AP65200

AP65200
LIGHT LOAD IMPROVED 2A SYNCH DC/DC BUCK CONVERTER
Description
Pin Assignments
The AP65200 is a 340kHz switching frequency external compensated
synchronous DC-DC buck converter. It has integrated low RDSON high
( Top View )
( Top View )
and low-side MOSFETs.
BS
1
8
SS
BS
1
8
SS
IN
2
7
EN
IN
2
7
EN
SW
3
6
COMP SW
3
6
COMP
GND
4
5
FB
GND
4
5
FB
The AP65200 enables a continuous load current of up to 2A with
efficiency as high as 95%.
The AP65200 features current mode control operation, which enables
fast, transient response times and easy loop stabilization.
SO-8EP
SO-8
( Top View )
The AP65200 simplifies board layout and reduces space
requirements with its high level of integration and minimal need for
external components, making it ideal for distributed power
architectures.
BS
1
8
SS
IN
2
7
EN
3
6
COMP
GND
4
5
FB
Applications

VIN 4.7V to 18V




2A Continuous Output Current, 3A Peak
Efficiency Up to 95%
Automated Light Load Improvement
VOUT Adjustable to 0.925 to 16V






340kHz Switching Frequency
External Programmable Soft-Start
Enable Pin
OCP and Thermal Protection
Totally Lead-Free & Fully RoHS Compliant (Notes 1 & 2)
Halogen and Antimony Free. “Green” Device (Note 3)









SS
EN
AGND
BS
1
10
2
9
IN
3
8
COMP
SW
GND
4
7
5
6
FB
GND
U-DFN2626-10
MSOP-8EP
Features
Notes:
( Top View )
SW
The AP65200 is available in a standard Green SO-8, MSOP-8EP,
U-DFN2626-10 and SO-8EP package and is RoHS compliant.
Gaming Consoles
Flat Screen TV Sets and Monitors
Set Top Boxes
Distributed Power Systems
Home Audio
Consumer Electronics
Network Systems
FPGA, DSP and ASIC Supplies
Green Electronics
1. No purposely added lead. Fully EU Directive 2002/95/EC (RoHS) & 2011/65/EU (RoHS 2) compliant.
2. See http://www.diodes.com/quality/lead_free.html for more information about Diodes Incorporated’s definitions of Halogen- 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.
Typical Applications Circuit
100
5VIN
INPUT
90
12VIN
ON
OFF
85
7
EN
C5
10nF
3
SW
AP65200
Document number: DS35548 Rev. 7 - 2
8
SS
6
COMP
4
GND
OUTPUT
VOUT
3.3V
R1
26.1kΩ
5
FB
C4
0.1μF
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
Efficiency vs. Load Current
VOUT = 3.3V
L1
10µH
AP65200
C1
10μF
80
75
0.0 0.2
1
BST
2
IN
95
EFFICIENCY (%)
NEW PRODUCT
The AP65200 implements an automatic custom light-load efficiency
improvement algorithm.
R2
10kΩ
C2
2 x 22μF
C3
6.8nF
R3
6.8kΩ
Figure 1 Typical Application Circuit
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AP65200
Pin Descriptions
Pin Number
SO-8
SO-8EP
U-DFN2626-10
MSOP-8EP
BS
1
2
IN
2
3
SW
3
4
GND
4
5. 6
FB
5
7
COMP
6
8
EN
7
9
SS
8
10
Function
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET a
0.01µF or greater capacitor from SW to BS to power the high side switch.
Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive
IN with a 4.7V to 18V power source. Bypass IN to GND with a suitably large capacitor to eliminate
noise on the input to the IC. See Input Capacitor.
Power Switching Output. SW is the switching node that supplies power to the output. Connect the
output LC filter from SW to the output load. Note that a capacitor is required from SW to BS to
power the high-side switch.
