SGM61413 [SGMICRO]
570kHz, 600mA, 42V Synchronous Buck Converter;
| 型号： | SGM61413 |
| 厂家： | 
Shengbang Microelectronics Co, Ltd |
| 描述： | 570kHz, 600mA, 42V Synchronous Buck Converter |
| 文件： | 总21页 (文件大小：1485K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SGM61413
570kHz, 600mA, 42V
Synchronous Buck Converter
GENERAL DESCRIPTION
FEATURES
The SGM61413 is a high frequency, synchronous Buck
converter with integrated switches. It can deliver up to
600mA to the output over a wide input voltage range of
5V to 42V. It is suitable for various industrial or
automotive applications with high input voltage or for
power conditioning from unregulated sources.
Moreover, the low 14μA quiescent current and ultra-low
shutdown current of only 0.6µA make it a suitable
choice for battery-powered applications.
● Wide 5V to 42V Operating Input Voltage Range
● 0.8V Internal Reference
● Shutdown Current: 0.6μA (TYP)
● Current Output up to 600mA
● 570kHz Switching Frequency
● Internal Compensation and Soft-Start
● Simple Design and Minimal External Components
● Up to 95% Efficiency at 12V/400mA
● 0.8V to 20V Adjustable Output Voltage
● Current Limit and Short-Circuit Protection
● Output Over-Voltage Protection and Thermal
Shutdown
SGM61413 features high efficiency over a wide load
range achieved by scaling down the switching
frequency at light loads to reduce switching and gate
driving losses. Other features include internal
compensation, internal monotonic soft-start even with
pre-biased output and fast loop response thanks to the
peak-current mode controller. Switching at 570kHz, the
SGM61413 can prevent EMI noise problems, such as
the ones found in AM radio, ADSL and PLC applications.
● Power-Save Mode Operation
● Monotonic Startup with Pre-biased Output
● 94% Maximum Duty Cycle
● Available in a Green SOT-23-6 Package
● -40℃ to +125℃ Operating Temperature Range
Protection features include current limiting and
short-circuit protection, thermal shutdown with auto
recovery and output over-voltage protection. Frequency
fold-back helps prevent inductor current runaway
during startup.
APPLICATIONS
High Voltage Power Conversions
Automotive Systems
Industrial Power Systems
Distributed Power Systems
Battery Powered Systems
Power Meters
SGM61413 is available in a Green SOT-23-6 package.
It operates over a wide ambient temperature range of
-40℃ to +125℃.
TYPICAL APPLICATION
1
VIN
2
CIN
10μF
5
1
VIN
EN
BOOT
CBOOT
0.47μF
R3
10kΩ
L
4
2
6
SW
SGM61413
VOUT
5V
22μH to 47μH
COUT
22μF
3
GND
FB
C1
R1
330pF
52.5kΩ
R2
10kΩ
Figure 1. Typical Application Circuit
SG Micro Corp
MAY 2022–REV. A.1
www.sg-micro.com
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
PACKAGE/ORDERING INFORMATION
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
DESCRIPTION
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
MODEL
SGM61413
SOT-23-6
SGM61413XN6G/TR
R10XX
Tape and Reel, 3000
-40℃ to +125℃
MARKING INFORMATION
NOTE: XX = Date Code.
YYY X X
Date Code - Week
Date Code - Year
Serial Number
Green (RoHS & HSF): SG Micro Corp defines "Green" to mean Pb-Free (RoHS compatible) and free of halogen substances. If
you have additional comments or questions, please contact your SGMICRO representative directly.
OVERSTRESS CAUTION
ABSOLUTE MAXIMUM RATINGS
VIN to GND........................................................ -0.3V to 45V
EN to GND................................................-0.3V to VIN + 0.3V
FB to GND ........................................................ -0.3V to 5.5V
SW to GND...............................................-0.3V to VIN + 0.3V
BOOT to SW..................................................... -0.3V to 5.5V
Package Thermal Resistance
Stresses beyond those listed in Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to
absolute maximum rating conditions for extended periods
may affect reliability. Functional operation of the device at any
conditions beyond those indicated in the Recommended
Operating Conditions section is not implied.
SOT-23-6, θJA .......................................................... 170℃/W
Junction Temperature .................................................+150℃
Storage Temperature Range........................-65℃ to +150℃
Lead Temperature (Soldering, 10s) ............................+260℃
ESD Susceptibility
ESD SENSITIVITY CAUTION
This integrated circuit can be damaged if ESD protections are
not considered carefully. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failureto observe proper handlingand installation procedures
can cause damage. ESD damage can range from subtle
performance degradation tocomplete device failure. Precision
integrated circuits may be more susceptible to damage
because even small parametric changes could cause the
device not to meet the published specifications.
