RT8290ZSP

RT8290 3A, 23V, 340kHz Synchronous Step-Down Converter General Description Features zz z zz 4.5V to 23V Input Voltage Range The RT8290 is a high efficiency synchronous step-down zz z zz 1.5% High Accuracy Feedback Voltage DC/DC converter that can deliver up to 3A output current zz z zz 3A Output Current from 4.5V to 23V input supply. The RT8290 s current mode zz z zz Integrated N-MOSFET Switches architecture and external compensation allow the transient zz z zz Current Mode Control response to be optimized over a wide range of loads and zz z zz Fixed Frequency Operation : 340kHz output capacitors. Cycle-by-cycle current limit provides zz z zz Output Adjustable from 0.925V to 20V protection against shorted outputs and soft-start eliminates zz z zz Up to 95% Efficiency input current surge during start-up. The RT8290 also zz z zz Programmable Soft-Start provides output under voltage protection and thermal zz z zz Stable with Low-ESR Ceramic Output Capacitors shutdown protection. The low current (<3A) shutdown zz z zz Cycle-by-Cycle Over Current Protection mode provides output disconnection, enabling easy power zz z zz Input Under Voltage Lockout management in battery-powered systems. The RT8290 zz z zz Output Under Voltage Protection is awailable in an SOP-8 (Exposed Pad) package. zz z zz Thermal Shutdown Protection Applications zz z zz Thermally Enhanced SOP-8 (Exposed Pad) Package z Industrial and Commercial Low Power Systems zz z zz RoHS Compliant and Halogen Free z Computer Peripherals Ordering Information z LCD Monitors and TVs RT8290 z Green Electronics/Appliances Package Type z Point of Load Regulation of High-Performance DSPs, SP : SOP-8 (Exposed Pad-Option 1) FPGAs and ASICs. Lead Plating System G : Green (Halogen Free and Pb Free) Pin Configurations Z : ECO (Ecological Element with Halogen Free and Pb free) (TOP VIEW) Note : BOOT 8 SS VIN 2 7 EN Richtek products are : GND 3 6 SW COMP 9 RoHS compliant and compatible with the current require- 4 5 GND FB ments of IPC/JEDEC J-STD-020. SOP-8 (Exposed Pad) Suitable for use in SnPb or Pb-free soldering processes. Typical Application Circuit 1 2 V IN VIN BOOT C 4.5V to 23V C IN BOOT L1 R RT8290 EN 10Fx2 10H 10nF V 3 OUT 100k SW 3.3V/3A 7 EN R1 26.1k 8 C SS OUT 5 FB C 22Fx2 SS 4, C C R 0.1F C R2 3.9nF 9 (Exposed Pad) 6.8k 10k GND 6 COMP C P NC DS8290-02 March 2011 www.richtek.com 1RT8290 Marking Information RT8290GSP : Product Number RT8290ZSP : Product Number RT8290 YMDNN : Date Code RT8290 YMDNN : Date Code GSPYMDNN ZSPYMDNN Table 1. Recommended Component Selection VOUT (V) R1 (k) R2 (k) RC (k) CC (nF) L ( H) COUT ( F) 15 153 10 30 3.9 33 22 x 2 10 97.6 10 20 3.9 22 22 x 2 8 76.8 10 15 3.9 22 22 x 2 5 45.3 10 13 3.9 15 22 x 2 3.3 26.1 10 6.8 3.9 10 22 x 2 2.5 16.9 10 6.2 3.9 6.8 22 x 2 1.8 9.53 10 4.3 3.9 4.7 22 x 2 1.2 3 10 3 3.9 3.6 22 x 2 Functional Pin Description Pin No. Pin Name Pin Function Bootstrap for High Side Gate Driver. Connect a 10nF or greater ceramic capacitor 1 BOOT from the BOOT pin to SW pin. Voltage Supply Input. The input voltage range is from 4.5V to 23V. A suitable large 2 VIN capacitor must be bypassed with this pin. 3 SW Switching Node. Connect the output LC filter between the SW pin and output load. 4, Ground. The exposed pad must be soldered to a large PCB and connected to GND 9 (Exposed Pad) GND for maximum power dissipation. Output Voltage Feedback Input. The feedback reference voltage is 0.925V 5 FB typically. Compensation Node. This pin is used for compensating the regulation control 6 COMP loop. A series RC network is required to be connected from COMP to GND. If needed, an additional capacitor can be connected from COMP to GND. Enable Input. A logic high enables the converter, a logic low forces the converter 7 EN into shutdown mode reducing the supply current to less than 3 A. For automatic startup, connect this pin to VIN with a 100k pull up resistor. Soft-Start Control Input. The soft-start period can be set by connecting a capacitor 8 SS from SS to GND. A 0.1F capacitor sets the soft-start period to 15.5ms typically. www.richtek.com DS8290-02 March 2011 2