MIC38300 HELDO™ 3A High Efficiency Low Dropout Regulator General Description HELDO™ The MIC38300 is a 3A peak, 2.2A continuous output current step down converter. This is the first device in a Features new generation of HELDO™ (High Efficiency Low • 3A peak output current Dropout) regulators that provide the benefits of an LDO in • 2.2A continuous operating current respect to ease of use, fast transient performance, high PSRR and low noise while offering the efficiency of a • Input voltage range: 3.0V to 5.5V switching regulator. • Adjustable output voltage down to 1.0V As output voltages move lower, the output noise and • Output noise less than 5mV transient response of a switching regulator become an • Ultra fast transient performance increasing challenge for designers. By combining a • Unique switcher plus LDO architecture switcher whose output is slaved to the input of a high performance LDO, high efficiency is achieved with a clean • Fully integrated MOSFET switches low noise output. The MIC38300 is designed to provide • Micro-power shutdown less than 5mV of peak to peak noise and over 70dB of • Easy upgrade from LDO as power dissipation PSRR at 1kHz. Furthermore, the architecture of the becomes an issue MIC38300 is optimized for fast load transients that allow a • Thermal shutdown and current limit protection maintenance of less than 30mV of output voltage deviation ® even during ultra fast load steps, making the MIC38300 an • 4mm × 6mm × 0.9mm MLF package ideal choice for low voltage ASICs and other digital ICs. The MIC38300 features a fully integrated switching Applications regulator and LDO combo, operates with input voltages • Point-of-load applications from 3.0V to 5.5V input and offers adjustable output voltages down to 1.0V. • Networking, server, industrial power The MIC38300 is offered in the small 28-pin 4×6×0.9mm • Wireless base-stations ® MLF package and can operate from –40°C to +125°C. • Sensitive RF applications Datasheets and support documentation can be found on Micrel’s web site at: www.micrel.com ___________________________________________________________________________________________________________ Typical Application HELDO is a trademark of Micrel, Inc. MLF and MicroLeadFrame are registered trademark of Amkor Technology. Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com June 2010 M9999-061010-D Micrel, Inc. MIC38300 Block Diagram PVIN Switch Control AVIN SW SWO PGND LPF LDOIN VREF Voltage Reference VEN-VREF + VOUT FB EN + - AGND MIC38300 Ordering Information Part Number MIC38300HYHL Output Current 3.0A Voltage (1) Junction Temperature Range ADJ –40°C to +125°C Package PB-Free 28-Pin 4x6 MLF ® Note: For additional voltage options, contact Micrel. June 2010 2 M9999-061010-D Micrel, Inc. MIC38300 Pin Configuration SWO 1 28 SW SWO 2 27 SW SWO 3 26 SW SWO 4 25 SW SWO 5 24 SW SW 6 23 SW ePAD 7 22 ePAD AVIN 8 21 PGND LPF 9 20 PGND AGND 10 18 EN 12 13 14 15 16 17 LDOOUT LDOIN LDOIN PVIN PVIN 11 LDOOUT FB 19 PGND ® 28-Pin 4mm x 6mm MLF (ML) (Top View) Pin Description Pin Number MIC38300HYHL Pin Name 1, 2, 3, 4, 5 SWO 6, 23, 24, 25, 26, 27, 28 SW 7, 22 ePAD Exposed heat-sink pad. Connect externally to PGND. 8 AVIN Analog Supply Voltage: Supply for the analog control circuitry. Requires bypass capacitor to ground. Nominal bypass capacitor is 1µF. 9 LPF Low Pass Filter: Attach external resistor from SW to increase hysteretic frequency. 