MIC4744YTSE

MIC4744 4 MHz Dual 2A Integrated Switch Buck Regulator General Description Features The Micrel MIC4744 is a high efficiency dual PWM buck (step-down) regulator that provides dual 2A current output. The MIC4744 operates at 4MHz. A proprietary internal compensation technique allows a closed loop bandwidth of over 200kHz. • • • • • • • • The low on-resistance internal P-Channel MOSFET of the MIC4744 allows efficiencies over 90%, reduces external components count and eliminates the need for an expensive current sense resistor. The MIC4744 operates from 2.9V to 5.5V input and the output can be adjusted down to 0.6V. The device can operate with a maximum duty cycle of 100% for use in lowdropout conditions. The MIC4744 is available in the exposed pad 16-pin 3mm x 3mm MLF® and ETSSOP-16 packages with junction operating temperature ranging from –40°C to +125°C. All support documentation can be found on Micrel’s web site at: www.micrel.com. • • • • • 2.9 to 5.5V supply voltage 4MHz PWM mode 2A Dual output Greater than 90% efficiency 100% maximum duty cycle Output voltage adjustable down to 0.6V Ultra-fast transient response Ultra-small external components Stable with a 0.47µH inductor and a 10µF output capacitor Fully integrated 2A MOSFET switches Micro-power shutdown Thermal shutdown and current limit protection Available in 3mm x 3mm 16-pin MLF® and 16-pin TSSOP packages –40°C to +125°C junction temperature range Applications • • • • • • Broadband: xDSL modems Automotive satellite radios HD STB, DVD/TV recorder Computer peripherals: printers and graphic cards FPGA/ASIC General point of load Typical Application 5.0Vin 3.3Vout Efficiency 100 98 EFFICIENCY (%) 96 94 92 90 88 86 84 82 80 0.0 0.4 0.8 1.2 1.6 2.0 OUTPUT CURRENT (A) 2A 4MHz Dual Buck Regulator MLF and MicroLeadFrame are registered trademarks of Amkor Technology, Inc. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com March 2009 1 M9999-030209-C Micrel, Inc. MIC4744 Ordering Information Output Voltage Junction Temp. Range MIC4744YML Part Number Adj. –40° to +125°C 16-Pin 3mm x 3mm MLF® Package Lead Finish Pb-Free MIC4744YTSE Adj. –40° to +125°C 16-Pin EPAD TSSOP Pb-Free Note: ® MLF is a GREEN RoHS-compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free. Pin Configuration 16-Pin 3mm x 3mm MLF® (YML) March 2009 16-Pin EPAD-TSSOP (YTSE) 2 M9999-030209-C Micrel, Inc. MIC4744 Pin Description Pin Number ® (MLF ) Pin Number (EPAD-TSSOP) Pin Name 1 7 FB2 Feedback for output 2 (Input). Input to the error amplifier, connect to the external resistor divider network to set the output voltage. 2(1) 8(1) EN2 Enable for output 2 (Input). Logic level low, will shutdown the device, reducing the current draw to less than 5µA (both EN1 and EN2 are low). 3,4 9,10 SW2 Switch for output 2 (Output): Internal power P-Channel MOSFET output switch 5 11 PGND2 Pin Function Power Ground for output 2. Provides the ground return path for the high-side drive current. PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes. 6,15 5,12 VIN2 Supply Voltage for output 2 (Input): Supply voltage for the source of the internal P-Channel MOSFET and driver. Requires bypass capacitor to GND. VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes. 7,14 4,13 VIN1 Supply Voltage for output 1 (Input): Supply voltage for the source of the internal P-Channel MOSFET and driver. Requires bypass capacitor to GND. VIN1 pins and VIN2 pins are internally connected by anti-parallel diodes. 8 14 PGND1 Power Ground for output 1. Provides the ground return path for the high-side drive current. PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes. 9,10 15,16 SW1 Switch for output 1 (Output): Internal power P-Channel MOSFET output switch 11(1) 1(1) EN1 Enable for output 1 (Input). Logic level low, will shutdown the device, reducing the current draw to less than 5µA (both EN1 and EN2 are low). 