Ground
Feedback Input. FB senses the output voltage and regulates it. Drive FB with a resistive voltage
divider connected to it from the output voltage. The feedback threshold is 0.925V. See Setting the
Output Voltage.
Compensation Node. COMP is used to compensate the regulation control loop. Connect a series
RC network from COMP to GND. In some cases, an additional capacitor from COMP to GND is
required. See Compensation Components.
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the
regulator; low to turn it off.
Attach EN to IN with a 100kΩ pull up resistor for automatic startup. With this configuration an
internal voltage clamp ensures that a safe voltage is set for Enable not to exceed the absolute
maximum voltage for this pin.
Soft-Start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND to
set the soft-start period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the softstart feature, leave SS floating.
AGND
NA
1
Analog GND
PAD
Exposed PAD for thermal performance improvement connect to GND
Note: PAD’s soldering area needs to be at least 80%.
Functional Block Diagram
+
OVP
RAMP
1.1V
E
+
5
2
IN
1
BS
-
FB
OSCILLATOR
CURRENT
SENSE
AMPLIFIER
+
NEW PRODUCT
Pin
Name
100/340 KHz
CLK
Logic
0.3 V
100mΩ
+
SS
8
3
-
+
+
ERROR
AMPLIFIER
0.923 V
6uA
CURRENT
COMPARATOR
100mΩ
4
COMP
SW
GND
6
+
2.5V
EN OK
-
disable
LOCKOUT
COMPARATOR
IN < 4.10V
IN
EN
+
7
0.9V
AP65200
Document number: DS35548 Rev. 7 - 2
SHUTDOWN
COMPARATOR
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INTERNAL
REGULATORS
5V
June 2015
© Diodes Incorporated
AP65200
Absolute Maximum Ratings (Note 4) (@TA = +25°C, unless otherwise specified.)
Symbol
VIN
Supply Voltage
VSW
Switch Node Voltage
VBS
Rating
Unit
-0.3 to +20
V
-1.0 to VIN +0.3
V
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 +6.0
V
Comp Voltage
-0.3V to +6.0
V
VCOMP
NEW PRODUCT
Parameter
TST
Storage Temperature
-65 to +150
°C
TJ
Junction Temperature
+160
°C
+260
°C
1.5
150
kV
V
Lead Temperature
TL
ESD Susceptibility (Note 5)
HBM
MM
Notes:
Human Body Model
Machine Model
4. Stresses greater than the 'Absolute Maximum Ratings' specified above may cause permanent damage to the device. These are stress ratings only;
functional operation of the device at these or any other conditions exceeding those indicated in this specification is not implied. 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
Note:
Parameter
θJA
Junction to Ambient
θJC
Junction to Case
Rating
SO-8
SO-8EP
MSOP-8EP
U-DFN2626-10
SO-8
SO-8EP
MSOP-8EP
U-DFN2626-10
Unit
119
40
48
53
31
9
9
8.5
°C/W
°C/W
6. Test condition: SO-8: Device mounted on 1"x1" FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout.
SO-8EP: Device mounted on 2"x2" FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout and thermal vias to bottom layer GND
plane.
MSOP-8EP: Device mounted on 2"x2" FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout.
U-DFN2626-10: Device mounted on 2"x2" FR-4 substrate PCB, 2oz copper, with minimum recommended pad layout.
Recommended Operating Conditions (Note 7) (@TA = +25°C, unless otherwise specified.)
Symbol
Note:
Min
Max
VIN
Supply Voltage
Parameter
4.7
18.0
Unit
V
TA
Operating Ambient Temperature Range
-40
+85
°C
7. The device function is not guaranteed outside of the recommended operating conditions.
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Electrical Characteristics
Symbol
(@TA = +25°C, VIN = 12V, unless otherwise specified.)
