LSP5523

LSP5523 LITEON | Alldatasheet

Document overview

• Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
• PDF pages: 16

Technical content

Features

• 3A Output Current
• Wide 4.5V to 27V Operating Input Range
• Fixed 340KHZ Frequency
• Integrated Power MOSFET Switches
• Output Adjustable from 0.925V to 0.8Vin
• Up to 93% Efficiency
• Programmable Soft-Start
• Stable with Low ESR Ceramic Output Capacitors
• Cycle by Cycle Over Current Protection
• Short Circuit Protection
• In put Under Voltage Lockout
• Package ： ESOP-8L

Applications

• Distributed Power Systems
• Networking Systems
• FPGA, DSP, ASIC Power Supplies
• Green Electronics/ Appliances
• Notebook Computers Please be aware that an Important Notice concerning availability, disclaimers, and use in critical applications of LSC products is at the end of this document.

3A 27V Synchronous Buck Converter 2 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Block Diagram INTERNAL REGULATORS FB SS COMP EN 1.1V 0.3V 0.925V 2.5V 1.5V OVP SHUTDOWN COMPARATOR ERROR AMPLIFIER LOCKOUT COMPARATOR EN OK 6uA OSCILLATOR 340/120KHz RAMP CLK 1.2V OVP IN<4.10V IN CURRENT COMPARATOR CURRENT SENSE AMPLIFIER VIN BS SW GND S Q R Q

Ordering Information

R8 : ESOP-8L Blank : ADJ A : Tape & Reel Package Output Voltage Packing LSP 5523 - Packing Output Voltage Package XX X X

3A 27V Synchronous Buck Converter 3 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Pin Assignment 1 8 SS EN COMP FB BS VIN SW GND (TOP View) Exposed Pad on Backside ESOP-8L Pin Descriptions Pin Name Name Pin Description 1 BS Bootstrap. This pin acts as the positive rail for the high-side switch’s gate driver. Connect a 0.01uF capacitor between BS and SW. 2 VIN Input Supply. Bypass this pin to GND with a low ESR capacitor. See Input Capacitor in the Application Information section. 3 SW Switch Output. Connect this pin to the switchi ng end of the inductor. 4 GND Ground. 5 FB Feedback Input. The voltage at this pin is regulated to 0.925V. Connect to the resistor divider between output and ground to set output voltage. 6 COMP Compensation Pin. See Stability Compensation in the Application Information section. 7 EN Enable Input. When higher than 2.7V, this pin turns the IC on. When lower than 1.1V, this pin turns the IC off. Output voltage is discharged when the IC is off. This pin should not be left open. Recommend to put a 150K  pull-up resistor to Vin for startup. 8 SS Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to set the soft-start period. A 0.1uF capacitor sets the soft-start period to 13ms. To disable the soft-start feature, leave SS unconnected. Exposed Pad Exposed Pad. Need to connect to GND p in.

3A 27V Synchronous Buck Converter 4 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Absolute Maximum Ratings (at T A=25°C) Note: Operate over the “Absolute Maximum Ratings” may cause permanent damage to the device. Exposure to such conditions for extended time may still affect the reliability of the device. Characteristics Value Unit Input Supply Voltage -0.3 to 30 V SW Voltage -0.3 to V IN + 0.3 V BS Voltage VSW – 0.3 to V SW + 6 V EN, FB, COMP Voltage -0.3 to 5 V Continuous SW Current Internally limited A Maximum Junction Temperature 150 °C Storage Temperature Range -65 to 150 °C ESOP-8L Thermal Resistance(Junction to Case) 19 °C/W ESOP-8L Thermal Resistance(Junction to Ambient) 84 °C/W ESOP-8L Power dissipation 1450 mW Moisture Sensitivity (MSL) Please refer the MSL label on the IC package bag/carton for detail Note1:Ratings apply to ambient temperature at 25°C Recommended Operating Conditions Characteristics Min Max Unit Input Supply Voltage 4.5 27 (1) V Operating Junction Temperature -20 +125 (2) °C Note (1): Operating the IC over this voltage is very easy to cause over voltage condition to VIN pin, SW pin, BS pin & EN pin) Note (2): If the IC experienced OTP, then the temperature may need to drop to <125 degree C to let the IC recover.)

