AP65251

AP65251

Document overview

• Manufacturer or author: Diodes Incorporated
• PDF pages: 19

Technical content

greater capacitor from SW to BST to power the high side switch. turn it off. Attach to IN with a 100kΩ pull up resistor for automatic startup. the IC. See Input Capacitor. Figure 2. Functional Block Diagram

Document number: DS39921 Rev. 3 - 4 3 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.) Symbol Parameter Rating Unit VIN Supply Voltage -0.3 to 20 V VSW Switch Node Voltage -1.0 to VIN +0.3 V VBST Bootstrap Voltage VSW -0.3 to VSW +6.0 V VFB Feedback Voltage -0.3V to +6.0 V VEN Enable/UVLO Voltage -0.3V to +16.0 V TST Storage Temperature -65 to +150 °C TJ Junction Temperature +160 °C TL Lead Temperature +260 °C ESD Susceptibility (Note 5) HBM Human Body Mode 2000 V CDM Charge Device Model 1000 V Notes: 4. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings o nly; functional operation of the device at these or any other conditions exceeding those indicated in this specification is not im plied. Device reliability may be affected by exposure to absolute maximum rating conditions for extended periods of time. 5. Semiconductor devices are ESD sensitive and may be damaged by exposure to ESD events. Suitable ESD precautions should be taken when handling and transporting these devices. Thermal Resistance (Note 6) Symbol Parameter Rating Unit θJA Junction to Ambient TSOT26 122 °C/W θJC Junction to Case TSOT26 28 °C/W Note: 6. Test condition for SOT26: Device mounted on FR-4 substrate, single-layer PC board, 2oz copper, with minimum recommended pad layout Recommended Operating Conditions (Note 7) (@TA = +25°C, unless otherwise specified.) Symbol Parameter Min Max Unit VIN Supply Voltage 4.5 16 V TA Operating Ambient Temperature Range -40 +85 °C Note: 7. The device function is not guaranteed outside of the recommended operating conditions.

Document number: DS39921 Rev. 3 - 4 4 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Electrical Characteristics (@TA = +25°C, VIN = 12V, unless otherwise specified.) Symbol Parameter Test Conditions Min Typ Max Unit ISHDN Shutdown Supply Current VEN = 0V 0.1 1.0 µA IQ Supply Current (Quiescent) VEN = 2.0V, VFB = 1.0V 0.8 mA RDS(ON)1 High-Side Switch On-Resistance (Note 8) 150 mΩ RDS(ON)2 Low-Side Switch On-Resistance (Note 8) 90 mΩ IVALLEY_LIMIT LS Valley Current Limit (Note 8) TA = -40°C to +85°C 1.9 2.5 3 A FSW Oscillator Frequency 500 kHz DMAX Maximum Duty Cycle 75 % TON Minimum On Time 130 ns VFB Feedback Voltage TA = -40°C to +85°C, CCM 591 600 609 mV VEN_H EN Logic High 1.8 V VEN_L EN Logic Low 0.4 V IEN EN Input Current VEN = 2V 6 μA VEN = 0V 0 μA UVLO VIN Under Voltage Threshold Rising TA = -40°C to +85°C 3.55 3.9 4.25 V VIN Under Voltage Threshold Hysteresis 300 mV TSS Soft-Start Period 0.8 ms TSD Thermal Shutdown (Note 8) 150 °C Thermal Hysteresis (Note 8) 20 °C Note: 8. Compliance to the datasheet limits is assured by one or more methods: production test, characterization, and/or design.

Document number: DS39921 Rev. 3 - 4 5 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Typical Performance Characteristics (@TA = +25°C, VIN = 12V, VOUT = 1.2V, unless otherwise specified.) 85˚C -40˚C 25˚C 85˚C 25˚C -40˚C VIN=4.5V VIN=16V VIN=12V Io=2A Io=0mA Io=10mA

Document number: DS39921 Rev. 3 - 4 6 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Typical Performance Characteristics (cont.) (@TA = +25°C, VIN = 12V, VOUT = 1.2V, unless otherwise specified.) VO=5.0V VO=3.3V VO=2.5V VO=1.2V Vin=4.5V Vin=12V Vin=16V VIN=4.5V VIN=16V VIN=12V

