AX3051ESA(BIN2)

AX3051/A 2.8A,Wide-Input Sensorless CC/CV Step-Down DC/DC Converter  GENERAL DESCRIPTION AX3051/A is a wide input voltage, high efficiency Active CC step-down DC/DC converter that operates in either CV (Constant Output Voltage) mode or CC (Constant Output Current) mode. AX3051/A consists of step-down switching regulator with PWM control. The device includes a reference voltage source, oscillation circuit, error amplifier and etc. AX3051/A provides low-ripple power, high efficiency, and excellent transient characteristics. The PWM control circuit is able to the duty ratio linearly forms 0 up to 90%. An over current protection function is built outside that it can set by a resistance. An external compensation is easily to system stable; the low ESR output capacitor can be used. With the addition of an internal N-channel Power MOS, a coil, capacitors, and a diode connected externally, these ICs can function as step-down switching regulators. They serve as ideal power supply units for portable devices when coupled with the SOP-8L-EP packages, providing such outstanding features as low current consumption. Since this converter can accommodate an input voltage up to 34V. 1/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A  FEATURES - Input Voltage：8V to 34V - Vout Accuracy (VFB=1V) ±1% /±2% CC/CV mode(Constant Current and Constant Voltage) Up to 2.8A output current ±5%/±15% Current limit Accuracy Duty ratio：0% to 90% PWM control Oscillation frequency： AX3051: 100KHz - AX3051A: 250KHz Thermal Shutdown function. Short Circuit Protect (SCP). Built-in internal LX N-channel MOS. Current mode non-synchronous PWM converter External current limit setting. Over Voltage Protection 5.8V. Built in adjustable line-compensation. SOP-8L-EP Pb-Free packages  APPLICATIONS - Car charger - Portable charger Device.  BLOCK DIAGRAM CURRENT SENSE AMPLIFIER OSCILLATOR FB RAMP IN +  - CLK 5V 100KHz/250KHz BS + 1V + - ERROR AMPLIFIER S Q R Q M1 0.15Ω CURRENT COMPARATOR LX M2 5Ω OVP GND COMP IN CURRENT Limit AMPLIFIER + 7V Zener 1.5V - INTERNAL REGULATORS SHUTDOWN COMPARATOR + SENSE1 - SENSE2 5V 2/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A  PIN ASSIGNMENT The package of AX3051/A is SOP-8L-EP; the pin assignment is given by: Name Description Bootstrap Pin. This provides power to the internal high-side MOSFET gate BS driver. Connect a 0.1uF capacitor ( Top View ) from BS pin to LX pin. Power Switching Output to LX BS 1 8 GND External Inductor. SENSE1 Current Sense input1 LX 2 7 VIN GND SENSE1 3 6 SENSE2 4 5 FB COMP SOP-8L-EP SENSE2 FB COMP VIN GND Current Sense input2 Output voltage feedback control Error Amplifier Output. This pin is used to compensate the converter. Power Supply Input. Bypass this pin with a 0.1uF ceramic capacitor to GND, placed as close to the IC as possible. GND pin  ORDER/MARKING INFORMATION Order Information AX3051 X XX X Blank:100KHz Package Type Packing A:250KHz ES: SOP-8L-EP Blank : Tube A : Taping Note: Bin 2: ±5%, Bin 3: ±15% (Sense Voltage) Top Marking Logo AX 3 0 5 1 A Y Y W WX AX3051A Part number ID code: internal WW: 01~52 Year: 11=2011 12=2012 : : 19=2019 3/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A  ABSOLUTE MAXIMUM RATINGS (at TA = 25°C) Characteristics IN to GND LX to GND BS to GND FB, SENSE1, SENSE2, COMP to GND Operating Junction Temperature Storage Junction Temperature Lead Temperature (Soldering 10 sec.) Thermal Resistance from Junction to case Thermal Resistance from Junction to ambient Symbol Rating Unit θJC θJA -0.3 to 40 -1 to VIN + 1 VLX - 0.3 to VLX + 7 -0.3 to + 6 -40 to 150 -65 to 150 300 15 75 V V V V °C °C °C °C/W °C/W Note : θJA is measured with the PCB copper are (need connect to Exposed pad) of approximately 1 in2(Multi-layer).  