EC3618

EC3618 E-CMOS | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 8

Technical content

Features

• Input voltage ：8V to 58V - Output voltage ：3.3V to 56V - Duty ratio ：0% to 100% PWM control - Enable and Soft-Start function - Current Limit, Short Circuit Protect (SCP) and Thermal Shutdown protection - Built-in internal SW P-channel MOS. - SOP-8L-EP Pb-Free package. Block Diagram

PWM Control 2A Step-Down Converter Pin Assignments The package of EC3618 is SOP-8L-EP; the pin ass ignment is given by:

Ordering Information

Part Number Package Marking Marking Information EC3618NNMHR EC3618ANMHR SOP 8L (Exposed Pad) EC3618 LLLLL YYWWX 1. LLLLL ：Lot No. 2. YY ：Year ；Ex: 2012=12 、2013=13 3. WW ：Week ；01~52 weeks 4. X ：N=120KHz ；A=250 KHz Name Description EN ON/OFF Shutdown pin VSS GND pin VGATE Driver GATE clamping pin. The pin must connect a 0.1uF capacitor to V CC VCC IC power supply pin SW Switch pin. Connect external inductor and diode here. FB Feedback pin COMP Compensation pin SS Soft-start pin EC3618 XN XX X MH : SOP 8L (Exposed Pad) N ：： ：： 120 KHz A ：： ：： 250 KHz T ：： ：： Tube

PWM Control 2A Step-Down Converter Absolute Maximun Rating (at TA=25° C) Characteristics Symbol Rating Unit VCC Pin Voltage VCC VSS - 0.3 to V SS + 63 V Feedback Pin Voltage VFB VSS - 0.3 to 6 V EN Pin Voltage VEN VSS - 0.3 to V CC V SS Pin Voltage SS VSS - 0.3 to 6 V COMP Pin Voltage VCOMP VSS - 0.3 to 6 V VGATE Pin Voltage VGATE VSS - 0.3 to VCC V Switch Pin Voltage VSW VSS - 0.3 to VCC + 0.3 V Power Dissipation PD Internally limited mW Storage Temperature Range TST -65 to +150 ° C Operating Junction Temperature Range TOJP -40 to +125 ° C Operating Input Voltage(Note 1) VOP 8 to 58 V Thermal Resistance from Junction to case θJC 15 ° C/W Thermal Resistance from Junction to ambient (Note 2) θJA 75 ° C/W Note: 1. When Vop(Operating Input Voltage)<10V then Maximum output current is 0.45A 。 2. θJA is measured with the PCB copper area (need connect to Exposed Pad) of approximately 1.5 in2 (Multi-layer).

Electrical Characteristics

(V CC = 24V, T A=25° C, unless otherwise specified) Characteristics Symbol Conditions Min Typ Max Units Feedback Voltage VFB IOUT =10mA 0.98 1.00 1.02 V Quiescent Current ICCQ VFB =1.2V, force driver off - 3 6 mA Feedback Bias Current IFB IOUT =0.1A - 0.1 0.5 uA Shutdown Supply Current ISD VEN =0V - 0.5 1 mA Line Regulation △VOUT /V OUT VCC =10V~58V, IOUT =10mA - 0.3 0.6 % Load Regulation △VOUT /V OUT IOUT = 0.2 to 2A - 0.3 0.6 % Current Limit ICL 2.8 - - A FOSC EC3618N 90 120 150 KHz Oscillator frequency FOSC EC3618A 200 250 300 KHz FOSC1 EC3618N ICL - 50 - KHz FOSC1 EC3618A ICL - 110 - KHz Short frequency FOSC2 EC3618N/EC3618A VFB < 0.3 - 30 - KHz VSH High (regulator ON) 2.0 - - V EN Pin Logic input threshold voltage VSL Low (regulator OFF) - - 0.8 ISH VEN =2.5V (ON) - 5 - uA EN Pin Input Current ISL VEN =0.3V (OFF) - 5 - uA SS Current ISS VSS =0V - 10 - uA Internal MOSFET R DSON R DSON VCC =12V, 1A,V FB =0V - 220 300 m Ω Efficiency (EC3618) EFFI VCC = 24V, VOUT = 5V, I OUT = 2A - 90 - % Thermal shutdown Temp (Junction Temp) TSD - 150 - ° C Thermal shutdown Hysteresis TSH - 40 - ° C

PWM Control 2A Step-Down Converter Application Circuit Function Descriptions EN ：： ：：This pin can be supplied shutdown function. It is inside pull high function. Allow the switching regulator circuit to be shutdown pulling this pin below a 0.8V threshold voltage. SS ：： ：： This pin can be supplied soft start function. The pin must be connected a capacitor to ground. There is a 10uA current to charge this capacitor, vary the different capacitor value to control soft start time. COMP ：： ：：Compensation pin. For EL output capacitor application, the COMP pin connects R2 and C9 to ground for all condition; please refer the compensation table.

APPLICATION INFORMATION

Setting the Output Voltage Application circuit item shows the basic application circuit with adjustable output version. The external resistor sets the output voltage according to the following equation: Table 1 Resistor select for output voltage setting VOUT R4 R1 5V 1.5K 6K 3.3V 1.3K 3K

PWM Control 2A Step-Down Converter Inductor Selection For most designs, the different frequency can be reducing the inductor value; The EC3618 is suggested 33µH. Where is inductor Ripple Current. Large value inductors lower ripple current and small value inductors result in high ripple currents. Choose inductor ripple current approximately 20% of the maximum load current 2A, ∆IL=0.4A. The DC current rating of the inductor should be at least equal to the maximum load current plus half the ripple current to prevent core saturation (2A+0.2A). Input Capacitor Selection This capacitor should be located close to the IC using short leads and the voltage rating should be approximately 1.5 times the maximum input voltage. The RMS current rating requirement for the input capacitor of a buck regulator is approximately 1⁄2 the DC load current. A low ESR input capacitor sized for maximum RMS current must be used. A 470µF low ESR capacitor for most applications is sufficient. Output Capacitor Selection The output capacitor is required to filter the output and provide regulator loop stability. The important capacitor parameters are; the 100 KHz Equivalent Series Resistance (ESR), the RMS ripples current rating, voltage rating, and capacitance value. For the output capacitor, the ESR value is the most important parameter. The ESR can be calculated from the following formula. An aluminum electrolytic capacitor's ESR value is related to the capacitance and its voltage rating. In most case, higher voltage electrolytic capacitors have lower ESR values. Most of the time, capacitors with much higher voltage ratings may be needed to provide the low ESR values required for low output ripple voltage. It is recommended to replace this low ESR capacitor by using a 470µF low ESR values < 80m Ω.

PWM Control 2A Step-Down Converter Typical Characteristics

PWM Control 2A Step-Down Converter Typical Characteristics (Continuous)

PWM Control 2A Step-Down Converter Package Outlines