HBM.............................................................................2500V
CDM ............................................................................1000V
RECOMMENDED OPERATING CONDITIONS
Supply Input Voltage Range...................................5V to 42V
Operating Junction Temperature Range......-40℃ to +125℃
DISCLAIMER
SG Micro Corp reserves the right to make any change in
circuit design, or specifications without prior notice.
SG Micro Corp
www.sg-micro.com
MAY 2022
2
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
PIN CONFIGURATION
(TOP VIEW)
BOOT
GND
FB
1
2
3
6
5
4
SW
VIN
EN
SOT-23-6
PIN DESCRIPTION
PIN
NAME
FUNCTION
Bootstrap pin is used to provide a drive voltage, higher than the input voltage, to the
high-side power switch. Place a 0.47µF Boost capacitor (CBOOT) as close as possible to the
IC between this pin and SW pin.
1
BOOT
Ground pin is the reference for input and the regulated output voltages. Special layout
considerations are required.
2
3
GND
FB
Feedback pin for programming the output voltage. The SGM61413 regulates the FB pin to
0.8V. Connect the feedback resistor divider tap to this pin. If the FB voltage exceeds 111% of
0.8V, over-voltage protection (OVP) will stop all PWM switching.
Enable pin should not be left open and it should not be driven above VIN + 0.3V. Device will
operate when the EN pin is high and shut down when the EN pin is low. EN can be tied to
VIN pin via a resistor if the shutdown feature is not required or to a logic input for controlling
shutdown.
4
EN
VIN pin is connected to the input supply voltage and powers the internal control circuitry. This
voltage is monitored by a UVLO lockout comparator. VIN is also connected to the drain of the
converter high-side switch. Due to power switching, this pin has high di/dt transition edges
and must be decoupled to the GND by input capacitors as close as possible to the GND pin
to minimize the parasitic inductances.
5
6
VIN
SW
Switching node pin is the output of the internal power converter and should be connected to
the output inductor. Bootstrap capacitor also connects to this pin. This node should be kept
small on the PCB to minimize capacitive coupling, noise coupling and radiation.
SG Micro Corp
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
ELECTRICAL CHARACTERISTICS
(VIN = 18V, VEN = VIN, TJ = -40℃ to +125℃, typical values are at TJ = +25℃, unless otherwise noted.)
PARAMETER
Supply Input Voltage
Under-Voltage Lockout Threshold
SYMBOL
CONDITIONS
MIN
TYP
MAX
42
UNITS
V
VIN
5
VUVLO
4.4
4.7
380
0.6
5.0
V
Under-Voltage Lockout Threshold Hysteresis VUVLO_HYS
Shutdown
mV
VEN = 0V
1.4
20
VIN Quiescent Current
IQ
µA
Sleep Mode
VEN = 2V, Not Switching, VIN ≤ 36V
14
Feedback Reference Voltage
Feedback Pin Input Current
Minimum High-side Switch On-Time
Minimum High-side Switch Off-Time
Switching Frequency
VFB
IFB
VIN = 5V
0.770
0.800
0.1
0.830
1
V
µA
ns
VFB = 1V
tON_MIN
tOFF_MIN
fSW
ILOAD = 600mA
100
100
570
0.1
ns
400
1.0
1.3
740
1
kHz
µA
µA
A
ISW_H
ISW_L
ILIM
VSW = 42V
VSW = 0V
Switch Leakage Current
0.1
1
High-side Power NMOS Current Limit
High-side Power NMOS On-Resistance
Low-side Power NMOS On-Resistance
EN Input High Voltage
1.3
1.7
TJ = +25℃
ILOAD = 0.1A
ILOAD = 0.1A
700
300
mΩ
mΩ
RDSON
VIH
VIL
V
EN Input Low Voltage
0.6
EN Threshold, Hysteresis
VEN_HYS
IEN
120
0.1
mV
Enable Leakage Current
VEN = 5V
1
μA
OVP Rising
OVP Falling
0.84
0.79
0.89
0.85
145
20
0.94
0.90
Output Over-Voltage Threshold
VOUT_OV
V
Thermal Shutdown
TSHDN
THYS
℃
℃
Thermal Shutdown Hysteresis
SG Micro Corp
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS
TA = +25℃, VIN = 18V, L = 22μH and COUT = 22μF, unless otherwise noted.