12 2 FB1 Feedback for output 1 (Input). Input to the error amplifier, connect to the external resistor divider network to set the output voltage. 13 3 SGND Signal (Analog) Ground. Provides return path for control circuitry and internal reference. 16 6 BIAS Internal circuit bias supply. Must be bypassed with a 0.1µF ceramic capacitor to SGND. Biased through a 10Ω resistor to VIN. EPAD EPAD GND Connect to ground. Note: 1. Do not float Enable Input. March 2009 3 M9999-030209-C Micrel, Inc. MIC4744 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) ......................................... -0.3V to +6V Output Switch Voltage (VSW1, VSW2).................. -0.3V to +6V Output Switch Current (ISW1, ISW2)………...Internally Limited Input Voltage (VEN), (VFB), (VBIAS) ...................... -0.3V to VIN Storage Temperature (Ts) .........................–60°C to +150°C Junction Temperature ................................................ 150°C Lead Temperature (soldering, 10sec.)....................... 260°C ESD Rating(3) ................................................................. 2KV Supply Voltage (VIN)..................................... +2.9V to +5.5V Logic Input Voltage (VEN) ....................................... 0V to VIN Junction Temperature (TJ) ........................ –40°C to +125°C Junction Thermal Resistance MLF® (θJA)..........................................................60°C/W EPAD TSSOP (θJA)............................................35°C/W Electrical Characteristics(4) VIN = VEN = 3.6V; L = 1.0µH; COUT = 4.7µF; TA = 25°C, unless noted. Bold values indicate –40°C< TJ < +125°C. Parameter Condition Min 2.9 Supply Voltage Range Under-Voltage Lockout Threshold 2.45 Turn-on UVLO Hysteresis Quiescent Current Typ 2.6 Max Units 5.5 V 2.7 100 VFB = 0.9 * VNOM (not switching); VIN = 5.5V 1.4 V mV 3.0 mA VFB = 0.9 * VNOM (not switching); VIN = 3.6V 1.0 Shutdown Current VEN = 0V 1.6 10 µA [Adjustable] Feedback Voltage ± 2% (over temperature) ILOAD = 100µA 0.6 0.612 V 0.588 FB pin input current mA 1 2.5 nA Current Limit VFB = 0.9 * VNOM 4.3 A Output Voltage Line Regulation VIN = 2.9V to 5.5V; ILOAD= 100µA 0.07 % Output Voltage Load Regulation 20mA < ILOAD < 2A 0.2 % Maximum Duty Cycle VFB ≤ 0.9 * VNOM Switch ON-Resistance ISW = 50mA VFB =GND 100 % 155 3.0 Oscillator Frequency Switching Phase 3.8 mΩ 4.4 180 0.5 Enable Threshold Enable Hysteresis 0.9 MHz °C 1.3 55 V mV 2 Enable Input Current 0.1 Over-Temperature Shutdown 153 µA °C Over-Temperature Hysteresis 18 °C Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 4. Specification for packaged product only. March 2009 4 M9999-030209-C Micrel, Inc. MIC4744 Typical Characteristics 5.0Vin 1.0Vout Efficiency 74 74 78 72 72 76 70 68 66 64 62 3.0Vin 3.3Vin 58 EFFICIENCY (%) 80 60 70 68 66 64 62 60 4.5Vin 58 5.0Vin 3.6Vin 0.4 0.8 1.2 1.6 0.4 OUTPUT CURRENT (A) 68 66 0.8 1.2 1.6 3.3Vin 1.5Vout Efficiency 80 72 70 68 66 4.5Vin 64 78 76 74 72 70 76 74 72 2 0 0.4 0.8 1.2 1.6 2 0 86 92 84 84 90 82 82 88 76 74 72 70 EFFICIENCY (%) 86 EFFICIENCY (%) 94 78 80 78 76 74 3.0Vin 72 3.3Vin 70 4.5Vin 5.0Vin 3.6Vin 0.4 94 90 92 88 90 86 84 82 80 0.8 1.2 1.6 0 0.4 80 78 4.5Vin 1.6 2 1.005 1.000 0.995 Vin=3.3V 5.5Vin 76 2.0 1.2 5.0Vin 5.5Vin 74 0.8 Load Regulation 82 5.0Vin March 2009 3.3Vin 1.010 84 76 OUTPUT CURRENT (A) 3.0Vin 76 OUTPUT CURRENT (A) 86 4.5Vin 1.6 78 2 88 78 1.2 80 OUTPUT VOLTAGE (V) 92 0.8 82 5.0Vin 3.3Vout Efficiency 96 EFFICIENCY (%) EFFICIENCY (%) 5.0Vin 2.5Vout Efficiency 94 0.4 84 OUTPUT CURRENT (A) OUTPUT CURRENT (A) 0.0 86 74 0 2 2 3.6Vin 68 1.6 1.6 5.5Vin 68 1.2 1.2 3.3Vin 2.5Vout Efficiency 88 80 0.8 OUTPUT CURRENT (A) 5.0Vin 1.8Vout Efficiency 3.3Vin 1.8Vout Efficiency 0.8 0.4 