EA8421T6R

40V, 800mA, 600KHz Buck Converter EA8421 Datasheet General Description The EA8421 is a 800mA buck regulator, designed to operate from 5V to 40V input voltage range. Built-in 400mΩ high side Power-MOSFET has up to 92% efficiency, ideal for 800mA output current applications. The fixed 600KHz operating frequency allowing the use of small inductor and ceramic capacitor. The EA8421 has complete protection functions, including cycle-by-cycle current limit, short circuit protection, OTP and UVLO protection. The internal compensation design allows users to more simplified application, and can reduce the cost of external components. The EA8421 is available in the SOT-23-6 package and easy to use. Features              5V to 40V Input Voltage Range Output Adjustable Down to 0.8V 800mA Continuous Load Current Fixed 600KHz Switching Frequency Efficiency Up to 92% 400uA Quiescent Current Internal Compensation Internal Soft-Start Function Cycle-by-Cycle Current Limit Input UVLO Protection Auto Recovery Short Circuit Protection Auto Recovery OTP Protection Available in SOT-23-6 Package Applications     Distributed Power Systems Smart Phones Power Meters Portable Handsets Pin Configurations (TOP VIEW) SWITCH PWR 6 5 RUN 4 1 2 3 BOOT GND FBK SOT-23-6 1 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. Ver. 1.0 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Pin Description Pin Name Function Description Pin No. BOOT The power input of the internal high side N-MOSFET gate driver. Connect a 100nF ceramic capacitor from BOOT pin to SWITCH pin. 1 GND Ground pin. 2 FBK Feedback input. Connect FBK pin and GND pin with voltage dividing resistors to set the output voltage. 3 RUN The device turns on/turns off control input. The EA8421 on/off state can be controlled by RUN pin voltage level. Connect RUN pin to PWR pin with a 150KΩ pull up resistor for automatic startup. Don’t leave RUN pin floating. 4 PWR The EA8421 power input pin. Recommended to use a 10uF MLCC capacitor between PWR pin and GND pin. 5 SWITCH Internal MOSFET switching output. Connect SWITCH pin with a low pass filter circuit to obtain a stable DC output voltage. 6 Function Block Diagram PWR UVLO Regulator VREG VREG RUN Current Sense 950KΩ BOOT Control Logic SWITCH OSC Current Sense VREG VREF FBK POR GND OTP Figure 1. EA8421 internal function block diagram Ver. 1.0 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. 2 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Absolute Maximum Ratings Parameter Value Input Voltage (VPWR) -0.3V to +45V RUN Pin Input Voltage (VRUN) -0.3V to +45V BOOT Pin Voltage (VBOOT) VSWITCH-0.3V to VSWITCH+5V SWITCH Pin Voltage (VSWITCH) -1V to +45V FBK Pin Voltage (VFBK) -0.3V to +6V Junction Temperature Range (TJ) -55°C to +125°C Maximum Junction Temperature (TJmax) +150°C Lead Temperature (Soldering, 10 sec) +260°C Storage Temperature Range (TS) -65°C to +150°C ESD (HBM) 2KV Note (1):Stresses beyond those listed under ”Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to “Absolute Maximum Ratings” conditions for extended periods may affect device reliability and lifetime. Package Thermal Characteristics Parameter Value SOT-23-6 Thermal Resistance (θJC) 125°C/W SOT-23-6 Thermal Resistance (θJA) 250°C/W SOT-23-6 Power Dissipation at TA=25°C (PDmax) 0.5W Note (1): PDmax is calculated according to the formula: PDMAX=(TJMAX-TA)/ θJA. Recommended Operating Conditions Parameter Value Input Voltage (VPWR) RUN Pin Input Voltage (VRUN) 3 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. +5V to +40V -0.3V to +40V Ver. 1.0 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Electrical Characteristics VPWR=12V, VOUT=3.3V, TA=25°C, unless otherwise noted Parameter Input Voltage Symbol Test Conditions VPWR Min Quiescent Current ISD IQ Max Unit 40 V 10 uA 20 uA 600 uA 1 mA 0.816 V 5 VRUN = 0V Shutdown Supply Current Typ 2 TJ = -55°C to 125°C VRUN = 2V, VFBK = 105% VREF, ILOAD = 0A 400 TJ = -55°C to 125°C 5V ≤ VPWR ≤ 40V Reference Voltage VREF 0.784 Switching Frequency FSW 600 KHz High Side MOSFET On-Resistance RDS(ON)-HM 400 mΩ Low Side MOSFET On-Resistance RDS(ON)-LM 250 mΩ High Side MOSFET Current Limit ILIM-HM 2 A High Side MOSFET Leakage Current ILEAK-HM RUN Pin Input Low Voltage VRUN-L RUN Pin Input High Voltage VRUN-H VRUN = 0V, VSWITCH = 0V 0.8 0 10 uA 0.4 V 2 V RUN Pin Pull-Low Resistance RRUN 950 KΩ Maximum Duty Cycle DMAX 92 % TONMIN 80 ns 1 ms 160 °C High Side MOSFET Minimum On Time Internal Soft-Start Time Thermal Shutdown Threshold TOTP Note (1): MOSFET on-resistance specifications are guaranteed by correlation to wafer level measurements. (2): Thermal shutdown specifications are guaranteed by correlation to the design and characteristics analysis. Ver. 1.0 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. 