Steady State
Steady State
VIN
VIN
VSW
VSW
VOUT
IL
VOUT
IL
VIN = 12V, VOUT = 5V, IOUT = 200mA
VIN = 12V, VOUT = 5V, IOUT = 600mA
Time (2μs/div)
Time (2μs/div)
Steady State
Steady State
VIN
VIN
VSW
VOUT
VSW
VOUT
IL
IL
VIN = 18V, VOUT = 12V, IOUT = 200mA
VIN = 18V, VOUT = 12V, IOUT = 600mA
Time (2μs/div)
Time (2μs/div)
Power-Up
Power-Down
VEN
VEN
VSW
VSW
VOUT
VOUT
IL
IL
VIN = 18V, VOUT = 12V, IOUT = 600mA
VIN = 18V, VOUT = 12V, IOUT = 600mA
Time (2ms/div)
Time (500μs/div)
SG Micro Corp
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 18V, L = 22μH and COUT = 22μF, unless otherwise noted.
Power-Up
Power-Down
VEN
VEN
VSW
VSW
VOUT
VOUT
IL
IL
VIN = 24V, VOUT = 5V, IOUT = 600mA
VIN = 24V, VOUT = 5V, IOUT = 600mA
Time (2ms/div)
Time (500μs/div)
Short-Circuit Entry
Short-Circuit Recovery
VIN
VIN
VSW
VSW
VOUT
VOUT
IL
IL
VIN = 18V, VOUT = 5V
VIN = 18V, VOUT = 5V
Time (100μs/div)
Time (500μs/div)
Load Transient Response
VIN
VOUT
IOUT
VOUT = 5V, IOUT = 50mA to 600mA
Time (1ms/div)
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 18V, L = 22μH and COUT = 22μF, unless otherwise noted.
Efficiency vs. Load Current
Efficiency vs. Load Current
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
VIN = 12V
V
IN = 18V
IN = 24V
IN = 36V
VOUT = 3.3V
L = 22μH
DCR = 14.6mΩ
VIN = 12V
VOUT = 5V
L = 22μH
DCR = 14.6mΩ
V
V
V
V
IN = 15V
IN = 18V
0
0
5
100
200
300
400
500
600
600
50
0
100
200
300
400
500
600
Load Current (mA)
Load Current (mA)
Efficiency vs. Load Current
Load Regulation
100
90
80
70
60
50
40
30
20
10
0
5.060
5.055
5.050
5.045
5.040
5.035
5.030
VOUT = 5V
VIN = 15V
VIN = 12V
V
V
V
IN = 18V
IN = 24V
IN = 36V
VOUT = 12V
L = 47μH
DCR = 33.5mΩ
V
V
V
IN = 18V
IN = 24V
IN = 36V
100
200
300
400
500
0
100
200
300
400
500
600
Load Current (mA)
Load Current (mA)
Line Regulation
Shutdown Current and Quiescent Current vs. Input Voltage
100
5.2
5.0
4.8
4.6
4.4
4.2
4.0
VOUT = 5V
IQ
10
1
ISHUTDOWN
0.1
0.01
IOUT = 100mA
I
I
OUT = 300mA
OUT = 600mA
VOUT = 5V
14
23
32
41
0
5
10 15 20 25 30 35 40 45 50
Input Voltage (V)
Input Voltage (V)
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 18V, L = 22μH and COUT = 22μF, unless otherwise noted.
Dropout Curve
Switching Frequency vs. Temperature
5.5
5.0
4.5
4.0
3.5
3.0
600
580
560
540
520
500
IOUT = 10mA
IOUT = 100mA
I
I
OUT = 300mA
OUT = 600mA
VOUT = 5V
4.7
5.1
5.5
5.9
6.3
6.7
7.1
7.5
-40 -25 -10
5
20 35 50 65 80 95 110 125
Input Voltage (V)
Junction Temperature (℃)
Switch Leakage vs. Temperature
Quiescent Current vs. Temperature
0.18
0.15
0.12
0.09
0.06
0.03
0.00
-0.03
-0.06
20
16
12
8
ISW_L
4
ISW_H
0
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Junction Temperature (℃)
Junction Temperature (℃)
Shutdown Current vs. Temperature
EN Voltage vs. Temperature
Rising
1.0
0.8
0.6
0.4
0.2
0.0
1.2
1.0
0.8
0.6
0.4
0.2
0.0
Falling
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Junction Temperature (℃)
Junction Temperature (℃)
SG Micro Corp
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 18V, L = 22μH and COUT = 22μF, unless otherwise noted.
