MPM3515
36V, 1.5A Module,
Synchronous, Step-Down Converter
with an Integrated Inductor
AEC-Q100 Qualified
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MPM3515 is a synchronous, rectified, stepdown converter with built-in power MOSFETs,
inductors, and capacitors. The MPM3515 offers
a very compact solution and requires only four
external components to achieve 1.5A of
continuous output current with excellent load
and line regulation over a wide input supply
range. The MPM3515 operates with a 2.2MHz
switching frequency to achieve a fast load
transient response.
Full protection features include over-current
protection (OCP) and thermal shutdown.
The MPM3515 eliminates design and
manufacturing risks while improving the time to
market dramatically.
The MPM3515 is available in a space-saving
QFN-17 (3mmx5mmx1.6mm) package.
Complete Switch-Mode Power Supply
Wide 4V to 36V Operating Input Range
1.5A Continuous Load Current
90mΩ/50mΩ Low RDS(ON) Internal Power
MOSFETs
Fixed 2.2MHz Switching Frequency
Frequency Foldback at a High Input Voltage
450kHz to 2.2MHz Frequency Sync
Forced Continuous Conduction Mode
(CCM )
Power Good (PG) Indicator
Over-Current Protection (OCP) with ValleyCurrent Detection and Hiccup
Thermal Shutdown
Output Adjustable from 0.8V
Available in a QFN-17 (3mmx5mmx1.6mm)
Package
CISPR25 Class 5 Compliant
Available in a Wettable Flank Package
Available in AEC-Q100 Grade 1
APPLICATIONS
Industrial Controls
Automotive
Medical and Imaging Equipment
Telecom Applications
Distributed Power Systems
All MPS parts are lead-free, halogen-free, and adhere to the RoHS directive.
For MPS green status, please visit the MPS website under Quality
Assurance. “MPS” and “The Future of Analog IC Technology” are registered
trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
VIN
4V-36V
VOUT
3.3V/1.5A
IN
C1
4.7µF
EN/
SYNC
MPM3515
OUT
R1
75kΩ
EN/SYNC
C2
47µF
FB
R2
24.3kΩ
PGND
AGND
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
ORDERING INFORMATION
Part Number
MPM3515GQV*
MPM3515GQV-AEC1
MPM3515GQVE-AEC1**
Package
Top Marking
MSL Rating***
QFN-17
(3mmx5mmx1.6mm)
See Below
3
* For Tape & Reel, add suffix –Z (e.g. MPM3515GQV–Z)
** Wettable flank
*** Moisture Sensitivity Level Rating
TOP MARKING (MPM3515GQV & MPM3515GQV-AEC1)
MP: MPS prefix
Y: Year code
W: Week code
3515: First four digits of the part number
LLL: Lot number
M: Module
TOP MARKING (MPM3515GQVE-AEC1)
MP: MPS prefix:
Y: Year code;
W: Week code:
3515: First four digits of the part number;
LLL: Lot number;
E: Wettable lead flank
M: Module
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
PACKAGE REFERENCE
TOP VIEW
QFN-17 (3mmx5mmx1.6mm)
ABSOLUTE MAXIMUM RATINGS (1)
VIN .................................................... -0.3V to 40V
VSW, VOUT ............................... -0.3V to VIN + 0.3V
VBST........................................................ VSW + 6V
All other pins ................................ -0.3V to 6V (2)
Continuous power dissipation (TA = +25°C) (3)
..................................................................... 2.7W
Junction temperature ................................ 150°C
Lead temperature...................................... 260°C
Storage temperature ................... -65°C to 150°C
Electrostatic Discharge (ESD rating)
HBM (Human Body Model) ........................ ±2kV
CDM (Charged Device Model) ................ ±750V
Recommended Operating Conditions
Supply voltage (VIN) ............................ 4V to 36V
Output voltage (VOUT) .................0.8V to VIN*DMax
Operating junction temp. (TJ). ...-40°C to +125°C
Thermal Resistance (4)
θJA
θJC
QFN-17 (3mmx5mmx1.6mm)...46 ...... 10 ... °C/W
NOTES:
1) Exceeding these ratings may damage the device.