Parameter
Test Conditions
Min
Typ
Max
Unit
IIN
Shutdown Supply Current
VEN = 0V
-
0.3
3.0
µA
IIN
Supply Current (Quiescent)
VEN = 2.0V, VFB = 1.0V
-
0.6
1.5
mA
RDS(ON)1
High-Side Switch On-Resistance (Note 8)
-
-
130
-
mΩ
RDS(ON)2
Low-Side Switch On-Resistance (Note 8)
-
-
130
-
mΩ
ILIMIT
HS Current Limit
Minimum Duty Cycle
-
4.4
-
A
ILIMIT
LS Current Limit
From Drain to Source
-
0.9
-
A
High-Side Switch Leakage Current
VEN = 0V, VSW = 0V, VSW =12V
0
10
μA
AVEA
Error Amplifier Voltage Gain
(Note 8)
-
-
800
-
V/V
GEA
Error Amplifier Transconductance
ΔIC = ±10µA
-
1,000
-
µA/V
GCS
COMP to Current Sense
Transconductance
-
-
2.8
-
A/V
FSW
Oscillator Frequency
VFB = 0.75V
300
340
380
kHz
FFB
Fold-back Frequency
VFB = 0V
-
0.30
-
fSW
DMAX
Maximum Duty Cycle
VFB = 800mV
-
90
-
%
TON
Minimum On Time
-
-
130
-
ns
VFB
Feedback Voltage
TA = -40°C to +85°C
900
925
950
mV
Feedback Overvoltage Threshold
-
-
1.1
-
V
EN Rising Threshold
-
0.7
0.8
1.2
V
EN Lockout Threshold Voltage
EN Lockout Hysteresis
-
2.2
-
2.5
220
2.7
-
V
mV
INUVVTH
VIN Under Voltage Threshold Rising
-
3.80
4.05
4.40
V
INUVHYS
VIN Under Voltage Threshold Hysteresis
-
-
250
-
mV
-
Soft-Start Current
VSS = 0V
-
6
-
μA
-
Soft-Start Period
CSS = 0.1µF
-
15
-
ms
Thermal Shutdown (Note 8)
-
-
160
-
°C
NEW PRODUCT
-
VEN_RISING
-
TSD
Note:
8. Guaranteed by design.
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Typical Performance Characteristics (@TA = +25°C, VIN = 12V, VOUT = 3.3V, unless otherwise specified.)
0.022
SHUTDOWN SUPPLY CURRENT (µA)
0.30
0.25
0.20
0.15
0.10
0.05
5
10
15
INPUT VOLTAGE (V)
Quiescent Supply Current vs. Input Voltage
0.020
0.018
0.016
0.014
0.012
0.010
0.008
0.006
0.004
0
20
3.330
4.60
3.329
4.55
3.328
OUTPUT VOLTAGE (V)
4.65
4.50
4.45
4.40
4.35
4.30
3.325
3.321
3.320
4.75
0.932
344
0.930
343
0.928
0.926
0.924
0.922
0.920
0.918
0.916
-50
0
50
TEMPERATURE (°C)
Feedback Voltage vs. Temperature
AP65200
Document number: DS35548 Rev. 7 - 2
100
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VIN = 12V
3.323
4.20
100
20
3.324
3.322
0
50
TEMPERATURE (°C)
Current Limit vs. Temperature
10
15
INPUT VOLTAGE (V)
Shutdown Supply Current vs. Input Voltage
3.326
4.25
4.15
-50
5
3.327
OSCILLATOR FREQUENCY (KHZ)
QUIESCENT SUPPLY CURRENT (mA)
CURRENT LIMIT (A)
0.024
0.35
0.00
0
FEEDBACK VOLTAGE (V)
NEW PRODUCT
0.40
9.75
14.75
19.75
INPUT VOLTAGE (V)
Line Regulation
24.75
342
341
340
339
338
337
336
-50
0
50
TEMPERATURE (°C)
Oscillator Frequency vs. Temperature
100
June 2015
© Diodes Incorporated
AP65200
Typical Performance Characteristics (continued) (@TA = +25°C, VIN = 12V, VOUT = 3.3V, unless otherwise specified.)