Reference Voltage vs. Temperature
Output Over-Voltage Protection vs. Temperature
0.82
0.81
0.80
0.79
0.78
0.91
0.90
0.89
0.88
0.87
0.86
0.85
0.84
0.83
Raising
Falling
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Junction Temperature (℃)
Junction Temperature (℃)
RDSON vs. Temperature
High-side Switch
Under-Voltage Lockout vs. Temperature
1200
1000
800
600
400
200
0
4.9
4.8
4.7
4.6
4.5
4.4
4.3
4.2
4.1
Rising
Falling
Low-side Switch
-40 -25 -10
5
20 35 50 65 80 95 110 125
-40 -25 -10
5
20 35 50 65 80 95 110 125
Junction Temperature (℃)
Junction Temperature (℃)
Temperature Derating
120
100
80
60
40
20
0
-55 -35 -15
5
25 45 65 85 105 125 145 165
Ambient Temperature (℃)
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
FUNCTIONAL BLOCK DIAGRAM
EN
VIN
Thermal
UVLO
Hiccup
Shutdown Logic
OV Comparator
-
Reference
EN Comparator
Boot Charge
Current
Sense
+
Minimum Clamp
Pulse Skip
Boot UVLO
BOOT
-
FB
Error Amplifier
+
+
HS_FET
Current
Comparator
SW
Power Stage
and
Dead Time
Control
VIN
0.8V
Voltage
Logic
Regulator
Reference
Slope
Compensation
Soft-Start
Current
Sense
Overload
Protection
LS_FET
Current Limit
Oscillator
GND
Figure 2. Block Diagram
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
DETAILED DESCRIPTION
During initial power-up of the device (soft-start), current
limit and frequency fold-back are activated to prevent
inductor current runaway while the output capacitor is
Overview
The SGM61413 is an internally compensated wide
input range current mode controlled synchronous Buck
converter. It is designed for high reliability and is
particularly suitable for power conditioning from
unregulated sources or battery-powered applications
that need low sleep/shutdown currents. At no load and
with switching stopped, the total operating current is
approximately 14μA. If the device is disabled, the total
consumption is typically 0.6μA.
charging to the desired VOUT
.
Peak-Current Mode (PWM Control)
Figure 2 shows the functional block diagram and Figure
3 shows the switching node operating waveforms of the
SGM61413. Switching node voltage is generated by
controlling the duty cycles of the complementary
high-side and low-side switches. The high-side duty
cycle is used as control parameter of the Buck
converter to regulate output voltage and is defined as:
D = tON/tSW, where tON is the high-side switch on-time
and tSW is the switching period. When high-side switch
is turned on, the SW pin voltage sharply rises towards
VIN, and the inductor current (IL) starts ramping up with
(VIN - VOUT)/L slope. When high-side switch is turned off,
the low-side switch is turned on after a very short dead
time to avoid shoot-through, and IL ramps down with
-VOUT/L slope. In ideal case, the output voltage is
proportional to the input voltage and duty cycle (D =
Figure 2 shows the simplified block diagram of the
SGM61413. The two integrated MOSFET switches of
the power stage are both over-current protected and can
provide up to 600mA of continuous current for the load.
Current limiting of the switches also prevents inductor
current runaway. The converter switches are optimized
for high efficiency at low duty cycle.
At the beginning of each switching cycle, the high-side
switch is turned on. This is the time that feedback
voltage (VFB) is below the reference voltage (VREF) and
power must be delivered to the output. After the
on-period, the high-side switch is turned off and the
low-side switch is turned on until the end of switching
cycle. For reliable operation and preventing shoot
through, a short dead time is always inserted between
gate pulses of the converter complimentary switches.
During dead time, both switch gates are kept off.
VOUT/VIN) if component parasitics are ignored.
The SGM61413 employs fixed-frequency peak-current
mode control in continuous conduction mode (when
inductor minimum current is above zero). In light load
conditions (when the inductor current reaches zero) the
SGM61413 will enter discontinuous conduction mode
and the control mode will change to shift frequency,
peak-current mode to reduce the switching frequency
and the associated switching and gate driving losses
(power-save mode).
The device is designed for safe monotonic start-up
even if the output is pre-biased.
If the junction temperature exceeds a maximum
threshold (TSHDN, typically +145℃), thermal shutdown
protection will happen and switching will stop. The
device will automatically recover with soft-start when
the junction temperature drops back well below the trip
point. This hysteresis is typically 20℃.
VSW
D = tON/tSW
VIN
tON
tOFF
The SGM61413 has current limit on both the high-side
and low-side MOSFET switches. When current limit is
activated, frequency fold-back is also activated. This
occurs in the case of output overload or short circuit.
