SGM61040 [SGMICRO]
4A High Efficiency Synchronous Buck Converter;
| 型号： | SGM61040 |
| 厂家： | 
Shengbang Microelectronics Co, Ltd |
| 描述： | 4A High Efficiency Synchronous Buck Converter |
| 文件： | 总19页 (文件大小：1177K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
SGM61040
4A High Efficiency
Synchronous Buck Converter
GENERAL DESCRIPTION
FEATURES
The SGM61040 is a high efficiency and miniature size
synchronous Buck converter for low input voltage
applications. This high frequency device does not need
external compensation and is a perfect solution for
compact designs. The 2.5V to 5.5V input voltage range
is suitable for almost all available battery chemistries.
For the SGM61040A version, to keep the high
efficiency in the whole load range, the device operates
in pulse width modulation (PWM) mode at normal load
and automatically enters the power-save mode (PSM)
at light loads. For the SGM61040B version, the device
operates in continuous current mode (CCM) at light and
heavy loads.
● 2.5V to 5.5V Input Voltage Range
● Adjustable Output Voltage from 0.6V to VIN
● Adaptive Off-Time Architecture
● Up to 95% Efficiency
● Low RDSON MOSFET Switches (28mΩ/13mΩ)
● SGM61040A: 42μA (TYP) Operating Quiescent
Current
● Ultra-Low Quiescent Current in Shutdown Mode
● Power-Save Mode at Light Loads (SGM61040A)
● Continuous Current Mode (SGM61040B)
● 100% Duty Cycle Capability for Low Dropout
● Startup with Pre-biased Output
● Output Discharge Function
● Power Good Output
This device is based on adaptive off-time architecture,
but still allows a wide range of output capacitors up to
150μF and even more. This flexibility makes the device a
good choice for system power rails supplies. The
adaptive off-time architecture provides excellent output
voltage accuracy and superb load transient response.
● Hiccup Mode Short-Circuit Protection
● Thermal Shutdown Protection
● Available in a Green TDFN-2×2-7L Package
APPLICATIONS
The SGM61040 is available in a Green TDFN-2×2-7L
package.
Battery-Powered Applications
Point-of-Load
Processor Power Supplies
Hard Disk Drives (HDD)/Solid State Drives (SSD)
TYPICAL APPLICATION
L1
0.47μH
VIN
VOUT
1.8V
VIN
EN
SW
2.5V to 5.5V
C1
22μF
C2
10μF
3 × 22μF
R1
C3
6pF
100kΩ
SGM61040
R3
1MΩ
FB
R2
GND
PG
49.9kΩ
Power Good
Figure 1. SGM61040 Typical Application Circuit
SG Micro Corp
www.sg-micro.com
NOVEMBER 2022 – REV. A
4A High Efficiency
SGM61040
Synchronous Buck Converter
PACKAGE/ORDERING INFORMATION
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
DESCRIPTION
ORDERING
NUMBER
PACKAGE
MARKING
PACKING
OPTION
MODEL
GAM
XXXX
SGM61040A
SGM61040B
TDFN-2×2-7L
TDFN-2×2-7L
SGM61040AXTEP7G/TR
SGM61040BXTEP7G/TR
Tape and Reel, 3000
Tape and Reel, 3000
-40℃ to +125℃
-40℃ to +125℃
03M
XXXX
MARKING INFORMATION
NOTE: XXXX = Date Code, Trace Code and Vendor Code.
Serial Number
Y Y Y
X X X X
Vendor Code
Trace Code
Date Code - Year
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
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.
Pin Voltages Referred to GND
VIN, FB, EN, PG.................................................. -0.3V to 6V
SW (DC) ...................................................-0.3V to VIN + 0.3V
SW (AC, Less than 10ns) while Switching.............. -3V to 9V
Package Thermal Resistance
TDFN-2×2-7L, θJA .................................................... 109℃/W
Junction Temperature.................................................+150℃
Storage Temperature Range .......................-65℃ to +150℃
ESD SENSITIVITY CAUTION
Lead Temperature (Soldering, 10s)............................+260℃
This integrated circuit can be damaged if ESD protections are
not considered carefully. SGMICRO recommends that all
integrated circuits be handled with appropriate precautions.
