RT6206AHGQW

® RT6206A 5.5A, 18V, 650kHz, ACOTTM Synchronous Step-Down Converter General Description Features The RT6206A is a synchronous step-down DC/DC converter with Advanced Constant On-Time (ACOTTM) mode control.  It achieves high power density to deliver up to 5.5A output current from a 4.5V to 18V input supply. The proprietary ACOTTM mode offers an optimal transient response over a wide range of loads and all kinds of ceramic capacitors, which allows the device to adopt very low ESR output capacitor for ensuring performance stabilization. In addition, RT6206A keeps an excellent constant switching frequency under line and load variation and the integrated synchronous power switches with the ACOTTM mode operation provides high efficiency in whole output current load range. Cycle-by-cycle current limit provides an accurate protection by a valley detection of low side MOSFET and external soft-start setting eliminates input current surge during startup. Protection functions include thermal shutdown for RT6206A.  The RT6206A are available in the TSSOP-14 (Exposed pad), SOP-8 (Exposed Pad) and WDFN-10L 3x3 packages.             ACOTTM Mode Enables Fast Transient Response 4.5V to 18V Input Voltage Range 5.5A Output Current 35mΩ Ω Internal Low Side N-MOSFET Advanced Constant On-Time Control Support All Ceramic Capacitors Up to 95% Efficiency Adjustable Output Voltage from 0.765V to 8V Adjustable Soft-Start Cycle-by-Cycle Current Limit Input Under-Voltage Lockout Thermal Shutdown RoHS Compliant and Halogen Free Applications     Industrial and Commercial Low Power Systems Computer Peripherals LCD Monitors and TVs Green Electronics/Appliances Point of Load Regulation for High-Performance DSPs, FPGAs, and ASICs Simplified Application Circuit RT6206A VIN VIN VINR* Enable Power Good EN PGOOD* VREG5 GND* SW VOUT BOOT FB SS PGND * : VINR, GND pin for TSSOP-14 (Exposed Pad) only. * : PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS6206A-02 July 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT6206A Ordering Information Pin Configurations RT6206A (TOP VIEW) Package Type CP : TSSOP-14 (Exposed Pad) EN Lead Plating System G : Green (Halogen Free and Pb Free) FB 2 VREG5 3 SS 4 UVP Trim Operation L : Latch-Off Package Type SP : SOP-8 (Exposed Pad-Option 2) QW : WDFN-10L 3x3 (W-Type) PWM/PSM Mode A : Force-PWM BOOT 6 SW 5 PGND 10 9 1 2 3 4 5 PGND EN FB VREG5 SS PGOOD RT6206A 8 7 6 11 VIN VIN BOOT SW SW WDFN-10L 3x3 VOUT FB VREG5 SS GND PGOOD EN 2 14 13 3 12 4 5 6 PGND UVP Trim Operation H : Hiccup 9 VIN 7 SOP-8 (Exposed Pad) PWM/PSM Mode A : Force-PWM Lead Plating System G : Green (Halogen Free and Pb Free) PGND 8 11 10 15 7 9 8 VINR VIN BOOT SW SW PGND PGND TSSOP-14 (Exposed Pad) Note : Richtek products are :  RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Suitable for use in SnPb or Pb-free soldering processes. Marking Information RT6206AHGSP RT6206AHGSP : Product Number RT6206AH GSPYMDNN YMDNN : Date Code RT6206AHGQW 5K= : Product Code 5K=YM DNN RT6206ALGP RT6206AL GCPYMDNN Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 YMDNN : Date Code RT6206ALGCP : Product Number YMDNN : Date Code is a registered trademark of Richtek Technology Corporation. DS6206A-02 July 2015 RT6206A Functional Pin Description Pin No. TSSOP-14 SOP-8 WDFN-10L 3x3 (Exposed Pad) (Exposed Pad) 1 -- -- Pin Name Pin Function VOUT Optional Output Voltage Discharge Connection. This open drain output connects to ground when the device is disabled. If output voltage discharge is desired, connect VOUT to the output voltage. 