DATASHEET SEARCH SITE | WWW.ALLDATASHEET.COM
Document overview
- Manufacturer or author: Provided By ALLDATASHEET.COM(FREE DATASHEET DOWNLOAD SITE)
- PDF pages: 13
Technical content
Features
Input Voltage: 2.7V to 5.5V Output Voltage: 0.6V to VIN 0.6V Reference Voltage with ±1.5% Precision 55µA (Typ) No Load Quiescent Current Shutdown Current: <1µA 100% Duty Cycle Operation 1MHz Switching Frequency No External Compensation Required Short Circuit Protection 445L: Latch Off Protection AP3445: Hiccup Mode Protection Over Voltage Protection 3445L: Latch Off Protection 445: Non Latch Off Protection Thermal Shutdown SOT26 (SC74R) Package Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2) Halogen and Antimony Free. “Green” Device (Note 3) Pin Assignments (Top View) SOT26 (SC74R)
Applications
Post DC-DC Voltage Regulation Set Top Boxes Notebook Computer PAD Notes: 1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS), 2011/65/EU (RoHS 2) & 2015/863/EU (RoHS 3) compliant. 2. See https://www.diodes.com/quality/lead-free/ for more information about Diodes Incorporated’s definitions of Hal ogen- and Antimony-free, "Green" and Lead-free. 3. Halogen- and Antimony-free "Green” products are defined as those which contain <900ppm bromine, <900ppm chlorine (<1500ppm total Br + Cl) and <1000ppm antimony compounds. EN LX VIN FB GND PG 3 4 Pin 1 Mark
Document number: DS39755 Rev. 1 - 2 2 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Typical Applications Circuit VIN EN LX FB L1 2.2mH CIN 22mF VIN=2.7V to 5.5V GND COUT 22mFx2 VOUT=1.8V OFF ON AP3445/L 22pF 200kΩ 100kΩ PG Pin Descriptions Pin Number Pin Name Function 1 EN Enable control input. Force this pin voltage above 1.5V enables the chip, and below 0.4V shuts down the device.
2 GND Ground pin
3 LX The drains of the internal main and synchronous power MOSFET. 4 VIN Bias supply. Chip main power supply pin 5 PG Power good indicator, open drain output. PG is pulled up to VIN when the output voltage is within 20% of the regulation level, otherwise it is low 6 FB Feedback voltage to internal error amplifier, the threshold voltage is 0.6V.
Document number: DS39755 Rev. 1 - 2 3 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Functional Block Diagram 1.5M OSC SLOPE COMP FREQ SHIFT S R Q QEA SWITCHING LOGIC AND BLOCKING CIRCUIT ANTI - SHOOT THRU PWM COMP IAMPFB EN VIN LX GNDSHUTDOWN ____ OSC V REF0.6 CONTROL LOGIC PG Functional Block Diagram of AP3445/L
Document number: DS39755 Rev. 1 - 2 4 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Absolute Maximum Ratings (Note 4) Symbol Parameter Rating Unit VIN Input Voltage -0.3 to 6 V VEN EN Pin Voltage -0.3 to VIN+0.3 V VFB FB Pin Voltage -0.3 to VIN+0.3 V VLX LX Pin Voltage -0.3 to VIN+0.3 V VLX LX Pin Voltage -3 to VIN +3 for <20ns V VFB Feedback Pin Voltage -0.3 to VIN+0.3 V PD Power Dissipation (On PCB, TA = +25° C) 0.588 W θJA Thermal Resistance (Junction to Ambient) 170 ° C/W θJC Thermal Resistance (Junction to Case, Simulation) 130 °C/W TJ Operating Junction Temperature +150 °C TSTG Storage Temperature -55 to +150 °C VHBM ESD (Human Body Model, JESD22-A114) 2000 V VCDM ESD (Charge Device Mode, JESD22-C101) 1000 V Note: 4. Stresses greater than those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stres s ratings only, and functional operation of the device at these or a ny other conditions beyond those indicated under “Recommended Operating Conditions” is not implied. Exposure to “Absolute Maximum Ratings” for extended periods may affect device reliability. Recommended Operating Conditions Symbol Parameter Min Max Unit VIN Supply Voltage 2.7 5.5 V TJ Junction Temperature Range -40 +125 °C TA Operating Ambient Temperature -40 +85 °C
Document number: DS39755 Rev. 1 - 2 5 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Electrical Characteristics (@TA = +25ºC, VIN = 5.0V, VOUT = 2.5V, COUT = 22µF*2, L = 2.2µH, unless otherwise specified.) Symbol Parameters Conditions Min Typ Max Unit VIN VIN Input Voltage Range – 2.7 – 5.5 V VOUT Output Voltage Range – 0.6 – VIN V IQ Quiescent Current VFB = 0.65V – 55 – µA ISD Shutdown Current VEN = 0V – 0.1 1 µA VUVLO Input UVLO Threshold VIN Rises – 2.4 2.5 V VHYS Input UVLO Hysteresis VIN Falls – 0.2 – V Feedback Input VFB Regulated Feedback Voltage – 0.591 0.6 0.609 V IFB FB Leakage Current VFB = 1V – – 0.2 µA ILIM Peak Inductor Current – 2.5 – – A Oscillator fOSC Oscillator Frequency – 0.8 