RT2652

RT2652 RICHTEK | Alldatasheet

Document overview

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Technical content

Features

zzzzz High Efficiency : Up to 95% zzzzz Fixed Frequency : 1.2MHz zzzzz No Schottky Diode Required zzzzz Internal Compensation zzzzz 0.6V Reference Allows Low Output Voltage zzzzz 100% Duty Cycle for Low Dropout Operation zzzzz OCP, UVP, OTP zzzzz RoHS Compliant and Halogen Free

Applications

z Ethernet Switches & Routers z Global Storage z Telecom & Industrial z Cell Phones & DSC's General Description The RT2652 is a high efficiency synchronous, step-down DC/DC converter. The available input voltage range is from 2.7V to 5.5V the regulated output voltage is adjustable from 0.6V to VIN while delivering up to 2A of output current. The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The switching frequency is fixed internally at 1.2MHz. The 100% duty cycle provides low dropout operation extending battery life in portable systems. Current mode operation with internal compensation allows the transient response to be optimized. The RT2652 is available in the WDFN-10L 3x3 package. Simplified Application Circuit Marking Information 0K=YM DNN 0K= : Product Code YMDNN : Date Code

Ordering Information

Note : Richtek products are : \ RoHS compliant and compatible with the current require- ments of IPC/JEDEC J-STD-020. \ Suitable for use in SnPb or Pb-free soldering processes. RT2652 Package Type QW : WDFN-10L 3x3 (W-Type) Lead Plating System G : Green (Halogen Free and Pb Free) RT2652 PGND VINVIN VOUT AGND LX FBEN Pin Configurations (TOP VIEW) WDFN-10L 3x3 EN VIN FB AGND PGND PGND LX AGND LX VIN PGND

DS2652-00 November 2012www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Function Block Diagram Functional Pin Description Pin No. Pin Name Pin Function 1 EN Enable Control Input. Pull high to turn on. Do not float. 2, 3 VIN Power Input. Decouple this pin to GND with a 22 μF ceramic capacitor at least. 4, 6 AGND Analog Ground. 5 FB Feedback Voltage Input. This pin receives the feedback voltage from an external resistive divider connected across the output. 7, 8 LX Power MOSFET Switch Node. Connect this pin to the inductor. 9, 10, 11 (Exposed Pad) PGND Power Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Operation The RT2652 is a monolithic, constant-frequency, current mode step-down DC/DC converter. During normal operation, the internal high side MOSFET is turned on at the beginning of each cycle. Current in the inductor increases until the peak inductor current reaches the value defined by the internal error amplifier. The error amplifier adjusts the voltage of its output by comparing the feedback signal from a resistor divider on the FB pin with an internal 0.6V reference. When the load current increases, it causes a reduction in the feedback voltage relative to the reference. The error amplifier raises its output voltage until the average inductor current matches the new load current. When the high side MOSFET turns off, the synchronous power switch (N-MOSFET) turns on until either the bottom current limit is reached or the beginning of the next cycle. The operating frequency is set by the internal oscillator at 1.2MHz. In VIN larger than 6V condition, the high side MOSFET is turned off and the low side MOSFET is switched on until either the VIN over voltage condition is cleared or the low side MOSFET's current limit is reached. In FB larger than 1.05V condition, the high side MOSFET turns off, and the low side MOSFET turns on, and IC is latched until restarted. Driver Control Logic LX PGND OSC Slope Comp. EN FB Output Clamp VINEN N-MOSFET Limit NISEN ISEN OC Limit 0.6V SS EA UV0.2V POR OTP AGND

DS2652-00 November 2012 www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Absolute Maximum Ratings (Note 1) z Power Dissipation, PD @ TA = 25°C z Package Thermal Resistance (Note 2) z ESD Susceptibility (Note 3) Recommended Operating Conditions (Note 4)