2 2 2 FB Feedback Voltage Input. It is used to regulate the output of the converter to a set value via an external resistive voltage divider. The feedback threshold voltage is 0.765V typically. 3 3 3 VREG5 Internal Regulator Output. Connect a 1F capacitor to GND to stabilize output voltage. 4 4 4 SS Soft-Start Time Setting. Connect an external capacitor between this pin and GND to set the soft- start time. 5 -- -- GND Analog Ground. 6 -- 5 PGOOD Open Drain Power Good Indicator Output. 7 1 1 EN Enable Control Input. A logic-high enables the converter; a logic-low forces the IC into shutdown mode reducing the supply current to less than 10A. 8, 9, 15 5, 9 11 PGND (Exposed Pad) (Exposed Pad) (Exposed Pad) 10, 11 6 6, 7 12 7 8 13 8 9, 10 14 -- -- Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS6206A-02 July 2015 SW BOOT Power Ground. The exposed pad must be soldered to a large PCB and connected to PGND for maximum power dissipation. Switch Node. Connect this pin to an external L-C filter. Bootstrap Supply for High Side Gate Driver. Connect a 0.1F capacitor between the BOOT and SW pin. VIN Power Input. The input voltage range is from 4.5V to 18V. Must bypass with a suitably large ( 10F x 2) ceramic capacitor. VINR Internal Linear Regulator Supply Input. For the TSSOP-14 (Exposed Pad) package, VINR supplies power for the internal linear regulator that powers the IC. Connect VIN to the input voltage and bypass to ground with a 0.1F ceramic capacitor. is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT6206A Function Block Diagram VINR* POR & Reg EN VBIAS BOOT VREG5 Min. Off-Time VREG5 6µA SS VIN FB VIN VREF OC UV & OV VREG5 Control SW Driver SW PGND ZC Ripple Gen. FB + Comparator GND* Comparator FB - 0.9 x VREF + PGOOD* On-Time * : VINR, GND pin for TSSOP-14 (Exposed Pad) only. * : PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Operation The RT6206A is a synchronous step-down converter with advanced constant on-time control mode. Using the ACOTTM control mode can reduce the output capacitance and provide fast transient response. It can minimize the component size without additional external compensation network. UVLO Protection To protect the chip from operating at insufficient supply voltage, the UVLO is needed. When the input voltage of VIN is lower than the UVLO falling threshold voltage, the device will be latch-off. Thermal Shutdown Internal Regulator The regulator provides 5V power to supply the internal control circuit. Connecting a 1μF ceramic capacitor for decoupling and stability is required. Soft-Start In order to prevent the converter output voltage from overshooting during the startup period, the soft-start function is necessary. The soft-start time is adjustable and can be set by an external capacitor. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 When the junction temperature exceeds the OTP threshold value, the IC will shut down the switching operation. Once the junction temperature cools down and is lower than the OTP lower threshold, the converter will automatically resume switching Power Good (for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only) After soft-start is finished, the power good function will be activated. When the FB is activated, the PGOOD will become an open-drain output. If the FB is below, the PGOOD pin will be pulled low. is a registered trademark of Richtek Technology Corporation. DS6206A-02 July 2015 RT6206A Absolute Maximum Ratings           (Note 1) Supply Voltage, VIN ----------------------------------------------------------------------------------------------Switch