2) For details on EN/SYNC’s ABS MAX rating, please refer to
the EN/SYNC section on page 13.
3) The maximum allowable power dissipation is a function of
the maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature
TA. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by PD (MAX) = (TJ
(MAX)-TA)/θJA. Exceeding the maximum allowable power
dissipation produces an excessive die temperature, causing
the regulator to go into thermal shutdown. Internal thermal
shutdown circuitry protects the device from permanent
damage.
4) Measured on JESD51-7, 4-layer PCB.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
ELECTRICAL CHARACTERISTICS
VIN = 12V, TJ = -40°C to +125°C, unless otherwise noted. Typical values are at TJ = +25°C.
Parameter
Supply
(shutdown)
Symbol
current
IIN
Supply current (quiescent)
Iq
HS switch on resistance
LS switch on resistance
Inductor DC resistance
Switch leakage
Current limit (5)
Low-side valley current
limit
Reverse current limit
Oscillator frequency
Foldback
frequency
during soft start (5)
Maximum duty cycle
Minimum on time (5)
HSRDS(ON)
LSRDS(ON)
LDCR
SWLKG
ILIMIT
Min
Typ
Max
Units
8
μA
0.6
0.8
mA
90
50
75
155
105
VEN/SYNC = 0V
VEN/SYNC = 2V , VFB = 1V,
no switching
VBST-SW = 5V
VCC = 5V
VEN/SYNC = 0V, VSW = 12V
20% duty cycle
2.4
4.0
1
5.5
mΩ
mΩ
mΩ
μA
A
1.5
2.5
3.5
A
1800
1.2
2200
2600
A
kHz
fSW
VFB = 700mV
fFB
VFB = 200mV
0.2
fSW
DMAX
TON_MIN
VFB = 700mV
85
40
807
807
10
819
824
50
%
ns
mV
mV
nA
Feedback voltage
VFB
Feedback current
EN/SYNC
rising
threshold
EN/SYNC
falling
threshold
EN/SYNC input current
IFB
EN/SYNC turn off delay
EN/SYNC
frequency
range
VIN under-voltage lockout
threshold rising
VIN under-voltage lockout
threshold hysteresis
PG rising threshold
PG falling threshold
PG rising delay
PG falling delay
PG sink current capability
PG leakage current
VCC regulator
VCC load regulation
Soft-start time
Thermal shutdown (5)
Thermal hysteresis (5)
Condition
TA = 25°C
TA = -40°C to 125°C
VFB = 820mV
795
790
VEN_RISING
1.2
1.45
1.7
V
VEN_FALLING
0.8
1
1.3
V
5
10
μA
IEN
VEN/SYNC = 2V
ENTd_off
3
450
3
INUVVth
INUVHYS
PGVth_Hi
PGVth_Lo
PGTD_RISING
PGTD_FALLING
VPG
IPG_LEAK
VCC
tSS
3.5
μs
2200
kHz
3.8
V
330
0.83
0.78
40
30
0.88
0.83
90
55
4.5
4.8
1.5
1.7
170
20
Sink 4mA
ICC = 5mA
VOUT from 10% to 90%
0.5
mV
0.93
0.88
160
95
0.4
100
5.1
4
3
VFB
VFB
μs
μs
V
nA
V
%
ms
°C
°C
NOTE:
5) Not tested in production and guaranteed by over-temperature correlation.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
VIN = 12V, Vout = 3.3V, IOUT = 1.5A, L = 2.2μH, FSW = 2.2MHz, with EMI filters, TA = +25°C, unless
otherwise noted.(6)
CISPR25 Class 5 Peak Radiated Emissions
(150kHz - 30MHz)
0.15
5.15
10.15
15.15
20.15
Frequency (MHz)
Amplitude (dBuV/m)
Data
Class 5 Peak
Class 5 Avg
0
100
200
300
400
500
600
700
800
100
200
300
400
500
600
Frequency (MHz)
700
800
900 1000
20.15
25.15
Data
Class 5 Peak
Class 5 Avg
0
