MPS EV1570DN-00A 3a, 23v, 340khz synchronous rectified step-down converter Datasheet

TM
MP1570
3A, 23V, 340KHz Synchronous Rectified
Step-Down Converter
The Future of Analog IC Technology
TM
DESCRIPTION
FEATURES
The MP1570 is a monolithic synchronous buck
regulator. The device integrates 100mΩ
MOSFETS that provide 3A continuous load
current over a wide operating input voltage of
4.75V to 23V. 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 output is
actively discharged by transferring energy in the
output capacitor to the input capacitor, dropping
the supply current to 1µA.
This device, available in an 8-pin SOIC
package, provides a very compact system
solution with minimal reliance on external
components.
3A Output Current
Wide 4.75V to 23V Operating Input Range
Integrated 100mΩ Power MOSFET Switches
Output Adjustable from 1.23V to 20V
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
APPLICATIONS
•
•
•
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.
EVALUATION BOARD REFERENCE
Board Number
Dimensions
EV1570DN-00A
2.0”X x 1.5”Y x 0.5”Z
TYPICAL APPLICATION
C5
10nF
INPUT
4.75V to 23V
100
Efficiency vs.
Load Current
VIN=9V
7
8
2
IN
EN
1
BS
3
SW
MP1570
SS
GND
FB
COMP
4
5
6
C6
OUTPUT
3.3V
3A
C3
3.3nF
D1
B130
(optional)
EFFICIENCY (%)
95
90
VIN=12V
85
80
VIN=23V
75
70
VOUT=5V
65
(optional)
60
0
0.5 1.0 1.5 2.0 2.5 3.0 3.5
LOAD CURRENT (A)
MP1570_TAC01
MP1570 Rev. 1.5
1/31/2006
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MP1570-EC02
1
TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
ABSOLUTE MAXIMUM RATINGS (1)
PACKAGE REFERENCE
BS
1
8
SS
IN
2
7
EN
Supply Voltage VIN ....................... –0.3V to +26V
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
SW
3
6
COMP
Recommended Operating Conditions
GND
4
5
FB
Input Voltage VIN ............................ 4.75V to 23V
Output Voltage VOUT ...................... 1.23V to 20V
Ambient Operating Temperature ... –40°C to +85°C
TOP VIEW
MP1570_PD01-SOIC8N
Thermal Resistance
Part Number*
Package
Temperature
MP1570DN
SOIC8N
(Exposed Pad)
–40° to +85°C
*
For Tape & Reel, add suffix –Z (eg. MP1570DN–Z)
For Lead Free, add suffix –LF (eg. MP1570DN–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
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameter
Symbol Condition
Shutdown Supply Current
Supply Current
Typ
Max
Units
0.3
1.3
3.0
1.5
µA
mA
1.202
1.230
1.258
V
1.4
1.5
400
1.6
V
V/V
550
820
1100
µA/V
VEN = 0V
VEN = 2.7V, VFB = 1.4V
Feedback Voltage
VFB
Feedback Overvoltage Threshold
Error Amplifier Voltage Gain (4)
AEA
Error Amplifier Transconductance
GEA
(4)
High Side Switch On Resistance
Low Side Switch On Resistance (4)
High Side Switch Leakage Current
Upper Switch Current Limit
Lower Switch Current Limit
COMP to Current Sense
Transconductance
Oscillation Frequency
Short Circuit Oscillation Frequency
Maximum Duty Cycle
Minimum On Time (4)
EN Shutdown Threshold Voltage
EN Shutdown Threshold Voltage
Hysteresis
MP1570 Rev. 1.5
1/31/2006
Min
4.75V ≤ VIN ≤ 23V,
VCOMP < 2V
∆IC = ±10µA
RDS(ON)1
RDS(ON)2
VEN = 0V, VSW = 0V
4.0
From Drain to Source
GCS
Fosc1
Fosc2
DMAX
10
7.6
mΩ
mΩ
µA
A
A
4.0
5.4
6.8
A/V
300
340
110
90
220
1.5
380
KHz
KHz
%
ns
V
VFB = 0V
VFB = 1.0V
VEN Rising
100
100
0
5.8
0.9
1.1
220
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2.0
mV
2
TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS (continued)
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameter
Symbol Condition
EN Lockout Threshold Voltage
EN Lockout Hysteresis
Input Under Voltage Lockout
Threshold
Input Under Voltage Lockout
Threshold Hysteresis
Soft-Start Current
Soft-Start Period
Thermal Shutdown (4)
VIN Rising
VSS = 0V
CSS = 0.1µF
Min
Typ
Max
Units
2.2
2.5
210
2.7
V
mV
3.80
4.05
4.30
V
210
mV
6
20
160
µA
ms
°C
Note:
4) Guaranteed by design, not tested.
TYPICAL PERFORMANCE CHARACTERISTICS
VIN = 12V, VOUT = 3.3V, TA = +25°C, unless otherwise noted.
Load Transient
Waveforms
1A - 2A STEP
VOUT
50mV/div.
VOUT
1V/div.
IL
1A/div.
IL
1A/div.
MP1570-TPC01
MP1570-TPC02
IL
1A/div.
