MPS MP2303 3a, 28v, 340khz synchronous rectified step-down converter Datasheet

TM
MP2303
3A, 28V, 340KHz Synchronous Rectified
Step-Down Converter
The Future of Analog IC Technology
TM
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
DESCRIPTION
FEATURES
The MP2303 is a monolithic synchronous buck
regulator. The device integrates 120mΩ
MOSFETS that provide 3A continuous load
current over a wide operating input voltage of
4.75V to 28V. Current mode control provides
fast transient response and cycle-by-cycle
current limit.
•
•
•
•
•
•
•
•
•
•
•
An adjustable soft-start prevents inrush current
at turn-on. In shutdown mode, the supply
current drops to 1µA.
This device, available in an 8-pin SOIC
package, provides a very compact system
solution with minimal reliance on external
components.
APPLICATIONS
•
•
•
EVALUATION BOARD REFERENCE
Board Number
Dimensions
EV2303DN-00A
2.0”X x 1.5”Y x 0.5”Z
3A Output Current
Wide 4.75V to 28V Operating Input Range
Integrated 120mΩ Power MOSFET Switches
Output Adjustable from 0.8V to 25V
Up to 95% Efficiency
Programmable Soft-Start
Stable with Low ESR Ceramic Output Capacitors
Fixed 340KHz Frequency
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
Thermally Enhanced 8-Pin SOIC Package
Distributed Power Systems
Pre-Regulator for Linear Regulators
Notebook Computers
“MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic
Power Systems, Inc.
TYPICAL APPLICATION
Efficiency vs
Load Current
VIN
4.75V-28V
100
1
2
3
4
BS
SS
IN
EN
MP2303
SW
GND
COMP
FB
VIN = 12V
8
90
7
6
5
C3
3.3nF
C6
(optional)
EFFICIENCY (%)
C5
10nF
VIN = 24V
80
70
60
VOUT
5V/3A
VOUT = 5V
50
0
MP2303_TAC01
0.5
1.0
1.5
2.0
2.5
3.0
LOAD CURRENT (A)
MP2303-EC01
MP2303 Rev. 0.91
3/10/2006
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1
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
ABSOLUTE MAXIMUM RATINGS (1)
PACKAGE REFERENCE
Supply Voltage VIN ....................... –0.3V to +30V
Switch Voltage VSW ................. –1V to VIN + 0.3V
Boost Voltage VBS ..........VSW – 0.3V to VSW + 6V
All Other Pins................................. –0.3V to +6V
Junction Temperature...............................150°C
Lead Temperature ....................................260°C
Storage Temperature .............–65°C to +150°C
TOP VIEW
BS
1
8
SS
IN
2
7
EN
SW
3
6
COMP
Recommended Operating Conditions
GND
4
5
FB
Input Voltage VIN ............................ 4.75V to 28V
Output Voltage VOUT ........................ 0.8V to 25V
Ambient Operating Temperature ... –40°C to +85°C
MP2303_PD01_SOIC8N
Thermal Resistance
Part Number*
Package
Temperature
MP2303DN
SOIC8N
(Exposed Pad)
–40°C to +85°C
*
For Tape & Reel, add suffix –Z (eg. MP2303DN–Z)
For Lead Free, add suffix –LF (eg. MP2303DN–LF–Z)
(3)
θJA
(2)
θJC
SOIC8N .................................. 50 ...... 10... °C/W
Notes:
1) Exceeding these ratings may damage the device.
2) The device is not guaranteed to function outside of its
operating conditions.
3) Measured on approximately 1” square of 1 oz copper.