100
200
300
400
500
600
Frequency (MHz)
700
800
900 1000
CISPR25 Class 5 Average Radiated Emissions
(Horizontal, 30MHz - 1GHz)
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Amplitude (dBuV/m)
Amplitude (dBuV/m)
0
15.15
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
CISPR25 Class 5 Peak Radiated Emissions
(Horizontal, 30MHz - 1GHz)
Class 5 Avg
10.15
CISPR25 Class 5 Average Radiated Emissions
(Vertical, 30MHz - 1GHz)
900 1000
Data
Class 5 Peak
5.15
Frequency (MHz)
Frequency (MHz)
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Data
Class 5 Peak
Class 5 Avg
0.15
25.15
CISPR25 Class 5 Peak Radiated Emissions
(Vertical, 30MHz - 1GHz)
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Amplitude (dBuV/m)
Data
Class 5 Peak
Class 5 Avg
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
Amplitude (dBuV/m)
Amplitude (dBuV/m)
50
45
40
35
30
25
20
15
10
5
0
-5
-10
-15
CISPR25 Class 5 Average Radiated Emissions
(150kHz - 30MHz)
Data
Class 5 Peak
Class 5 Avg
0
100
200
300
400
500
600
700
Frequency (MHz)
800
900 1000
NOTE:
6) The EMC test results are based on the application circuit with EMI filters (see Figure 12).
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
VOUT
1V/div.
VIN
5V/div.
VOUT
1V/div.
PG
5V/div.
VIN
5V/div.
SW
5V/div.
IL
500mA/div.
VOUT
2V/div.
PG
5V/div.
VIN
5V/div.
SW
5V/div.
IL
1A/div.
VEN
5V/div.
VOUT
1V/div.
PG
5V/div.
SW
5V/div.
IL
1A/div.
VOUT
1V/div.
PG
5V/div.
VIN
5V/div.
SW
5V/div.
PG
5V/div.
SW
5V/div.
IL
1A/div.
IL
1A/div.
VOUT
1V/div.
PG
5V/div.
VEN
5V/div.
VOUT
1V/div.
PG
5V/div.
VEN
5V/div.
SW
10V/div.
SW
5V/div.
IL
1A/div.
IL
1A/div.
VOUT
2V/div.
VOUT
1V/div.
PG
5V/div.
VEN
5V/div.
SW
10V/div.
IL
1A/div.
PG
5V/div.
VIN
5V/div.
SW
10V/div.
IL
2A/div.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS (CONTINUED)
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
PIN FUNCTIONS
Package
Pin #
1
Name
PG
2
EN/SYNC
3
FB
4
VCC
5
AGND
6, 7, 8, 12
SW
9, 10, 11
OUT
13,
BST
14,15
PGND
16
IN
17
NC
Description
Power good indicator. PG is an open-drain structure.
Enable/sync. Pull EN/SYNC high to enable the MPM3515. Float EN/SYNC or
connect EN/SYNC to ground to disable the MPM3515. Apply an external clock to
EN/SYNC to change the switching frequency.
Feedback. Connect FB to the tap of an external resistor divider from the output to
AGND to set the output voltage. The frequency foldback comparator lowers the
oscillator frequency when the FB voltage is below 400mV to prevent current-limit
runaway during a short-circuit fault. Place the resistor divider as close to FB as
possible. Avoid placing vias on the FB traces.
Internal 4.8V LDO output. Since an internal circuit integrates the LDO output
capacitor, there is no need to add an external capacitor.
Analog ground. Reference ground of the logic circuit. AGND is connected to
PGND internally. There is no need to add external connections to PGND.
