MP9115 MPS | Alldatasheet

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Technical content

2.7-6V Input, 2.5A,1.2MHz Synchronous Step-Down Converter MP9115 Rev. 0.92 www.MonolithicPower.com 1 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. The Future of Analog IC Technology

DESCRIPTION

The MP9115 is a fully integrated, internally compensated 1.2MHz fixed frequency PWM step-down converter. It is ideal for powering portable equipment that runs from a single cell Lithium-Ion (Li+) Battery, with an input range from 2.7V to 6V. The MP9115 can provide up to 2.5A of load current with output voltage as low as 0.8V. It can also operate at 100% duty cycle for low dropout applications. With peak current mode control and internal compensation, the MP9115 is stable with ceramic capacitors and small inductors. Fault condition protection includes cycle-by-cycle current limiting and thermal shutdown. MP9115 is available in the small 10-pin 3mmx3mm TQFN package.

FEATURES

  • Output Adjustable from 0.8V to VIN
  • Up to 91% Efficiency
  • 100% Duty Cycle for Low Dropout

Applications

  • 1 μA Shutdown Current
  • 1.2MHz Fixed Switching Frequency
  • 2.7V-6V Input Operation Range
  • 3A Peak Output Current
  • Stable with Low ESR Output Ceramic Capacitors
  • Thermal Shutdown
  • Cycle-by-Cycle Over Current Protection
  • Short circuit protection
  • No reverse current of LS MOS for Pre-bias start up
  • Available in 10-pin 3x3mm TQFN
  • Smart Phones
  • PDA’s
  • DVD+/-RW Drives
  • Digital Cameras
  • Portable Instruments “MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic Power Systems, Inc. TYPICAL APPLICATION C Cf 22pF SHDN 2.2uH 1.2 MP9115 SHDN GND LX LX N/C N/C FB VIN N/C PVIN Efficiency VOUT=1.2V LOAD CURRENT (A) EFFICIENCY(%) 0.01 0.1 1 10 100 VIN=3V VIN=5V

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 2 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved.

ORDERING INFORMATION

Part Number* Package Top Marking Free Air Temperature (TA) MP9115DQT TQFN10 (3mm x 3mm) 2N -40°C to +85°C *For Tape & Reel, add suffix –Z (eg. MP9115DQT–Z); For RoHS compliant packaging, add suffix –LF (eg. MP9115DQT–LF–Z) PACKAGE REFERENCE TOP VIEW SHDN GND LX LX N/C N/C FB VIN N/C PVIN ABSOLUTE MAXIMUM RATINGS (1) Continuous Power Dissipation (T A = +25°C) (2) Storage Temperature…………-65°C to +150°C Recommended Operating Conditions (3) Thermal Resistance (4) θJA θJC Notes: 1) Exceeding these ratings may damage the device. 2) The maximum allowable power dissipation is a function of the maximum junction temperature T J(MAX), the junction-to- ambient thermal resistance θJA, and the ambient temperature TA. The maximum allowable continuous power dissipation at any ambient temperature is calculated by PD(MAX)=(TJ(MAX)- TA)/θJA. Exceeding the maximum allowable power dissipation will cause excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage. 3) The device is not guaranteed to function outside of its operating conditions. 4) Measured on JESD51-7, 4-layer PCB.