Note that SGM61413 will continue to provide its
maximum output current and will not shut down or
hiccup. In such a case, the junction temperature may
rise rapidly and trigger thermal shutdown.
t
0
tSW
IL
ILPK
IOUT
ΔIL
t
0
Figure 3. Converter Switching Waveforms in CCM
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
DETAILED DESCRIPTION (continued)
In continuous conduction mode, SGM61413 operates
at fixed-frequency using peak-current mode control
scheme. The controller has an outer voltage feedback
loop to get accurate DC voltage regulation. The output
of the outer loop is fed to an inner peak-current control
loop as reference command that adjusts the
peak-current of the inductor. The inductor peak-current
is sensed from the high-side switch and is compared to
the peak-current reference to control the duty cycle. In
other words, as soon as the inductor current reaches
the reference peak-current determined by voltage loop,
the high-side switch is turned off and the low-side
switch is turned on after dead time.
Floating Driver and Bootstrap Charging
UVLO Protection
The high-side MOSFET driver is powered by a floating
supply provided by an external bootstrap capacitor. The
bootstrap capacitor is charged and regulated to about
5V by the dedicated internal bootstrap regulator. When
the voltage between BOOT and SW nodes is below
regulation, a PMOS pass transistor turns on and
connects VIN and BOOT pins internally, otherwise it will
turn off. The power supply for the floating driver has its
own UVLO protection. The rising UVLO threshold is
about 4.7V and with 380mV hysteresis, the falling
threshold is about 4.32V. In case of UVLO, the
reference voltage of the controller is reset to zero and
after recovery a new soft-start process will start.
The internally compensated voltage feedback loop
allows for simpler design, fewer external components,
and stable operation with almost any combination of
output capacitors.
Output Over-Voltage Protection (OVP)
The SGM61413 contains an over-voltage comparator
that monitors the FB pin voltage. The over-voltage
threshold is approximately 111% of nominal FB voltage.
When the voltage at the FB pin exceeds the
over-voltage threshold (VOUT_OV), PWM switching will
be stopped and both high-side and low-side switches
will be turned off. If the over-voltage fault is removed,
the regulator will automatically recover.
Power-Save Mode
When the load is reduced, the inductor minimum (valley)
current eventually reaches zero level (boundary
condition). Synchronous rectifier (low-side switch)
current is always sensed and when it reaches zero, the
controller turns off the low-side switch and does not let
the low-side switch sink current. This prevents inductor
current from going below zero (negative). This results
in discontinuous conduction mode (DCM) operation in
which inductor current remains zero until next switching
cycle. Both switches are off during this period and do
not act as complementary switches. This off-time will
extend (that means lower frequency) until output
voltage falls below reference voltage again and triggers
a new switching cycle. With a new cycle, the high-side
switch is turned on again for almost the same tON time
as CCM. Therefore, the output capacitors take almost
the same charge in each cycle and with lighter loads it
will take longer off-times until output capacitor voltage
falls below the reference voltage. The extended
off-times mean lower switching frequency that is called
frequency fold-back and significantly reduces the
switching losses, but usually increases the output ripple
a little bit.
The error amplifier is normally able to maintain
regulation since the synchronous output stage has
excellent sink and source capability. However it is not
able to regulate output when the FB pin is disconnected
or when the output is shorted to a higher supply like
input supply. Also when VOUT is set to its minimum
(0.8V) usually there is no voltage divider and VOUT is
directly connected to FB through a resistor (R1 in the
divider) and there is no resistor to ground (no R2). In
such case and with no load, an internal current source
of 5μA ~ 6μA from BOOT into the SW pin, which can
slowly charge the output capacitor and pull VOUT up to
VIN. Therefore a minimum load of at least 10μA must be
always present on VOUT (for example an 80kΩ resistor:
0.8V/10μA = 80kΩ).
If the FB pin is disconnected, a tiny internal current
source will force the voltage at the FB pin to rise above
VOUT_OV that triggers over-voltage protection and
disables the regulator to protect the loads from a
significant over-voltage. Also, if by accident a higher
external voltage is shorted to the output, VFB will rise
above the over-voltage threshold and trigger an OVP
event to protect the low-side switch.
Note that the on-time of synchronous rectifier switch
should always be long enough to fully charge the
bootstrap capacitor and prevent bootstrap under-voltage
lockout due to insufficient voltage for the high-side
switch gate driver.
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
DETAILED DESCRIPTION (continued)
An 80kΩ resistor to ground will prevent the output
voltage floating up.
Minimum High-side On/Off-Time and
Frequency Fold-Back
The shortest duration for the high-side switch on-time
(tON_MIN) is 100ns (TYP). For the off-time (tOFF_MIN) the
minimum value is 100ns (TYP). The duty cycle (or
equivalently the VOUT/VIN ratio) range in CCM operation
is limited by tON_MIN and tOFF_MIN depending on the
switching frequency. Note that at 570kHz the total cycle
time is tSW = 1.75μs.