ELECTRICAL CHARACTERISTICS (4)
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameter
Symbol Condition
Shutdown Supply Current
Supply Current
Feedback Voltage
VEN = 0V
VEN = 2.7V, VFB = 1.0V
VFB
OVP Threshold Voltage
Error Amplifier Voltage Gain
AEA
Error Amplifier Transconductance
GEA
High-Side Switch-On Resistance
Low-Side Switch-On Resistance
High-Side Switch Leakage Current
Upper-Switch Current Limit
Lower-Switch Current Limit
COMP to Current Sense
Transconductance
RDS(ON)1
RDS(ON)2
4.75V ≤ VIN ≤ 28V,
TA = +25°C
0.780
–40°C ≤ TA ≤ +85°C
0.772
∆IC = ±10µA
0.3
1.3
3.0
1.5
µA
mA
0.800
0.820
V
0.828
V
V
V/V
550
820
1100
µA/V
10
mΩ
mΩ
µA
A
A
120
120
0
6.3
1.25
9
GCS
Fosc2
DMAX
Units
1.00
From Drain to Source
Short Circuit Oscillation Frequency
Maximum Duty Cycle
Minimum On-Time
EN Shutdown Threshold Voltage
Max
0.95
400
4.3
Fosc1
Typ (4)
0.90
VEN = 0V, VSW = 0V
Oscillation Frequency
MP2303 Rev. 0.91
3/10/2006
Min
TA = +25°C
300
–40°C ≤ TA ≤ +85°C
270
VFB = 0V
VFB = 0.7V
VEN Rising
1.1
340
110
90
220
1.5
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A/V
380
KHz
400
KHz
2.0
KHz
%
ns
V
2
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
ELECTRICAL CHARACTERISTICS (4) (continued)
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameter
Symbol Condition
Min
EN Shutdown Threshold Voltage
Hysteresis
Typ (4)
Max
220
2.2
EN Lockout Threshold Voltage
–40°C ≤ TA ≤ +85°C
2.5
2.1
EN Lockout Hysteresis
mV
2.7
V
2.8
V
210
Input Under Voltage Lockout
Threshold
Input Under Voltage Lockout
Threshold Hysterisis
Soft-Start Current
Thermal Shutdown
UVLO
VIN rising, TA = +25°C
3.8
–40°C ≤ TA ≤ +85°C
3.5
VSS = 0V
4.05
Units
mV
4.30
V
4.70
V
210
mV
6
160
µA
°C
Note:
4) 100% production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization.
PIN FUNCTIONS
Pin #
1
2
3
4
5
6
7
8
Name Description
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-Channel MOSFET
BS
switch. Connect 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.
IN
Drive IN with a 4.75V to 28V 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
SW
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.
GND Ground (Connect Exposed Pad to Pin 4).
Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a
FB
resistive voltage divider from the output voltage. The feedback reference voltage is 0.8V. 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 to compensate the regulation control loop. In some
COMP
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 higher than 2.7V
EN
to turn on the regulator, drive it lower than 1.1V to turn it off. Pull up to the IN pin with 100kΩ
resistor for automatic startup.
Soft-start Control Input. SS controls the soft-start period. Connect a capacitor from SS to GND
SS
to set the soft-start period. See Soft-Start Capacitor.
MP2303 Rev. 0.91
3/10/2006
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TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 12V, VO = 3.3V, L = 10µH, CIN = 10µF, COUT = 22µF x 2, TA = +25°C, unless otherwise noted.
Feeback Voltage vs.
Efficiency vs
Temperature
Load Current
0.810
95
EFFICIENCY (%)
FEEDBACK VOLTAGE (V)
VIN = 12V
90
85
80
VIN = 24V
75
70
65
60
55
0.805
VIN = 12V
VIN = 28V
0.800
0.795
0.790
VIN = 4.75V
0.7850
VOUT = 2.5V
50
0
0.5
1.0
1.5
2.0
3.0
2.5
0.780
-40
3.5
-20
0
20
40
TEMPERATURE (oC)
LOAD CURRENT (A)
2.65
4.3
4.2
4.1
4.0
3.9
3.8
345
FREQUENCY (KHz)
4.4
ENABLE VOLTAGE (V)
UVLO THRESHOLD (V)
2.70
3.7
Oscillator Frequency
Enable Lockout Threshold
vs. Temperature
4.5
80
MP2303-TPC01
MP2303-EC02
UVLO Rising vs.