ELECTRICAL CHARACTERISTICS (VIN=12V, TA=25°C, unless otherwise specified) Characteristics Symbol Conditions Input Voltage OVP detect voltage VOVP Internal define OVP Hysteresis Quiescent Current ICCQ VFB = 1.5V, force driver off. Standby Supply Current V0 = 5V, No Load Line compensation Current IFB VSENSE1-VSENSE2=100mV Feedback Voltage(Bin2) AX3051ES Feedback Voltage(Bin2) AX3051AES Feedback Voltage(Bin3) AX3051ES/AX3051AES High-Side Switch On RDSON VIN=12V, IOUT = 1A Resistance Low-Side Switch On RDSON VIN=12V Resistance AX3051; IOUT=200mA Switching Frequency FOSC AX3051A; IOUT=200mA AX3051 Maximum Duty Cycle AX3051A Minimum On-Time Secondary Cycle-by-Cycle Minimum Duty Cycle, no CC Current Limit Reference Voltage of the Short Circuit Fold back VSCP Comparator Sense Voltage (Bin2) VSENSE VSENSE1-VSENSE2 Sense Voltage (Bin3) VSENSE VSENSE1-VSENSE2 Thermal shutdown Temp TSD Thermal Shutdown TSH Hysteresis Min Typ Max 8 34 5.8 0.3 2 10 15 3.5 5 6.5 0.99 1 1.01 0.98 1 1.02 0.98 1 1.02 Units V V V mA mA uA V V V - 150 200 mΩ - 5 80 200 90 87 - 100 250 93 90 150 - 3.5 - A - 0.4 0.45 V 95 85 - 100 100 140 105 mV 115 mV °C - 30 - Ω 120 KHz 300 KHz % % ns - °C 4/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A  APPLICATION CIRCUIT AL CAPACITOR (1) Frequency=100KHz L1 68μH VIN=8~34V C1 100μF/35V C8 2.2μF ~10μF D1 40V/3A C3 0.1μF IN R2 BS R3 4kΩ LX C5 2.2nF C6 10μF R4 1KΩ SENSE2 FB GND C2 2.2nF C4 470μF SENSE1 COMP 8.2KΩ Vout=5V/2.5A R1 37mΩ C7 Option (2) Frequency=250KHz D2 1N4148 VIN=8~34V C1 100μF/35V C3 0.1μF IN R2 COMP GND C2 4.7nF Vout=5V/2.5A R1 37mΩ C8 2.2μF ~10μF 10KΩ L1 22μH BS D1 40V/3A LX C4 47uF~ 220uF R3 4kΩ C5 Option C6 Option SENSE1 SENSE2 FB R4 1KΩ C7 39pF 5/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A  FUNCTION DESCRIPTIONS CV/CC Loop Regulation As seen in Functional Block Diagram, the AX3051/A is a peak current mode pulse width modulation (PWM) converter with CC and CV control. The converter operates as follows: A switching cycle starts when the rising edge of the Oscillator clock output causes the High-Side Power Switch to turn on. With the LX side of the inductor now connected to Sense1, the inductor current ramps up to store energy in the magnetic field. The inductor current level is measured by the Current Sense Amplifier and added to the Oscillator ramp signal. If the resulting summation is higher than the COMP voltage, the output of the PWM Comparator goes high. When this happens or when Oscillator clock output goes low, the High-Side Power Switch turns off. At this point, the LX side of the inductor swings to a diode voltage below ground, causing the inductor current to decrease and magnetic energy to be transferred to output. This state continues until the cycle starts again. The High-Side Power Switch is driven by logic using BS as the positive rail. This pin is charged to VLX + 5V when the Low-Side Power Switch turns on. The COMP voltage is the integration of the error between FB input and the internal 1V reference. If FB is lower than the reference voltage, COMP tends to go higher to increase current to the output. Output current will increase until it reaches the CC limit set by the R1 resistor. At this point, the device will transition from regulating output voltage to regulating output current, and the output voltage will drop with increasing load. Current Limit Protection The Current limit is set by outside resistance (RSENSE), When the SENSE1-SENSE2 voltage larger than 100mV, the current limit is happened that driver can be turned off. The current limit set according to the following equation: Current Limit (A) = 100mV R SENSE 6/15 Axelite Confidential Materials, do not copy or distribute without written consent. Rev.1.9 May. 06, 2015 AX3051/A Output Over-Voltage protection The AX3051/A provides output over-voltage protection function. When output over-voltage happens (VSENS2> 5.8V), the AX3051/A shuts down. When output over-voltage is released (VSENS2< 5.7V), the AX3051/A recovers to normal state automatically. Output Short-Circuit protection The AX3051/A provides output short-circuit protection function. When VOUT is short (VFB