RT2875A/B 3A, 36V, Synchronous Step-Down Converter General Description Features 3A Output Current The RT2875A/B is a high efficiency, current-mode Internal N-MOSFETs synchronous DC/DC step-down converter that can deliver Current Mode Control up to 3A output current over a wide input voltage range Adjustable Switching Frequency : 300kHz to 2.1MHz from 4.5V to 36V. The device integrates 95m high-side Adjustable Current Limit : 1.5A to 6A and 70m low-side MOSFETs to achieve high conversion Synchronous to External Clock : 300kHz to 2.1MHz efficiency. The current-mode control architecture Adjustable Output Voltage from 0.6V to 24V supports fast transient response and simple external High Efficiency Up to 95% compensation. A cycle-by-cycle current limit function Stable with Low ESR Ceramic Output Capacitors provides protection against shorted output and an external Cycle-by-Cycle Current Limit soft-start eliminates input current surge during start-up. Input Under-Voltage Lockout The RT2875A/B provides complete protection functions Output Under-Voltage Protection such as input under-voltage lockout, output under-voltage Thermal Shutdown protection, over-current protection and thermal shutdown. AEC-Q100 Grade 2 Certification The RT2875A/B is available in the thermal enhanced RoHS Compliant and Halogen Free TSSOP-14 (Exposed Pad) package. Applications Pin Configurations Point of Load Regulator in Distributed Power Systems (TOP VIEW) Digital Set Top Boxes SW 14 BOOT Broadband Communications 2 13 SW VIN 3 12 VIN PGND Vehicle Electronics 4 11 RT/SYNC PGND PGOOD 5 10 AGND EN 6 9 RLIM SS 15 7 8 FB COMP TSSOP-14 (Exposed Pad) Simplified Application Circuit VIN BOOT V IN C C RT2875A/B BOOT IN L V SW OUT Enable EN R1 PGOOD PGOOD FB C OUT RLIM C COMP R COMP R2 RT/SYNC COMP R LIM R OSC SS C SS AGND PGND Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. DS2875A/B-04 August 2015 www.richtek.com 1RT2875A/B Ordering Information Marking Information RT2875AQGCP RT2875A/B RT2875AQGCP : Product Number Package Type RT2875AQ YMDNN : Date Code CP: TSSOP-14 (Exposed Pad) GCPYMDNN Lead Plating System G : Green (Halogen Free and Pb Free) RT2875BQGCP AQ : Latched UVP RT2875BQGCP : Product Number BQ : Hiccup Mode UVP RT2875BQ YMDNN : Date Code Note : GCPYMDNN 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. Functional Pin Description Pin No. Pin Name Pin Function 1, 2 SW Switch Node. Connect to external L-C filter. 3, Power Ground. The exposed pad must be soldered to a large PCB and PGND 15 (Exposed Pad) connected to PGND for maximum power dissipation. Oscillator Resistor and External Frequency Synchronization Input. Must connect 4 RT/SYNC a resistor from this pin to GND to set the switching frequency. If SYNC clock is requested, connect an external clock to change the switching frequency. 5 AGND Analog Ground. Current Limit Setting. Connect a resistor from this pin to GND to set the current 6 RLIM limit value. Feedback Voltage Input. The pin is used to set the output voltage of the 7 FB converter to regulate to the desired via a resistive divider. Feedback reference = 0.6V. Compensation Node. COMP is used to compensate the regulation control loop. 8 COMP Connect a series RC network from COMP to GND. In some cases, an additional capacitor from COMP to GND is required. Soft-Start Time Setting. Connect a capacitor from SS to GND to set the 9 SS soft-start period. 10 EN Enable Control Input. High = Enable. 11 PGOOD Power Good Indicator Output. Power Input. Support 4.5V to 36V input voltage. Must bypass with a suitable 12, 13 VIN large ceramic capacitor at this pin. Bootstrap Supply for High-Side Gate Driver. Connect a 0.1F ceramic capacitor 14 BOOT between the BOOT and SW pins. Copyright 2015 Richtek Technology Corporation. All rights reserved. is a registered trademark of Richtek Technology Corporation. www.richtek.com DS2875A/B-04 August 2015 2