjustable output voltage mode is also available. Independent Enable/Disable Control Minimal External Components 3x3mm, Thin-DFN (TDFN33-10) Package − Only 0.75mm Height − RoHS-Compliant The ACT8325 is available in a tiny 3mm x 3mm 10-pin Thin-DFN package that is just 0.75mm thin. APPLICATIONS • Portable Devices and PDAs • MP3/MP4 Players • Wireless Handhelds • GPS Receivers SYSTEM BLOCK DIAGRAM REG1 Step-Down DC/DC Battery ON1 System Control REG2 ON2 Step-Down DC/DC OUT1 Adjustable, or 1.2V to 3.3V Up to 350mA OUT2 Adjustable, or 1.2V to 3.3V Up to 550mA ACT8325 PMU TM Active Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -1- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 FUNCTIONAL BLOCK DIAGRAM Active-Semi VP1 To Battery ACT8325 ON1 REG1 UVLO ON2 SW1 OUT1 FB1 GP12 VP2 GA REG2 To Battery SW2 OUT2 FB2 GP12 Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -2- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 ORDERING INFORMATIONcd PART NUMBER VOUT1 VOUT2 PACKAGE PINS TEMPERATURE RANGE ACT8325NDAAA-T Adjustable Adjustable TDFN33-10 10 -40°C to +85°C OUTPUT VOLTAGE CODES A C P J D E F I Q G H Adjustable 1.2V 1.3V 1.4V 1.5V 1.8V 2.5V 2.8V 2.85V 3.0V 3.3V c: Output voltage options detailed in this table represent standard voltage options, and are available for samples or production orders. Additional output voltage options, as detailed in the Output Voltage Codes table, are available for production subject to minimum order quantities. Contact Active-Semi for more information regarding semi-custom output voltage combinations. d: All Active-Semi components are RoHS Compliant and with Pb-free plating unless specified differently. The term Pb-free means semiconductor products that are in compliance with current RoHS (Restriction of Hazardous Substances) standards. PIN CONFIGURATION TOP VIEW VP1 1 10 FB1 SW1 2 9 ON2 GP12 3 8 ON1 SW2 4 7 GA VP2 5 6 FB2 Active-Semi ACT8325 Thin - DFN (TDFN 33-10) Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -3- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 PIN DESCRIPTIONS PIN NAME DESCRIPTION 1 VP1 Power Input for REG1. Bypass to GP12 with a high quality ceramic capacitor placed as close as possible to the IC. 2 SW1 Switching Node Output for REG1. Connect this pin to the switching end of the inductor. 3 GP12 Power Ground for REG1, REG2. Connect GA and GP12 together at single point as close to the IC as possible. 4 SW2 Switching Node Output for REG2. Connect this pin to the switching end of the inductor. 5 VP2 Power Input for REG2. Bypass to GP12 with a high quality ceramic capacitor placed as close as possible to the IC. 6 FB2 Feedback Node for REG2. For fixed output voltage options, connect this pin directly to the output. For the adjustable output voltage options the voltage at this pin is regulated to 0.625V, connect this pin to the center of the output feedback resistor divider for voltage setting. 7 GA Analog Ground. Connect GA directly to a quiet ground node. Connect GA and GP12 together at a single point as close to the IC as possible. 8 ON1 Enable Control Input for REG1. Drive ON1 to VP1 or to a logic high for normal operation, drive to GA or to a logic low to disable REG1. 9 ON2 Enable Control Input for REG2. Drive ON2 to VP1or to a logic high for normal operation, drive to GA or to a logic low to disable REG2. 10 FB1 Feedback Node for REG1. For fixed output voltage options, connect this pin directly to the output. For the adjustable output voltage options the voltage at this pin is regulated to 0.625V, connect this pin to the center of the output feedback resistor divider for voltage setting. EP EP Exposed Pad. Must be soldered to ground on PCB. Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -4- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 ABSOLUTE MAXIMUM RATINGSc PARAMETER VALUE UNIT VP1, SW1, VP2, SW2 to GP12, FB1, FB2, ON1, ON2 to GA -0.3 to +6 V SW1 to VP1, SW2 to VP2 -6 to +0.3 V -0.3 to +0.3 V 33 °C/W -40 to 85 °C Junction Temperature 125 °C Storage Temperature -55 to 150 °C 300 °C GP12 to GA Junction to Ambient Thermal Resistance (θJA) Operating Temperature Range 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 PowerTM ActivePMUTM is a trademark of Active-Semi. -5- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 STEP-DOWN DC/DC CONVERTER ELECTRICAL CHARACTERISTICS (REG1) (VVP1 = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS VP1 Operating Voltage Range MIN 3.1 VP1 UVLO Threshold Input Voltage Rising VP1 UVLO Hysteresis Input Voltage Falling 2.9 ON1 = GA, VVP1 = 4.2V Adjustable Output Option Regulation Voltage Output Voltage Regulation Accuracy UNIT 5.5 V 3.1 V mV 130 200 µA 0.1 1 µA 0.625 V VNOM1 < 1.3V, IOUT1 = 10mA -2.4% VNOM1 +1.8% VNOM1 ≥ 1.3V, IOUT1 = 10mA -1.2% VNOM1c +1.8% Line Regulation VVP1 = Max(VNOM1 + 1V, 3.2V) to 5.5V Load Regulation IOUT1 = 10mA to 350mA Current Limit Oscillator Frequency 3 MAX 80 Standby Supply Current Shutdown Supply Current TYP VOUT1 ≥ 20% of VNOM1 V 0.15 %/V 0.0017 %/mA 0.45 0.6 A 1.35 1.6 1.85 MHz VOUT1 = 0V 530 PMOS On-Resistance ISW1 = -100mA 0.52 0.88 Ω NMOS On-Resistance ISW1 = 100mA 0.27 0.46 Ω SW1 Leakage Current VVP1 = 5.5V, VSW1 = 5.5V or 0V 1 µA kHz Power Good Threshold 94 %VNOM1 Minimum On-Time 70 ns Logic High Input Voltage ON1 1.4 V Logic Low Input Voltage ON1 Thermal Shutdown Temperature Temperature Rising 160 °C Thermal Shutdown Hysteresis Temperature Falling 20 °C 0.4 V c: VNOM1 refers to the nominal output voltage level for VOUT1 as defined by the Ordering Information section. Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -6- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 STEP-DOWN DC/DC CONVERTER ELECTRICAL CHARACTERISTICS (REG2) (VVP2 = 3.6V, TA = 25°C, unless otherwise specified.) PARAMETER TEST CONDITIONS VP2 Operating Voltage Range MIN 3.1 VP2 UVLO Threshold Input Voltage Rising VP2 UVLO Hysteresis Input Voltage Falling 2.9 ON2 = GA, VVP2 = 4.2V Adjustable Output Option Regulation Voltage Output Voltage Regulation Accuracy UNIT 5.5 V 3.1 V mV 130 200 µA 0.1 1 µA 0.625 V VNOM2 < 1.3V, IOUT2 = 10mA -2.4% VNOM2c +1.8% VNOM2 ≥ 1.3V, IOUT2 = 10mA -1.2% VNOM2 +1.8% Line Regulation VVP2 = Max(VNOM2 + 1V, 3.2V) to 5.5V Load Regulation IOUT2 = 10mA to 550mA Current Limit Oscillator Frequency 3 MAX 80 Standby Supply Current Shutdown Supply Current TYP VOUT2 ≥ 20% of VNOM2 V 0.15 %/V 0.0017 %/mA 0.65 0.85 A 1.35 1.6 1.85 MHz VOUT2 = 0V 530 PMOS On-Resistance ISW2 = -100mA 0.40 0.68 Ω NMOS On-Resistance ISW2 = 100mA 0.27 0.46 Ω SW2 Leakage Current VVP2 = 5.5V, VSW2 = 5.5V or 0V 1 µA kHz Power Good Threshold 94 %VNOM2 Minimum On-Time 70 ns Logic High Input Voltage ON2 1.4 V Logic Low Input Voltage ON2 Thermal Shutdown Temperature Temperature Rising 160 °C Thermal Shutdown Hysteresis Temperature Falling 20 °C 0.4 V c: VNOM2 refers to the nominal output voltage level for VOUT2 as defined by the Ordering Information section. Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. -7- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 STEP-DOWN DC/DC CONVERTER TYPICAL PERFORMANCE CHARACTERISTICS (ACT8325NDAAA, VVP1 = VVP2 = 3.6V, L = 3.3µH, CVP1 = CVP2 = 2.2µF, COUT1 = COUT2 = 10µF, TA = 25°C, unless otherwise specified.) REG1 Efficiency vs. Load Current Efficiency (%) 85 80 100 VIN = 4.2V 75 3.6V VOUT2 = 3.3V 90 Efficiency (%) VIN = 3.6V ACT8325-002 VOUT1 = 1.2V 90 REG2 Efficiency vs. Load Current ACT8325-001 95 70 65 60 4.2V 80 70 60 55 50 50 1 10 1000 100 1 0.1 Output Current (mA) OUT1 Regulation Voltage 0.22 OUT2 Voltage (%) OUT1 Voltage (%) 0.44 0.33 0.11 0.00 -0.11 -0.22 -0.33 0.18 0.09 0.00 -0.09 -0.18 -0.27 -0.36 -0.56 -0.45 -0.55 -0.67 -20 0 20 40 60 IOUT2 = 35mA 0.36 0.27 -0.44 -40 -40 85 -20 Temperature (°C) REG1 MOSFET Resistance 20 40 60 85 REG2 MOSFET Resistance PMOS RDSON (mΩ) 400 PMOS 360 NMOS 200 ACT8325-006 440 ACT8325-005 500 RDSON (mΩ) 0 Temperature (°C) 600 300 1000 ACT8325-004 IOUT1 = 35mA 0.56 100 OUT2 Regulation Voltage 0.55 0.45 ACT8325-003 0.67 10 Output Current (mA) 280 NMOS 200 120 100 40 0 0 2.5 3.0 3.5 4.0 4.5 5.0 2.5 5.5 ActivePMUTM is a trademark of Active-Semi. 3.5 4.0 4.5 5.0 5.5 VP2 Voltage (V) VP1 Voltage (V) Innovative PowerTM 3.0 -8- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 STEP-DOWN DC/DC CONVERTER FUNCTIONAL DESCRIPTION General Description Compensation REG1 and REG2 are fixed-frequency, currentmode, synchronous PWM step-down converters that achieve peak efficiencies of up to 97%. REG1 is capable of supplying up to 350mA of output