MP2214ADN-LF

MP2214 16V, 4A, 600kHz Synchronous Step-Down Converter The Future of Analog IC Technology DESCRIPTION FEATURES The MP2214 is an internally compensated 600kHz fixed frequency PWM synchronous step-down regulator with a 3V to 6V bias supply (VCC). MP2214 operates from a 3V to 16V input and generates an adjustable output voltage from 0.8V to 0.9xVIN at up to 4A load current. • • • • • • • • • • • • • • The MP2214 integrates an 80mΩ high-side switch and an 80mΩ synchronous rectifier for high efficiency without an external Schottky diode. With peak current mode control and internal compensation, it is stable with a output ceramic capacitor and a small inductor. Fault protection includes hiccup short-circuit protection, cycle-by-cycle current limiting and thermal shutdown. Other features include frequency synchronization and internal softstart. 4A Output Current Input Supply Range: 3V to 16V 80mΩ Internal Power MOSFET Switches All Ceramic Output Capacitors Design Up to 95% Efficiency 600kHz Fixed Switching Frequency Adjustable Output from 0.8V to 0.9xVIN Internal Soft-Start Power Good Pin Frequency Synchronization Input Thermal Shutdown Cycle-by-Cycle Current Limiting Hiccup Short Circuit Protection 14-Lead, 3mm x 4mm QFN and 8-lead SOICE Packages APPLICATIONS The MP2214 is available in small 3mm x 4mm 14-lead QFN and 8-lead SOIC with exposed pad packages. • • • • µP/ASIC/DSP/FPGA Core and I/O Supplies Printers and LCD TVs Network and Telecom Equipment Point of Load Regulators “MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION VIN 3V to 16V C1 33uF VCC 3V to 6V OFF ON 5,10 8 7 IN VCC C4 1uF C3 100nF BS SW 4,11 MP2214 13 9 EN/SYNC L1 3.3uH C6 560PF FB POK GND VOUT 1.8V / 4A 14 C2 47uF 1,3,12 MP2214 Rev. 0.9 9/1/2010 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 1 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER PACKAGE REFERENCE TOP VIEW PIN 1 ID AGND 1 14 FB N/C 2 13 EN/SYNC PGND 3 12 PGND SW 4 11 SW IN 5 10 IN N/C 6 9 POK BS 7 8 VCC TOP VIEW FB 1 8 EN/SYNC GND 2 7 SW IN 3 6 SW BS 4 5 VCC EXPOSED PAD ON BACKSIDE CONNECT TO GND EXPOSED PAD ON BACKSIDE CONNECT TO GND Part Number* MP2214DL * Package QFN14 (3mm x 4mm) Temperature –40°C to +85°C For Tape & Reel, add suffix –Z (e.g. MP2214DL–Z) For RoHS Compliant Packaging, add suffix –LF (e.g. MP2214DL–LF–Z) ABSOLUTE MAXIMUM RATINGS (1) IN to GND .................................... –0.3V to +18V SW to GND .......................... –0.3V to VIN + 0.3V ...................................-3V to VIN + 3V for < 50ns FB, EN/SYNC, VCC to GND.......... –0.3V to +6.5V BS to SW .................................... –0.3V to +6.5V Junction Temperature ...............................150°C Lead Temperature ....................................260°C Storage Temperature............... –65°C to +150°C Part Number* Package Temperature MP2214ADN SOIC8E –40°C to +85°C ** For Tape & Reel, add suffix –Z (e.g. MP2214ADN–Z) For RoHS Compliant Packaging, add suffix –LF (e.g. MP2214ADN–LF–Z) Recommended Operating Conditions (2) Supply Voltage VIN .............................. 3V to 16V Bias Voltage VCC ................................... 3V to 6V Output Voltage VOUT ................. 0.8V to 0.9 x VIN Operating Temperature ............. –40°C to +85°C Thermal Resistance (3) θJA θJC SOIC8E .................................. 50 ...... 10... °C/W QFN14 (3mm x 4mm) ............. 48 ...... 10... °C/W Notes: 1) Exceeding these ratings may damage the device. 2) The device is not guaranteed to function outside of its operating conditions. 