OUTPUT CURRENT (A) 88 0.4 5.0Vin 64 OUTPUT CURRENT (A) 0 4.5Vin 5.5Vin 64 1.6 2 78 66 3.6Vin 60 1.6 68 3.3Vin 66 5.5Vin 1.2 70 3.0Vin 68 5.0Vin 62 EFFICIENCY (%) 82 80 EFFICIENCY (%) 82 76 74 0.8 5.0Vin 1.5Vout Efficiency 78 1.2 0.4 OUTPUT CURRENT (A) 84 0.8 3.6Vin 0 84 0.4 3.3Vin 2 80 0 3.0Vin OUTPUT CURRENT (A) 5.0Vin 1.2Vout Efficiency EFFICIENCY (%) 70 60 0 2 72 62 56 0 74 64 5.5Vin 56 EFFICIENCY (%) 3.3Vin 1.2Vout Efficiency 76 EFFICIENCY (%) EFFICIENCY (%) 3.3Vin 1.0Vout Efficiency 76 0.990 0.0 0.4 0.8 1.2 1.6 OUTPUT CURRENT (A) 5 2.0 0 0.4 0.8 1.2 1.6 2 OUTPUT CURRENT (A) M9999-030209-C Micrel, Inc. MIC4744 Typical Characteristics (continue) Feedback Voltage vs. Temperature Frequency vs. Temperature 1.0030 0.605 1.0028 0.604 4.2 1.0026 0.603 4.1 1.0024 1.0022 1.0020 1.0018 1.0016 1.0014 4.3 FREQUENCY (MHz) FEEDBACK VOLTAGE (V) OUTPUT VOLTAGE (V) Line Regulation 0.602 0.601 0.600 0.599 0.598 4.0 3.9 3.8 3.7 3.6 0.597 3.5 1.0012 0.596 3.4 1.0010 0.595 2.9 3.3 3.7 4.1 4.5 4.9 5.3 3.3 -40 -20 0 SUPPLY VOLTAGE (V) 20 40 60 80 100 120 -40 -20 TEMPERATURE (°C) Feedback Voltage vs. Supply Voltage 20 40 60 80 100 120 TEMPERATURE (°C) Quiescent Current vs. Supply Voltage 0.8 0 Rdson vs. Supply Voltage 1600 180 0.4 0.2 1200 160 Rdson (mΩ) QUIESCENT CURRENT (μA) FEEDBACK VOLTAGE (V) 170 0.6 800 2 3 4 5 100 0 1 SUPPLY VOLTAGE (V) 2 3 4 2.9 5 1.2 1.2 1.0 1.0 140 130 120 110 ENABLE THRESHOLD (V) ENABLE THRESHOLD (V) Rdson (mΩ) 150 0.8 0.6 0.4 0.2 0.0 100 0 20 40 60 TEMPERATURE (°C) March 2009 80 100 120 4.1 4.5 4.9 5.3 Enable Threshold vs. Temperature 170 160 3.7 SUPPLY VOLTAGE (V) Enable Threshold vs. Supply Voltage 180 -20 3.3 SUPPLY VOLTAGE (V) Rdson vs. Temperature -40 130 110 0 1 140 120 400 0.0 0 150 0.8 0.6 0.4 0.2 0.0 2.9 3.3 3.7 4.1 4.5 4.9 SUPPLY VOLTAGE (V) 6 5.3 -40 -20 0 20 40 60 80 100 120 TEMPERATURE (°C) M9999-030209-C Micrel, Inc. MIC4744 Functional Characteristics March 2009 7 M9999-030209-C Micrel, Inc. MIC4744 Functional Diagram MIC4744 Block Diagram March 2009 8 M9999-030209-C Micrel, Inc. MIC4744 Pin Description SW1/SW2 The switch pins (SW1 and SW2) connect directly to the inductor and provide the switching current necessary to operate in PWM mode. Due to the high speed switching on these pins, the switch nodes should be routed away from sensitive nodes. These pins also connect to the cathodes of the free-wheeling diodes. VIN1/VIN2 VIN pins (two pins for VIN1 and two pins for VIN2) provide power to the source of the internal P-Channel MOSFET along with the current limiting sensing. VIN1 pins and VIN2 pins are internally connected by antiparallel diodes. The VIN operating voltage range is from 2.9V to 5.5V. Due to the high switching speeds, a 10µF capacitor is recommended close to VIN and the power ground (PGND) for each pin for bypassing. Please refer to layout recommendations for more details. PGND1/PGND2 Power ground pins (PGND1 and PGND2) are the ground paths for the MOSFET drive current. PGND1 pin and PGND2 pin are internally connected by anti-parallel diodes. The current loop for the power ground should be as small as possible and separate from the Signal ground (SGND) loop. Refer to the layout recommendation for more details. BIAS The bias (BIAS) provides power to the internal reference and control sections of the MIC4744. A 10Ω resistor from VIN to BIAS and a 0.1µF from BIAS to SGND are required for clean operation. SGND Signal ground (SGND) is the ground path for the biasing and control circuitry. The current loop for the signal ground should be separate from the power ground (PGND) loop. Refer to the layout recommendation for more details. EN1/EN2 The enable pins (EN1 and EN2) provides a logic level control of the outputs 1 and 2. In the off state, supply current of the device is greatly reduced (typically