Switch output. There is no need to connect these SW pins, but a large copper
plane is recommended on pins 6, 7, and 8 for better heat sinking.
Power output. Connect the load to OUT. An output capacitor is required.
Bootstrap. The bootstrap capacitor is integrated internally. There is no need for
external connections.
Power ground. PGND is the reference ground of the power device and requires
careful consideration during PCB layout. For best results, connect PGND with
copper pours and vias.
Supply voltage. IN supplies power for the internal MOSFET and regulator. The
MPM3515 operates from a +4V to +36V input rail. A low-ESR and low-inductance
capacitor is required to decouple the input rail. Place the input capacitor very close
to IN and connect it with wide PCB traces and multiple vias.
Do not connect. NC must be left floating.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
BLOCK DIAGRAM
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
OPERATION
The
MPM3515
is
a
high-frequency,
synchronous, rectified, step-down, switch-mode
converter with built-in power MOSFETs, an
integrated inductor, and two capacitors. The
MPM3515 offers a very compact solution that
achieves 1.5A of continuous output current with
excellent load and line regulation over a 4V to
36V input supply range.
The MPM3515 operates in a fixed-frequency,
peak-current-control mode to regulate the
output voltage. An internal clock initiates a
PWM cycle. The integrated high-side power
MOSFET (HS-FET) turns on and remains on
until the current reaches the value set by the
COMP voltage (VCOMP). When the power switch
is off, it remains off until the next clock cycle
begins. If the current in the power MOSFET
does not reach the value set by VCOMP within
85% of one PWM period, the power MOSFET is
forced off.
Internal Regulator
A 4.8V internal regulator powers most of the
internal circuitries. This regulator takes VIN and
operates in the full VIN range. When VIN is
higher than 4.8V, the output of the regulator is
in full regulation. When VIN is lower than 4.8V,
the output decreases. The MPM3515 integrates
an internal decoupling capacitor, so there is no
need to add an external VCC output capacitor.
CCM Operation
The MPM3515 uses continuous conduction
mode (CCM) to ensure that the part works with
a fixed frequency from a no-load to a full-load
range. The advantage of CCM is the
controllable frequency and lower output ripple
at light load.
Frequency Foldback
The MPM3515 enters frequency foldback when
the input voltage is higher than about 21V. The
frequency decreases to half the nominal value
and changes to 1.1MHz. Frequency foldback
also occurs during soft start and short-circuit
protection.
Error Amplifier (EA)
The error amplifier compares the FB voltage to
the internal 0.807V reference (VREF) and
outputs a current proportional to the difference
between the two. This output current then
charges
or
discharges
the
internal
compensation network to form VCOMP, which
controls the power MOSFET current. The
optimized internal compensation network
minimizes the external component count and
simplifies the control loop design.
Under-Voltage Lockout (UVLO)
Under-voltage lockout (UVLO) protects the chip
from operating at an insufficient supply voltage.
The UVLO comparator monitors the output
voltage of the internal regulator (VCC). The
UVLO rising threshold is about 3.5V, while its
falling threshold is 3.17V.
Enable/SYNC
EN/SYNC is a control pin that turns the
regulator on and off. Drive EN/SYNC high to
turn on the regulator; drive EN/SYNC low to
turn off the regulator. An internal 500kΩ resistor
from EN/SYNC to GND allows EN/SYNC to be
floated to shut down the chip.
EN/SYNC is clamped internally using a 6.5V
series Zener diode (see Figure 2). Connecting
the EN/SYNC input through a pull-up resistor to
the voltage on VIN limits the EN/SYNC input
current below 100µA. For example, with 12V
connected to VIN, RPULLUP ≥ (12V - 6.5V) ÷
100µA = 55kΩ.
Connecting EN/SYNC to a voltage source
directly without a pull-up resistor requires
limiting the amplitude of the voltage source to
≤6V to prevent damage to the Zener diode.