Soft-Start
Soft-start is necessary to limits the input inrush current
right after power-up or enabling the device. Soft-start is
implemented by slowly ramping up the reference
voltage that in turn slowly ramps up the output voltage
to its target regulation value.
The minimum and maximum duty cycles without
frequency fold-back are given by Equations 1 and 2:
Enable
EN pin turns the SGM61413 operation on or off
conditions. If an applied voltage less than 0.5V, the
device will shut down. If the voltage more than 1.2V,
the device will start the regulator. The EN pin is an input
and must not be left open. The simplest way to enable
the device is to connect the EN pin to VIN pin via a
resistor. This enables the SGM61413 to start up
automatically when VIN is within the operating range.
An external logic signal can be used to drive the EN
input for power savings, power supply sequencing
and/or protection. If the EN pin is driven by an external
logic signal, a 10kΩ resistor in series with the input is
recommended.
DMIN = tON_MIN × fSW
(1)
and
DMAX = 1 - tOFF_MIN × fSW
(2)
For any given output voltage, the highest input voltage
without frequency fold-back can be calculated from:
VOUT
(3)
V
=
IN_MAX
fSW ×tON_MIN
The minimum VIN is estimated by:
VOUT
(4)
V
=
IN_MIN
1 - fSW ×tOFF_MIN
Note: Voltage on the EN pin should never exceed VIN +
0.3V. Do not drive the EN pin with a logic level if VIN is
not present. This can damage the EN pin and the
device.
Input Voltage
The SGM61413 can operate efficiently for inputs as high
as 42V. For CCM operation (continuous conduction
mode) keep duty cycle between 6% and 94%.
Thermal Shutdown
Thermal protection is designed to protect the die
Output Voltage
against overheating damage. If the junction
The output voltage can be stepped down to as low as
the 0.8V reference voltage (VREF). As explained before,
when the output voltage is set to 0.8V and there is no
voltage divider, a minimum small load will be needed.
temperature exceeds +145℃, the switching stops and
the device shuts down. Automatic recovery with an
internal soft-start will begin when the junction
temperature drops below the +120℃ falling threshold.
SG Micro Corp
www.sg-micro.com
MAY 2022
13
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
TYPICAL APPLICATION CIRCUITS
5
1
VIN
VIN
BOOT
CIN
CBOOT
0.47μF
10μF
R3
10kΩ
SGM61413
L
4
2
6
3
VOUT
EN
SW
FB
5V/0.6A
22μH
COUT
22μF
R1
52.5kΩ
GND
R2
10kΩ
Figure 4. 5V Output Typical Application Circuit
5
1
VIN
VIN
BOOT
CIN
CBOOT
0.47μF
R3
10kΩ
10μF
SGM61413
L
4
2
6
3
VOUT
EN
SW
FB
12V/0.6A
47μH
COUT
47μF
R1
140kΩ
GND
R2
10kΩ
Figure 5. 12V Output Typical Application Circuit
SG Micro Corp
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MAY 2022
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570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
APPLICATION INFORMATION
External Components
The following guides can be used to select external components.
fSW (kHz)
VOUT (V)
R1 (kΩ)
31.2
R2 (kΩ)
10
L (µH)
22
CBOOT (µF)
0.47
CIN (µF)
10
COUT (µF)
3.3
5
22
22
47
570
52.5
10
22
0.47
10
12
140
10
47
0.47
10
Inductor peak-current should never exceed the
saturation even in transients to avoid over-current
protection. Also inductor RMS rating should always be
larger than operating RMS current even at maximum
ambient temperature.
Output Voltage Programming
Output voltage can be set with a resistor divider
feedback network between output and FB pin as shown
in Figure 4 and Figure 5. Usually, a design is started by
selecting lower resistor R1 and calculating R2 with the
following equation:
VOUT ×(V
- VOUT
)
(6)
IN_MAX
∆IL =
VIN_MAX ×L× fSW
R
(5)
1
VOUT = VREF
×
1 +
R2
V
- VOUT
VOUT
(7)
IN_MAX
LMIN
=
×
IOUT ×KIND
VIN_MAX × fSW
where VREF = 0.8V.
To keep operating quiescent current small and prevent
voltage errors due to leakage currents, it is
recommended to choose R1 in the range of 10kΩ to
200kΩ.
where KIND = ΔIL/IOUT (DC Current, MAX).