Failure to observe proper handling and 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.
ESD Susceptibility
HBM.............................................................................4000V
CDM ............................................................................1000V
RECOMMENDED OPERATING CONDITIONS
Input Voltage Range, VIN ....................................2.5V to 5.5V
Output Voltage Range, VOUT................................. 0.6V to VIN
PG Pin Sink Current, ISINK_PG ..........................................1mA
Maximum Pull-Up Voltage for PG, VPG ...........................5.5V
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
NOVEMBER 2022
2
4A High Efficiency
SGM61040
Synchronous Buck Converter
PIN CONFIGURATION
(TOP VIEW)
1
2
3
4
EN
PG
7
VIN
6
5
SW
FB
GND
NC
TDFN-2×2-7L
PIN DESCRIPTION
PIN
NAME
I/O
DESCRIPTION
Active High Device Enable Input Pin. Pull this pin to logic high to enable the device and pull it
low to disable it. An internal 550kΩ (TYP) pull-down resistor disables the device by default. This
resistor is removed when the device is enabled.
1
EN
I
Open-Drain Power Good Output Pin. This output is released to go high if the device is in power
good status. Pull up this pin to a 5.5V or less voltage rail. It can be left open if not used.
2
3
4
5
6
7
PG
FB
O
I
Feedback Pin. Connect a resistor divider between the output voltage sense point and ground,
and tap it to the FB pin to set the output voltage.
NC
—
G
P
P
No Connection.
GND
SW
VIN
Ground Pin.
Switch Node of the Power Converter. Connect it to the output inductor.
Input Voltage Pin.
NOTE: I = input, O = output, P = power, G = ground.
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4A High Efficiency
SGM61040
Synchronous Buck Converter
ELECTRICAL CHARACTERISTICS
(VIN = 5V and TJ = -40℃ to +125℃, all typical values are measured at TJ = +25℃, unless otherwise noted.)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
Supply
Input Voltage Range
VIN
IQ
2.5
5.5
70
V
Enabled, no load, no switching (SGM61040A)
Enabled, no load, no switching (SGM61040B)
TJ = +25℃, Disabled (EN = Low)
VIN falling
42
420
0.06
2.2
Quiescent Current into VIN
µA
600
1.5
2.3
Shutdown Current into VIN
Under-Voltage Lockout Threshold
Under-Voltage Lockout Hysteresis
Thermal Shutdown Threshold
Thermal Shutdown Hysteresis
EN Input
ISD
µA
V
VUVLO
2.1
1.2
VUVLO_HYS VIN rising
210
160
25
mV
℃
℃
TJ rising
TJSD
TJ falling
Logic High Input Voltage
VIH
VIL
TJ = +25℃, VIN = 2.5V to 5.5V
V
V
Logic Low Input Voltage
TJ = +25℃, VIN = 2.5V to 5.5V
EN = High
0.4
1
Input Leakage Current (into EN Pin)
Pull-Down Resistance at EN Pin
Soft-Start, Power Good
IEN_LKG
RPD
0.01
550
µA
kΩ
EN = Low
Time interval from EN rising edge to
VOUT reaching 95% of nominal
Soft-Start Time
tSS
0.8
ms
VOUT rising, as percentage of the nominal VOUT
VOUT falling, as percentage of the nominal VOUT
ISINK = 1mA, TJ = -40℃ to +125℃
95%
90%
0.14
0.01
VOUT
(set)
Power Good Threshold
VPG
PG Low State Output Voltage
PG Leakage Current (into PG Pin)
Output and Feedback
VPG_OL
IPG_LKG
0.3
0.5
V
VPG = 5V, TJ = -40℃ to +125℃
µA
TJ = +25℃
596
594
592
600
604
606
608
100
PWM mode,
VIN = 2.5V to 5.5V
Feedback Regulation Voltage
VFB
TJ = 0℃ to +85℃
mV
TJ = -40℃ to +125℃
Feedback Input Leakage Current
Output Discharge Resistor
IFB_LKG
RDIS
VFB = 1V
10
43
nA
EN = Low, VOUT = 1.8V
Ω
Power Switches
High-side MOSFET On-Resistance
Low-side MOSFET On-Resistance
High-side MOSFET Current Limit
TJ = +25℃, ISW = 500mA
TJ = +25℃, ISW = 500mA
28
13
35
20
mΩ
mΩ
A
RDSON
ILIM
4.5
5.8
2.5
2.0
7.1
IOUT = 1A (SGM61040A)
IOUT = 1A (SGM61040B)
PWM Switching Frequency
fSW
MHz
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS
TA = +25℃, VIN = 5V, VOUT = 1.8V and L1 = 0.47μH, unless otherwise noted.