EN/SYNC
EN/SYNC
Figure 2: 6.5V Zener Diode Connection
Connect an external clock with a range of
450kHz to 2.2MHz to synchronize the internal
clock rising edge to the external clock rising
edge. The pulse wide of the external clock
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
signal should be below 350ns, and the off time
of external clock signal should be below 1.9µs.
drops below its lower threshold (typically
150°C), the power supply resumes operation.
Internal Soft Start (SS)
The soft start (SS) prevents the converter
output voltage from overshooting during startup. When the chip starts up, the internal
circuitry generates a soft-start (SS) voltage that
ramps up from 0V to 4.8V. When SS is lower
than REF, the error amplifier uses SS as the
reference. When SS is higher than REF, the
error amplifier uses REF as the reference. The
SS time is set to 1.7ms internally.
Floating Driver and Bootstrap Charging
An internal bootstrap capacitor powers the
floating power MOSFET driver. A dedicated
internal regulator charges and regulates the
bootstrap capacitor voltage to ~4.8V (see
Figure 3). When the voltage between the BST
and SW nodes drops below the regulation
voltage, a PMOS pass transistor connected
from VIN to BST turns on. The charging current
path is from VIN to BST to SW. The external
circuit should provide enough voltage
headroom to facilitate charging. As long as VIN
is higher than SW significantly, the bootstrap
capacitor remains charged. When the HS-FET
is on, VIN ≈ VSW, so the bootstrap capacitor
cannot charge. When the LS-FET is on, VIN VSW reaches its maximum for fast charging.
When there is no inductor current, VSW is equal
to VOUT, so the difference between VIN and VOUT
can charge the bootstrap capacitor. The floating
driver has its own UVLO protection with a rising
threshold of 2.2V and hysteresis of 150mV.
Over-Current Protection (OCP) and Hiccup
The MPM3515 has cycle-by-cycle peak-currentlimit protection and valley-current detection
protection. The inductor current is monitored
during the HS-FET on-state. If the inductor
current exceeds the current-limit value set by
the COMP high-clamp voltage, the HS-FET
turns off immediately. The low-side MOSFET
(LS-FET) then turns on to discharge the energy,
and the inductor current decreases. The HSFET remains off unless the inductor valley
current is lower than a certain current threshold
(the valley current limit), even though the
internal clock pulses high. If the inductor current
does not drop below the valley current limit
when the internal clock pulses high, the HSFET misses the clock, and the switching
frequency decreases to half the nominal value.
Both the peak and valley current limits assist in
keeping the inductor current from running away
during an overload or short-circuit condition.
If the output voltage drops below the undervoltage (UV) threshold (typically 50% below the
reference), the MPM3515 enters hiccup mode
to restart the part periodically. Simultaneously,
the peak-current limit is reached.
This protection mode is useful when the output
is dead-shorted to ground and reduces the
average short-circuit current greatly to alleviate
thermal issues and protect the regulator. The
MPM3515 exits hiccup mode once the overcurrent condition is removed.
Thermal Shutdown
Thermal shutdown prevents the chip from
operating at exceedingly high temperatures.
When the die temperatures exceed 170°C, the
device stops switching. When the temperature
Figure 3: Internal Bootstrap Charging Circuit
Start-Up and Shutdown
If VIN exceeds its thresholds, the MPM3515
starts up. The reference block starts first,
generating a stable reference voltage and
current. The internal regulator is then enabled.
The regulator provides a stable supply for the
remaining circuitries.
Three events can shut down the chip: VIN low,
EN/SYNC low, and thermal shutdown. During
the shutdown procedure, the signaling path is
first blocked to avoid any fault triggering. VCOMP
and the internal supply rail are then pulled down.
The floating driver is not subject to this
shutdown command.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
APPLICATION INFORMATION
Setting the Output Voltage
The external resistor divider sets the output
voltage (see the Typical Application on page 1).