Document number: DS39921 Rev. 3 - 4 7 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Typical Performance Characteristics (cont.) (@TA = +25°C, VIN = 12V, VOUT = 1.2V, L = 2.2µH, C1 = 10µF, C2 = 22µF, unless otherwise specified.) Startup Through VEN 0A Load Time-500µs/div Startup Through VEN 2A Load Time-500µs/div Startup Through VIN 2A Load Time-500µs/div Shutdown Through VEN 0A Load Time-200ms/div Shutdown Through VEN 2A Load Time-20µs/div Shutdown Through VIN 2A Load Time-100µs/div Short Circuit Test Time-1ms/div Short Circuit Recovery Time-1ms/div Startup Through VIN 0A Load Time-500µs/div Load Transient Response (0 to 2A) Time-100µs/div Load Transient Response (0 to 1A) Time-100µs/div Shutdown Through VIN 0A Load Time-200ms/div Load Transient Response (1 to 2A) Time-100µs/div Switching State 2A Load Time-1µs/div Switching State 1A Load Time-1µs/div VOUT_AC (20mV/DIV) VSW (10V/DIV) IL (2A/DIV) VEN (5V/DIV) VOUT (500mV/DIV) IL (2A/DIV) VSW (10V/DIV) VEN (5V/DIV) VSW (10V/DIV) IL (500mA/DIV) VOUT (500mV/DIV) VEN (5V/DIV) VOUT (500mV/DIV) IL (500mA/DIV) VSW (10V/DIV) VEN (5V/DIV) VOUT (500mV/DIV) IL (2A/DIV) VSW (10V/DIV) VIN (5V/DIV) VOUT (500mV/DIV) IL (2A/DIV) VSW (10V/DIV) VIN (5V/DIV) VOUT (500mV/DIV) IL (2A/DIV) VSW (10V/DIV) VOUT_AC (100mV/DIV) IOUT (1A/DIV) VOUT (500mV/DIV) IL (2A/DIV) VIN (5V/DIV) VOUT (500mV/DIV) IL (500mA/DIV) VSW (10V/DIV) VIN (5V/DIV) VOUT (500mV/DIV) IL (500mA/DIV) VSW (10V/DIV) VOUT (500mV/DIV) IL (2A/DIV) VIN_AC (200mV/DIV) VOUT_AC (20mV/DIV) VIN_AC (100mV/DIV) VSW (10V/DIV) IL (2A/DIV) VOUT_AC (100mV/DIV) IOUT (1A/DIV) VOUT_AC (50mV/DIV) IOUT (1A/DIV)

Document number: DS39921 Rev. 3 - 4 8 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED

Application Information

2.2μH 10kΩ 10kΩ 100nF 22μF C1 10μF IN EN SW BST FB GND OUTPUT VOUT 1.2V INPUT Figure 3. Typical Application of AP65251 the fixed on time expire and turn on the low -side MOSFET. Once the output voltage dropped below the output regulation, the low -side turned off. The one-shot timer then reset and the high-side MOSFET is turned on again. minimum OFF time will be applied, which is about 260ns typical.