Efficiency vs. Load Current (SGM61040A)
Efficiency vs. Load Current (SGM61040B)
VOUT = 0.9V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
VIN = 5V
VIN = 5V
VOUT = 0.9V
4
4
0.001
0.01
0.1
1
0.001
0.01
0.1
1
Load Current (A)
Load Current (A)
Efficiency vs. Load Current (SGM61040A)
Efficiency vs. Load Current (SGM61040B)
VOUT = 1.2V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
V
IN = 5V
VIN = 5V
VOUT = 1.2V
0.001
0.01
0.1
1
4
4
0.001
0.01
0.1
1
Load Current (A)
Load Current (A)
Efficiency vs. Load Current (SGM61040A)
Efficiency vs. Load Current (SGM61040B)
VOUT = 1.8V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
VIN = 2.5V
VIN = 3.3V
VIN = 4.2V
V
IN = 5V
VIN = 5V
VOUT = 1.8V
0.001
4
0.01
0.1
1
4
0.001
0.01
0.1
1
Load Current (A)
Load Current (A)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 5V, VOUT = 1.8V and L1 = 0.47μH, unless otherwise noted.
Efficiency vs. Load Current (SGM61040A)
Efficiency vs. Load Current (SGM61040B)
VOUT = 3.3V
100
90
80
70
60
50
40
30
20
10
0
100
90
80
70
60
50
40
30
20
10
0
VIN = 3.6V
IN = 4.2V
VIN = 3.6V
IN = 4.2V
V
V
VIN = 5V
VIN = 5V
VOUT = 3.3V
0.001
4
0.001
0.01
0.1
1
4
0.01
0.1
1
Load Current (A)
Load Current (A)
Switching Frequency vs. Input Voltage (SGM61040A)
IOUT = 2A
Switching Frequency vs. Input Voltage (SGM61040B)
IOUT = 2A
3500
3000
2500
2000
1500
1000
500
3500
3000
2500
2000
1500
1000
500
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
V
OUT = 3.3V
V
OUT = 3.3V
0
0
2.5
3
3.5
4
4.5
5
5.5
2.5
3
3.5
4
4.5
5 5.5
Input Voltage (V)
Input Voltage (V)
Switching Frequency vs. Load Current (SGM61040A)
VIN = 5V
Switching Frequency vs. Load Current (SGM61040B)
VIN = 5V
3500
3000
2500
2000
1500
1000
500
3500
3000
2500
2000
1500
1000
500
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
VOUT = 1.2V
VOUT = 1.8V
VOUT = 2.5V
V
OUT = 3.3V
V
OUT = 3.3V
0
0
0
0.4 0.8 1.2 1.6
2
2.4 2.8 3.2 3.6
4
0
0.4 0.8 1.2 1.6
2
2.4 2.8 3.2 3.6
4
Load Current (A)
Load Current (A)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 5V, VOUT = 1.8V and L1 = 0.47μH, unless otherwise noted.