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 3 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. ELECTRICAL CHARACTERISTICS (5) VIN = PVIN =3.6V, VSHDN = GND, TA = +25°C, unless otherwise noted. Parameters Symbol Condition Min Typ Max Units Supply Current I IN V SHDN = 0V, VFB = 0.9V 600 900 μA Shutdown Current I SHUT V SHDN = VIN, VIN = 6V 0.01 1 μA Thermal Shutdown Trip Threshold TSD Hysteresis = 20°C 150 °C SHDN Trip Threshold SHDN VTH -40°C ≤ TA ≤ +85°C 0.3 1.0 1.5 V SHDN Input Current I SHDN V SHDN = 0V to 6.5V -5 5 μA IN Undervoltage Lockout Threshold INUVVTH Rising Edge 2.15 2.40 2.65 V IN Undervoltage Lockout Hysteresis INUVHYS 160 mV FB Input Bias Current I FB V FB = 0.9V -50 -2 +50 nA PFET On Resistance HS RDS-ON ILx = 100mA 0.25 Ω NFET On Resistance LS RDS-ON I Lx = -100mA 0.20 Ω LXHSLKG VSHDN=3.6V; V IN=6V; VLx_=0V -1 1 μA LX Leakage Current LXLSLKG VSHDN =3.6V; V IN=6V; VLx_=6V -5 5 μA PFET Peak Current Limit I LIMIT Duty Cycle=100%, 3.5 4.5 6 A Switching Frequency F SW 1.0 1.2 1.4 MHz Notes: 5) Production test at +25°C. Specificat ions over the temperature range are guaranteed by design and characterization.

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 4 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. PIN FUNCTIONS Pin # Name Description 1 SHDN Shut down input, “High” disables MP9115.

2 GND Ground pin

3,4 LX Switching node to the inductor

5 N/C No connection

6 PVIN Input supply pin for power FET

7 N/C No connection

8 VIN Input Supply pin for controller

9 FB Feedback input pin

10 N/C No connection

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 5 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS VIN = 5V, VOUT = 1.2V, L=2.2uH, TA = +25ºC, unless otherwise noted. INPUT VOLTAGE (V) Line Regulation Efficiency vs. Load Current VOUT=2.5V Efficiency vs. Load Current VOUT=1.2V Supply Current vs. Input Voltage 450 470 490 510 530 550 570 590 234567 SUPPLY CURRENT (uA) Case Temperature Rise vs. Output Current 0 0.5 1 1.5 2 2.5 OUTPUT CURRENT (A) CASE TEMPERATURE RISE ( oC ) Load Regulation -0.004 -0.002 0.000 0.002 0.004 0 0.5 1 1.5 2 2.5 LOAD CURRENT (A) LOAD REGUALTION VIN=3V VIN=5V -0.006 -0.004 -0.002 0.000 0.002 0.004 0.006 INPUT VOLTAGE (V) LINE REGULATION IO=0A IO=1.25A IO=2.5A Ipeak vs. Duty 3.5 3.75 4.25 4.5 4.75 50 60 70 80 90 100 DUTY CYCLE (%) IPEAK (A) LOAD CURRENT (A) EFFICIENCY(%) 100 0.01 0.1 1 10 VIN=5.5V VIN=5V VIN=4.5V LOAD CURRENT (A) EFFICIENCY(%) 0.01 0.1 1 10 100 VIN=3V VIN=5V

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 6 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. TYPICAL PERFORMANCE CHARACTERISTICS (continued) VIN = 5V, VOUT = 1.2V, L=2.2uH, TA = +25ºC, unless otherwise noted. VOUT 500mV/div. V_Lx 5V/div. I_inductor 5A/div. VOUT 500mV/div. V_Lx 5V/div. I_inductor 2A/div. 10us/div. 40us/div. 100us/div. 100us/div. 100us/div. 100us/div. 400ns/div. 400ns/div. 100us/div. Short Entry Full Load Short Recovery Full Load Power up without Load Power up with 2.5A Load VOUT 1V/div. VIN 50mV/div. VIN 5V/div. V_Lx 2V/div. V_Lx 2V/div. I_inductor 2A/div. VOUT 1V/div. VIN 2V/div. V_Lx 2V/div. I_inductor 500mA/div. VOUT 50mV/div. V_SHDN 2V/div. V_Lx 5V/div. I_inductor 2A/div. IOUT 1A/div. VOUT 1V/div. VOUT 1V/div. V_SHDN 2V/div. V_Lx 5V/div. I_inductor 500mA/div. VOUT 20mV/div. VIN 5V/div. V_Lx 2V/div. I_inductor 2A/div. SHDN Start Up with 2.5A LoadSHDN Start up without Load Input Ripple Voltage Full Load Output Ripple Voltage Full Load Load Transient Response (1.25A-2.5A, Slew Rate:2.5A/uS)