Electrical Characteristics

(VIN = 3.3V, TA = 25°C unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Feedback Reference Voltage V REF 0.594 0.6 0.606 V Feedback Leakage Current I FB -- 0.1 0.4 μA Active, VFB = 0.58V, not switching -- -- -- μA DC Bias Current Shutdown -- -- 1 μA Output Voltage Line Regulation V IN = 2.7V to 5.5V -- 0.04 -- %/V Output Voltage Load Regulation I OUT = 10mA to 2000mA -- 0.2 -- %/A Switch Leakage Current EN = 0V -- -- 1 μA Switching Frequency 0.96 1.2 1.44 MHz High R DS(ON)_H -- 110 130 Switch On-Resistance Low R DS(ON)_L -- 70 90 mΩ P-MOSFET Current Limit I LIM 2.5 3.5 -- A VDD Rising -- 2.4 -- V Under Voltage Lockout Threshold VDD Falling -- 2.2 -- V Logic-High V IH 1.5 -- -- EN Input Voltage Logic-Low V IL -- -- 0.3 V EN Pull Low Resistance -- 500 -- k Ω

DS2652-00 November 2012www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Note 1. Stresses beyond those listed “Absolute Maximum Ratings ” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions may affect device reliability. Note 2. θ JA is measured at T A = 25 °C on a high effective thermal conductivity four-layer test board per JEDEC 51-7. θJC is measured at the exposed pad of the package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions.. Parameter Symbol Test Conditions Min Typ Max Unit Over Temperature Protection (latch-off) -- 150 -- °C Soft-Start Time 1.3 -- -- ms VOUT Discharge Resistance -- 100 150 Ω VOUT UVP (latch-off) -- 33 -- %

©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Table 1. Recommended Component Selection

DS2652-00 November 2012www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Typical Operating Characteristics Switching Frequency vs. Temperature 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 -50 -25 0 25 50 75 100 125 Temperature (°C) Switching Frequency (MHz) 1 VIN = 3.3V VIN = 5V VOUT = 1.2V, IOUT = 0.6A Switching Frequency vs. Temperature 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 -50 -25 0 25 50 75 100 125 Temperature (°C) Switching Frequency (MHz) 1 VIN = 5V, VOUT = 3.3V, IOUT = 0.6A Output Voltage vs. Output Current 3.32 3.33 3.34 3.35 3.36 3.37 3.38 Output Current (A) Output Voltage (V) VIN = 5V, VOUT = 3.3V, IOUT = 0 to 2A Output Voltage vs. Output Current 1.180 1.185 1.190 1.195 1.200 1.205 1.210 1.215 1.220 Output Current (A) Output Voltage (V) VIN = 5V VIN = 3.3V VOUT = 1.2V, IOUT = 0 to 2A Efficiency vs. Output Current 100 0.001 0.01 0.1 1 10 Output Current (A) Efficiency (%) VIN = 5V, VOUT = 3.3V VIN = 5V, VOUT = 1.2V VIN = 3.3V, VOUT = 1.2V IOUT = 0 to 2A Efficiency vs. Output Current 100 Output Current (A) Efficiency (%) IOUT = 0 to 2A VIN = 5V, VOUT = 3.3V VIN = 3.3V, VOUT = 1.2V VIN = 5V, VOUT = 1.2V

DS2652-00 November 2012 www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Time (100 μs/Div) Load Transient Response VOUT (100mV/Div) IOUT (1A/Div) VIN = 5V, VOUT = 1.2V, IOUT = 1A to 2A Time (100 μs/Div) Load Transient Response VOUT (100mV/Div) IOUT (1A/Div) VIN = 5V, VOUT = 3.3V, IOUT = 1A to 2A Time (500ns/Div) Output Ripple Voltage VOUT (5mV/Div) VLX (5V/Div) VIN = 5V, VOUT = 1.2V, IOUT = 2A Time (500ns/Div) Output Ripple Voltage VIN = 5V, VOUT = 3.3V, IOUT = 2A VOUT (5mV/Div) VLX (5V/Div) VIN UVLO vs. Temperature 1.8 1.9 2.0 2.1 2.2 2.3 2.4 2.5 2.6 2.7 2.8 -50 -25 0 25 50 75 100 125 Temperature (°C) VIN UVLO (V) Falling Rising Enable Voltage vs. Temperature 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 1.4 1.5 -50 -25 0 25 50 75 100 125 Temperature (°C) Enable Voltage (V) Falling Rising