Line Regulation vs. Input Voltage (SGM61040A)
VOUT = 1.8V
Line Regulation vs. Input Voltage (SGM61040B)
VOUT = 1.8V
0.5
0.4
0.3
0.2
0.1
0
0.5
0.4
0.3
0.2
0.1
0
-0.1
-0.2
-0.3
-0.4
-0.5
-0.1
-0.2
-0.3
-0.4
-0.5
IOUT = 0.01A
IOUT = 2A
IOUT = 0.01A
IOUT = 2A
I
OUT = 2A
I
OUT = 3A
2.5
3.0
3.5
4.0
4.5
5.0
5.5
2.5
3.0
3.5
4.0
4.5
5.0
5.5
Input Voltage (V)
Input Voltage (V)
Load Regulation vs. Load Current (SGM61040A)
VOUT = 1.8V
Load Regulation vs. Load Current (SGM61040B)
VOUT = 1.8V
1
0.8
0.6
0.4
0.2
0
1
0.8
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
-0.2
-0.4
-0.6
-0.8
-1
VIN = 2.5V
VIN = 3.3V
VIN = 2.5V
VIN = 3.3V
V
IN = 5V
V
IN = 5V
0
0.5
1
1.5
2
2.5
3
3.5
4
0
0.5
1
1.5
2
2.5
3
3.5
4
Load Current (A)
Load Current (A)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 5V, VOUT = 1.8V, L1 = 0.47μH and CFF = 6pF, unless otherwise noted.
Typical Application (SGM61040A)
Typical Application (SGM61040B)
VSW
VSW
AC Coupled
AC Coupled
VO
VO
IL
IL
ILOAD = 0.1A
ILOAD = 0.1A
Time (2μs/div)
Time (200ns/div)
Load Transient (SGM61040A)
Load Transient (SGM61040B)
ILOAD
VO
ILOAD
VO
AC Coupled
AC Coupled
VSW
VSW
IL
IL
ILOAD = 0.6A to 3.4A, Slew Rate = 6A/µs
ILOAD = 0.6A to 3.4A, Slew Rate = 6A/µs
Time (5μs/div)
Time (5μs/div)
Short-Circuit, Entry (SGM61040A)
Short-Circuit, Entry (SGM61040B)
VPG
VPG
VO
VO
IL
IL
Time (2ms/div)
Time (2ms/div)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 5V, VOUT = 1.8V, L1 = 0.47μH and CFF = 6pF, unless otherwise noted.
Short-Circuit Recovery (SGM61040A)
Short-Circuit Recovery (SGM61040B)
VPG
VPG
VO
VO
IL
IL
Time (2ms/div)
Time (2ms/div)
Start-up with Load (SGM61040A)
Start-up with Load (SGM61040B)
VEN
VPG
VO
IL
Time (200μs/div)
Time (200μs/div)
Start-up without Load (SGM61040A)
Start-up without Load (SGM61040B)
VEN
VPG
VEN
VPG
VO
VO
IL
IL
Time (200μs/div)
Time (200μs/div)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
TA = +25℃, VIN = 5V, VOUT = 1.8V, L1 = 0.47μH and CFF = 6pF, unless otherwise noted.
Shutdown with Load (SGM61040A)
Shutdown with Load (SGM61040B)
VEN
VPG
VEN
VPG
VO
VO
IL
IL
Time (50μs/div)
Time (50μs/div)
Shutdown without Load (SGM61040A)
Shutdown without Load (SGM61040B)
VEN
VPG
VEN
VPG
VO
VO
IL
IL
Time (2ms/div)
Time (2ms/div)
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4A High Efficiency
SGM61040
Synchronous Buck Converter
FUNCTIONAL BLOCK DIAGRAM
VIN
Current Sense
Soft-Start
Hiccup Counter
PWM
Comparator
+
+
+
-
SW
Control Logic
and Driver
R
S
Q
-
VREF
gm
FB
NC
VZCD
Zero Current Detector
GND
Off-Time
Calculation
Output
Discharge Logic
EN/TSD/OVP
Control Contains
UVLO, TSD, etc.
EN
PG
550kΩ
V
REF × 95%
FB
+
-
Figure 2. SGM61040 Block Diagram
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4A High Efficiency
SGM61040
Synchronous Buck Converter
DETAILED DESCRIPTION
The PG output is useful for power supply sequencing
as well. Usually, the multiple power rails of a system
need to be powered in a specific sequence for proper
startup. The PG output of the leading power supply is
connected to the EN input of the subsequent power
supply to implement such sequencing.