10 AGND 11 FB Feedback: Input to the error amplifier. Connect to the external resistor divider network to set the output voltage. 12, 13 LDOOUT LDO Output: Output of voltage regulator. Place capacitor to ground to bypass the output voltage. Nominal bypass capacitor is 10µF. 14, 15 LDOIN LDO Input: Connect to SW output. Requires a bypass capacitor to ground. Nominal bypass capacitor is 10µF. 16, 17 PVIN Input Supply Voltage (Input): Requires bypass capacitor to GND. Nominal bypass capacitor is 10µF. 18 EN Enable (Input): Logic low will shut down the device, reducing the quiescent current to less than 50µA. This pin can also be used as an under-voltage lockout function by connecting a resistor divider from EN/UVLO pin to VIN and GND. It should be not left open. 19, 20, 21 PGND June 2010 Pin Name Switch (Output): This is the output of the PFM Switcher. Switch Node: Attach external resistor from LPF to increase hysteretic frequency. Analog Ground. Power Ground. 3 M9999-061010-D Micrel, Inc. MIC38300 Absolute Maximum Ratings(1) Operating Ratings(2) Supply Voltage (VIN) .........................................................6V Output Switch Voltage (VSW) ...........................................6V LDO Output Voltage (VOUT) .............................................6V Logic Input Voltage (VEN) .................................–0.3V to VIN (3) Power Dissipation .................................. Internally Limited Storage Temperature (TS)...................–65°C ≤ TJ ≤ +150°C (4) ESD Rating .............................................................. 1.5kV Supply voltage (VIN) ...................................... 3.0V to 5.5V Junction Temperature Range .........–40°C ≤ TJ ≤ +125°C Enable Input Voltage (VEN) ................................. 0V to VIN Package Thermal Resistance 4mm × 6mm MLF-28 (θJA) .............................24°C/W Electrical Characteristics(5) TA = 25°C with VIN = VEN = 5V; IOUT = 10mA, VOUT = 1.8V. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted. Parameter Conditions Min Supply Voltage Range Under-Voltage Lockout Threshold Typ 3.0 Turn-on UVLO Hysteresis Max Units 5.5 V 2.85 V 100 mV 1 mA Quiescent Current IOUT = 0A, Not switching, Open Loop Turn-on Time VOUT to 95% of nominal 200 500 µs Shutdown Current VEN = 0V 30 50 µA Feedback Voltage ±2.5% 1 1.025 V 0.975 Feedback Current 5 0.85 nA Dropout Voltage (VIN – VOUT) ILOAD = 2.2A; VOUT = 3V Current Limit VFB = 0.9×VNOM Output Voltage Load Regulation VOUT = 1.8V, 10mA to 2.2A 0.3 1 % Output Voltage Line Regulation VOUT = 1.8V, VIN from 3.0V to 5.5V 0.35 0.5 %/V Output Ripple ILOAD = 1.5A, COUTLDO = 20µF, COUTSW = 20µF LPF=25kΩ 3 1.2 5 V A 2 mV Over-Temperature Shutdown 150 °C Over-Temperature Shutdown Hysteresis 15 °C Enable Input (6) Enable Input Threshold Regulator enable Enable Hysteresis 0.90 1 1.1 V 20 100 200 mV 0.03 1 µA Enable Input Current Notes: 1. Exceeding the absolute maximum rating may damage the device. 2. The device is not guaranteed to function outside its operating rating. 3. The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable power dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. 