Voltage, SW ----------------------------------------------------------------------------------------------< 10ns ---------------------------------------------------------------------------------------------------------------BOOT to SW -------------------------------------------------------------------------------------------------------EN ---------------------------------------------------------------------------------------------------------------------Other Pins -----------------------------------------------------------------------------------------------------------Power Dissipation, PD @ TA = 25°C TSSOP-14 (Exposed Pad) --------------------------------------------------------------------------------------SOP-8 (Exposed Pad) -------------------------------------------------------------------------------------------WDFN-10L 3x3 -----------------------------------------------------------------------------------------------------Package Thermal Resistance (Note 2) TSSOP-14 (Exposed Pad), θJA --------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJA --------------------------------------------------------------------------------------SOP-8 (Exposed Pad), θJC -------------------------------------------------------------------------------------WDFN-10L 3x3, θJA -----------------------------------------------------------------------------------------------WDFN-10L 3x3, θJC -----------------------------------------------------------------------------------------------Junction Temperature Range ------------------------------------------------------------------------------------Lead Temperature (Soldering, 10 sec.) -----------------------------------------------------------------------Storage Temperature Range ------------------------------------------------------------------------------------- Recommended Operating Conditions    −0.3V to 20V −0.8V to (VIN + 0.3V) −5V to 25V −0.3V to 6V −0.3V to 20V −0.3V to 6V 2.5W 2.041W 1.667W 40°C/W 49°C/W 15°C/W 60°C/W 7.5°C/W 150°C 260°C −65°C to 150°C (Note 3) Supply Voltage, VIN ----------------------------------------------------------------------------------------------- 4.5V to 18V Junction Temperature Range ------------------------------------------------------------------------------------- −40°C to 125°C Ambient Temperature Range ------------------------------------------------------------------------------------- −40°C to 85°C Electrical Characteristics (VIN = 12V, TA = 25°C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit Supply Current Shutdown Current ISHDN VEN = 0V -- 1 10 A Quiescent Current IQ VEN = 5V, VFB = 0.8V -- 1 1.3 mA Logic-High 2 -- 18 Logic-Low -- -- 0.4 Logic Threshold EN Input Voltage V VFB Voltage TA = 25C 0.757 0.765 0.773 TA = 40C to 85C 0.755 -- 0.775 -- 0.01 0.1 A 4.8 5.1 5.4 V -- -- 20 mV Feedback Threshold Voltage VFB Feedback Input Current IFB VFB = 0.8V VREG5 6V  VIN  18V, 0 < IVREG5  5mA V VREG5 Output VREG5 Output Voltage Line Regulation 6V  VIN  18V, IVREG5 = 5mA Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS6206A-02 July 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RT6206A Parameter Symbol Min Typ Max Unit 0  IVREG5  5mA -- -- 100 mV IVREG5 VIN = 6V, VREG5 = 4V, TA = 25C -- 70 -- mA High-Side RDS(ON)_H (VBOOT  VSW ) = 5.5V -- 80 -- Low-Side RDS(ON)_L -- 35 -- 5.8 6.9 8.4 -- 150 -- -- 20 -- Load Regulation Output Current Test Conditions RDS(ON) Switch On Resistance m Current Limit Current Limit ILIM A Thermal Shutdown Thermal Shutdown Threshold TSD Shutdown Temperature Thermal Shutdown