Overview
The SGM61040 is a high efficiency Buck switching
converter optimized for handheld battery-powered
applications. It operates at a quasi-fixed frequency of
2.5MHz (SGM61040B 2MHz) and uses adaptive
off-time PWM control for the moderate to heavy load
range. This allows using a small inductor and small
capacitors for compact designs. At light load condition,
the SGM61040A operates in power-save mode to
reduce the switching frequency and losses for longer
battery life. The power-save mode quiescent current is
42μA (TYP) while the shutdown current is only 0.06μA
(TYP). For the SGM61040B, it operates in continuous
current mode from no load to heavy loads.
Table 1. PG Output State in Different Conditions
PG State
Reason
Condition(s)
High-Z Low
EN = High, VFB ≥ VPG
EN = High, VFB ≤ VPG
EN = Low
√
√
√
√
√
√
Output Voltage
Shutdown by EN
Thermal Shutdown
UVLO
TJ > TJSD
0.6V < VIN < VUVLO
VIN ≤ 0.6V
Power Supply Removal
Under-Voltage Lockout (UVLO)
Operating with insufficient supply voltage can cause
device malfunction or failure. The UVLO protection
shuts down the device if the input voltage is below the
VUVLO threshold. The UVLO comparator has a 210mV
hysteresis band.
Soft-Start and Pre-biased Output
An 800μs internal soft-start circuit is designed to
prevent input inrush current and voltage drops during
startup. This circuit slowly ramps up the error amplifier
reference voltage (VREF = 0.6V) after exiting the
shutdown state or under-voltage lockout (UVLO). Slow
increase of the output voltage prevents the excessive
inrush current for charging the output capacitors and
creates a smooth output voltage rise. The other
advantage of a soft-start is avoiding supply voltage
drops especially on the high internal impedance
sources such as the primary cells and rechargeable
batteries.
Device Enable and Disable
When the input voltage is valid, pulling the EN input to
logic high will enable the device, and pulling it to logic
low will shut it down. In the shutdown mode, the
switches and all control circuits are turned off to reduce
the device current to 0.06μA (TYP). A 550kΩ pull-down
resistor is internally placed between EN and GND pins
when the device is disabled.
During shutdown, an internal 43Ω resistor is connected
between SW and GND pins and softly discharges the
output capacitors. This discharge function is also
activated when the shutdown is caused by a thermal
shutdown, UVLO, or short-circuit protection.
The SGM61040 is also capable of starting with a
pre-biased output capacitor when it is powered up or
enabled. When the device is turning on, a bias on the
output may exist due to the other sources connected to
the load(s) such as multi-voltage ICs or simply because
of residual charges on the output capacitors. For
example, when a device with light load is disabled and
re-enabled, the output may not drop during the off
period and the device must restart under pre-biased
output condition. Without the pre-biased capability, the
device may not be able to start up properly. The output
ramp is automatically initiated with the bias voltage and
ramps up to the nominal output value.
Power Good Output (PG)
The PG pin is an open-drain output with 1mA sinking
capability. This pin should be pulled up with an external
resistor to a logic high rail no more than 5.5V unless it
is not used. The PG signal is in high-impedance state
when the output voltage is in regulation range. PG
remains low until VOUT exceeds 95% of its nominal (set)
value and goes low if VOUT drops below 90% of its
nominal value. Table 1 shows how the PG state is
changed in different conditions. VPG is the threshold of
the PG hysteretic comparator. It has a 5% hysteresis
band and goes high when VFB rises above 95% of the VREF
.
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4A High Efficiency
SGM61040
Synchronous Buck Converter
DETAILED DESCRIPTION (continued)
high-side switch is always turned on, and the output
voltage is determined by the load current times the
RDSON composed by the high-side switch and inductor.
Power-Save Mode (SGM61040A)
At light load conditions, the SGM61040A shifts to the
power-save mode to reduce the switching frequency
and minimize the losses. It also shuts down most of the
internal circuits in power-save mode. In this mode, one
or more PWM pulses are sent to charge the output
capacitor and then the switches are kept off. The output
capacitor voltage gradually drops due to small load
current and when it falls below the nominal voltage
threshold, the PWM pulses resume. If the load is still
low, the output will go slightly higher than normal value
again and the switches will be turned off. In power-save
mode, the output voltage is slightly higher than nominal
output voltage. This effect can be mitigated by a larger
output capacitor.