100
95
5VIN
5VIN
85
95
EFFICIENCY (%)
EFFICIENCY (%)
75
18VIN
65
55
90
12VIN
85
18VIN
80
45
35
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
Efficiency vs. Load Current
VOUT = 1.2V
75
0.0 0.2
0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT (A)
Efficiency vs. Load Current
VOUT = 3.3V
100
95
12VIN
90
EFFICIENCY (%)
NEW PRODUCT
12VIN
18VIN
85
80
75
70
65
60
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6 1.8 2.0
LOAD CURRENT
Efficiency vs. Load Current
VOUT = 5V
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Typical Performance Characteristics (cont.)
NEW PRODUCT
(@TA = +25°C, VIN = 12V, VOUT = 3.3V, L = 3.3µH, C1 = 22µF, C2 = 47µF, unless otherwise specified.)
Steady State Test 2A
Startup Through Vin No Load
Startup Through Vin 2A Load
Time-2µs/div
Time-5ms/div
Time-5ms/div
Load Transient Test 0.15 to 2A
Shutdown Through Vin no load
Shutdown Through Vin 2A
Time-500µs/div
Time-20ms/div
Time-100µs/div
Short Circuit Test
Short Circuit Recovery
Load Transient Test 0.15 to 2A
Time-20µs/div
Time-50µs/div
Time-20µs/div
Load Transient Test 2A to 0.15A
Time-20µs/div
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Application Information
Theory of Operation
The AP65200 is a 2A current mode control, synchronous buck regulator with built in power MOSFETs. Current mode control assures excellent
line and load regulation and a wide loop bandwidth for fast response to load transients. Figure 1 depicts the functional block diagram of
AP65200.
NEW PRODUCT
The operation of one switching cycle can be explained as follows. At the beginning of each cycle, HS (high-side) MOSFET is off. The error
amplifier (EA) output voltage is higher than the current sense amplifier output, and the current comparator’s output is low. The rising edge of the
340kHz oscillator clock signal sets the RS Flip-Flop. Its output turns on HS MOSFET. The current sense amplifier is reset for every switching
cycle.
When the HS MOSFET is on, inductor current starts to increase. The current sense amplifier senses and amplifies the inductor current. Since
the current mode control is subject to sub-harmonic oscillations that peak at half the switching frequency, ramp slope compensation is utilized.
This will help to stabilize the power supply. This ramp compensation is summed to the current sense amplifier output and compared to the error
amplifier output by the PWM comparator. When the sum of the current sense amplifier output and the slope compensation signal exceeds the
EA output voltage, the RS Flip-Flop is reset and HS MOSFET is turned off.
For one whole cycle, if the sum of the current sense amplifier output and the slope compensation signal does not exceed the EA output, then the
falling edge of the oscillator clock resets the Flip-Flop. The output of the error amplifier increases when feedback voltage (VFB) is lower than the
reference voltage of 0.925V. This also increases the inductor current as it is proportional to the EA voltage.
If in one cycle the current in the power MOSFET does not reach the COMP set current value, the power MOSFET will be forced to turn off. When
the HS MOSFET turns off, the synchronous LS MOSFET turns on until the next clock cycle begins. There is a “dead time” between the HS turn
off and LS turn on that prevents the switches from “shooting through” from the input supply to ground.
The voltage loop is compensated through an internal transconductance amplifier and can be adjusted through the external compensation
components.
Enable
Above the ‘EN Rising Threshold’, the internal regulator is turned on and the quiescent current can be measured above this threshold. The enable
(EN) input allows the user to control turning on or off the regulator. To enable the AP65200, EN must be pulled above the ‘EN Lockout Threshold
Voltage’ and to disable the AP65200, EN must be pulled below ‘EN Lockout Threshold Voltage - EN Lockout Hysteresis’
(2.2V - 0.22V = 1.98V).
Automated No-Load and Light-Load Operation
The AP65200 operates in light-load high-efficiency mode during light load operation. The advantage of this light-load high-efficiency mode is low
power loss at no-load and light-load conditions.