The feedback resistor (R1) sets the feedback
loop bandwidth with the internal compensation
capacitor. Choose R1 to be around 75kΩ when
VOUT 1V. R2 can then be calculated with
Equation (1):
R2
R1
Figure 4 shows the feedback network.
C3
VOUT
R2
R1
Figure 4: Feedback Network
Table 1 lists recommended resistor values for
common output voltages.
Table 1: Resistor Selection for Common Output
Voltages
VOUT (V)
1.5
1.8
2.5
3.3
5
R1 (kΩ)
75
75
75
75
75
IC1 ILOAD x
R2 (kΩ)
87
61
35.7
24.3
14.3
Selecting the Input Capacitor
The input current to the step-down converter is
discontinuous and therefore requires a
capacitor to supply AC current to the converter
while maintaining the DC input voltage. For the
best performance, use low ESR capacitors.
Ceramic capacitors with X5R or X7R dielectrics
are highly recommended because of their low
ESR and small temperature coefficients. For
most applications, use a 4.7µF capacitor.
VOUT
VIN
V
x1 OUT
VIN
(2)
The worst-case condition occurs at VIN = 2VOUT,
shown in Equation (3):
(1)
VOUT
1
0.807V
FB
Since C1 absorbs the input switching current, it
requires an adequate ripple current rating. The
RMS current in the input capacitor can be
estimated with Equation (2):
IC1
ILOAD
2
(3)
For simplification, choose an input capacitor
with an RMS current rating greater than half of
the maximum load current.
The input capacitor can be electrolytic, tantalum,
or ceramic. When using electrolytic or tantalum
capacitors, add a small, high-quality ceramic
capacitor (e.g.: 0.1μF) as close to the IC as
possible. When using ceramic capacitors,
ensure that they have enough capacitance to
provide a sufficient charge to prevent excessive
voltage ripple at the input. The input voltage
ripple caused by the capacitance can be
estimated with Equation (4):
∆VIN
ILOAD VOUT
x
fS xC1 VIN
V
x 1 OUT
VIN
(4)
Selecting the Output Capacitor
The output capacitor (C2) maintains the DC
output voltage. Use ceramic, tantalum, or lowESR electrolytic capacitors. For best results,
use low ESR capacitors to keep the output
voltage ripple low. The output voltage ripple can
be estimated with Equation (5):
∆VOUT
VOUT VOUT
x1
fS xL1
VIN
1
x R ESR
8xf
xC2
S
(5)
Where L1 is the inductor value and RESR is the
equivalent series resistance (ESR) value of the
output capacitor.
For ceramic capacitors, the capacitance
dominates the impedance at the switching
frequency, and the capacitance causes the
majority of the output voltage ripple.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
For simplification, the output voltage ripple can
be estimated with Equation (6):
∆VOUT
V
x1 OUT
VIN
8xfS xL1xC2
1
2
(6)
For tantalum or electrolytic capacitors, the ESR
dominates the impedance at the switching
frequency. For simplification, the output ripple
can be approximated with Equation (7):
PCB Layout Guidelines (7)
Efficient PCB layout, especially of the input
capacitor placement, is critical for stable
operation. For best results, refer to Figure 6 and
follow the guidelines below.
1.
Connect a large ground plane to PGND
directly. If the bottom layer is a ground
plane, add vias near PGND.
2.
Ensure that the high-current paths at GND
and IN have short, direct, and wide traces.
3.
The characteristics of the output capacitor also
affect the stability of the regulation system. The
MPM3515 can be optimized for a wide range of
capacitance and ESR values.
Place the ceramic input capacitor close to
IN and PGND.
4.
Keep the connection of the input capacitor
and IN as short and wide as possible.
External Bootstrap Diode
An external bootstrap diode can enhance the
efficiency of the regulator given the following
conditions:
5.
Place the external feedback resistors next
to FB.
6.
Keep the feedback network away from the
switching node.
