RTQ2130B-50GQW-QT

® RTQ2130B-QT 0.7A, 36V, 2.1MHz Synchronous Small Form Factor StepDown Converter General Description Features The RTQ2130B is a high-efficiency, monolithic synchronous step-down DC-DC converter that can deliver up to 0.7A output current from a 3V to 36V widely input supply. The RTQ2130B current-mode control with external compensation allows the transient response to be optimized over various loads and output capacitors. Cycleby-cycle current limit provides protection against shortcircuit output, and soft-start can eliminate input current surge during startup. Input under-voltage lockout, output under-voltage protection, over-current protection and overtemperature protection offer completely safe and smooth operation in all applied conditions. The RTQ2130B is fully specified over the temperature range of TA = −40°C to 125°C  and is available in WDFN-8SL 2x3 package.           Applications        Automotive Systems Car Camera Module and Car Cockpit Systems Connected Car Systems Point of Load Regulator in Distributed Power Systems Digital Set Top Boxes Broadband Communications     AEC-Q100 Grade 1 Qualified Wide Input Voltage Range  4V to 36V  3V to 36V (Soft-start is finished) 99% Duty Cycle Operation Tight Switching Frequency Variation 2.1MHz ± 10% Over Operating Ambient Temperature 5V Fixed Output Voltage ( see Ordering Information for availability) 0.7A Output Current −40°°C to 125°°C Operating Ambient Temperature Range Current-Mode Control Integrated 200mΩ Ω/160mΩ Ω MOSFETs Enable Control Over-Temperature Protection Output Under-Voltage Protection with Hiccup Mode Adjacent Pin Short-Circuit Protection Cycle-by-Cycle Over-Current Protection Input Under-Voltage Lockout RoHS Compliant and Halogen Free Ordering Information RTQ2130B (- ) Pin Configuration Grade QT : AEC-Q100 Qualified 1 2 3 4 PAD (TOP VIEW) VIN BOOT SW GND 9 8 7 6 5 -QT Package Type QW : WDFN-8SL 2x3 (W-Type) VCC EN FB/VS COMP Lead Plating System G : Green (Halogen Free and Pb Free) Fixed Output Voltage 50 : 5V WDFN-8SL 2x3 Note : Richtek products are :  RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020.  Copyright © 2018 Richtek Technology Corporation. All rights reserved. DSQ2130B-QT-01 May 2018 Suitable for use in SnPb or Pb-free soldering processes. is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RTQ2130B-QT Marking Information RTQ2130BGQW-QT RTQ2130B-50GQW-QT 17 : Product Code 1E : Product Code W : Date Code 17W 1EW W : Date Code Functional Pin Description Pin No. Pin Name Pin Function 1 VIN Supply input. Supply the power to the internal control circuit as well as the power switches of the device. Drive VIN with a 3V to 36V power source and bypass VIN to GND with a suitable large capacitor to eliminate noise. 2 BOOT Bootstrap supply for high-side gate driver. Connect a 100nF or greater capacitor from SW to BOOT to power the high-side switch. 3 SW Switch node. SW is the switching node that supplies power to the output and connect the output LC filter from SW to the output load. 4 GND System ground. Provide the ground return path for the control circuitry and low-side power MOSFET. 5 COMP Compensation node. The current comparator threshold increases with this control voltage. Connect external compensation elements to this pin to stabilize the control loop. 6 FB/VS Output voltage sense. There are two output voltage setting options : one is a fixed output voltage available for the VS pin, and the other is through a resistive divider to sense the output voltage at the FB pin. The feedback reference voltage is 0.8V typically. 7 EN Enable control input. Connect this pin to logic high can enable the device and connect this pin to GND can disable the device. 8 VCC Linear regulator output. VCC is the output of the internal 5V linear regulator powered by VIN. Decouple with a 1F ceramic capacitor from VCC to ground for normal operation. 9 (Exposed Pad) PAD Exposed pad. The exposed pad is internally unconnected and must be soldered to a large PCB copper area for maximum power dissipation. Copyright © 2018 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DSQ2130B-QT-01 May 2018 RTQ2130B-QT Functional Block Diagram Adjustable Output Voltage VCC VIN + EN Enable Threshold Enable Comparator 0.8V Current Sense BOOT Power Stage & Dead-time Control HS Switch Current Comparator + EA + Internal Regulator BOOT UVLO Logic & Protection Control Fold-back Control FB UVLO SW LS Switch Current Comparator Current Sense SS Oscillator GND Slope Compensation COMP Fixed 5V Output Voltage VCC VIN + EN Enable Threshold VS Enable Comparator Fold-back Control 0.8V UVLO BOOT UVLO Logic & Protection Control Current Sense BOOT Power Stage & Dead-time Control HS Switch Current Comparator + EA + Internal Regulator SW LS Switch Current Comparator Current Sense SS GND Oscillator Slope Compensation COMP Copyright © 2018 Richtek Technology Corporation. All rights reserved. DSQ2130B-QT-01 May 2018 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RTQ2130B-QT Operation Switching Frequency and Operational Duty Cycle Internal Regulator With normal duty cycle, the RTQ2130B operates at fixed switching frequency = 2.1MHz. If the duty cycle is too high/low, in order to extend the operational input voltage range, the RTQ2130B is forced to lower its switching frequency by skipping on/off pulses. The internal regulator generates a 5V regulated voltage, VCC, to drive internal circuit. When VIN is below 5V, VCC The minimum on time of the RTQ2130B is 60ns (typ., at IOUT = 0.5A). If input voltage is too high and the required on pulse width becomes smaller than minimum on time, IC starts to skip on pulse once the V(COMP) has reached its low clamped value. The minimum off time of the RTQ2130B is 60ns (typ.). If input voltage drops and the required off pulse width becomes smaller than minimum off time, IC starts to skip off pulse and keeps H/S MOSFET on continuously. With this feature, IC can support > 99% duty cycle. will track with VIN. A capacitor ( = 1μF), connected from VCC to GND, is required. Internal Soft-Start Function The RTQ2130B provides an