current, while REG2 supports up to 550mA. These regulators operate with a fixed frequency of 1.6MHz, minimizing noise in sensitive applications and allowing the use of small external components. REG1 and REG2 are available with a variety of standard and custom output voltages, as described in the Ordering Information section of this datasheet. REG1 and REG2 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. Thermal Shutdown The ACT8325 integrates thermal shutdown protection circuitry to prevent damage resulting from excessive thermal stress, as may be encountered under fault conditions. This circuitry disables all regulators if the ACT8325 die temperature exceeds 160°C, and prevents the regulators from being enabled until the IC temperature drops by 20°C (typ). 100% Duty Cycle Operation Both REG1 and REG2 are capable of operating at up to 100% duty cycle. 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. Input Capacitor Selection The input capacitor reduces peak currents and noise induced upon the voltage source. A 2.2µF ceramic capacitor for each of REG1 and REG2 is recommended for most applications. Synchronous Rectification Output Capacitor Selection REG1 and REG2 both feature integrated n-channel synchronous rectifiers, maximizing efficiency and minimizing the total solution size and cost by eliminating the need for external rectifiers. For most applications, 10µF ceramic output capacitors are recommended for both REG1 and REG2. 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. Enabling and Disabling REG1 and REG2 Each of the ACT8325's regulators features independent pin-controlled enable control. Drive ON1 to a logic-high to enable REG1, drive ON1 to a logiclow to disable REG1. Similarly, drive ON2 to a logic-high to enable REG2, drive ON2 to a logic-low to disable REG2. When disabled, each regulator's supply current drops to less than 1µA. Output Voltage Programming Figure 4: Output Voltage Programming OUTx Soft-Start REG1 and REG2 each include matched soft-start circuitry. When enabled, the output voltages track the internal 80µs soft-start ramp and both power up in a monotonic manner that is independent of loading on either output. This circuitry ensures that both outputs power up in a controlled manner, greatly simplifying power sequencing design considerations. Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. CFF ACT8325 RFB1 FBx RFB2 Figure 4 shows the feedback network necessary to set the output voltage when using the adjustable -9- www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 STEP-DOWN DC/DC CONVERTER output voltage option. output voltage option. Select components as follows: Set RFB2 = 51kΩ, then calculate RFB1 using the following equation: ⎛V ⎞ RFB1 = RFB2 ⎜⎜ OUTX − 1 ⎟⎟ ⎝ VFBX ⎠ (1) where VFBX is 0.625V. Finally choose CFF using the following equation: C FF = 2.2 × 10 −6 R FB1 (2) Where RFB1 = 47kΩ, use 47pF. Inductor Selection REG1 and REG2 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. These devices were optimized for operation with 3.3µH inductors, although inductors in the 2.2µH to 4.7µH range can be used. Choose an inductor 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%. Innovative PowerTM ActivePMUTM is a trademark of Active-Semi. 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. Stepdown 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, connect the output node directly to the FBx pin. For adjustable output voltage options, connect the feedback resistors and feed-forward capacitor to the FBx pin through the shortest possible route. In both cases, the feedback path should be routed to maintain sufficient distance from switching nodes to prevent noise injection. - 10 - www.active-semi.com Copyright © 2008 Active-Semi, Inc. ACT8325 Active-Semi Rev0, 13-May-08 PACKAGE INFORMATION PACKAGE OUTLINE TDFN33-10 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 0.0000 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 2.350 2.450 0.093 0.096 E2 1.650 1.750 0.065 0.069 b 0.200 0.320 0.008 0.012 e L 0.500 TYP 0.300 0.500 0.020 TYP 0.012 0.020 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 PowerTM ActivePMUTM is a trademark of Active-Semi. - 11 - www.active-semi.com Copyright © 2008 Active-Semi, Inc.