Document number: DS39921 Rev. 3 - 4 10 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Application Information (cont.) Setting the Output Voltage The output voltage can be adjusted from 0.6V using an external resistor divider. An optional C5, in figure 3, of 10pF to 47pF used to improve the transient response. Resistor R1 is selected based on a design tradeoff between efficiency and output voltage accuracy. Table 2 shows a list of resistor selection for common output voltages. For high values of R1 there is less current consumption in the feedback networ k. R1 can be determined by the following equation:  −⋅= 10.6 VRR OUT Output Voltage (V) Cout (uF) L(µH) C5 (pF) R1 (KΩ) R2 (KΩ) 1.2 22 2.2 NC 10 10 2.5 22 3.6 NC 25.5 8.06 3.3 22 3.6 20-33 115 25.5 5 22 4.7 20-39 110 15 Table 1 Recommended Components Selection Inductor Calculating the inductor value is a critical factor in designing a buck converter. For most designs, the following equation c an be used to calculate the inductor value: SWLIN OUTINOUT fΔIV )V(VVL ⋅⋅ −⋅= Where LΔI is the inductor ripple current and SWf is the buck converter switching frequency. Choose the inductor ripple current to be 30% to 50% of the maximum load current. The maximum inductor peak current is calculated from: ΔIII L LOADL(MAX) += Peak current determines the requi red saturation current rating, which influences the size of the inductor. Saturating the inductor decreases the converter efficiency while increasing the temperatures of the inductor and the internal MOSFETs. Hence choosing an inductor w ith appropriate saturation current rating is important. A 2.2µH to 4.7 µH inductor with a DC current rating of at least 25% percent higher than the maximum load current is recommended for most applications. For highest efficiency, the inductor’s DC resistance should be less than 100mΩ. Use a larger inductance for improved efficiency under light load conditions. Input Capacitor The input capacitor reduces the surge current drawn from the input supply and the switching noise from the device. The input capacitor has to sustain the ripple current produced during the on time on the upper MOSFET. It must 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 greater than half of the maximum load current. Due to large dI/dt through the input capacitors, electrolytic or ceramics should be used. If a tantalum must be u sed it must be surge protected, otherwise, capacitor failure could occur. For most applications greater than 10µF, 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. Maximum capacitance required can be calculated from the following equation: ESR of the output capacitor dominates the output voltage ripple. The amount of ripple can be calculated from the equation below: ESR*ΔIVout inductorRipple = An output capacitor with large capacitance and low ESR is the best option. For most applications, a 22µF to 68µF ceramic capacitor will be sufficient. To meet the load transient requirement, Co should be greater than the following:

Document number: DS39921 Rev. 3 - 4 11 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Application Information (cont.) out out 2inductor out o V)V V(Δ ΔIL(I C Where ΔV is the maximum output voltage overshoot. Bootstrap Capacitor To ensure the proper operation, a ceramic capacitor must be connected between the VBST and SW pin. A 0.1µF ceramic capacitor is sufficient. PC Board Layout 1. The AP65251 works at 2A load current, heat dissipation is a major concern in layout the PCB. A 2oz Copper in both top and bottom layer is recommended. 2. Provide sufficient vias in the thermal exposed pad for heat dissipate to the bottom layer. 3. Provide sufficient vias in the Output capacitor GND side to dissipate heat to the bottom layer. 4. Make the bottom layer under the device as GND layer for heat dissipation. The GND layer should be as large as possible to provide better thermal effect. 5. Make the Vin capacitors as close to the device as possible. 6. Make the VREG5 capacitor as close to the device as possible. BST IN EN SW FB GND Ren Cout Vout GND SW Vin Cin

• Input Capacitor recommend to be placed as close as possible to device
• Wider trace of Vin is better for thermal
• Add as many GND via as possible
• The trace connected to inductor and SW is recommended to be wide and short
• Keep sensitive signal trace away from SW
• Feedback components are recommended to be placed as close as possible to device
• Wider trace of GND is better for thermal
• Add as many GND via as possible

Document number: DS39921 Rev. 3 - 4 12 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED

Ordering Information

WU : TSOT26 7 : Tape & Reel Part Number Package Code Part Marking Identification Code Tape and Reel Quantity Part Number Suffix AP65251WU-7 WU TSOT26 SB 3000 -7 Marking Information TSOT26 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 Part Number Package Identification Code AP65251WU-7 TSOT26 SB

Document number: DS39921 Rev. 3 - 4 13 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED

PACKAGE INFORMATION

• Surface Mount Package
• Case Material: Molded Plastic, UL Flammability Classification Rating 94V-0
• Terminals: Finish – Matte Tin Plated Leads, Solderable per MIL-STD-202, Method 208
• Weight: 0.013 grams (Approximate)
• Max Soldering Temperature +260°C for 30 secs as per JEDEC J-STD-020 Package View Package Outline Dimensions TSOT26 TSOT26 Dim Min Max Typ A − 1.00 − A1 0.010 0.100 − A2 0.840 0.900 − D 2.800 3.000 2.900 E 2.800 BSC E1 1.500 1.700 1.600 b 0.300 0.450 − c 0.120 0.200 − e 0.950 BSC e1 1.900 BSC L 0.30 0.50 − L2 0.250 BSC θ 0° 8° 4° θ1 4° 12° − All Dimensions in mm Suggested Pad Layout TSOT26 Dimensions Value (in mm) C 0.950 X 0.700 Y 1.000 Y1 3.199 Note: The suggested land pattern dimensions have been provided for reference only, as actual pad layouts may vary depending on appl ication. These dimensions may be modified based on user equipment capability or fabrication criteria. A more robust pattern may be desired for wave soldering and is calculated by adding 0.2 mm to the ‘Z’ dimension. For further information, please reference document IPC -7351A, Naming Convention for Standard SMT Land Patterns, and for International grid details, please see document IEC, Publication 97. Note: For high voltage applications, the appropriate industry sector guidelines should be considered with regards to creepage and c learance distances between device Terminals and PCB tracking. D E1/2 E E/2 e A Seating Plane0 L Gauge Plane 01( 4x) 01( 4x) c b Seating Plane C X Y Top View

Document number: DS39921 Rev. 3 - 4 14 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Minimum Packing Quantity Note: Package quantities given are for minimum packaging quantity only, not minimum order quantity. For minimum order quantity, please contact Sales Department. Note: No mixed date codes or partial quantity (less than minimum packaging quantity) per packaging is allowed. Note: In no case shall there be two or more consecutive components missing from any reel for any reason. Device Tape Orientation Tape Width Part Number Suffix Tape Orientation 8mm -7 -13 Note: For part marking, refer to product datasheet. Note: Tape and package drawings are not to scale and are shown for device tape orientation only. Quantity Tape Width Part Number Suffix 7” Reel 3,000 8mm -7 13” Reel 10,000 8mm -13 Direction of feed

Document number: DS39921 Rev. 3 - 4 15 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Embossed Carrier Tape Specifications Tape Width (W) Dimension Value (mm) Dimension Value (mm) Dimension Value (mm) 8mm A0 B0 K0 Determined by component size. The clearance between the component and the cavity must comply to the rotational and lateral movement requirement provided in figures in the "Maximum Component Movement in Tape Pocket” section.

Document number: DS39921 Rev. 3 - 4 16 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Embossed Carrier Tape Specifications (Continued)

Document number: DS39921 Rev. 3 - 4 17 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Maximum Component Movement in Tape Pocket

Document number: DS39921 Rev. 3 - 4 18 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED Surface Mount Reel Specifications Tape Width Reel Size A (mm) B Max (mm) C (mm) D Max (mm) N Min (mm) G (mm) T Max (mm) 8mm Tape Leader and Trailer Specifications Note: There shall be a leader of at least 230mm which may consist of carrier tape and/or cover tape or a start tape followed by at least 160mm of empty carrier tape sealed with cover tape. Note: There shall be a trailer of at least 160mm of empty carrier tape sealed with cover tape. The entire carrier tape must release from the reel hub as the last portion of the tape unwinds from the reel without dam age to the carrier tape and the remaining components in the cavities.

Document number: DS39921 Rev. 3 - 4 19 of 19 www.diodes.com March 2021 © Diodes Incorporated AP65251 OBSOLETE – PART DISCONTINUED IMPORTANT NOTICE 1. DIODES INCORPORATED AND ITS SUBSIDIARIES (“DIODES”) MAKE NO WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, WITH REGARDS TO ANY INFORMATION CONTAINED IN THIS DOCUMENT, INCLUDING, BUT NOT LIMITED TO , THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE OR NON -INFRINGEMENT OF THIRD PARTY INTELLECTUAL PROPERTY RIGHTS (AND THEIR EQUIVALENTS UNDER THE LAWS OF ANY JURISDICTION). 2. The Information contained herein is for informat ional purpose only and is provided only to illustrate the operation of Diodes products described herein and application examples. Diodes does not assume any liability arising out of the application or use of this document or any product described herein. This document is intended for skilled and technically trained engineering customers and users who design with Diodes products. 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