Hysteresis TSD C On-Time Timer Control On-Time tON VOUT = 1.05V -- 135 -- ns Minimum Off-Time tOFF(MIN) VFB = 0.7V -- 260 310 ns SS Charge Current VSS = 0V -- 6 -- A SS Discharge Current VSS = 0.5V 0.1 0.2 -- mA Wake Up VREG5 3.6 3.85 4.1 0.16 0.35 0.47 115 120 125 % OVP Prop Delay -- 5 -- s UVP Trip Threshold 65 70 75 UVP Hysteresis -- 10 -- UVP Prop Delay -- 250 -- s Relative to Soft-Start Time -- tSS x 1.7 -- ms VFB Rising 85 90 95 VFB Falling -- 85 -- 2.5 5 -- Soft-Start UVLO UVLO Threshold Hysteresis V Output Under Voltage and Over Voltage Protection OVP Trip Threshold UVP Enable Delay OVP Detect tUVPEN % Power Good PGOOD Threshold PGOOD Sink Current PGOOD = 0.5V % mA 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. θJA is measured at TA = 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. Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 6 is a registered trademark of Richtek Technology Corporation. DS6206A-02 July 2015 RT6206A Typical Application Circuit L1 1.4µH RT6206A VIN C1 10µF x 2 C2 0.1µF Input Signal Power Good VIN SW VINR* EN FB PGOOD* SS R3 100k C4 1µF BOOT C6 0.1µF C5 3.3nF VOUT 1.05V/5.5A C3 R1 8.25k C7 22µF x 2 R2 22k VREG5 GND* PGND * : VINR, GND pin for TSSOP-14 (Exposed Pad) only. * : PGOOD pin for TSSOP-14 (Exposed Pad) and WDFN-10L 3x3 only. Table 1. Suggested Component Values (VIN = 12V) VOUT (V) R1 (k) R2 (k) C3 (pF) L1 (H) C7 (F) 1 6.81 22.1 -- 1.4 22 to 68 1.05 8.25 22.1 -- 1.4 22 to 68 1.2 12.7 22.1 -- 1.4 22 to 68 1.8 30.1 22.1 5 to 22 2 22 to 68 2.5 49.9 22.1 5 to 22 2 22 to 68 3.3 73.2 22.1 5 to 22 2 22 to 68 5 124 22.1 5 to 22 3.3 22 to 68 7 180 22.1 5 to 22 3.3 22 to 68 Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS6206A-02 July 2015 is a registered trademark of Richtek Technology Corporation. www.richtek.com 7 RT6206A Typical Operating Characteristics Efficiency vs. Output Current Output Voltage vs. Output Current 100 1.10 90 Output Voltage (V) 80 Efficiency (%) 1.09 VOUT = 5V VOUT = 1.05V 70 60 50 40 30 20 1.08 1.07 1.06 1.05 1.04 1.03 1.02 10 1.01 VIN = 12V 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 5.5 VIN = 12V, VOUT = 1.05V, IOUT = 0A to 5.5A 1.00 6 0 0.5 1 1.5 Output Current (A) Switching Frequency vs. Output Current 3 3.5 4 4.5 5 5.5 Switching Frequency vs. Temperature 700 Switching Frequency (kHz)1 700 Frequency (kHz)1 2.5 Output Current (A) 800 600 500 400 300 200 100 VIN = 12V, VOUT = 1.05V, IOUT = 0A to 5.5A 680 660 640 620 600 580 560 540 520 500 0 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 -50 5.5 -25 0 Output Current (A) 0.775 0.790 Feedback Voltage (V) 0.800 0.765 0.760 0.755 0.750 0.745 VIN = 12V, VOUT = 0.765V, IOUT = 0.6A 0.740 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Input Voltage (V) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 8 50 75 100 125 Feedback Voltage vs. Temperature 0.780 0.770 25 Temperature (°C) Feedback Voltage vs. Input Voltage Feedback Voltage (V) 2 0.780 0.770 0.760 0.750 0.740 0.730 0.720 0.710 VIN = 12V, VOUT = 0.765V, IOUT = 0.6A 0.700 -50 -25 0 25 50 75 100 125 Temperature (°C) is a registered trademark of Richtek Technology Corporation. DS6206A-02 July 2015 RT6206A Shutdown Current vs. Temperature Quiescent Current vs. Temperature 1000 VIN = 12V, VOUT = 1.05V, IOUT = 0A VIN = 12V, VOUT = 1.05V, IOUT = 0A 950 25 Quiescent Current (μA) Shutdown Current (μA)1 30 20 15 10 5 900 850 800 750 700 650 0 600 -50 -25 0 25 50 75 100 125 -50 -25 0 25 50 75 Temperature (°C) Temperature (°C) Current Limit vs. Input Voltage Output Ripple Voltage 100 125 9.0 Current Limit (A) 8.5 