1 1.2 MHz DMAX Maximum Duty Cycle – 100 – – % MOSFET RDS(ON) Drain-Source On-State Resistance ILX = 100mA High Side – 100 – mΩ ILX = 100mA Low Side – 60 – mΩ RDISCH Output Discharge Switch On Resister – – 50 – Ω EN Pin VENH EN Threshold High – 1.5 – – V VENL EN Threshold Low – – – 0.4 V IEN EN Leakage Current VIN= VEN =5V -1.0 – 1.0 µA Protection VSCP Short Circuit Protection Latch Off Threshold AP3445L only – 0.42 – V TDELAY_SCP Short Circuit Protection Delay Time – – 30 – ms TOTP Over Temperature Protection – – +150 – °C TDTH OTP Hysteresis – – +20 – °C VOVP VOUT Over Voltage Protection AP3445L only – 0.72 – V VIOVP VIN Over Voltage Protection VIN Rises – 6.3 – V VIHSY IOVP Hysteresis VIN Falls – 0.35 – V Soft Start tSS Soft-start Time – 0.7 1.0 1.3 ms
Document number: DS39755 Rev. 1 - 2 6 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Performance Characteristics (@TA = +25° C, VIN = 5V, VOUT = 1.8V, unless otherwise specified.) Efficiency vs. Load Current Output Voltage vs. Output Current 10 100 1000 100 Efficiency (%) Output Current (mA) VIN=5V, VOUT=1.0V VIN=5V, VOUT=1.8V VIN=5V, VOUT=3.3V 0 200 400 600 800 1000 1200 1400 1600 1800 2000 1.807 1.808 1.809 1.810 1.811 1.812 1.813 1.814 1.815 1.816 1.817 Output Voltage (V) Ouput Current (mA) VIN=5.0V Vo=1.8V Output Voltage vs. Input Voltage Feedback Reference Voltage vs. Temperature PFET Drain-Source On-State Resistance vs. Temperature NFET Drain-Source On-State Resistance vs. Temperature 1.804 1.806 1.808 1.810 1.812 1.814 1.816 1.818 Ouput Voltage (V) Input Voltage (V) Vo=1.8V Io=2A -60 -40 -20 0 20 40 60 80 100 120 140 0.594 0.595 0.596 0.597 0.598 0.599 0.600 0.601 0.602 0.603 0.604 Feedback Voltage (V) Temperature (℃) -60 -40 -20 0 20 40 60 80 100 120 140 PFETRDS(ON) (mΩ) Temperature (℃) -60 -40 -20 0 20 40 60 80 100 120 140 NFETRDS(ON) (mΩ) Temperature (℃)
Document number: DS39755 Rev. 1 - 2 7 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Performance Characteristics (@TA = +25° C, VIN = 5V, VOUT = 1.8V, unless otherwise specified.) Inductor Current Limit vs. Temperature Oscillation Frequency vs. Temperature -60 -40 -20 0 20 40 60 80 100 120 140 700 750 800 850 900 950 1000 1050 1100 1150 1200 Oscillation Frequency (kHz) Temperature (℃) -60 -40 -20 0 20 40 60 80 100 120 140 3.4 3.6 3.8 4.0 4.2 4.4 4.6 4.8 5.0 5.2 5.4 5.6 5.8 6.0 Inductor Current Limit (A) Temperature (℃)
Document number: DS39755 Rev. 1 - 2 8 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Performance Characteristics (@TA = +25° C, VIN = 5V, VOUT = 1.8V, unless otherwise specified.) Enable Turn on Characteristic (IOUT=2A) Enable Turn off Characteristic (IOUT=2A) Output Ripple (IOUT=0A) Output Ripple (IOUT=2A) Load Transient (IOUT=1A to 2A) Short Current Protection (IOUT=2A) for AP3445L Over Temperature Protection Over Temperature Recovery VEN (5V/div) VOUT (1V/div) IL (2A/div) VPG (5V/div) VEN (5V/div) VOUT (1V/div) IL (2A/div) VPG (5V/div) VOUT_AC (20mV/div) VSW (5V/div) IL (500mA/div) VOUT_AC (20mV/div) VSW (5V/div) IL (2A/div) VOUT_AC (20mV/div) IL (1A/div) VSW (5V/div) VOUT (1V/div) VPG (5V/div) IL (2A/div) VSW (5V/div) VOUT (1V/div) VPG (5V/div) IL (2A/div) VOUT (1V/div) VSW (5V/div) VPG (5V/div) IL (2A/div)
Document number: DS39755 Rev. 1 - 2 9 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT
Application Information
The AP3445/L is a 2A current mode control, s ynchronous buck regulator with integrated power MOSFETs. Current mode control assures excellent line regulation, load regulation, and a wide loop bandwidt h for fast response to load transients. See the typical application schematic and functional block diagram of AP3445/L for more details . The buck controller drives the internal high side P -FETs. The buck regulator can operate from an unregulated DC source, such as a battery, with a voltage ranging from 2.7V to 5.5V. The converter output can be regulated as low as 0.6V to as high as VIN. The feedback loop is compensated internally. Under Voltage Lockout (UVLO) Circuit When the V IN drops lower than the UVLO d etector threshold, the UVLO circuit starts to operate, V REF stops, and high -side switch and low -side switch built-in switch transistors turn “OFF”. As a result, V OUT drops according to the COUT capacitance value and the load. When the V IN is rising higher than UVLO released voltage, the IC will restart the operation. Short Circuit Protection and Recovery When