The AP65200 automatically detects the output current and enters the light-load high-efficiency mode. The output current reaches a critical level
at which the transitions between the light-load and heavy-current mode occurs. Once the output current exceeds the critical level, the AP65200
transitions from light-load high-efficiency mode to continuous PWM mode.
External Soft Start
Soft start is traditionally implemented to prevent the excess inrush current. This in turn prevents the converter output voltage from overshooting
when it reaches regulation. The AP65200 has an internal current source with a soft start capacitor to ramp the reference voltage from 0V to
0.925V. The soft start current is 6µA. The soft start sequence is reset when there is a Thermal Shutdown, Undervoltage Lockout (UVLO) or when
the part is disabled using the EN pin.
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Application Information (continued)
External Soft Start (continued)
External Soft Start can be calculated from the formula below:
ISS  C *
DV
DT
Where:
ISS = Soft Start Current
NEW PRODUCT
C = External Capacitor
DV= Change in feedback voltage from 0V to maximum voltage
DT = Soft Start Time
Current Limit Protection
In order to reduce the total power dissipation and to protect the application, AP65200 has cycle-by-cycle current limiting implementation. The
voltage drop across the internal high-side MOSFET is sensed and compared with the internally set current limit threshold. This voltage drop is
sensed at about 30ns after the HS turns on. When the peak inductor current exceeds the set current limit threshold, current limit protection is
activated. During this time the feedback voltage (VFB) drops down. When the voltage at the FB pin reaches 0.3V, the internal oscillator shifts the
frequency from the normal operating frequency of 340kHz to a fold-back frequency of 102kHz. The current limit is reduced to 70% of the nominal
current limit when the part is operating at 102kHz. This low fold-back frequency prevents runaway current.
Undervoltage Lockout (UVLO)
Undervoltage Lockout is implemented to prevent the IC from insufficient input voltages. The AP65200 has a UVLO comparator that monitors the
input voltage and the internal bandgap reference. If the input voltage falls below 4.0V, the AP65200 will latch an undervoltage fault. In this event
the output will be pulled low and power has to be re-cycled to reset the UVLO fault.
Overvoltage Protection
When the AP65200 FB pin exceeds 20% of the nominal regulation voltage of 0.925V, the overvoltage comparator is tripped and the COMP pin
and the SS pin are discharged to GND, forcing the high-side switch off.
Thermal Shutdown
The AP65200 has on-chip thermal protection that prevents damage to the IC when the die temperature exceeds safe margins. It implements a
thermal sensing to monitor the operating junction temperature of the IC. Once the die temperature rises to approximately +160°C, the thermal
protection feature gets activated. The internal thermal sense circuitry turns the IC off, thus preventing the power switch from damage.
A hysteresis in the thermal sense circuit allows the device to cool down to approximately +120°C before the IC is enabled again through soft
start. This thermal hysteresis feature prevents undesirable oscillations of the thermal protection circuit.
Setting the Output Voltage
The output voltage can be adjusted from 0.925V to 16V using an external resistor divider. Table 1 shows a list of resistor selection for common
output voltages. Resistor R1 is selected based on a design tradeoff between efficiency and output voltage accuracy. For high values of R1 there
is less current consumption in the feedback network. However, the tradeoff is output voltage accuracy due to the bias current in the error
amplifier. R1 can be determined by the following equation:
V

R1  R 2   OUT  1
 0.925

R1
FB
Vout
R2
Document number: DS35548 Rev. 7 - 2
R1 (kΩ)
R2 (kΩ)
5
3.3
2.5
1.8
1.2
44.2
26.1
16.9
9.53
3
10
10
10
10
10
Table 1 Resistor Selection for Common Output
Voltages
Figure 2 Feedback Divider Network
AP65200
VOUT (V)
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AP65200
Application Information (cont.)