Current Limit and Hiccup Mode
Short-Circuit Protection
Limiting the switch current protects the switch itself and
also prevents over-current in the source and the
inductor. If the high-side (HS) switch current exceeds
the ILIM threshold, HS switch is turned off and the
low-side (LS) switch will be turned on to reduce the
inductor current and limit the peak.
If 2ms consecutive repetition of this event occurs, the
controller will stop switching and turns the output
discharge circuit on. Then a new startup will be
automatically initiated (hiccup) after 2.5ms (TYP). The
hiccup repeats until the overload or short-circuit fault is
cleared.
Continuous Conduction Mode (SGM61040B)
In continuous conduction mode (CCM), the frequency
is fixed and the output voltage ripple will be minimal.
The maximum output current of 4A is supplied in CCM.
Thermal Shutdown
Thermal protection is designed to protect the die
against overheating damage. If the junction
temperature exceeds TJSD threshold, the switching
stops and the device shuts down. Automatic recovery
Low Dropout Operation (100% Duty Cycle)
When the input voltage reduces, the on-time increases.
When the input voltage is lower than the regulation
output voltage, the output voltage drops, and the
SGM61040 goes into 100% duty cycle mode. The
with
a
soft-start will begin when the junction
temperature drops below the 135℃ falling threshold.
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4A High Efficiency
SGM61040
Synchronous Buck Converter
APPLICATION INFORMATION
In this section, power supply design with the SGM61040 synchronous Buck converter and selection of the external
component will be explained based on the typical application that is applicable for various input and output voltage
combinations.
L1
0.47μH
VIN
VOUT
1.8V
VIN
EN
SW
2.5V to 5.5V
C4
22μF
C5
C6
C1
22μF
C2
10μF
R1
C3
6pF
22μF 22μF
100kΩ
SGM61040
R3
1MΩ
FB
R2
GND
PG
49.9kΩ
Power Good
Figure 3. SGM61040 Circuit for 1.8V Output
Design Requirements
10μF ceramic capacitor with X5R or better dielectric
and 0805 or smaller size is sufficient in most cases. A
larger value can be selected to reduce the input current
ripple.
Table 2 summarizes the requirements for this example
as shown in Figure 3. The selected components are
given in Table 3.
Table 2. Design Parameters for the Application Example
Inductor Selection (L)
The important factors for inductor selection are
inductance (L), saturation current (ISAT), RMS rating
(IRMS), DC resistance (DCR) and dimensions. Use
Equation 1 to find the inductor peak current (IL_MAX) and
peak-to-peak ripple current (∆IL) in static conditions:
Design Parameter
Input Voltage
Example Value
2.5V to 5.5V
1.8V
Output Voltage
Output Current
≤ 4A
Output Ripple Voltage
< 30mV
ΔIL
IL_MAX = IO_MAX
+
2
1−D
L× fSW
Table 3. Selected Components for the Design Example
(1)
ΔIL = VOUT
×
Ref
Description
Manufacturer
C1, C4,
C5, C6
22µF, 10V, X5R, 0805, Ceramic
P/N: GRM21BR61A226ME44L
10µF, 10V, X7R, 0805, Ceramic
P/N: GRM21BR71A106KA73L
IO_MAX is the maximum load current, D = VOUT/VIN represents
duty cycle and fSW is the switching frequency.
Murata
C2
C3
L1
Murata
Standard
WE
ISAT should be higher than IL_MAX, and sufficient margin
should be reserved. Typically, the saturation current
above high-side current limit is enough, and a 10% to
30% ripple current is selected to calculate the
inductance. Larger inductance values reduce the ripple
current but lead to sluggish transient response.