3) Measured on approximately 1” square of 1 oz copper. MP2214 Rev. 0.9 9/1/2010 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 2 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER ELECTRICAL CHARACTERISTICS (4) VCC = 3.6V, VIN=12V, TA = +25°C, unless otherwise noted. Parameters VCC Supply Current VCC Shutdown Current VCC Under Voltage Lockout Threshold VCC Under Voltage Lockout Hysteresis IN Shutdown Current IN Under Voltage Lockout Threshold, Rising Edge IN Under Voltage Lockout Hysteresis Regulated FB Voltage FB Input Current EN High Threshold EN Low Threshold Internal Soft-Start Time High-Side Switch On-Resistance Low-Side Switch On-Resistance SW Leakage Current BS Under Voltage Lockout Threshold High-Side Switch Current Limit Low-Side Switch Current Limit Oscillator Frequency Synch Frequency Minimum On Time Maximum Duty Cycle Thermal Shutdown Threshold Condition VEN = VCC VFB = 0.85V VEN = 0V, VCC= 6V Rising Edge Min Typ 750 1 2.8 200 4 VEN = 0V 2.85 TA = +25°C –40°C ≤ TA ≤ +85°C VFB = 0.85V –40°C ≤ TA ≤ +85°C –40°C ≤ TA ≤ +85°C ISW = 300mA ISW = –300mA VEN = 0V; VIN = 12V VSW = 0V or 12V Sourcing Sinking Max 0.780 0.772 -50 1.6 300 0.800 μA 2.95 2.95 0.820 0.828 50 0.4 120 80 80 –10 5.5 450 Hysteresis = 20°C 10 1.8 7.5 3 600 2 50 90 150 Units 750 μA V mV μA V mV V V nA V V µs mΩ mΩ μA V A A KHz MHz ns % °C Note: 4) Production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization. MP2214 Rev. 0.9 9/1/2010 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 3 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER PIN FUNCTIONS 8-SOICE Pin # 14-QFN Pin # Name 5 8 VCC 3 5, 10 IN 6，7 4, 11 SW 2 1, 3, 12 PGND, AGND, Exposed Pad 4 7 BS 1 14 FB 8 13 EN/SYNC 9 2, 6 POK N/C MP2214 Rev. 0.9 9/1/2010 Description Bias Supply. This supplies power to both the internal control circuit and the gate drivers. A decoupling capacitor to ground is required close to this pin. Input Supply. This supplies power to the high side switch. A decoupling capacitor to ground is required close to this pin to reduce switching spikes. Switch Node Connection to the Inductor. These pins connect to the internal high and low-side power MOSFET switches. All SW pins must be connected together externally. Ground. Connect these pins with larger copper areas to the negative terminals of the input and output capacitors. Connect exposed pad to GND plane for proper thermal performance. Bootstrap. A capacitor between this pin and SW provides a floating supply for the high-side gate driver. Feedback. This is the input to the error amplifier. An external resistive divider connected between the output and GND is compared to the internal 0.8V reference to set the regulation voltage. Enable and Frequency Synchronization Input Pin. Forcing this pin below 0.4V shuts down the part. Forcing this pin above 1.6V turns on the part. Applying a 500kHz to 2MHz clock signal to this pin synchronizes the internal oscillator frequency to the external source. Power Good Pin. No Connect. www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 4 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER FUNCTIONAL BLOCK DIAGRAM VCC UVLO UVLO IN EN IN BS EN/SYNC LOGIC EN EXCLK LOGIC CLK OSC + -- EN/SYNC PWM CURRENT COMPARATOR SW SLOPE SW 0.5pF 1.2 MEG 17pF FB 0.8V -+ + COMP SLOPE COMPENSATION AND PEAK CURRENT LIMIT SOFT -START GND GND Figure 1—Functional Block Diagram MP2214 Rev. 0.9 9/1/2010 www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 5 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER FUNCTIONAL DESCRIPTION PWM Control The MP2214 is a constant frequency peakcurrent-mode control PWM switching regulator. Refer to the functional block diagram. The high side N-Channel DMOS power switch turns on at the beginning of each clock cycle. The current in the inductor increases until the PWM current comparator trips to turn off the high side DMOS switch. The peak inductor current at which the current comparator shuts off the high side power switch is controlled by the COMP voltage at the output of feedback error amplifier. The transconductance from the COMP voltage to the output current is set at 11.25A/V. This current-mode control greatly simplifies the feedback compensation design by approximating the switching converter as a single-pole system. Only Type II compensation network is needed, which is integrated into the MP2214. Compensation in the MP2214 simplifies the compensation