the AP3445/L output node is shorted to GND that VFB drops under 0.42V, AP3445 will enter hiccup mode to protect itself and AP3445L will enter latch-off mode. If short condition is removed, and V FB rises over 0.42V, the AP3445 recovers to normal operation again And AP3445L will remain in this state until VIN or EN voltage is recycled.. If the AP3445/L reaches OCP threshold while short circuit, the AP3445 will enter cycle by cycle current limit mode until the current under OCP threshold. Over Voltage Protection (AP3445L only) The AP3445L has internal output OVP circuits. When VOUT is exceeds 120% of the regulation level for more than 40µ s, the power switches will be turned off. AP3445L enters latch off mode and will restart until VIN or Enable voltage recycled. Over Temperature Protection The internal thermal temperature protection circuitry is provided to protect the integrated circuit in the event tha t the maximum junction temperature is exceeded. When the junction temperature exceeds +150°C, it shuts down the internal control circuit and switching power MOSFET. The AP3445/L will restart automatically under the control of soft start circuit when the junction temperature decreases to +130°C. Setting the Output Voltage Choose R1 and R2 to program the proper output voltage . Resistor R1 is selected based on a design tradeoff between efficiency and output voltage accuracy. For high values of R1 there is le ss current consumption in the feedback network. However the tradeoff is output voltage accuracy due to the bias current in the error amplifier. Table 1 shows a list of resistor s selection for common output voltages. An optional C1 of 10pF to 470pF used to boost the phase margin and improve stability. R2 in figure 6 can be determined by the following equation: 6.0V 6.0RR OUT Figure 1. Feedback Divider Network Table 1. Recommended Component Selection
Document number: DS39755 Rev. 1 - 2 10 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT The input capacitor reduces the surge current drawn from the input supply and the switching noise from th e device. The input capacitor has to sustain the ripple current produced during the on time on the upper MOSFET. It must hence have a low ESR to minimize the losses. The RMS current rating of the input capacitor is a critical parameter that must be higher than the RMS input current. As a rule of thumb, select an input capacitor which has RMs rating that is greater than half of the maximum load current. Due to large d i/dt through the input capacitors, electrolytic or ceramics should be used. If a tantalum must be used, it must be surge protected. Otherwise, capacitor failure could occur. For most applications, a 22µ F ceramic capacitor is sufficient . Output Capacitor The output capacitor keeps the output voltage ripple small, ensures feedback loop stability and reduces the overshoot of the output voltage. The output capacitor is a basic component for the fast response of the power supply. In fact, during load transient, for the firs t few microseconds it supplies the current to the load. The converter recognizes the load transient and sets the duty cycle to maximum, but the current slope is limited by the inductor value. ESR of the output capacitor dominates the output voltage ripple. The amount of ripple can be calculated from the equation below: ESR*ΔIV INDUCTORCAPACITOROUT An output capacitor with ample capacitance and low ESR is the best option. For most applications, 2x22µ F ceramic capacitor will be sufficient. OUT OUT 2INDUCTOROUT O V)V V(Δ ΔIL(I C Where ΔV is the maximum output voltage overshoot. Inductor election The inductor is used to supply smooth current to output when it is driven by a switching voltage. Its value is determined based on the operating frequency, load current, ripple current, and duty cycle. For most application, the value of the induc tor will fall in the range of 1.0 mH to 2.2 mH. Choose an inductor that has small DC resistance, has enough current rating and is hard to cause magnetic saturation. Vo L(mH) 1.0V 1.0µH 1.2V 1.0µH 1.5V 1.5 – 2.2µH 1.8V 1.5 – 2.2µH 2.5V 2.2µH 2.8V 2.2µH 3.3V 2.2µH Table 2: Recommended Inductor Selection Table
Document number: DS39755 Rev. 1 - 2 11 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT
Ordering Information