Temperature
60
2.60
2.55
2.50
2.45
2.40
340
335
330
2.35
-40
-20
0
20
40
60
TEMPERATURE (oC)
80
MP2303-TPC02
MP2303 Rev. 0.91
3/10/2006
2.30
-40
-20
0
20
40
TEMPERATURE (oC)
60
80
325
-40
-20
0
20
40
60
TEMPERATURE (oC)
MP2303-TPC03
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80
MP2303-TPC04
4
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN = 12V, VO = 3.3V, L = 10µH, CIN = 10µF, COUT = 22µF x 2, TA = +25°C, unless otherwise noted.
Power Off through Enable
VIN = 24V, VOUT = 3.3V, IOUT = 2A
VOUT
1V/div.
VEN
5V/div.
VOUT
1V/div.
IL
1A/div.
IL
1A/div.
VSW
10V/div.
4ms/div.
MP2303-TPC05
MP2303-TPC06
Steady State Test
Load Transient Test
Short Circuit Protection
VIN = 12V, VOUT = 3.3V, IOUT = 1A
VIN = 24V, VOUT = 3.3V,
IOUT = 0A-1A step with CFF = 470pF
VIN = 24V, VOUT = 3.3V, IOUT = 0A
VCOMP
200mV/div.
VIN
200mV/div.
VOUT
1V/div.
VCOMP
1V/div.
VOUT
100mV/div.
IL
500mA/div.
IL
1A/div.
VOUT
AC Coupled
10mV/div.
MP2303-TPC07
MP2303 Rev. 0.91
3/10/2006
IL
2A/div.
VSW
20V/div.
MP2303-TPC08
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MP2303-TPC09
5
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
OPERATION
+
CURRENT
SENSE
AMPLIFIER
OVP
0.95V
-OSCILLATOR
+
FB 5
340KHz
0.3V
RAMP
1
BS
3
SW
4
GND
5V
--+
+
0.8V
IN
--
CLK
--
SS 8
+
2
+
ERROR
AMPLIFIER
S
Q
R
Q
CURRENT
COMPARATOR
COMP 6
--
EN 7
2.5V
+
EN OK
OVP
1.2V
IN < 4.05V
LOCKOUT
COMPARATOR
IN
+
INTERNAL
REGULATORS
1.5V
--
SHUTDOWN
COMPARATOR
MP2303_BD01
Figure 1—Functional Block Diagram
The MP2303 is a synchronous rectified,
current-mode, step-down regulator. It regulates
input voltages from 4.75V to 28V down to an
output voltage as low as 0.8V, and supplies up
to 3A of load current.
The MP2303 uses current-mode control to
regulate the output voltage. The output voltage
is measured at FB through a resistive voltage
divider and amplified through the internal
transconductance error amplifier. The voltage at
COMP pin is compared to the switch current
measured internally to control the output
voltage.
MP2303 Rev. 0.91
3/10/2006
The converter uses internal N-Channel
MOSFET switches to step-down the input
voltage to the regulated output voltage. Since
the high side MOSFET requires a gate voltage
greater than the input voltage, a boost capacitor
connected between SW and BS is needed to
drive the high side gate. The boost capacitor is
charged from the internal 5V rail when SW is low.
When the MP2303 FB pin exceeds 20% of the
nominal regulation voltage of 0.8V, the over
voltage comparator is tripped; the COMP pin
and the SS pin are discharged to GND, forcing
the high-side switch off.
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TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
APPLICATIONS INFORMATION
COMPONENT SELECTION
Setting the Output Voltage
The output voltage is set using a resistive
voltage divider from the output voltage to FB
pin. The voltage divider divides the output
voltage down to the feedback voltage by the
ratio:
VFB = VOUT
R2
R1 + R2
Thus the output voltage is:
VOUT = 0.8 ×
R1 + R2
R2
Where VFB is the feedback voltage and VOUT is
the output voltage.
A typical value for R2 can be as high as 100kΩ,
but a typical value is 10kΩ. Using that value, R1
is determined by:
R1 = 12.5 × ( VOUT − 0.8)(kΩ )
For example, for a 3.3V output voltage, R2 is
10kΩ, and R1 is 31.3kΩ.