4 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Application Circuit Diagram VPWR L1 C3 10uH 100nF VOUT 3.3V/800mA C2 22uFx1 R1 140KΩ 1% 5V~40V BOOT SWITCH PWR C1 10uFx1 C4 (Optional) FBK R2 44.2KΩ 1% ON OFF RUN GND EA8421 Figure 2. Typical application circuit diagram Ordering Information Part Number Package Type Packing Information EA8421T6R SOT-23-6 Tape & Reel / 3000 Note (1): “T6”: Package type code. (2): “R”: Tape & Reel. 5 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. Ver. 1.0 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Typical Operating Characteristics VPWR=12V, VOUT=3.3V, L1=10uH, C1=10F, C2=22uF, TA=25°C, unless otherwise noted VPWR VPWR VSWITCH VSWITCH VPWR=12V, IOUT=0A Switching Waveform VPWR=12V, IOUT=0.8A Switching Waveform VPWR VPWR VSWITCH VSWITCH VPWR=24V, IOUT=0A Switching Waveform VPWR=24V, IOUT=0.8A Switching Waveform VPWR=24V, IOUT=0A Short-Circuit Waveform Ver. 1.0 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. 6 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Application Information Enable Control The EA8421 use RUN pin to control the regulator turns on / turns off. When the RUN pin input voltage is higher than 2V, the EA8421 enters the operating mode. Drive the RUN pin input voltage lower than 0.4V to ensure the EA8421 into shutdown mode, as shown in Figure3. When the device works in the shutdown mode, the shutdown supply current is less than 2uA. The EA8421 also provides automatic startup function as shown in Figure 4. Connect RUN pin and PWR pin with a 150KΩ resistor, when the PWR supply input voltage increasing and higher than RUN pin threshold voltage, the EA8421 will enter operating mode automatically. VPWR VPWR 5V~40V PWR RUN 5V~40V PWR C1 10uF R3 150KΩ C1 10uF RUN ON OFF GND EA8421 GND EA8421 Figure 3. Enable control by RUN pin voltage Figure 4. Automatic startup application circuit Output Voltage Setting The EA8421 output voltage can be set via a resistor divider (R1, R2). The output voltage is calculated by following equation: R1  0.8 V R2 Taking into account the loop stability, R1 resistance value must be greater than 100KΩ. The following table lists common output voltage and the corresponding R1, R2 resistance value for reference. VOUT  0.8  Output Voltage R1 Resistance R2 Resistance Tolerance 5V 220KΩ 30KΩ 1% 3.3V 140KΩ 44.2KΩ 1% 1.8V 200KΩ 100KΩ 1% 1.2V 100KΩ 100KΩ 1% Input / Output Capacitors Selection The input capacitors are used to suppress the noise amplitude of the input voltage and provide a stable and clean DC input to the device. Because the ceramic capacitor has low ESR characteristic, so it is suitable for input capacitor use. It is recommended to use X5R or X7R MLCC capacitors in order to have better temperature performance and smaller capacitance tolerance. In order to suppress the output voltage ripple, the MLCC capacitor is also the best choice. 7 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. Ver. 1.0 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Output Inductor Selection The output inductor selection mainly depends on the amount of ripple current through the inductor ∆IL. Large ∆IL will cause larger output voltage ripple and loss, but the user can use a smaller inductor to save cost and space. On the contrary, the larger inductance can get smaller ∆IL and thus the smaller output voltage ripple and loss. But it will increase the space and the cost. The inductor value can be calculated as: VPWR  VOUT VOUT L  ΔIL  FSW VPWR For most applications, 10uH to 22uH inductors are suitable for EA8421. PCB Layout Recommendations For EA8421 PCB layout considerations, please refer to the following suggestions in order to get good performance.  High current path traces (shown as Figure 5.) need to be widened.  Place the input capacitors as close as possible to the PWR pin to reduce noise interference.  Keep the feedback path (from VOUT to FBK) away from the noise node (ex. SWITCH).  SWITCH is a high current noise node. Complete the layout by using short and wide traces. VPWR L1 VOUT C2 R1 C4 (Optional) C3 BOOT SWITCH FBK R2 PWR R3 C1 RUN GND EA8421 * Bold lines indicate high current paths Ver. 1.0 Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. 8 EA8421 40V, 800mA, 600KHz Buck Converter Datasheet Package Information SOT-23-6 Package A 6 4 5 B K D L 1 3 2 C M N C1 Top View Recommended Layout Pattern E H1 H G F H2 Side View Front View Unit: mm A Dimension Min Max 0.25 0.52 K Dimension Typ 1.40 B 2.59 3.01 L 1.40 C 0.85 1.05 M 0.95 C1 1.70 2.10 N 0.65 D 1.40 1.80 E 2.70 3.10 F 0.30 0.62 G 0.08 0.25 H 0.89 1.35 H1 0.89 1.20 H2 0.00 0.15 Symbol 9 Symbol Copyright © 2022 Everanalog Integrated Circuit Limited. All Rights Reserved. Ver. 1.0