Compensation Components
The AP65200 has an external COMP pin through which system stability and transient response can be controlled. The COMP pin is the output of
the internal trans-conductance error amplifier. A series capacitor-resistor combination sets a pole-zero combination to control the characteristics
of the control system. The DC gain of the voltage feedback loop is given by:
VFB
VOUT
A VDC  RLOAD  GCS  A VEA 
NEW PRODUCT
Where VFB is the feedback voltage (0.925V), RLOAD is the load resistor value, GCS is the current sense trans-conductance and AVEA is the error
amplifier voltage gain. The control loop transfer function incorporates two poles: one is due to the compensation capacitor (C3) and the output
resistor of error amplifier, and the other is due to the output capacitor and the load resistor. These poles are located at:
fP1 
GEA
2  C3  A VEA
fP2 
1
2  C2  RLOAD
, where GEA is the error amplifier trans-conductance.
One zero is present due to the compensation capacitor (C3) and the compensation resistor (R3). This zero is located at:
f Z1 
1
2  C3  R3
The goal of compensation design is to shape the converter transfer function to get a desired loop gain. The system crossover frequency where
the feedback loop has the unity gain is crucial.
A rule of thumb is to set the crossover frequency to below one-tenth of the switching frequency. Use the following procedure to optimize the
compensation components:
1. Choose the compensation resistor (R3) to set the desired crossover frequency. Determine the R3 value by the following equation:
R3 
2  C2  f c VOUT 2  C2  0.1 f s VOUT



GEA  GCS
VFB
G  GCS
VFB
EA
Where fC is the crossover frequency, which is typically less than one-tenth of the switching frequency.
2. Choose the compensation capacitor (C3) to achieve the desired phase margin, set the compensation to zero, fZ1, to below one-fourth of the
crossover frequency to provide sufficient phase margin. Determine the C3 value by the following equation:
C3 
2
  R3  f c
, where R3 is the compensation resistor value.
VOUT
(V)
CIN/C1
(µF)
COUT/C2
(µF)
RC/R3
(kΩ)
CC/C3
(nF)
L1
(µH)
1.2
1.8
2.5
3.3
5
12
22
22
22
22
22
22
47
47
47
47
47
47
3.24
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
6.8
3.3
3.3
10
10
10
15
Table 2 Recommended Component Selection
Inductor
Calculating the inductor value is a critical factor in designing a buck converter. For most designs, the following equation can be used to calculate
the inductor value:
L
VOUT  (VIN  VOUT )
VIN  ΔIL  fSW
, where ΔIL is the inductor ripple current,
and fSW is the buck converter switching frequency.
AP65200
Document number: DS35548 Rev. 7 - 2
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AP65200
Application Information (cont.)
Inductor (continued)
Choose the inductor ripple current to be 30% of the maximum load current. The maximum inductor peak current is calculated from:
IL(MAX)  ILOAD 
ΔIL
2
NEW PRODUCT
Peak current determines the required 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 with appropriate
saturation current rating is important.
A 1µH to 10µH inductor with a DC current rating of at least 25% higher than the maximum load current is recommended for most applications.
For highest efficiency, the inductor’s DC resistance should be less than 200mΩ. 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 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 an RMS rating that is 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 used, it must be surge protected,
otherwise, capacitor failure could occur. For most applications, a 4.7µF 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 first 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:
Vout capacitor  ΔIinductor * ESR
An output capacitor with ample capacitance and low ESR is the best option. For most applications, a 22µF ceramic capacitor will be sufficient.
ΔIinductor 2
)
2
Co 
2
(Δ V  Vout )  Vout2
L(Iout 
, where ΔV is the maximum output voltage overshoot.
AP65200
Document number: DS35548 Rev. 7 - 2
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© Diodes Incorporated
AP65200
Application Information (cont.)
PC Board Layout
NEW PRODUCT
This is a high-switching frequency converter. Hence, attention must be paid to the switching currents interference in the layout. Switching current
from one power device to another can generate voltage transients across the impedances of the interconnecting bond wires and circuit traces.
These interconnecting impedances should be minimized by using wide, short printed circuit traces.