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 7 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. FUNCTIONAL BLOCK DIAGRAM Main Switch (PCH ) Synchronou s Rectifier (NCH ) 0.04 PWM Control Logic Current Sense Amp Feedback Error Amp PWMSlope Comp ICS 1.2MHz Oscillator OSC Bias Voltage Reference 0.8 V SHDN FB LX EAO IAMP 10X PWMCMP EAMP PVIN VIN To controller blocks R I 48k 17pF CCRZ 1. 1M GND Figure 1—Functional Block Diagram

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 8 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. OPERATION The MP9115 is a fixed frequency 1.2MHz current mode 2.5A step-down converter, optimized for low voltage, Li-Ion battery powered applications where high efficiency and small size are critical. MP9115 integrates a high side PFET main switch and a low side synchronous rectifier. It always operates in continuous conduction mode, simplifies the control scheme and eliminates the random spectrum noise due to discontinuous conduction mode. The steady state duty cycle D for this mode can be calculated as: %100V V%100fTD IN OUT OSCON ×≈××= Where TON is the main switch on time and f OSC is the oscillator frequency (1.2MHz typ.). Current Mode PWM Control Slope compensated current mode PWM control provides stable switching and cycle-by-cycle current limiting for superior load and line response as well as protection of the internal main switch and synchronous rectifier. The MP9115 switches at a constant frequency (1.2MHz) and modulates the inductor peak current to regulate the output voltage. Specifically, for each cycle the PWM controller forces the inductor peak current to an internal reference level derived from the feedback error voltage. At normal operation, the main switch is turned on at each rise edge of the internal oscillator, and remains on for a certain period of time to ramp up the inductor current. As soon as the inductor current reaches the reference level, the main switch is turned off and immediately the synchronous rectifier will be turned on to provide the inductor current. In forced PWM mode, the synchronous rectifier will stay on until the next oscillator cycle. Dropout Operation The MP9115 allows the main switch to remain on for more than one switching cycle to increase the duty cycle when the input voltage is dropping close to the output voltage. When the duty cycle reaches 100%, the main switch is held on continuously to deliver current to the output up to the PFET current limit. In this case, the output voltage becomes the input voltage minus the voltage drop across the main switch and the inductor. Maximum Load Current The MP9115 can operate down to 2.7V input voltage; however the maximum load current decreases at lower input due to a large IR drop on the main switch and synchronous rectifier. The slope compensation signal reduces the peak inductor current as a function of the duty cycle to prevent sub-harmonic oscillations at duty cycles greater than 50%. Conversely, the current limit increases as the duty cycle decreases. Short Circuit Protection When the output is shorted to ground, the oscillator frequency is reduced to prevent the inductor current from increasing beyond the PFET current limit. The PFET current limit is also reduced to lower the short circuit current. The frequency and current limit will return to the normal values once the short circuit condition is removed and the feedback voltage approaches 0.8V.

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 9 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved.