internal soft-start function. The soft-start function is used to prevent large inrush current while the converter is being powered-up. The typical softstart time (i.e. for the FB voltage to ramp from 0V to 0.8V) is 2ms. When voltage of EN pin exceeds threshold voltage, VCC will start up first and after 0.8ms output voltage ramp up during soft-start time as shown in Figure 1. VIN = 12V VIN Input Under-Voltage Lockout Threshold The RTQ2130B includes an input under-voltage lockout protection (UVLO) circuit. If input voltage exceeds a UVLO rising threshold voltage (VUVLO), the converter will reset and prepare the PWM for operation. If the input voltage falls below a UVLO falling threshold voltage (i.e. VUVLO − ΔVUVLO) during normal operation, the converter will stop switching. There is some hysteresis between UVLO rising and falling threshold voltages to prevent a reset caused by noise. Note that V IN = 3V is only design for cold crank requirement. Normal input voltage should be larger than UVLO rising threshold to turn on. Chip Enable The EN pin is the chip enable input. Pulling the EN pin low to 1.25V (typ) will disable output voltage and low to 0.4V will shut down the device. During shutdown mode, the shutdown current of the RTQ2130B is lower than 10μA. The EN pin has an internal pull-down current source. When VCC exceeds 5V, the current source typically sinks 1.2μA for V_EN < 4V and up to 70μA for V_EN > 4V. Copyright © 2018 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 VCC = 5V VCC EN 0.8ms 2ms VOUT Figure 1. Soft-Start Sequence High-Side MOSFET Over-Current Limit IC detects the inductor current during the period highside MOSFET turns on. When inductor current reaches the current limit value, IC will turn off high-side MOSFET, so it can provide cycle-by-cycle peak current limit protection to prevent IC from over current. Low-Side MOSFET Over-Current Limit The RTQ2130B not only implements the high-side switch current limit but also provides the low-side switch sourcing current limit and low-side switch sinking current limit for low-side MOSFET. With these current protections, the IC can easily control inductor current at both side power switches and avoid current runaway for short-circuit condition. is a registered trademark of Richtek Technology Corporation. DSQ2130B-QT-01 May 2018 RTQ2130B-QT For the low-side switch sourcing current limit, there is a specific comparator in internal circuitry to compare the low-side MOSFET sourcing current to the internal set current limit at the end of every clock cycle. When the low-side sourcing current is higher than the set sourcing limit, the high-side power switch is not turned on and lowside power switch is kept on until the following clock cycle for releasing the above sourcing current to the load. It is allowed to turn on the high-side MOSFET again when the low-side current is lower than the set sourcing current limit at the beginning of a new cycle. For the low-side switch sinking current limit protection, it is implemented by detecting the voltage across the lowside power switch. If the low-side reverse current exceeds the set sinking limit, both power switches are off immediately, and it is held to stop switching until the beginning of next cycle. Output Under-Voltage Protection The RTQ2130B includes output under-voltage protection (UVP) against over-load or short-circuited condition by constantly monitoring the feedback voltage VFB. If VFB drops below the under-voltage protection trip threshold, 50% (typ.) of the internal reference voltage, the UV comparator will go high to turn off the internal high-side MOSFET switches. If the output under-voltage condition continues for a period of time, the RTQ2130B will enter output under-voltage protection with hiccup mode. During hiccup mode, the device remains shut down. After a period of time, a soft-start sequence for auto-recovery will be initiated. Upon completion of the soft-start sequence, if the fault condition is removed, the converter will resume normal operation; otherwise, such cycle for auto-recovery will be repeated until the fault condition is cleared. Hiccup mode allows the circuit to operate safely with low input current and power dissipation, and then resume normal operation as soon as the over-load or short-circuit condition is removed. The UVP profile is shown in Figure 2. Abnormal case detected (UV) 0.58ms VOUT 1.3ms SW Figure 2. Output Under-Voltage Protection with Hiccup Mode Over-Temperature Protection Over-temperature protection is implemented to prevent the chip from operating at excessively high temperatures. When the junction temperature is higher than 175°C, the OTP will shut down switching operation. The chip will automatically resume normal operation with a complete soft-start sequence once the junction temperature cools down by approximately 15°C. Adjacent Pin Short-Circuit Protection The RTQ2130B provide adjacent Pin short-circuit protection. For the RTQ2130B, an internal protection fuse will be blown to prevent IC smoke, fire and spark when the BOOT pin is shorted to VIN pin. Copyright © 2018 Richtek Technology Corporation. All rights reserved. DSQ2130B-QT-01 May 2018 Hiccup mode protection will be triggered to prevent the IC from being burned out when the SW pin is shorted to GND. BOOT UVLO To ensure that high-side switch can be controlled normally, the RTQ2130B implements BOOT UVLO function to prevent operation under low V(BOOT−SW) condition. When V(BOOT−SW) is lower than BOOT_UVLO_L level 2.5V (typ.), IC will disable 99% duty cycle operation, and the minimum off time will be enlarged to 100ns (typ.) to extend BOOT charging time. BOOT UVLO condition will be removed after V(BOOT−SW) is higher than 2.8V (typ.). is a registered trademark of Richtek Technology Corporation. www.richtek.com 5 RTQ2130B-QT Absolute Maximum Ratings            (Note 1) Supply Input Voltage, VIN ---------------------------------------------------------------------------------------Switch Voltage, SW ----------------------------------------------------------------------------------------------