3A 27V Synchronous Buck Converter 5 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16

Electrical Characteristics

(T A=25°C, unless otherwise specified) Characteristics Symbol Conditions Min Typ Max Unit Feedback Voltage VFB 4.5V ≤ VIN ≤ 27V 0.900 0.925 0.950 V Feedback Overvoltage Threshold 1.1 V High-Side Switch-On Resistance* 90 mΩ Low-Side Switch-On Resistance* 70 mΩ High-Side Switch Leakage V EN = 0V, V SW = 0V 0.1 10 uA Upper Switch Current Limit Minimum Duty Cycle 3.8 4.5 A Lower Switch Current Limit From Drain to Source 1 .2 A COMP to Current SenseLimit Transconductance G CS 5.2 A/V Error Amplifier Transconductance GEA ∆I COMP = ±10uA 900 uA/V Error Amplifier DC Gain* AVEA 400 V/V Switching Frequency fSW 300 340 380 KHz Short Circuit Switching Frequency V FB = 0 100 KHz Minimum Duty Cycle* Dmin 7.5 % Maximum Duty Cycle Dmax 92 % EN Shutdown Threshold Voltage V EN Rising 1.1 1.4 2 V EN Shutdown Threshold Voltage Hysteresis 180 mV EN Lockout Threshold Voltage 2.2 2.5 2.7 V EN Lockout Hysteresis 150 mV Supply Current in Shutdown V EN = 0 0.3 3.0 uA IC Supply Current in Operation V EN = 3V, V FB = 1.0V 1.3 1.5 mA Input UVLO Threshold Rising UVLO V EN Rising 3.8 4.0 4.5 V Input UVLO Threshold Hysteresis 150 mV Soft-start Current V SS = 0V 6 uA Soft-start Period C SS = 0.1uF 13 mS Thermal Shutdown Temperature* Hysteresis =25°C 15 5 °C Note : * Guaranteed by design, not tested.

3A 27V Synchronous Buck Converter 6 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Application Circuit LSP5523 application circuit, 3.3V/3A output. LSP5523 application circuit, 3.3V/3A output with EN function Note: C2 is required for separate EN signal.

3A 27V Synchronous Buck Converter 7 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Output Voltage Setting FB VOUT Figure1. Output Voltage Setting Figure 1 shows the connections for setting the output voltage. Select the proper ratio of the two feedback resistors R1 and R2 based on the output voltage. Typically, use R2 ≈ 10KΩ and determine R1 from the following equation: Table1 － Recommended Resistance Values Inductor Selection The inductor maintains a continuous current to the output load. This inductor current has a ripple that is dependent on the inductance value: higher induct ance reduces the peak-to-peak ripple current. The t rade off for high inductance value is the increase in in ductor core size and series resistance, and the red uction in current handling capability. In general, select an inductance value L based on the ripple current requirement: RIPPLE OUTMAX SW IN OUT IN OUT KIfV )VV (VL −•= where V IN is the input voltage, V OUT is the output voltage, f SW is the switching frequency, I OUTMAX is the maximum output current, and K RIPPLE is the ripple factor. Typically, choose K RIPPLE = ~ 30% to correspond to the peak-to-peak ripple current being ~30% of the maximum output current. With this inductor value, the peak inductor current is I OUT • (1 + K RIPPLE / 2). Make sure that this peak inductor current is less than the upper switch current limit . Finally, select the inductor core size so that it does not saturate at the current limit. Typical inductor values for various output voltages are shown in Table 2. L 4.7uH 4.7uH 10uH 10uH 10uH 10uH 10uH 22uH VOUT R1 R2 1.0V 1.0 KΩ 12 KΩ 1.2V 3.0 KΩ 10 KΩ 1.8V 9.53 KΩ 10 KΩ 2.5V 16.9 KΩ 10 KΩ 3.3V 26.1 KΩ 10 KΩ 5V 44.2 KΩ 10 KΩ 12V 121 KΩ 10 KΩ (1) (2)

Table 2. Typical Inductor Values out of this capacitor during switching, its ESR also affects efficiency. little bit away if a small parallel 0.1uF ceramic capacitor is placed right next to the IC. high voltage and damage the IC. capacitors, choose a capacitor with less than 50mΩ ESR. example Schottky diodes and their Manufacturers. <20V B130 30V, 1A Lite-on semiconductor corp.

20V SK14 40V, 1A Lite-on semiconductor corp.