APPLICATION INFORMATION

The output voltage is set by the external resistor divider: OUT The feedforward capacitor is recommended when output voltage is low, as Figure 2 shows. Figure 2—Feedback Network Table 1 lists the recommended resistors and feedforward capacitors value for common output voltages. Table 1—Resistor and Feedforward Capacitor Selection for Common Output Voltages Vout (V) (kΩ) (kΩ) Cf (pF) C2 (uF) Ceramic (uH) 1.2 120 240 22 44 2.2 1.5 120 137 18 44 2.2 1.8 120 95.3 18 44 2.2 2.5 120 56.2 NS 44 2.2 3.3 120 38.3 NS 44 2.2 Inductor Selection A 1μH to 10μH 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 <200mΩ. See Table2 for recommended inductors and manufacturers. For most designs, the inductance value can be derived from the following equation: OSCLIN OUTINOUT fIV VVVL ×Δ× −×= Where ΔIL is inductor ripple current. Choose inductor ripple current approximately 30% of the maximum load current, 2.5A. The maximum inductor peak current is: III L LOAD)MAX(L Δ+= Table 2—Suggested Inductors Manufactu rer Part Number Inductance (μH) Dimensions LxWxH (mm3) Wurth 7447745022 2.2 5.8X5.2X2 TDK SLF6045T- 2R2N3R3-3PF 2.2 6X6X4.5 Input Capacitor CIN Selection The input capacitor reduces the surge current drawn from the input and switching noise from the device. Ceramic capacitors with X5R or X7R dielectrics are highly recommended because of their low ESR and small temperature coefficients. For most applications, a 10μF capacitor is sufficient. Output Capacitor C OUT Selection The output capacitor keeps output voltage ripple small and ensures regulation loop stable. The output capacitor impedance shall be low at the switching frequency. Ceramic capacitors with X5R or X7R dielectrics are recommended. For forced PWM mode operation, the output ripple ΔV OUT is approximately: OUT IN OUT OUT ESR IN OSC OSC OUT V( V V ) 11V( R ) Vf L 8 f C For most applications, a 33 μF capacitor is sufficient. Thermal Dissipation Power dissipation shall be considered when operates MP9115 at maximum 2.5A output current. If the junction temperature rises above 150°C, MP9115 will be shut down by internal thermal protection circuitry. The junction-to-ambient thermal resistance of the 10-pin TQFN (3mm x 3mm) R ΘJA is 50°C/W. The maximum allowable power dissipation is about1.6W when MP9115 is operating in a 70 °C ambient temperature environment: W6.1 W/C50 C70C150PD o oo MAX =−=

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER MP9115 Rev. 0.92 www.MonolithicPower.com 10 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved. PC Board Layout The high current paths (GND, PVIN and Lx) should be placed very close to the device with short, direct and wide traces. Input capacitors should be placed as close as possible to the respective PVIN and GND pins. The external feedback resistors shall be placed next to the FB pins. Keep the switching nodes Lx short and away from the feedback network. GND Top Layer Bottom Layer Figure 3— PCB Layout

MP9115 – 2.7-6V, 2.5A, 1.2MHZ SYNCHRONOUS STEP-DOWN CONVERTER NOTICE: The information in this document is subject to change wi thout notice. Users should warra nt and guarantee that third party Intellectual Property rights are not infringed upon w hen integrating MPS products into any application. MPS will not assume any legal responsibility for any said applications. MP9115 Rev. 0.92 www.MonolithicPower.com 11 1/14/2010 MPS Proprietary Information. Unaut horized Photocopy and Duplication Prohibited. © 2010 MPS. All Rights Reserved.

PACKAGE INFORMATION

TQFN10 (3mmx3mm) SIDE VIEW TOP VIEW 110 6 5 BOTTOM VIEW 2.90 3.10 1.45 1.752.90 3.10 2.25 2.55 0.50 BSC 0.18 0.30 0.70 0.80 0.00 0.05

0.20 REF

1.70 0.50 0.25 RECOMMENDED LAND PATTERN

2.90 NOTE:

1) ALL DIMENSIONS ARE IN MILLIMETERS. 2) EXPOSED PADDLE SIZE DOES NOT INCLUDE MOLD FLASH. 3) LEAD COPLANARITY SHALL BE 0.10 MILLIMETER MAX. 4) DRAWING CONFORMS TO JEDEC MO-229, VARIATION VEED-5. 5) DRAWING IS NOT TO SCALE. PIN 1 ID SEE DETAIL A 2.50 0.70 PIN 1 ID OPTION B R0.20 TYP. PIN 1 ID OPTION A R0.20 TYP. DETAIL A 0.30 0.50 PIN 1 ID INDEX AREA