VOUT
1V/div.
VOUT
10mV/div.
VIN
100mV/div.
IL
1A/div.
VSW
10V/div.
4ms/div.
MP1570-TPC03
MP1570 Rev. 1.5
1/31/2006
MP1570-TPC04
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
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 23V 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 threshold is 1.230V. 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 high to turn on
EN
the regulator, drive it low to turn it off. Pull up 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. A 0.1µF capacitor sets the soft-start period to 20ms. To disable the
soft-start feature, leave SS unconnected.
BLOCK DIAGRAM
+
LATCH
1.5V
OSCILLATOR
+
FB 5
CURRENT
SENSE
AMPLIFIER
OVP
100/340KHz
RAMP
+
2
IN
1
BS
3
SW
4
GND
5V
CLK
0.3V
+
+
SS 8
1.23V
+
ERROR
AMPLIFIER
S
Q
R
Q
CURRENT
COMPARATOR
COMP 6
EN 7
EN OK
2.5V
+
OVP
1.2V
IN < 4.05V
LOCKOUT
COMPARATOR
IN
+
INTERNAL
REGULATORS
1.5V
SHUTDOWN
COMPARATOR
MP1570_BD01
Figure 1—Functional Block Diagram
MP1570 Rev. 1.5
1/31/2006
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
OPERATION
FUNCTIONAL DESCRIPTION
The MP1570 is a synchronous rectified,
current-mode, step-down regulator. It regulates
input voltages from 4.75V to 23V down to an
output voltage as low as 1.230V, and supplies
up to 3A of load current.
The MP1570 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.
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 MP1570 FB pin exceeds 20% of the
nominal regulation voltage of 1.230V, the over
voltage comparator is tripped and latched; the
COMP pin and the SS pin are discharged to
GND, forcing the high-side switch off. Latch
cannot be cleared unless the EN or IN pin is
reset.
Following discharge, the MP1570 actively
recycles the energy stored in the output
capacitor. Initially the low-side synchronous
rectifier turns on. Once the internal, negative
900mA current limit is reached, the low-side
switch turns off, forcing inductor current to flow
through the high-side switch body diode. The
inductor current is recycled back into the input
as an energy saving feature. This cycle
continues until the output voltage is discharged
below 10% of the initial regulation voltage
(0.123V at FB), at which time the low-side
switch turns off.
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 = 1.23 ×
R1 + R2
R2
Where VFB is the feedback voltage and VOUT is
the output voltage.
MP1570 Rev. 1.5
1/31/2006
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 = 8.18 × ( VOUT − 1.23 )(kΩ )
For example, for a 3.3V output voltage, R2 is
10kΩ, and R1 is 17kΩ.
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
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
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 × f S × L ⎜⎝
VIN
⎞
⎟⎟
⎠
Where ILOAD is the load current.
Table 1 lists a number of suitable inductors
from various manufacturers. The choice of
which style inductor to use mainly depends on
the price vs. size requirements and any EMI
requirement.
Table 1—Inductor Selection Guide
Vendor/
Model
Sumida
CR75
CDH74
CDRH5D28
CDRH5D28
CDRH6D28
CDRH104R
Toko
D53LC
Type A
D75C
D104C
D10FL
Coilcraft
DO3308
DO3316
MP1570 Rev. 1.5
1/31/2006
Package
Dimensions
(mm)
W
L
H
Core
Type
Core
Material
Open
Open
Shielded
Shielded
Shielded
Shielded
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
7.0 7.8
7.3 8.0
5.5 5.7
5.5 5.7
6.7 6.7
10.1 10.0
5.5
5.2
5.5
5.5
3.0
3.0
Shielded
Ferrite
5.0
3.0
5.0
Shielded
Shielded
Open
Ferrite
Ferrite
Ferrite
7.6 7.6
10.0 10.0
9.7 1.5
5.1
4.3
4.0
Open
Open
Ferrite
Ferrite
9.4
9.4
3.0
5.1
13.0
13.0
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:
IC1 = ILOAD ×
VOUT ⎛⎜ VOUT ⎞⎟
× 1−
VIN ⎜⎝
VIN ⎟⎠
The worst-case condition occurs at VIN = 2VOUT,
where:
IC1 =
ILOAD
2
For simplification, choose the input capacitor
whose RMS current rating greater than half of
the maximum load current.
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
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 =
⎛
ILOAD
V
V
× 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
f S × L ⎜⎝
VIN
⎞
⎞ ⎛
1
⎟
⎟⎟ × ⎜ R ESR +
⎜
⎟
8
×
f
×
C
2
S
⎠ ⎝
⎠
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 =
MP1570 Rev. 1.5
1/31/2006
VOUT ⎛
V
× ⎜1 − OUT
f S × L ⎜⎝
VIN
The characteristics of the output capacitor also
affect the stability of the regulation system. The
MP1570 can be optimized for a wide range of
capacitance and ESR values.
Compensation Components
MP1570 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, 5.4A/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
Where,
GEA
transconductance, 800µA/V.
error
amplifier
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
⎞
⎟⎟ × R ESR
⎠
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
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
In this case (as shown in Figure 2), a third pole
set by the 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
unstable. A good rule of thumb is to set the
crossover frequency to approximately one-tenth
of the switching frequency. Switching frequency
for the MP1570 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.