6pF, 50V, C0G, 0603, Ceramic
0.47μH, DCRTYP = 7.3mΩ, ISAT(10%) = 9.6A
P/N:744373340047
Value Depends on VOUT
,
R1
Standard
100kΩ, 1%, 0603, 1/16W Chip Resistor
49.9kΩ, 1%, 0603, 1/16W Chip Resistor
1MΩ, 5%, 0603, 1/16W Chip Resistor
Output Capacitor Selection (COUT
)
R2
R3
Standard
Standard
This device is capable to operate with low ESR ceramic
capacitors to get low voltage ripple and fast response. 3 × 22μF
capacitors with X7R or X5R dielectric type are
recommended. If an output capacitor larger than 150μF
is used, appropriate startup current reduction should be
considered to avoid current limiting or false triggering of
the short-circuit protection during startup.
Input Capacitor Selection (CIN)
High frequency decoupling input capacitors with low
ESR are needed to circulate and absorb the high
frequency switching currents of the converter. Place
this capacitor right beside the VIN and GND pins. A
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4A High Efficiency
SGM61040
Synchronous Buck Converter
APPLICATION INFORMATION (continued)
Output Voltage Setting
L1 = 0.47µH, COUT = 3 × 22µF and C3 = 6pF are the
Use Equation 2 to select the R1/R2 resistor divider to
set the VOUT. Select the R2 value less than 100kΩ to
compromise noise sensitivity and light load losses.
recommended values for the typical application.
Table 4. Proper Output Capacitor and Inductor Combination
L1
COUT
22µF × 3
100µF
C3
6pF
R1
R2
R
1
VOUT = VFB × 1+
= 0.6V × 1+
(2)
R2
0.47µH (1)
150µF
Output Filter Design
Table 4 can be used to select the proper LC filter
components for most design requirements. The
inductor initial tolerance can be as high as -30% to +20%
of the nominal value and proper current derating is
usually required. Bias voltage may cause significant
capacitance drops in the ceramic capacitors. The
effective deviation of a ceramic capacitor can be as
high as -50% to +20% of the nominal value.
6pF
22µF × 3
100µF
1µH (1)
150µF
NOTE:
1. SGM61040A is recommend to use smaller inductor
at low output voltage, such as 0.24μH.
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4A High Efficiency
SGM61040
LAYOUT
Synchronous Buck Converter
A good printed-circuit-board (PCB) layout is a critical element of any high performance design. Follow the guidelines
below for designing a good layout for the SGM61040.
• Place the input capacitor close to the device with the shortest possible connection traces.
• Share the same GND return point for the input and output capacitors and locate it as close as possible to the
device GND pin to minimize the AC current loops. Place the inductor close to the switching node and connect it
with a short trace to minimize the parasitic capacitances coupled to the SW node.
• Keep the signal traces like the FB sense line away from SW or other noisy sources.
• Use GND planes in mid-layers for shielding and minimizing the ground potential drifts.
Refer to Figure 4 for a recommended PCB layout.
Top Layer
Bottom Layer
Figure 4. PCB Layout
REVISION HISTORY
NOTE: Page numbers for previous revisions may differ from page numbers in the current version.
Changes from Original (NOVEMBER 2022) to REV.A
Page
Changed from product preview to production data .................................................................................................................................................All
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PACKAGE INFORMATION
PACKAGE OUTLINE DIMENSIONS
TDFN-2×2-7L
D
b1
e1
L1
E
L
PIN 1#
e
b
BOTTOM VIEW
TOP VIEW
0.60
0.30
1.50
A
1.35
0.50
A1
A2
0.60
0.25
RECOMMENDED LAND PATTERN (Unit: mm)
SIDE VIEW
Dimensions In Millimeters
Symbol
MIN
MOD
0.750
MAX
0.800
0.050
A
A1
A2
b
0.700
0.000
-
0.200 REF
0.250
0.200
0.250
1.900
1.900
0.300
0.350
2.100
2.100
b1
D
0.300
2.000
E
2.000
e
0.500 BSC
0.600 BSC
0.400
e1
L
0.300
1.200
0.500
1.400
L1
1.300
NOTE: This drawing is subject to change without notice.
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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
TDFN-2×2-7L
7″
9.5
2.30
2.30
1.00
4.0
4.0
2.0
8.0
Q1
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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
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