RT8097CHGB

RT8097C 2A, 1MHz, 6V CMCOT Synchronous Step-Down Converter General Description Features The RT8097C is a high efficiency synchronous stepdown DC-DC converter. Its input voltage range is from 2.7V to 6V and provides an adjustable regulated output voltage from 0.6V to 3.4V while delivering up to 2A of output current.      Efficiency Up to 95% RDS(ON) 100m HS / 70m LS VIN Range 2.7V to 6V VREF 0.6V with 1.2% Accuracy at 25C CMCOT ™ Control Loop Design for Best Transient Response, Robust Loop Stability with Low-ESR (MLCC) COUT The internal synchronous low on-resistance power switches increase efficiency and eliminate the need for an external Schottky diode. The Current Mode   Constant-On-time (CMCOT) operation with internal compensation allows the transient response to be optimized over a wide range of loads and output capacitors. The RT8097C is available in the SOT-235/6 package. Soft-Start 1.2ms; PGOOD Function in SOT-23-6 Power Saving at Light Load Applications    STB, Cable Modem, & xDSL Platforms LCD TV Power Supply & Metering Platforms General Purpose Point of Load (POL) Ordering Information RT8097C Package Type B : SOT-23-5 E : SOT-23-6 Lead Plating System G : Green (Halogen Free and Pb Free) UVP Option H : Hiccup L : Latched-Off C : PSM/PWM 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. Simplified Application Circuit RT8097C LX VIN VIN CIN L VOUT R1 EN PG* COUT FB GND R2 *For SOT-23-6 Package Only Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS8097C-09 June 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 1 RT8097C Pin Configuration Marking Information RT8097CHGB (TOP VIEW) FB VIN 5 4 5P=DNN 5P= : Product Code DNN : Date Code RT8097CLGB 2 3 5N=DNN 5N= : Product Code DNN : Date Code EN GND LX RT8097CHGE SOT-23-5 FB 6 2L=DNN PG VIN 5 4 2 3 2L= : Product Code DNN : Date Code RT8097CLGE 2J=DNN 2J= : Product Code DNN : Date Code EN GND LX SOT-23-6 Functional Pin Description Pin No. Pin Name Pin Function SOT-23-5 SOT-23-6 1 1 EN Enable control input. 2 2 GND Power ground. 3 3 LX Switch node. 4 4 VIN Supply voltage input. The RT8097C operates from a 2.7V to 6V input. 5 6 FB Feedback voltage input. An external resistor divider from the output to GND, tapped to the FB pin, sets the output voltage. -- 5 PG Power good indicator. The output of this pin is an open-drain with external pull-up resistor. PG is pulled up when the FB voltage is within 90%, otherwise it is LOW. Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 2 is a registered trademark of Richtek Technology Corporation. DS8097C-09 June 2019 RT8097C Functional Block Diagram For SOT-23-5 Package EN VIN UVLO Shut Down Control OTP FB - VREF Error Amplifier Ton Comparator + RC CCOMP + - Logic Control LX VIN Driver Current Limit Detector LX GND Current Sense LX Ton LX For SOT-23-6 Package EN VIN UVLO Shut Down Control OTP - FB VREF Error Amplifier Comparator + + RC CCOMP - Logic Control VIN Driver Current Limit Detector LX GND + Current Sense - LX PG Copyright © 2019 Richtek Technology Corporation. All rights reserved. DS8097C-09 June 2019 is a registered trademark of Richtek Technology Corporation. www.richtek.com 3 RT8097C Operation The RT8097C is a synchronous low voltage step-down converter that can support the input voltage range from 2.7V to 6V and the output current can be up to 2A. The RT8097C uses a constant on-time, current mode architecture. In normal operation, the high side PMOSFET is turned on when the switch controller is set by the comparator and is turned off when the Ton Enable Comparator comparator resets the switch controller. track the internal ramp voltage during soft-start interval. The typical soft-start time is 1.2ms. Low side MOSFET peak current is measured by internal RSENSE. The error amplifier EA adjusts COMP voltage by comparing the feedback signal (VFB) from the output voltage with the internal 0.6V reference. When the load current increases, it causes a drop in the feedback voltage relative to the reference, then the COMP voltage rises to allow higher inductor current to match the load current. UV Comparator If the feedback voltage (VFB) is lower than threshold voltage 0.2V, the UV comparator's output will go high and the switch controller will turn off the high side MOSFET. The output under voltage protection is designed to operate in Hiccup mode for RT8097CH, Latch mode for RT8097CL. PGOOD Comparator A logic-high enables the converter; a logic-low forces the IC into shutdown mode. Soft-Start (SS) An internal current source charges an internal capacitor to build the soft-start ramp voltage. The VFB voltage will Over-Current Protection (OCP) The RT8097C provides over current protection by detecting low side MOSFET valley inductor current. If the sensed valley inductor current is over the current limit threshold (3.1A typ.), the OCP will be triggered. When OCP is tripped, the RT8097C will keep the over current threshold level then cause the UV protection. Thermal Shutdown (OTP) The device implements an internal thermal shutdown function when the junction temperature exceeds 150C. The thermal shutdown forces the device to stop switching when the junction temperature exceeds the thermal shutdown threshold. Once the die temperature decreases below the hysteresis of 20C, the device reinstates the power up sequence. When the feedback voltage (VFB) is higher than threshold voltage 0.54V, the PGOOD open drain output will be high impedance. The internal PG MOSFET is typical 10. The PGOOD signal delay time from EN is about 2ms. Copyright © 2019 Richtek Technology Corporation. All rights reserved. www.richtek.com 4 is a registered trademark of Richtek Technology Corporation. DS8097C-09 June 2019 RT8097C Absolute Maximum Ratings (Note 1)  Supply Input Voltage ------------------------------------------------------------------------------------------ 0.3V to 6.5V  LX Pin Switch Voltage----------------------------------------------------------------------------------------- 0.3V to (VIN + 0.3V)