4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF. 5. Specification for packaged product only. 6. Enable pin should not be left open. June 2010 4 M9999-061010-D Micrel, Inc. MIC38300 Typical Characteristics VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted MIC38300 PSRR Load Regulation 90 1.820 80 1.815 70 1.810 60 20 1.790 10 1.785 100 1k 10k FREQUENCY (Hz) 100k Output Voltage vs. Temperature 1.80 1.78 VIN = 3.3V COUT = 10µF IOUT = 10mA 20 40 60 80 TEMPERATURE (°C) Dropout Voltage vs. Load Current 0.6 0.3 0 0 VIN = 3.3V COUT = 20µF RLPF 0.5 1.0 1.5 2.0 2.5 3.0 LOAD CURRENT (A) 1.15 1.10 1.05 1.00 0.95 0.90 June 2010 50 40 30 20 10 210 Dropout Voltage vs. Temperature 0.4 VOUT = 1.8V COUT = 10µF 3.5 4.0 4.5 5.0 INPUT VOLTAGE (V) 5.5 60 0 0 5.5 VIN = 5V VOUT = 3.3V COUT = 10µF 0.5 1.0 1.5 2.0 2.5 LOAD CURRENT (A) 3.0 Current Limit vs. Input Voltage 5.3 5.1 4.9 2A 4.7 4.5 4.3 4.1 1A 0.5 OPERATING CURRENT (mA) 1.20 0.80 3.0 60 0.6 Enable Threshold 0.85 0.4 VOUT = 1.8V 0.2 COUT = 10µF 0 012345 INPUT VOLTAGE (V) 70 0.7 0.4 0.1 0.6 80 0.8 0.5 2A MIC38300 Efficiency 0.9 0.7 10mA 90 0.6 V = 3.3V 0.4 IN VOUT = 1.8V 0.2 COUT = 10µF 0 -40 10 60 110 160 TEMPERATURE (°C) 1.0 0.8 0.2 3.0 1.4 1.2 1.0 0.8 1.82 0.9 0.5 1.0 1.5 2.0 2.5 LOAD CURRENT (A) 2.0 1.8 1.6 1.84 1.72 1.780 0 VIN = 3.3V VOUT = 1.8V COUT = 10µF Thermal Shutdown 1.86 1.74 1.0 0.8 1.795 30 1.76 1.4 1.2 1.800 40 1.88 1.6 1.805 50 0 10 2.0 1.8 Output Voltage vs. Input Voltage VOUT = 4V COUT = 20µF 20 40 60 80 TEMPERATURE (°C) VOUT = 1V COUT = 20µF 3.7 RLPF 3.5 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5 INPUT VOLTAGE (V) 3.9 Operating Current vs. Input Voltage 50 40 30 20 10 0 3 VOUT = 1.8V COUT = 10µF 3.5 4 4.5 5 INPUT VOLTAGE (V) 5 5.5 M9999-061010-D Micrel, Inc. MIC38300 Typical Characteristics VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted Switch Frequency vs. RLPF Resistance (3.3V-1.0V) Switch Frequency vs. RLPF Resistance (3.3V-1.8V) 500mA 1 1.5A 0.5 0 10 Switch Frequency vs. RLPF Resistance (5.0V-1.8V) 1.5A 2.5 2A 1A 2 1.5 10mA 1 500mA 0.5 0 10 5.0V 2 1.5 5.5V 1 0.5 0 -40 -20 0 20 40 60 80 AMBIENT TEMPERATURE (°C) June 2010 1.5A 2.5 1.5A 2A 500mA 2 1.5 1 1A 10mA 0.5 3 2 5.5V 1.5 1 0.5 0 -40 -20 0 20 40 60 80 AMBIENT TEMPERATURE (°C) 6 1A 1.5 1 500mA 10mA 0.5 100 1000 RLPF RESISTANCE (kohms) 3.5 3.3V 3 2.5 2 5.0V 5.5V 1.5 1 0.5 0 -40 -20 0 20 40 60 80 AMBIENT TEMPERATURE (°C) Max Output Current @ 110°C Case Temp (2.5V VOUT) 3.5 2.5 2A 2 Max Output Current @ 110°C Case Temp (1.0V VOUT) 100 1000 RLPF RESISTANCE (kohms) 5.0V 1.5A 2.5 0 10 100 1000 RLPF RESISTANCE (kohms) Max Output Current @ 110°C Case Temp (1.8V VOUT) MAX OUTPUT CURRENT (A) MAX OUTPUT CURRENT (A) 3 2.5 10mA 1A 0.5 0 10 Max Output Current @ 110°C Case Temp (1.2V VOUT) 3.3V 1 3 100 1000 RLPF RESISTANCE (kohms) 3.5 1.5 Switch Frequency vs. RLPF Resistance (5.0V-2.5V) SWITCH FREQUENCY (MHz) SWITCH FREQUENCY (MHz) 3 2 0 10 100 1000 RLPF RESISTANCE (kohms) 2A SWITCH FREQUENCY (MHz) 1.5 10mA 500mA MAX OUTPUT CURRENT (A) 2A 2 2.5 3 3.5 MAX OUTPUT CURRENT (A) 1A 2.5 3 SWITCH FREQUENCY (MHz) SWITCH FREQUENCY (MHz) 3 Switch Frequency vs. RLPF Resistance (5.0V-1.0V) 3 5.0V 2.5 2 1.5 5.5V 1 0.5 0 -40 -20 0 20 40 60 80 AMBIENT TEMPERATURE (°C) M9999-061010-D Micrel, Inc. MIC38300 Functional Characteristics VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, Inductor = 470nH; RLPF = 25kΩ, IOUT = 100mA, unless noted June 2010 7 M9999-061010-D Micrel, Inc. MIC38300 EMI Performance VOUT =1.8V, IOUT =1.2A EMI Test – Horizontal Front EMI Test – Vertical Front Additional components to MIC38150 Evaluation Board (Performance similar to MIC38300): 1. Input Ferrite Bead Inductor. Part number: BLM21AG102SN1D 2. 