Table 3—Compensation Values for Typical
Output Voltage/Capacitor Combinations
VOUT
1.8V
L
4.7µH
C2
R3
C3
C6
100µF
Ceramic
5.6kΩ
3.3nF
None
2.5V
4.76.8µH
47µF
Ceramic
4.7kΩ
4.7nF
None
3.3V
6.810µH
22µFx2
Ceramic
5.6kΩ
3.3nF
None
5V
1015µH
22µFx2
Ceramic
7.5kΩ
3.3nF
None
12V
1522µH
22µFx2
Ceramic
10kΩ
1.2nF
None
1.8
4.7µH
100µF
SP-CAP
10kΩ
2.2nF 100pF
2.5V
4.76.8µH
47µF
SP-CAP
5.6kΩ
3.3nF
None
3.3V
6.810µH
47µF
SP-CAP
6.8kΩ
2.2nF
None
5V
1015µH
47µF
SP CAP
10kΩ
2.2nF
None
2.5V
4.76.8µH
560µF Al.
30mΩ ESR
10kΩ
7.5nF
1.5nF
3.3V
6.810µH
560µF Al
30mΩ ESR
10kΩ
10nF
1.5nF
5V
1015µH
470µF Al.
30mΩ ESR
15kΩ
7.5nF
1nF
12V
1522µH
220µF Al.
30mΩ ESR
15kΩ
10nF
390pF
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:
R3 =
2π × C2 × f C VOUT
×
G EA × G CS
VFB
Where fC is the desired crossover frequency,
34KHz.
MP1570 Rev. 1.5
1/31/2006
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TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
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 >
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:
BS
SW
MP1570_F02
Figure 2—External Bootstrap Diode
f
1
< S
2π × C2 × R ESR
2
This diode is also recommended for high duty
cycle operation (when
is the case, then add the second compensation
capacitor (C6) to set the pole fP3 at the location
of the ESR zero. Determine the C6 value by the
equation:
C6 =
10nF
MP1570
VOUT
>65%) and high
VIN
output voltage (VOUT>12V) applications.
C2 × R ESR
R3
TYPICAL APPLICATION CIRCUITS
C5
10nF
INPUT
4.75V to 23V
1
BS
3
SW
2
IN
7
EN
OUTPUT
2.5V
3A
MP1570
8
SS
GND
FB
COMP
4
5
6
C6
C3
3.3nF
D1
B130
(optional)
(optional)
MP1570_F03
Figure 3—MP1570 with AVX 47µF, 6.3V Ceramic Output Capacitor
MP1570 Rev. 1.5
1/31/2006
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
9
TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
C5
10nF
INPUT
4.75V to 23V
2
IN
EN
7
1
BS
3
SW
OUTPUT
2.5V
3A
MP1570
8
SS
GND
FB
COMP
4
5
6
D1
B130
C3
3.3nF
C6
(optional)
(optional)
MP1570_F04
Figure 4—MP1570 with Panasonic 47µF, 6.3V Solid Polymer Output Capacitor
B130
INPUT
6V
C5
10nF
1
BS
3
SW
2
IN
7
EN
OUTPUT
5V
3A
MP1570
8
SS
GND
FB
COMP
4
5
6
C6
C3
3.3nF
D1
B130
(optional)
(optional)
MP1570_F05
Figure 5—MP1570 Application Circuit with VIN = 6V and VO = 5V
MP1570 Rev. 1.5
1/31/2006
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
10
TM
MP1570 – 3A, 23V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
PACKAGE INFORMATION
SOIC8N (EXPOSED PAD)
0.229(5.820)
0.244(6.200)
PIN 1 IDENT.
NOTE 4
0.150(3.810)
0.157(4.000)
0.0075(0.191)
0.0098(0.249)
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
0o-8o
NOTE 3
0.189(4.800)
0.197(5.000)
0.053(1.350)
0.068(1.730)
DETAIL "A"
0.016(0.410)
0.050(1.270)
.050
0.049(1.250)
0.060(1.524)
.028
0.200 (5.07 mm)
SEATING PLANE
0.001(0.030)
0.004(0.101)
0.140 (3.55mm)
0.060
Land Pattern
NOTE:
1) Control dimension is in inches. Dimension in bracket is millimeters.
2) Exposed Pad Option (N-Package) ; 2.31mm -2.79mm x 2.79mm - 3.81mm.
Recommend Solder Board Area: 2.80mm x 3.82mm = 10.7mm 2 (16.6 mil2)
3) The length of the package does not include mold flash. Mold flash shall not exceed 0.006in. (0.15mm) per side.
With the mold flash included, over-all length of the package is 0.2087in. (5.3mm) max.
4) The width of the package does not include mold flash. Mold flash shall not exceed 0.10in. (0.25mm) per side.
With the mold flash included, over-all width of the package is 0.177in. (4.5mm) max.
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.
MP1570 Rev. 1.5
1/31/2006
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2006 MPS. All Rights Reserved.
11
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