Note that it is generally desired to choose a smaller
inductance value to have faster transient response,
smaller size, and lower DCR. On the other hand, if the
inductance is too small, current ripple will increase
which can trigger over-current protection. Larger
inductor current ripple also implies larger output voltage
ripple with the same output capacitors. For
peak-current mode control, it is recommended to
choose large current ripple, because controller
comparator performs better with higher signal to noise
ratio. So, for this design example, KIND = 0.4 is chosen,
and the minimum inductor value for 12V input voltage is
calculated to be 21.7µH. The nearest standard value
would be a 22µH ferrite inductor with a 1A RMS current
rating and 1.5A saturation current that are well above
the designed converter output current RMS and DC
respectively.
If the output has no load other than the FB divider,
make sure the divider draws at least 10μA from VOUT
or an internal current source (5μA ~ 6μA) from BOOT to
SW will slowly charge the output capacitor beyond the
desired voltage.
Inductor Selection
Higher operating frequency allows the designer to
choose smaller inductor and capacitor values; however,
the switching and gate losses are increased. On the
other hand, at lower frequencies the current ripple (∆IL)
is higher, which results in higher light load losses. Use
Equation 6 to calculate the required inductance (LMIN).
K is the ratio of the inductor peak-to-peak ripple (∆IL) to
the maximum operating DC current (IOUT). The
recommended selection range for K is between 0.2 and
0.4. Choosing a higher K value reduces the selected
inductance, but a too high K factor may result in
insufficient slope compensation. The inductance is
selected based on the desired peak-to-peak ripple
current (ΔIL) for CCM. Equation 7 shows that ∆IL is
inversely proportional to fSW × L and is increased at the
maximum input voltage (VIN_MAX). Therefore by
accepting larger ∆IL values, smaller inductances can be
chosen but the cost is higher output voltage ripple and
increased core losses.
Bootstrap Capacitor Selection
The SGM61413 requires a small external bootstrap
capacitor, CBOOT, between the BOOT and SW pins to
provide the gate drive supply voltage for the high-side
MOSFET. The bootstrap capacitor is refreshed when
the high-side MOSFET is off and the low-side switch
conducts. An X7R or X5R 0.47µF ceramic capacitor
with a voltage rating of 16V or higher is recommended
for stable operating performance over-temperature and
voltage variations.
SG Micro Corp
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MAY 2022
15
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
APPLICATION INFORMATION (continued)
These AC components are not in phase and the total
peak-to-peak ripple is less than ΔVOUT_ESR + ΔVOUT_C
Input Capacitor Selection
.
The input capacitor also provides the high frequency
switching transient currents. So, choosing a low-ESR
and small size capacitor with high self-resonance
frequency and sufficient RMS rating is necessary. The
recommended high frequency decoupling capacitor
value is 10μF X5R or X7R or higher. It is recommended
to choose the voltage rating of the capacitor(s) at least
twice the maximum input voltage to avoid derating of
the ceramic capacitors with DC voltage. Some bulk
capacitances may be needed, especially if the
SGM61413 is not located within 5cm distance from the
input voltage source for input stability.
Transient performance specification usually limits
output capacitance if the system requires tight voltage
regulation in presence of large current steps and/or fast
slew rate. The output capacitor must provide the
increased load current or absorb the excess inductor
current (when the load current steps down) until the
control loop can re-adjust the current of the inductor to
the new load level. The control loop of regulator usually
requires 8 or more clock cycles to adjust the inductance
current to the new load level. The output capacitance
must be as large as possible to provide a current
difference of 8 clock cycles to keep the output voltage
within the specified range. Equation 10 shows the
minimum output capacitance required to specify output
overshoot/undershoot.
Bulk capacitors have high Equivalent Series
Resistance (ESR) and can provide the damping
needed to prevent input voltage spiking due to the
wiring inductance of the input. The value for this
capacitor is not critical but must be rated to handle the
maximum input voltage including ripple.
8×(IOH −IOL
fSW × ∆VOUT_SHOOT
)
1
2
(10)
COUT
>
×
For this design, one 10μF, X7R, 50V is used for the
input decoupling capacitor. The ESR is approximately
10mΩ, and the current rating is 1A. To improve high
frequency filtering, a small parallel 0.1μF capacitor may
be placed as close as possible to the device pins.
where:
IOL = Low level of the output current step during load
transient.
IOH = High level of the output current during load
transient.
VOUT_SHOOT = Target output voltage over/undershoot.
Output Capacitor Selection
This device is designed to be used with external LC
filters. The minimum required capacitance to keep cost
and size down and bandwidth high. The main factors
for designing COUT are output voltage ripple, control
loop stability and the magnitude of output voltage
overshoot/undershoot after a load transients. So, COUT
should be chosen carefully. The output voltage ripple
has two main components. One is due to the ac current
(ΔIL) going through the capacitor ESR:
In this example, maximum acceptable ripple is 30mV.