Figure 2. Stability Compensation

3A 27V Synchronous Buck Converter 9 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 The feedback loop of the IC is stabilized by the components at the COMP pin, as shown in Figure 2. The DC loop gain of the system is determined by the following equation: COMPVEA OUT VDC GAI VA 925. 0= The dominant pole P1 is due to C COMP1 :

2 COMPVEA

P CA Gf π= The second pole P2 is the output pole: OUTOUT OUT P CV If π2 2 = The first zero Z1 is due to R COMP and C COMP1 : COMPCOMP Z CRf π= And finally, the third pole is due to R COMP and C COMP2 (if C COMP2 is used): 2COMP COMP

3 P CR π 2

1f = The following steps should be used to compensate the IC: STEP1. Set the crossover frequency at 1/10 of the switching frequency via R COMP : VGG fCVR COMPEA SWOUTOUT COMP 925. 010

• = π But limit R COMP to 10KΩ maximum. More than 10 KΩ is easy to cause overshoot at power on. STEP2. Set the zero fZ1 at 1/4 of the crossover frequency. If R COMP is less than 10KΩ, the equation for CCOMP is: )(637. 0

1 FfcRC

STEP3. If the output capacitor’s ESR is high enough to cause a zero at lower than 4 times the crossover frequency, an additional compensation capacitor C COMP2 is required. The condition for using C COMP2 is: ESRCOUTR 1≥××× fsR C ESROUTπ And the proper value for C COMP2 is: (4) (5) (6) (7) (8) (9) (10) (11)

3A 27V Synchronous Buck Converter 10 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 COMP ESRCOUT OUT 2COMP R RCC = Though C COMP2 is unnecessary when the output capacitor has sufficiently low ESR, a small value C COMP2 such as 100pF may improve stability against PCB layout parasitic effects. Table 4 Component Selection Guide for Stability Compensation Vin Range (V) Vout, (V) Cout Rcomp, (kΩ) Ccomp, (nF) Ccomp2, (pF) Inductor, (uH) 5 – 12 1.0 22uF x2 Ceramic 2.4 6.8 none 4.7 5 – 15 1.2 3 6.2 none 4.7 5 – 15 1.8 6.2 3 none 10 5 – 15 2.5 8 2.2 none 10 5 – 15 3.3 10 2.2 none 10 7 – 15 5 10 2.2 none 10 5 – 12 1.0 470uF/ 6.3V/ 120 mΩ 10 10 680 10 5 – 15 1.2 5 – 23 1.8 5 – 27 2.5 5 – 27 3.3 7 – 27 5 (12)

Figure 3. Load Transient Testing VS Compensation Value through Vin. through Enable.

3A 27V Synchronous Buck Converter 12 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Typical Characteristics (Continued) EFFICIENCY vs LOAD CURRENT (Vout=3.3V) 62.0 66.0 70.0 74.0 78.0 82.0 86.0 90.0 94.0 98.0 0 0.5 1 1.5 2 2.5 3 3.5 LOAD CURRENT (A) EFFICIENCY (%) Vin=23 V Vin=12V Vin=5 V OUTPUT VOLTAGE (3.3V) vs LOAD CURRENT 3.2 3.225 3.25 3.275 3.3 3.325 3.35 3.375 3.4 0 0.5 1 1.5 2 2.5 3 3.5 4 LOAD CURRENT, (A) OUTPUT VOLTAGE, (V) Vin=5 V Vin=23 V Vin=12V OUTPUT VOLTAGE vs AMBIENT TEMPERATURE 3.2775 3.28 3.2825 3.285 3.2875 3.29 3.2925 3.295 3.2975 3.3 3.3025 3.305 3.3075 3.31 -50 -30 -10 10 30 50 70 90 110 130 150 AMBIENT TEMPERATURE, (C) OUTPUT VOLTAGE, (V) SWITCHING FREQUENCY vs AMBIENT TEMPERATURE 310 315 320 325 330 335 340 345 350 -50 -30 -10 10 30 50 70 90 110 130 150 AMBIENT TEMPERATURE, (C) SWITCHING FREQUENCY, (kHz)