External Bootstrap Diode
It is recommended that an external bootstrap diode be added when the input voltage is no greater than 5V or the 5V rail is available in the
system. This helps to improve the efficiency of the regulator. This solution is also applicable for D > 65%. The bootstrap diode can be a low cost
one such as BAT54 or a Schottky that has a low VF.
5V
BST
AP65200
BOOST
DIODE
10nF
SW
Figure 7 External Bootstrap Compensation Components
Recommended Diodes:
AP65200
Document number: DS35548 Rev. 7 - 2
Part Number
Voltage/Current
Rating
Vendor
B130
SK13
30V, 1A
30V, 1A
Diodes Inc
Diodes Inc
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© Diodes Incorporated
AP65200
Ordering Information
AP65200 S - 13
Package
Packing
S : SO-8
NEW PRODUCT
13 : Tape & Reel
AP65200 XX - 13
Package
Packing
13 : Tape & Reel
SP : SO-8EP
MP : MSOP-8EP
AP65200 FK - 7
Package
Packing
FK : DFN2626-10EP
7 : Tape & Reel
Part Number
Package Code
Packaging
(Note 9)
Identification Code
AP65200S-13
AP65200SP-13
AP65200MP-13
AP65200FK-7
S
SP
MP
FK
SO-8
SO-8EP
MSOP-8EP
U-DFN2626-10
NA
NA
NA
R2
Note:
Quantity
Tape and Reel
Part Number Suffix
2,500
2,500
2,500
3,000
-13
-13
-13
-7
9. Pad layout as shown on Diodes Inc. suggested pad layout document AP02001, which can be found on our website at
http://www.diodes.com/datasheets/ap02001.pdf.
Marking Information
(1) SO-8
( Top View )
8
5
Logo
Part No
AP65200
YY WW X X
1
AP65200
Document number: DS35548 Rev. 7 - 2
4
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
G : Green
X : Internal Code
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© Diodes Incorporated
AP65200
Marking Information (continued)
(2) SO-8EP
( Top View )
5
8
Logo
1
4
(3) MSOP-8EP
( Top view )
8
7
6
Logo
5
YWXE
Part Number
AP65200
2
1
3
A~Z : Internal Code
E : MSOP-8EP
Y : Year : 0~9
W : Week : A~Z : 1~26 week;
a~z : 27~52 week; z represents
52 and 53 week
4
7
6
4
5
8
9
10
(4) U-DFN2626-10
AP65200
Document number: DS35548 Rev. 7 - 2
3
2
XX
YWX
1
NEW PRODUCT
YY : Year : 08, 09,10~
WW : Week : 01~52; 52
represents 52 and 53 week
E : SO-8EP Blank SO-8
G : Green
X : Internal Code
AP65200
YY WW X X E
Part No
XX : Identification Code
Y : Year : 0~9
W : Week :A~Z : 1~26
a~z : 27~52
z : represents
52 and 53
X : Internal Code
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© Diodes Incorporated
AP65200
Package Outline Dimensions (All dimensions in mm.)
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for the latest version.