design, minimizes external component counts. Enable and Frequency Synchronization (EN/SYNC PIN) This is a dual function input pin. Forcing this pin below 0.4V for longer than 4us shuts down the part; forcing this pin above 1.6V for longer than 4µs turns on the part. Applying a 500KHz to 2MHz clock signal to this pin also synchronizes the internal oscillator frequency to the external clock. When the external clock is used, the part turns on after detecting the first few clocks regardless of duty cycles. If any ON or OFF period of the clock is longer than 4µs, the signal will be intercepted as an enable input and disables the synchronization. Soft-Start and Output Pre-Bias Startup When the soft-start period starts, an internal current source begins charging an internal softstart capacitor. During soft-start, the voltage on the soft-start capacitor is connected to the noninverting input of the error amplifier. The soft-start period lasts until the voltage on the soft-start capacitor exceeds the reference voltage of 0.8V. At this point the reference voltage takes over at the non-inverting error amplifier input. The softstart time is internally set at 120µs. If the output of MP2214 Rev. 0.9 9/1/2010 the MP2214 is pre-biased to a certain voltage during startup, the IC will disable the switching of both high-side and low-side switches until the voltage on the internal soft-start capacitor exceeds the sensed output voltage at the FB pin. Over Current Protection The MP2214 offers cycle-to-cycle current limiting for both high-side and low-side switches. The high-side current limit is relatively constant regardless of duty cycles. When the output is shorted to ground, causing the output voltage to drop below 70% of its nominal output, the IC is shut down momentarily and begins discharging the soft start capacitor. It will restart with a full soft-start when the soft- start capacitor is fully discharged. This hiccup process is repeated until the fault is removed. Bootstrap (BST PIN) The gate driver for the high-side N-channel DMOS power switch is supplied by a bootstrap capacitor connected between the BS and SW pins. When the low-side switch is on, the capacitor is charged through an internal boost diode. When the high-side switch is on and the low-side switch turns off, the voltage on the bootstrap capacitor is boosted above the input voltage and the internal bootstrap diode prevents the capacitor from discharging. No external bootstrap diode is required for typical applications. For applications with low input VCC voltage or where output voltage is very close to input voltage, an external Schottky diode may be connected from the VCC to BS pins to charge the bootstrapped capacitor more strongly for increased gate drive voltage. When using the external bootstrap diode, a resistor at the regulator output or a minimal load current may be required as the bootstrapped capacitor always see the supply voltage even when the part is disabled. Input UVLO Both VCC and IN pins have input UVLO detection. Until both VCC and IN voltage exceed under voltage lockout threshold, the parts remain in shutdown condition. There are also under voltage lockout hysesteres at both VCC and IN pins. www.MonolithicPower.com MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. 6 MP2214 – 16V, 4A, 600kHz SYNCHRONOUS STEP-DOWN CONVERTER VCC Power Supply VCC is the power supply of both the internal control circuit and the gate drivers. Generally, the VCC power supply could be provided directly by a proper power rail or generated from other VCC generation circuits. For instance, Figure4 shows a typical VCC generation circuit for VOUT=5V application. It is noteworthy that the voltage applied on the VCC pin should never be higher than 6V. Selecting the Inductor A 1µH to 4.7µH inductor with DC current rating at least 25% higher than the maximum load current is recommended for most applications. For best efficiency, the inductor DC resistance shall be