DS2652-00 November 2012www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Time (500 μs/Div) Power On from EN VIN = 5V, VOUT = 1.2V, IOUT = 2A VOUT (5V/Div) VEN (5V/Div) IOUT (5A/Div) VLX (5V/Div) Time (500 μs/Div) Power On from EN VIN = 5V, VOUT = 3.3V, IOUT = 2A VOUT (5V/Div) VEN (5V/Div) IOUT (5A/Div) VLX (5V/Div) Time (5ms/Div) Power Off from VIN VIN = 5V, VOUT = 1.2V, IOUT = 2A VOUT (5V/Div) VIN (5V/Div) IOUT (5A/Div) VLX (5V/Div) Time (5ms/Div) Power Off from VIN VIN = 5V, VOUT = 3.3V, IOUT = 2A VOUT (5V/Div) VIN (5V/Div) IOUT (5A/Div) VLX (5V/Div) VIN = 5V, VOUT = 1.2V, IOUT = 2A Time (2.5ms/Div) Power On from VIN VOUT (5V/Div) VIN (5V/Div) IOUT (5A/Div) VLX (5V/Div) VIN = 5V, VOUT = 3.3V, IOUT = 2A Time (2.5ms/Div) Power On from VIN VOUT (5V/Div) VIN (5V/Div) IOUT (5A/Div) VLX (5V/Div)

DS2652-00 November 2012 www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. Time (500 μs/Div) Power Off from EN VIN = 5V, VOUT = 3.3V, IOUT = 2A VOUT (5V/Div) VEN (5V/Div) IOUT (5A/Div) VLX (5V/Div) Reference Voltage vs. Temperature 0.580 0.585 0.590 0.595 0.600 0.605 0.610 0.615 0.620 - 5 0 - 2 50 2 55 07 5 1 0 0 1 2 5 Temperature (°C) Reference Voltage (V) IOUT = 0.6A Time (500 μs/Div) Power Off from EN VOUT (5V/Div) VEN (5V/Div) VIN = 5V, VOUT = 1.2V, IOUT = 2A IOUT (5A/Div) VLX (5V/Div)

DS2652-00 November 2012www.richtek.com ©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation.

Application Information

The RT2652 is a single-phase buck PWM converter. It provides single feedback loop, current mode control with fast transient response. An internal 0.6V reference allows the output voltage to be precisely regulated for low output voltage applications. A fixed switching frequency (1.2MHz) oscillator and internal compensation are integrated to minimize external component count. Output Voltage Setting The output voltage is set by an external resistive voltage divider according to the following equation : Figure 1. Setting the Output Voltage Where VREF is equals 0.6V (typ.). fraction of the output voltage as shown in Figure 1. ΔIL = 0.4(IMAX) is a reasonable starting point. compensating ramp to the inductor current signal. output current relatively constant regardless of duty cycle.

©Copyright 2012 Richtek Technology Corporation. All rights reserved. is a registered trademark of Ric htek Technology Corporation. function when the junction temperature exceeds 150°C. on the maximum power dissipation. Figure 2. Derating Curve of Maximum Power Dissipation

DS2652-00 November 2012www.richtek.com Richtek Technology Corporation 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Richtek products are sold by description only. Richtek reserves the right to change the circuitry and/or specifications without notice at any time. Customers should obtain the latest relevant information and data sheets before placing orders and should verify that such information is current and complete. Richtek cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Richtek product. Information furnish ed by Richtek is believed to be accurate and reliable. However, no responsibility is assumed by Richtek or its subsidiaries for its use; nor for any infringeme nts of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of R ichtek or its subsidiaries. Outline Dimension Dimensions In Millimeters Dimensions In Inches Symbol Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.180 0.300 0.007 0.012 D 2.950 3.050 0.116 0.120 D2 2.300 2.650 0.091 0.104 E 2.950 3.050 0.116 0.120 E2 1.500 1.750 0.059 0.069 e 0.500 0.020 L 0.350 0.450 0.014 0.018 W-Type 10L DFN 3x3 Package 1 122 Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. DETAIL A Pin #1 ID and Tie Bar Mark Options D E A L be SEE DETAIL A