VOUT (10mV/Div) 8.0 7.5 7.0 6.5 VSW (5V/Div) 6.0 5.5 VIN = 12V, VOUT = 1.05V, IOUT = 5A 5.0 4 6 8 10 12 14 16 Time (500ns/Div) 18 Input Voltage (V) Load Transient Response Power On from VIN VIN (10V/Div) VOUT (20mV/Div) VOUT (0.5V/Div) IOUT (2A/Div) VIN = 12V, VOUT = 1.05V, IOUT = 1A to 5A Time (100μs/Div) Copyright © 2015 Richtek Technology Corporation. All rights reserved. DS6206A-02 July 2015 IOUT (5A/Div) VIN = 12V, VOUT = 1.05V, IOUT = 5A Time (2.5ms/Div) is a registered trademark of Richtek Technology Corporation. www.richtek.com 9 RT6206A Power Off from VIN Power On from EN VIN (10V/Div) VEN (5V/Div) VOUT (0.5V/Div) VOUT (0.5V/Div) IOUT (5A/Div) IOUT (5A/Div) VIN = 12V, VOUT = 1.05V, IOUT = 5A VIN = 12V, VOUT = 1.05V, IOUT = 5A Time (10ms/Div) Time (500μs/Div) EN Threshold Voltage vs. Temperature Power Off from EN EN Threshold Voltage (V) 1.4 VEN (5V/Div) VOUT (0.5V/Div) IOUT (5A/Div) 1.3 Rising 1.2 1.1 1.0 0.9 Falling 0.8 0.7 0.6 VIN = 12V, VOUT = 1.05V, IOUT = 5A Time (50μs/Div) VIN = 12V, VOUT = 1.05V 0.5 -50 -25 0 25 50 75 100 125 Temperature (°C) UVLO vs. Temperature 4.0 UVLO Voltage (V) 3.9 Rising 3.8 3.7 3.6 Falling 3.5 3.4 -50 -25 0 25 50 75 100 125 Temperature (°C) Copyright © 2015 Richtek Technology Corporation. All rights reserved. www.richtek.com 10 is a registered trademark of Richtek Technology Corporation. DS6206A-02 July 2015 RT6206A Application Information The RT6206A is a synchronous high voltage Buck converter that can support the input voltage range from 4.5V to 18V and the output current up to 5.5A. It adopts ACOTTM mode control to provide a very fast transient response with few external compensation components. on the device again. For external timing control, the EN pin can also be externally pulled high by adding a REN resistor and CEN capacitor from the VIN pin (see Figure 1). EN VIN PWM Operation It is suitable for low external component count configuration with appropriate amount of Equivalent Series Resistance (ESR) capacitors at the output. The output ripple valley voltage is monitored at a feedback point voltage. The synchronous high side MOSFET is turned on at the beginning of each cycle. After the internal on-time expires, the MOSFET is turned off. The pulse width of this on-time is determined by the converter's input and output voltages to keep the frequency fairly constant over the entire input voltage range. RT6206A GND Figure 1. External Timing Control An external MOSFET can be added to implement digital control on the EN pin when no system voltage above 2V is available, as shown in Figure 2. In this case, a 100kΩ pull-up resistor, REN, is connected between the VIN and EN pins. MOSFET Q1 will be under logic control to pull down the EN pin. VIN REN 100k EN Q1 EN RT6206A GND Figure 2. Digital Enable Control Circuit Soft-Start The RT6206A contains an external soft-start clamp that gradually raises the output voltage. The soft-start timing can be programmed by the external capacitor between the SS and GND pins. The chip provides a 6μA charge current for the external capacitor. If a 3.9nF capacitor is used, the soft-start will be 0.87ms (typ.). The available capacitance range is from 2.7nF to 220nF. t SS (ms) = EN CEN Advanced Constant On-Time Control The RT6206A has a unique circuit which sets the on-time by monitoring the input voltage and SW signal. The circuit ensures the switching frequency operating at 650kHz over input voltage range and loading range. REN C5 (nF)  1.365 ISS ( A) Chip Enable Operation The EN pin is the chip enable input. Pulling the EN pin low (