Inductor
The inductor is required to supply constant
current to the output load while being driven by
the switched input voltage. A larger value
inductor will result in less ripple current that will
result in lower output ripple voltage. However,
the larger value inductor will have a larger
physical size, higher series resistance, and/or
lower saturation current. A good rule for
determining the inductance to use is to allow
the peak-to-peak ripple current in the inductor
to be approximately 30% of the maximum
switch current limit. Also, make sure that the
peak inductor current is below the maximum
switch current limit. The inductance value can
be calculated by:
L=
⎞
VOUT ⎛
V
× ⎜⎜1 − OUT ⎟⎟
fS × ∆I ⎝
VIN ⎠
Where VIN is the input voltage, fS is the 340KHz
switching frequency, and ∆IL is the peak-topeak inductor ripple current.
Choose an inductor that will not saturate under
the maximum inductor peak current. The peak
inductor current can be calculated by:
ILP = ILOAD +
⎛
VOUT
V
× ⎜⎜1 − OUT
2 × fS × L ⎝
VIN
Where ILOAD is the load current.
Optional Schottky Diode
During the transition between high-side switch
and low-side switch, the body diode of the lowside power MOSFET conducts the inductor
current. The forward voltage of this body diode
is high. An optional Schottky diode may be
paralleled between the SW pin and GND pin to
improve overall efficiency. Table 2 lists example
Schottky diodes and their Manufacturers.
Table 2—Diode Selection Guide
Part Number
B130
SK13
Voltage/Current
Rating
30V, 1A
30V, 1A
MBRS130
30V, 1A
Vendor
Diodes, Inc.
Diodes, Inc.
International
Rectifier
Input Capacitor
The input current to the step-down converter is
discontinuous, therefore a capacitor is required
to supply the AC current to the step-down
converter while maintaining the DC input
voltage. Use low ESR capacitors for the best
performance. Ceramic capacitors are preferred,
but tantalum or low-ESR electrolytic capacitors
may also suffice. Choose X5R or X7R
dielectrics when using ceramic capacitors.
Since the input capacitor (C1) absorbs the input
switching current it requires an adequate ripple
current rating. The RMS current in the input
capacitor can be estimated by:
I C1 = ILOAD ×
VOUT ⎛⎜ VOUT ⎞⎟
× 1−
VIN ⎜⎝
VIN ⎟⎠
The worst-case condition occurs at VIN = 2VOUT,
where:
I C1 =
MP2303 Rev. 0.91
3/10/2006
⎞
⎟⎟
⎠
ILOAD
2
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MP2303 – 3A, 28V SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
For simplification, choose the input capacitor
whose 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, a small, high quality ceramic
capacitor, i.e. 0.1µF, should be placed as close
to the IC as possible. When using ceramic
capacitors, make sure that they have enough
capacitance to provide sufficient charge to
prevent excessive voltage ripple at input. The
input voltage ripple caused by capacitance can
be estimated by:
∆VIN
⎛
I
V
V
= LOAD × OUT × ⎜⎜1 − OUT
f S × C1
VIN
VIN
⎝
⎞
⎟⎟
⎠
Output Capacitor
The output capacitor is required to maintain the
DC output voltage. Ceramic, tantalum, or low
ESR electrolytic capacitors are recommended.
Low ESR capacitors are preferred to keep the
output voltage ripple low. The output voltage
ripple can be estimated by:
∆VOUT =
VOUT ⎛
V
× ⎜⎜1 − OUT
fS × L ⎝
VIN
⎞
⎞ ⎛
1
⎟
⎟⎟ × ⎜ R ESR +
⎜
8 × f S × C2 ⎟⎠
⎠ ⎝
Where C2 is the output capacitance value and
RESR is the equivalent series resistance (ESR)
value of the output capacitor.