3A 27V Synchronous Buck Converter 13 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Marking Information V YYWW UZ Internal Code Date code WW ： Week(01~53) Output Voltage Blank ： ADJ SWITCHES RdsON vs JUNCTION TEMPERATURE (Vin=12V) 0.06 0.07 0.08 0.09 0.1 0.11 0.12 0.13 10 30 50 70 90 110 130 150 170 JUNCTION TEMPERATURE (C) SWITCHES RdsON JUNCTION TEMPERATURE vs LOAD CURRENT (Ta=25C) 100 0 0.5 1 1.5 2 2.5 3 3.5 LOAD CURRENT, A JUNCTION TEMPERATURE, C Vin=23V Vin=12V Vin=5V ESOP-8L

3A 27V Synchronous Buck Converter 14 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Mechanical Information (1) Package type: ESOP-8L Unit:mm Symbol Min Max A - 1.70

3A 27V Synchronous Buck Converter 15 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 A1 - 0.15 A2 1.30 1.55 b 0.33 0.51 c 0.17 0.25 D 4.70 5.10 D1 3.10 REF E 5.80 6.20 E1 3.70 4.10 E2 2.21 REF e 1.27 BSC L 0.40 1.27 L1 1.00 1.10 Gauge Plane 0.25 BSC θ 0 o 8 o MSL (Moisture Sensitive Level) Information IPC/JEDEC J-STD-020D.1 Moisture Sensitivity Levels Table LEVEL FLOOR LIFE SOAK REQUIREMENTS Standard Accelerated Equivalent 1 eV 0.40-0.48 eV 0.30-0.39 CONDITION TIME CONDITION TIME (hours) CONDITION TIME (hours) TIME (hours)

1 Unlimited ≤30 °C /85%

+5/-0 85 °C /85% RH NA NA NA 2 1 year ≤30 °C /60% RH 168 +5/-0 85 °C /60% RH NA NA NA 2a 4 weeks ≤30 °C /60% RH 696 2 +5/-0 30 °C /60% RH 120 -1/+0 168 3 168 hours ≤30 °C /60% RH 192 2 +5/-0 30 °C /60% RH -1/+0 4 72 hours ≤30 °C /60% RH 96 2 +2/-0 30 °C /60% RH +0.5/-0 5 48 hours ≤30 °C /60% RH 72 2 +2/-0 30 °C /60% RH +0.5/-0 a 24 hours ≤30 °C /60% RH 48 2 +2/-0 30 °C /60% RH +0.5/-0

6 Time on Label

(TOL) ≤30 °C /60% RH TOL 30 °C /60% RH NA NA NA Note 1: CAUTION - To use the ‘‘accelerated equivalent’’ soa k conditions, correlation of damage response (inclu ding electrical, after soak and reflow), should be established with the ‘‘ standard’’ soak conditions. Alternatively, if the k nown activation energy for moisture diffusion of the package materials is in t he range of 0.40 - 0.48 eV or 0.30 - 0.39 eV, the ‘ ‘accelerated equivalent’’ document JESD22-A120 provides a method for determining the diffusion coefficient.

3A 27V Synchronous Buck Converter 16 of 15 www.liteonsemi.com LSP5523 Rev. 04 2015/4/16 Note 2: The standard soak time includes a default value of 24 hours for semiconductor manufacturer’s exposure time (MET) between bake and bag and includes the maximum time allowed out of the bag at the distributor’s facility. If the actual MET is less than 24 hours the soak time may be reduced. For soak con ditions of 30 °C/60% RH, the soak time is reduced b y 1 hour for each hour the MET is less than 24 hours. For soak condit ions of 60 °C/60% RH, the soak time is reduced by 1 hour for each 5 hours the MET is less than 24 hours. If the actual MET is greater than 24 hours the soak time must be increased. If soak conditions are 30 °C/60% RH, the soak time is increased 1 hour for each hour that the actual MET exceeds 24 hours. If soak conditions are 60 °C/60% RH, the soak time is increased 1 hour for each 5 hours that the actual MET exceeds 24 hours. Important Notice and Disclaimer LSC reserves the right to make changes to this docu ment and its products and specifications at any time without notice. Customers should obtain and c onfirm the latest product information and specifications before final design, purchase or use. LSC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does LSC assume any liabili ty for application assistance or customer product design. LSC does not warrant or accept any liabilit y with products which are purchased or used for any unintended or unauthorized application. No license is granted by implication or otherwise under any intellectual property rights of LSC. LSC products are not authorized for use as critical components in life support devices or systems without express written approval of LSC.