Assuming ΔVOUT_ESR = ΔVOUT_C = 30mV and KIND = 0.4.
Equation 8 results in ESR < 125mΩ and Equation 9
leads to COUT > 1.8μF. If the overshoot/undershoot
transient requirement is 5% then ΔVOUT_SHOOT = 5% ×
VOUT = 250mV. Equations 10, half load (0.3A) to full
load (0.6A) transient, lead to COUT > 8.6μF. So, in
summary, the most stringent criteria for the output
capacitor is transient constrain of COUT > 8.6μF. For the
derating margin, one 22μF, 10V, X7R ceramic capacitor
with 10mΩ ESR is used.
ΔVOUT_ESR = ΔIL × ESR = KIND × IOUT × ESR
(8)
and the other one is caused by the charge and
discharge of capacitor by the ac current (ΔIL):
∆IL
KIND ×IOUT
8× fSW ×COUT 8× fSW ×COUT
(9)
∆VOUT_C
=
=
SG Micro Corp
www.sg-micro.com
MAY 2022
16
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
APPLICATION INFORMATION (continued)
Layout Guide
Careful layout is always important to ensure good performance and stable operation to any kind of switching
regulator. Place the capacitors close to the device, use the GND pin of the device as the center of star-connection to
other grounds, and minimize the trace area of the SW node. With smaller transient current loops, lower parasitic
ringing will be achieved.
Figure 6. Suggested PCB
1
VIN
2
CIN
10μF
5
4
1
VIN
EN
BOOT
SW
CBOOT
0.47μF
R3
10kΩ
L
6
3
SGM61413
VOUT
5V
22μH to 47μH
COUT
22μF
2
GND
FB
C1*
R1
330pF
52.5kΩ
R2
10kΩ
* NOTE: An optional feed-forward capacitor can be used across R1 (as shown) to improve
transient performance and reduce the over/undershoot peaks during load steps.
Figure 7. Typical Application Circuit
SG Micro Corp
www.sg-micro.com
MAY 2022
17
570kHz, 600mA, 42V
SGM61413
Synchronous Buck Converter
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
MAY 2022 ‒ REV.A to REV.A.1
Page
Updated Detailed Description and Application Information sections.......................................................................................................... 11 to 17
Changes from Original (MARCH 2021) to REV.A
Page
Changed from product preview to production data.............................................................................................................................................All
SG Micro Corp
www.sg-micro.com
MAY 2022
18
PACKAGE INFORMATION
PACKAGE OUTLINE DIMENSIONS
SOT-23-6
D
e1
e
E1
E
2.59
0.99
b
0.95
0.69
RECOMMENDED LAND PATTERN (Unit: mm)
L
A
A1
c
θ
A2
0.2
Dimensions
In Millimeters
Dimensions
In Inches
Symbol
MIN
MAX
MIN
MAX
0.049
0.004
0.045
0.020
0.008
0.119
0.067
0.116
A
A1
A2
b
1.050
0.000
1.050
0.300
0.100
2.820
1.500
2.650
1.250
0.100
1.150
0.500
0.200
3.020
1.700
2.950
0.041
0.000
0.041
0.012
0.004
0.111
0.059
0.104
c
D
E
E1
e
0.950 BSC
1.900 BSC
0.037 BSC
0.075 BSC
e1
L
0.300
0°
0.600
8°
0.012
0°
0.024
8°
θ
SG Micro Corp
www.sg-micro.com
TX00034.000
PACKAGE INFORMATION
TAPE AND REEL INFORMATION
REEL DIMENSIONS
TAPE DIMENSIONS
P2
P0
W
Q2
Q4
Q2
Q4
Q2
Q4
Q1
Q3
Q1
Q3
Q1
Q3
B0
Reel Diameter
P1
A0
K0
Reel Width (W1)
DIRECTION OF FEED
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF TAPE AND REEL
Reel Width
Reel
Diameter
A0
B0
K0
P0
P1
P2
W
Pin1
Package Type
W1
(mm)
(mm) (mm) (mm) (mm) (mm) (mm) (mm) Quadrant
SOT-23-6
7″
9.5
3.17
3.23
1.37
4.0
4.0
2.0
8.0
Q3
SG Micro Corp
TX10000.000
www.sg-micro.com
PACKAGE INFORMATION
CARTON BOX DIMENSIONS
NOTE: The picture is only for reference. Please make the object as the standard.
KEY PARAMETER LIST OF CARTON BOX
Length
(mm)
Width
(mm)
Height
(mm)
Reel Type
Pizza/Carton
7″ (Option)
7″
368
442
227
410
224
224
8
18
SG Micro Corp
www.sg-micro.com
TX20000.000
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