In the case of ceramic capacitors, the
impedance at the switching frequency is
dominated by the capacitance. The output
voltage ripple is mainly caused by the
capacitance. For simplification, the output
voltage ripple can be estimated by:
∆VOUT =
⎛
⎞
V
× ⎜⎜1 − OUT ⎟⎟
VIN ⎠
× L × C2 ⎝
VOUT
8 × fS
2
In the case of tantalum or electrolytic
capacitors, the ESR dominates the impedance
at the switching frequency. For simplification,
the output ripple can be approximated to:
∆VOUT =
VOUT ⎛
V
⎞
× ⎜1 − OUT ⎟⎟ × R ESR
f S × L ⎜⎝
VIN ⎠
MP2303 can be optimized for a wide range of
capacitance and ESR values.
Compensation Components
MP2303 employs current mode control for easy
compensation and fast transient response. The
system stability and transient response are
controlled through the COMP pin. COMP pin is
the output of the internal transconductance
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:
A VDC = R LOAD × G CS × A VEA ×
VFB
VOUT
Where AVEA is the error amplifier voltage gain,
400V/V;
GCS
is
the
current
sense
transconductance, 7.0A/V; RLOAD is the load
resistor value.
The system has 2 poles of importance. 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
2π × C3 × A VEA
fP2 =
1
2π × C2 × R LOAD
is
the
error
amplifier
Where,
GEA
transconductance, 820µA/V, and RLOAD is the load
resistor value.
The system has one zero of importance, due to the
compensation
capacitor
(C3)
and
the
compensation resistor (R3). This zero is located at:
f Z1 =
1
2π × C3 × R3
The system may have another zero of
importance, if the output capacitor has a large
capacitance and/or a high ESR value. The zero,
due to the ESR and capacitance of the output
capacitor, is located at:
fESR =
1
2π × C2 × R ESR
The characteristics of the output capacitor also
affect the stability of the regulation system. The
MP2303 Rev. 0.91
3/10/2006
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TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
In this case, a third pole set by the optional
compensation capacitor (C6) and the
compensation resistor (R3) is used to
compensate the effect of the ESR zero on the
loop gain. This pole is located at:
fP 3 =
1
2π × C6 × 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
important.
Lower crossover frequencies result in slower
line and load transient responses, while higher
crossover frequencies could cause system
instability. A good rule of thumb is to set the
crossover frequency to approximately one-tenth
of the switching frequency. Switching frequency
for the MP2303 is 340KHz, so the desired
crossover frequency is 34KHz.
Table 3 lists the typical values of compensation
components for some standard output voltages
with various output capacitors and inductors. The
values of the compensation components have
been optimized for fast transient responses and
good stability at given conditions.
MP2303 Rev. 0.91
3/10/2006
Table 3—Compensation Values for Typical
Output Voltage/Capacitor Combinations
VOUT
L
C2
R3
C3
C6
100µF
Ceramic
5.6kΩ
5.6nF
None
1.8V
4.7µH
2.5V
4.7µH 6.8µH
47µF Ceramic
3.65kΩ
8.2nF
None
3.3V
6.8µH 10µH
22µFx2
Ceramic
4.42kΩ
4.7nF
None
5V
10µH 15µH
22µFx2
Ceramic
6.98kΩ
3.3nF
None
12V
15µH 22µH
22µFx2
Ceramic
16.5kΩ
1.8nF
None
1.8
4.7µH
100µF/100mΩ
SP-CAP
8.4kΩ
2.2nF
None
2.5V
4.7µH 6.8µH
47µF
SP-CAP
5.6kΩ
3.3nF
None
3.3V
6.8µH 10µH
47µF
SP-CAP
6.8kΩ
2.2nF
None
5V
10µH 15µH
47µF
SP CAP
10kΩ
2.2nF
None
2.5V
4.7µH 6.8µH
560µF Al.
30mΩ ESR
10kΩ
12nF
1.8nF
3.3V
6.8µH 10µH
560µF Al
30mΩ ESR
10kΩ
10nF
1.5nF
5V
10µH 15µH
470µF Al.
30mΩ ESR
15kΩ
8.2nF
1nF
12V
15µH 22µH
220µF Al.
30mΩ ESR
15kΩ
10nF
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390pF
9
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
To optimize the compensation components for
conditions not listed in Table 2, the following
procedure can be used.