∆VOUT
V
V
OUT x1 OUT
fS xL1
VIN
VOUT is 5V or 3.3V
Duty cycle is high: D =
xR ESR
(7)
NOTE:
7) The recommended layout is based on Figure 8.
VOUT
> 65%
VIN
C2
R2
R1
IN
R3
In these cases, add an external BST diode from
VCC to BST (see Figure 5).
Top Layer
Figure 5: Optional External Bootstrap Diode
Added to Enhance Efficiency
The recommended external BST diode is
IN4148.
Bottom Layer
Figure 6: Recommended PCB Layout
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
Design Example
Table 2 is a design example following the
application guidelines for the specifications
below.
Table 2: Design Example
12V
VIN
3.3V
VOUT
1.5A
IOUT
The typical performance and circuit waveforms
are shown in the Typical Performance
Characteristics section. For more device
applications, please refer to the related
evaluation board datasheet.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL APPLICATION CIRCUITS
Figure 7: VOUT = 5V, IOUT = 1.5A
Figure 8: VOUT = 3.3V, IOUT = 1.5A
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL APPLICATION CIRCUITS (continued)
Figure 9: VOUT = 2.5V, IOUT = 1.5A
Figure 10: VOUT = 1.8V, IOUT = 1.5A
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
TYPICAL APPLICATION CIRCUITS (continued)
Figure 11: VOUT = 1.5V, IOUT = 1.5A
VIN
BST
4V-36V
FB1
1206
SW
L1
2.2uH
16
VEMI
CIN1
1nF
CIN 2
10nF
CIN3
1uF
CIN 4
10uF
CIN 5
10uF
C1
4.7µF
GND
C3
R3
0.1µF
100 k
2
EN / SYNC
4
R4
100 k
PG
1
IN
OUT
13
6,7,8,12
L2
150nH
9,10.11
C2
MPM 3515
R1
VOUT
C4
1nF
3. 3 V/ 1. 5 A
47µF
75 k
EN/ SYNC
FB 3
VCC
R2
24.3k
PG
AGND PGND
5
14,15
Figure 12: VOUT = 3.3V, IOUT = 1.5A with EMI Filter
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
PACKAGE INFORMATION
QFN-17 (3mmx5mmx1.6mm)
Non-Wettable Flank
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) SHADED AREA IS THE KEEP-OUT ZONE. ANY PCB
METAL TRACE AND VIA ARE NOT ALLOWED TO
CONNECT TO THIS AREA ELECTRICALLY OR
MECHANICALLY.
3) LEAD COPLANARITY SHALL BE 0.10
MILLIMETERS MAX.
4) JEDEC REFERENCE IS MO-220.
5) DRAWING IS NOT TO SCALE.
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
PACKAGE INFORMATION (CONTINUED)
QFN-17 (3mmx5mmx1.6mm)
Wettable Flank
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) SHADED AREA IS THE KEEP-OUT ZONE. ANY PCB
METAL TRACE AND VIA ARE NOT ALLOWED TO
CONNECT TO THIS AREA ELECTRICALLY OR
MECHANICALLY.
3) THE LEAD SIDE IS WETTABLE.
4) LEAD COPLANARITY SHALL BE 0.10
MILLIMETERS MAX.
5) JEDEC REFERENCE IS MO-220.
6) DRAWING IS NOT TO SCALE.
MPM3515 Rev. 1.02
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MPM3515 – 36V, 1.5A, SYNCHRONOUS, STEP-DOWN, MODULE CONVERTER
CARRIER INFORMATION
Part Number
Package Description
Quantity/Reel
Reel
Diameter
Carrier
Tape Width
Carrier
Tape Pitch
MPM3515GQV
QFN-17
(3mmx5mmx1.6mm)
2500
13 in.
12mm
8mm
NOTICE: The information in this document is subject to change without notice. Users should warrant and guarantee that third
party Intellectual Property rights are not infringed upon when integrating MPS products into any application. MPS will not
assume any legal responsibility for any said applications.
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