SO-8
0.254
(1)
E1 E
Gauge Plane
Seating Plane
A1
NEW PRODUCT
SO-8
Dim
Min
Max
A
1.75
A1
0.10
0.20
A2
1.30
1.50
A3
0.15
0.25
b
0.3
0.5
D
4.85
4.95
E
5.90
6.10
E1
3.85
3.95
e
1.27 Typ
h
0.35
L
0.62
0.82

0
8
All Dimensions in mm
L
Detail ‘A’
7°~9°
h
45°
Detail ‘A’
A2 A A3
b
e
D
(2)
SO-8EP
Exposed Pad
8
5
E1
1
H
4
F
b
Bottom View
E
9° (All sides)
N
7°
A
e
(3)
Q
C
4° ± 3°
Gauge Plane
Seating Plane
E0
A1
D
45°
L
SO-8EP (SOP-8L-EP)
Dim Min Max Typ
A 1.40 1.50 1.45
A1 0.00 0.13
b 0.30 0.50 0.40
C 0.15 0.25 0.20
D 4.85 4.95 4.90
E 3.80 3.90 3.85
E0 3.85 3.95 3.90
E1 5.90 6.10 6.00
e
1.27
F 2.75 3.35 3.05
H 2.11 2.71 2.41
L 0.62 0.82 0.72
N
0.35
Q 0.60 0.70 0.65
All Dimensions in mm
MSOP-8EP
D
4X
10
°
0.25
D1
x
E
E2
Gauge Plane
Seating Plane
a
y
1
4X
10
°
8Xb
e
Detail C
E3
A1
A3
L
c
A2
A
D
E1
See Detail C
AP65200
Document number: DS35548 Rev. 7 - 2
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www.diodes.com
MSOP-8EP
Dim Min Max Typ
A
1.10
A1
0.05 0.15 0.10
A2
0.75 0.95 0.86
A3
0.29 0.49 0.39
b
0.22 0.38 0.30
c
0.08 0.23 0.15
D
2.90 3.10 3.00
D1
1.60 2.00 1.80
E
4.70 5.10 4.90
E1
2.90 3.10 3.00
E2
1.30 1.70 1.50
E3
2.85 3.05 2.95
e
0.65
L
0.40 0.80 0.60
a
0°
8°
4°
x
0.750
y
0.750
All Dimensions in mm
June 2015
© Diodes Incorporated
AP65200
Package Outline Dimensions (continued) (All dimensions in mm.)
Please see AP02002 at http://www.diodes.com/datasheets/ap02002.pdf for the latest version.
(4)
U-DFN2626-10
A
A3
A1
Seating Plane
U-DFN2626-10
Dim Min Max Typ
A
0.57 0.63 0.60
A1
0
0.05 0.03
A3
0.15
b
0.20 0.30 0.25
D
2.55 2.675 2.60
D2 2.05 2.25 2.15
E
2.55 2.675 2.60
E2 1.16 1.36 1.26
e
0.50 BSC
L
0.30 0.40 0.35
All Dimensions in mm
NEW PRODUCT
D
D2
C'0.2x45°
(Pin #1 ID)
D2/2
E
E2/2
E2
R0
.10
0
L
e
b
Suggested Pad Layout
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
(1) SO-8
X
C1
Dimensions
X
Y
C1
C2
Value (in mm)
0.60
1.55
5.4
1.27
Dimensions
C
X
X1
X2
Y
Y1
Y2
Value (in mm)
1.270
0.802
3.502
4.612
1.505
2.613
6.500
C2
Y
(2) SO-8EP
X2
Y1
Y2
X1
Y
C
AP65200
Document number: DS35548 Rev. 7 - 2
X
16 of 18
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June 2015
© Diodes Incorporated
AP65200
Suggested Pad Layout (continued)
Please see AP02001 at http://www.diodes.com/datasheets/ap02001.pdf for the latest version.
3) MSOP-8EP
X
C
NEW PRODUCT
Dimensions
Y
G
Y2
C
G
X
X1
Y
Y1
Y2
Y1
X1
Value
(in mm)
0.650
0.450
0.450
2.000
1.350
1.700
5.300
(4) U-DFN2626-10
X2
Y
Dimensions
X1
C
X
X1
X2
Y
Y1
Y2
Y2
Y1
Pin1
Value
(in mm)
0.500
0.300
2.250
2.300
0.600
1.360
3.000
C
X
AP65200
Document number: DS35548 Rev. 7 - 2
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© Diodes Incorporated
AP65200
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).
NEW PRODUCT
Diodes Incorporated and its subsidiaries 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 arising out of the
application or use of this document or any product described herein; neither does Diodes Incorporated convey any license under its 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 Diodes 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 Incorporated 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 English 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 systems 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 in 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 devices 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 © 2015, Diodes Incorporated
www.diodes.com
AP65200
Document number: DS35548 Rev. 7 - 2
18 of 18
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© Diodes Incorporated