1. Choose the compensation resistor (R3) to set
the desired crossover frequency. Determine the
R3 value by the following equation:
2π × C2 × f C VOUT
R3 =
×
G EA × G CS
VFB
Where fC is the desired crossover frequency,
34KHz.
2. Choose the compensation capacitor (C3) to
achieve the desired phase margin. For
applications with typical inductor values, setting
the compensation zero, fZ1, below one forth of
the crossover frequency provides sufficient
phase margin. Determine the C3 value by the
following equation:
C3 >
f
1
< S
2π × C2 × R ESR
2
If this is the case, then add the optional
compensation capacitor (C6) to set the pole fP3
at the location of the ESR zero. Determine the
C6 value by the equation:
MP2303 Rev. 0.91
3/10/2006
t SS = C4 ×
0.8 V
6µA
To reduce the susceptibility to noise, do not
leave SS pin open. Use a capacitor with small
value if you do not need soft-start function.
External Bootstrap Diode
It is recommended that an external bootstrap
diode be added when the system has a 5V
fixed input or the power supply generates a 5V
output. This helps improve the efficiency of the
regulator. The bootstrap diode can be a low
cost one such as IN4148 or BAT54.
5V
4
2π × R3 × f C
3. Determine if the second compensation
capacitor (C6) is required. It is required if the
ESR zero of the output capacitor is located at
less than half of the 340KHz switching
frequency, or the following relationship is valid:
C6 =
Soft-Start Capacitor
To reduce input inrush current during startup, a
programmable soft-start is provided by
connecting a capacitor (C4) from pin SS to
GND. The soft-start time is given by:
BS
MP2303
10nF
SW
MP2303_F02
Figure 2—External Bootstrap Diode
This diode is also recommended for high duty
cycle operation (
VOUT
>65%) and high output
VIN
voltage (VOUT>12V) applications.
C2 × R ESR
R3
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TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
TYPICAL APPLICATION CIRCUITS
C5
10nF
INPUT
4.75V to 28V
7
1
BS
3
SW
2
IN
EN
OUTPUT
2.5V
3A
MP2303
8
SS
GND
5
FB
COMP
4
6
D1
B130
C3
8.2nF
C6
(optional)
(optional)
MP2303_F03
Figure 3—MP2303 with 2.5V Output, 47µF/6.3V Ceramic Output Capacitor
D2
INPUT
4.75V to 28V
C5
10nF
1
BS
3
SW
2
IN
7
EN
OUTPUT
3.3V/3A
MP2303
8
SS
GND
FB
COMP
4
5
6
C6
C3
4.7nF
D1
B130
(optional)
(optional)
MP2303_F04
Figure 4—MP2303 with 3.3V Output, 47µF/6.3V Ceramic Output Capacitor
MP2303 Rev. 0.91
3/10/2006
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MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
11
TM
MP2303 – 3A, 28V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
INITIAL RELEASE – SPECIFICATIONS SUBJECT TO CHANGE
PACKAGE INFORMATION
SOIC8N (EXPOSED PAD)
PIN 1 IDENT.
0.229(5.820)
0.244(6.200)
0.0075(0.191)
0.0098(0.249)
0.150(3.810)
0.157(4.000)
SEE DETAIL "A"
NOTE 2
0.011(0.280) x 45o
0.020(0.508)
0.013(0.330)
0.020(0.508)
0.050(1.270)BSC
0.189(4.800)
0.197(5.004)
0.053(1.350)
0.068(1.730)
0o-8o
0.049(1.250)
0.060(1.524)
0.016(0.410)
0.050(1.270)
DETAIL "A"
SEATING PLANE
0.001(0.030)
0.004(0.101)
NOTE:
1) Control dimension is in inches. Dimension in bracket is millimeters.
2) Exposed Pad Option Only (N-Package) ; 2.55+/- 0.25mm x 3.38 +/- 0.44mm.
Recommended Solder Board Area: 2.80mm x 3.82mm = 10.7mm2 (16.6mil2)
NOTICE: The information in this document is subject to change without notice. Please contact MPS for current specifications.
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.
MP2303 Rev. 0.91
3/10/2006
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
12