0.1µF and 0.01µF ceramic bypass capacitors on PVIN, SW, SWO, and LDOOUT pins. June 2010 8 M9999-061010-D Micrel, Inc. MIC38300 Application Information Enable Input The MIC38300 features a TTL/CMOS compatible positive logic enable input for on/off control of the device. High enables the regulator while low disables the regulator. In shutdown the regulator consumes very little current (only a few microamperes of leakage). For simple applications the enable (EN) can be connected to VIN (IN). Adjustable Regulator Design Input Capacitor PVIN provides power to the MOSFETs for the switch mode regulator section and the gate drivers. Due to the high switching speeds, a 10µF capacitor is recommended close to PVIN and the power ground (PGND) pin for bypassing. Analog VIN (AVIN) provides power to the analog supply circuitry. AVIN and PVIN must be tied together externally. Careful layout should be considered to ensure high frequency switching noise caused by PVIN is reduced before reaching AVIN. A 1µF capacitor as close to AVIN as possible is recommended. Adjustable Regulator with Resistors The adjustable MIC38300 output voltage can be programmed from 1V to 5.0V using a resistor divider from output to the FB pin. Resistors can be quite large, up to 100kΩ because of the very high input impedance and low bias current of the sense amplifier. For large value resistors (>50kΩ) R1 should be bypassed by a small capacitor (CFF = 0.1µF bypass capacitor) to avoid instability due to phase lag at the ADJ/SNS input. The output resistor divider values are calculated by: Output Capacitor The MIC38300 requires an output capacitor for stable operation. As a µCap LDO, the MIC38300 can operate with ceramic output capacitors of 10µF or greater. Values of greater than 10µF improve transient response and noise reduction at high frequency. X7R/X5R dielectric-type ceramic capacitors are recommended because of their superior temperature performance. X7R-type capacitors change capacitance by 15% over their operating temperature range and are the most stable type of ceramic capacitors. Larger output capacitances can be achieved by placing tantalum or aluminum electrolytics in parallel with the ceramic capacitor. For example, a 100µF electrolytic in parallel with a 10µF ceramic can provide the transient and high frequency noise performance of a 100µF ceramic at a significantly lower cost. Specific undershoot/overshoot performance will depend on both the values and ESR/ESL of the capacitors. For less than 5mV noise performance at higher current loads, 20µF capacitors are recommended at LDOIN and LDOOUT. ⎛ R1 ⎞ VOUT = 1V ⎜ + 1⎟ R 2 ⎝ ⎠ Efficiency Considerations Efficiency is defined as the amount of useful output power, divided by the amount of power supplied. ⎛V ×I Efficiency _ % = ⎜⎜ OUT OUT ⎝ VIN × I IN Maintaining high efficiency serves two purposes. It reduces power dissipation in the power supply, reducing the need for heat sinks and thermal design considerations and it reduces consumption of current for battery powered applications. Reduced current draw from a battery increases the devices operating time and is critical in hand held devices. There are two types of losses in switching converters; DC losses and switching losses. DC losses are simply 2 the power dissipation of I R. Power is dissipated in the high side switch during the