W6 : SOT26 (SC74R) -7 : Tape & Reel Version Blank : AP3445 L : AP3445L Package Temperature Range Part Number Marking ID Packing SOT26 (SC74R) -40 to +85° C AP3445W6-7 9B -7 SOT26 (SC74R) -40 to +85° C AP3445LW6-7 9C -7 Marking Information (1) SOT26 (SC74R) 1 2 3 XX Y W X XX : Identification Code Y : Year 0~9 X : Internal Code ( Top View ) W : Week : A~Z : 1~26 week; a~z : 27~52 week; z represents 52 and 53 week
Document number: DS39755 Rev. 1 - 2 12 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT Package Outline Dimensions Please see http://www.diodes.com/package-outlines.html for the latest version. (1) Package Type: SOT26 (SC74R) D e E1 E b A2 A1 Seating Plane L c a SOT26 (SC74R) Dim Min Max Typ A1 0.013 0.10 0.05 A2 1.00 1.30 1.10 A3 0.70 0.80 0.75 b 0.35 0.50 0.38 c 0.10 0.20 0.15 D 2.90 3.10 3.00 e - - 0.95 e1 - - 1.90 E 2.70 3.00 2.80 E1 1.50 1.70 1.60 L 0.35 0.55 0.40 a - - 8° a1 - - 7° All Dimensions in mm Suggested Pad Layout Please see http://www.diodes.com/package-outlines.html for the latest version. (1) Package Type: SOT26 (SC74R) Y1 G X Y C Dimensions Value (in mm) C 2.40 C1 0.95 G 1.60 X 0.55 Y 0.80 Y1 3.20
Document number: DS39755 Rev. 1 - 2 13 of 13 www.diodes.com March 2018 © Diodes Incorporated AP3445/L NEW PRODUCT IMPORTANT NOTICE DIODES INCORPORATED MAKES NO WARRANTY OF ANY KIND , EXPRESS OR IMPLIED, WITH REGARDS TO THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). Diodes Incorporated and its su bsidiaries reserve the right to make modifications, enhancements, improvements, corrections or other changes without further notice to this document and any product described herein. Diodes Incorporated does not assume any liability a rising out of the application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under it s patent or trademark rights, nor the rights of others. Any Customer or user of this document or products described herein in such applications shall assume all risks of such use and will agree to hold Diodes Incorporated and all the companies whose products are represented on Diod es Incorporated website, harmless against all damages. Diodes Incorporated does not warrant or accept any liability whatsoever in respect of any products purchased through unauthorized sales channel. Should Customers purchase or use Diodes Incorporated products for any unintended or unauthorized application, Customers shall indemnify and hold Diodes Incor porated and its representatives harmless against all claims, damages, expenses, and attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized application. Products described herein may be covered by one or more United States, international or foreign patents pending. Product names and markings noted herein may also be covered by one or more United States, international or foreign trademarks. This document is written in Engl ish but may be translated into multiple languages for reference. Only the English version of this document is the final and determinative format released by Diodes Incorporated. LIFE SUPPORT Diodes Incorporated products are specifically not authorized for use as critical components in life support devices or system s without the express written approval of the Chief Executive Officer of Diodes Incorporated. As used herein: A. Life support devices or systems are devices or systems which: 1. are intended to implant into the body, or 2. support or sustain life and whose failure to perform when properly used in accordance with instructions for use provided i n the labeling can be reasonably expected to result in significant injury to the user. B. A critical component is any component in a life support device or system whose failure to perform can be reasonably expected to cause the failure of the life support device or to affect its safety or effectiveness. Customers represent that they have all necessary expertise in the safety and regulatory ramifications of their life support d evices or systems, and acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products and any use of Diodes Incorporated products in such safety -critical, life support devices or systems, notwithstanding any devices - or systems -related information or support that may be provided by Diodes Incorporated. Further, Customers must fully indemnify Diodes Incorporated and its representatives against any damages arising out of the use of Diodes Incorporated products in such safety-critical, life support devices or systems. Copyright © 2018, Diodes Incorporated www.diodes.com