on cycle. Power loss is equal to the high side MOSFET RDSON multiplied by the Switch 2 Current . During the off cycle, the low side N-channel MOSFET conducts, also dissipating power. Device operating current also reduces efficiency. The product of the quiescent (operating) current and the supply voltage is another DC loss. Over 100mA, efficiency loss is dominated by MOSFET RDSON and inductor losses. Higher input supply voltages will increase the Gate to Source threshold on the internal MOSFETs, reducing the internal RDDSON. This improves efficiency by reducing DC losses in the device. All but the inductor losses are inherent to the device. In which Low Pass Filter Pin The MIC38300 features a Low Pass Filter (LPF) pin for adjusting the switcher frequency. By tuning the frequency, the user can further improve output ripple without losing efficiency. Adjusting the frequency is accomplished by connecting a resistor between the LPF and SW pins. A small value resistor would increase the frequency while a larger value resistor decreases the frequency. Recommended RLPF value is 25kΩ. Please see Typical Characteristics for more details. June 2010 ⎞ ⎟⎟ × 100 ⎠ 9 M9999-061010-D Micrel, Inc. MIC38300 case, inductor selection becomes increasingly critical in efficiency calculations. As the inductors are reduced in size, the DC resistance (DCR) can become quite significant. The DCR losses can be calculated as follows: 2 L_PD = IOUT × DCR From that, the loss in efficiency due to inductor resistance can be calculated as follows; Current Sharing Circuit The following circuit allows two MIC38300 HELDO regulators to share the load current equally. HELDO1 senses the output voltage at the load, on the other side of a current sense resistor. As the load changes, a voltage equal to the output voltage, plus the load current times the sense resistor, is developed at the VOUT terminal of HELDO1. The Op-Amp (MIC7300) inverting pin senses this voltage and compares it to the voltage on the VOUT terminal of HELDO2. If the current through the current sense of HELDO2 is less than the current through the current sense of HELDO1, the inverting pin will be at a higher voltage than the non-inverting pin and the Op-Amp will drive the FB of HELDO2 low. The low voltage sensed on HELDO2 FB pin will drive the output up until the output voltage of HELDO2 matches the output voltage of HELDO1. Since VOUT will remain constant and both HELDO VOUT terminals and sense resistances are matched, the output currents will be shared equally ⎡ ⎛ ⎞⎤ VOUT × IOUT ⎟⎥ × 100 Efficiency _ Loss = ⎢1 − ⎜⎜ ⎟ ⎢⎣ ⎝ VOUT × IOUT + L _ PD ⎠⎥⎦ Efficiency loss due to DCR is minimal at light loads and gains significance as the load is increased. Inductor selection becomes a trade-off between efficiency and size in this case. Current Sharing Circuit for 6A Output June 2010 10 M9999-061010-D Micrel, Inc. MIC38300 Package Information ® 28-Pin 4mm x 6mm MLF (ML) June 2010 11 M9999-061010-D Micrel, Inc. MIC38300 Recommended Landing Pattern LP # HMLF46T-28LD-LP-1 All units are in mm Tolerance ± 0.05 if not noted Red circle indicates Thermal Via. Size should be .300-.350 mm in diameter and it should be connected to GND plane for maximum thermal performance. MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer. Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale. © 2007 Micrel, Incorporated. June 2010 12 M9999-061010-D