Page 1
MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
General Description
The MP1410 is a monolithic step-down switchmode regulator with a built in internal Power
MOSFET. It achieves 2A continuous output
current over a wide input supply range with
excellent load and line regulation.
Current mode operation provides fast transient
response and eases loop stabilization.
Fault condition protection includes cycle-bycycle current limiting and thermal shutdown. In
shutdown mode the regulator draws 25µa of
supply current.
The MP1410 requires a minimum number of
readily available standard external components.
Ordering Information
Part Number * Package Temperature
MP1410ES SOIC 8 pin -20 to +85 °C
MP1410EP PDIP 8 pin -20 to +85 °C
EV0012 Evaluation Board
* For Tape & Reel use suffix - Z (e.g. MP1410ES-Z)
Features
2A Output Current
0.18! Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic
capacitors
Up to 95% Efficiency
20uA Shutdown Mode
Fixed 380kHz frequency
Thermal Shutdown
Cycle-by-cycle over current protection
Wide 4.75 to 15V operating input range
Output Adjustable from 1.22 to 13V
Programmable under voltage lockout
Available in 8 pin SO
Evaluation Board Available
Applications
PC Monitors
Distributed Power Systems
Battery Charger
Pre-Regulator for Linear Regulators
Figure 1: Typical Application Circuit
Efficiency versus Output
INPUT
4.75 to 15V
ENABLE
SHUTDOWN
MP1410
OUTPUT
2.5V/2A
Current and Voltage. V
95
90
85
=10V
IN
5.0V
3.3V
2.5V
80
Efficiency (%)
75
70
0 0.5 1 1.5 2
Output Current ( A)
MP1410 Rev 1.0_ 05/29/02 www.monolithicpower.com 1
Page 2
MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Absolute Maximum Ratings (Note 1) Recommended Operating Conditions (Note 2)
IN Voltage -0.3V to 16V IN Input Voltage 4.75V to 15V
SW Voltage -1V to VIN +1V Operating Temperature -20°C to +85°C
BS Voltage V
All Other Pins –0.3 to 6V
Junction Temperature 150°C
Lead Temperature 260°C
Storage Temperature -65°C to 150°C "JA (8 pin SOIC) 105°C/W
Electrical Characteristics (Unless otherwise specified Circuit of Figure1, V
Parameters Condition Min Typ Max Units
Feedback Voltage 4.75V # VIN # 25V 1.184 1.222 1.258 V
Upper Switch On Resistance 0.25 $
Lower Switch On Resistance 10 $
Upper Switch Leakage VEN=0V; VSW=0V 10 µA
Current Limit 2.4 2.95 A
Oscillator Frequency 320 380 440 KHz
Short Circuit Frequency FB = 0V 42 KHz
Maximum Duty Cycle FB = 1.0V 90 %
Minimum Duty Cycle FB = 1.5V 0 %
Enable Threshold 0.7 1.0 1.3 V
Under Voltage Lockout Threshold
High Going
Under Voltage Lockout Threshold
Hysteresis
Shutdown Supply current VEN=0V 25 50 µA
Operating Supply current VEN=0V; VFB =1.4V 1.0 1.5 mA
Thermal Shutdown 160 °C
Note 1. Exceeding these ratings may damage the device.
Note 2. The device is not guaranteed to function outside its operating rating.
Note 3. Measured on 1” square of 1 oz. copper FR4 board.
-0.3V toVSW+6V
SW
Package Thermal Characteristics (Note 3)
=5V, VIN=12V, TA=25 C)
EN
2.0 2.5 3.0 V
200 mV
MP1410 Rev 1.0_ 05/29/02 www.monolithicpower.com 2
Page 3
MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Figure 2: Functional Block Diagram
2
IN
Interna l
Regulators
7
EN
Frequenc y
Foldback
Comparator
0.7V
2.30/2.53V
Pin Description
Shutdown
Comparator
0.7V
Oscillator
40/400KHz
Lockout
Comparator
5
FB
SW
GND
1uA
1.22V
BS 1
IN
Slope
Compensation
CLK
Error Amplifier
gm= 630uA/Volt
2
3
4
Σ
6
COMP
Current
Sense
Amplifier
Current
Comparator
1.8V
5V
Q
S
R
Q
1
BS
M1
3
SW
M2
4
GND
N/C
8
EN
7
COMP
6
FB
5
# Name Description
1 BS High-Side Gate Drive Boost Input. BS supplies the drive for the high-side n-channel MOSFET switch.
Connect a 0.1µF or greater capacitor from SW to BS to power the high-side switch.
2 IN Power Input. IN supplies the power to the IC, as well as the step-down converter switches. Drive IN
with a 4.75V to 15V power source. Bypass IN to GND with a suitably large capacitor to eliminate noise
on the input to the IC. See Input Capacitor.
3 SW Power Switching Output. SW is the switching node that supplies power to the output. Connect 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.
4 GND Ground.
5 FB Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a resistive
voltage divider from the output voltage. The feedback threshold is 1.22V. See Setting the Output
Voltage.
6 COMP 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. See Compensatiionr.
7 EN Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on the
regulator, drive it low to turn it off. For automatic startup, leave EN unconnected.
8 N/C No Connect
MP1410 Rev 1.0_ 05/29/02 www.monolithicpower.com 3
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MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Functional Description
The MP1410 is a current-mode step-down switch-mode regulator. It regulates input voltages from 4.75V to 15V down to an output voltage as low as 1.22V, and is able to supply up to 2A of load current.
The MP1410 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 error amplifier. The output current of
the transconductance error amplifier is
presented at COMP where a network
compensates the regulation control system.
The voltage at COMP is compared to the
switch current measured internally to control
the output voltage.
The converter uses an internal n-channel
MOSFET switch to step-down the input
voltage to the regulated output voltage. Since
the MOSFET requires a gate voltage greater
than the input voltage, a boost capacitor
connected between SW and BS drives the
gate. The capacitor is internally charged while
the switch is off. An internal 10$ switch from
SW to GND is used to insure that SW is pulled
to GND when the switch is off to fully charge
the BS capacitor.
Application Information
Setting the Output Voltage
The output voltage is set using a resistive
voltage divider from the output voltage to FB.
The voltage divider divides the output voltage
down by the ratio:
= V
V
FB
Thus the output voltage is:
V
OUT
* R2 / (R1 + R2).
OUT
= 1.222 * (R1 + R2) / R2.
A typical value for R2 can be as high as 100k,
but a typical value is 10k$. Using that value,
R1 is determined by:
R1 ~= 8.18 * (VOUT – 1.222) (k$).
For example, for a 3.3V output voltage, R2 is
10k$, and R1 is 17k$.
Input Capacitor
The input current to the step-down converter is
discontinuous, and so a capacitor is required
to supply the AC current to the step-down
converter while maintaining the DC input
voltage.
A low-ESR capacitor is required to keep the
noise at the IC to a minimum. Ceramic
capacitors are preferred, but tantalum or lowESR electrolytic capacitors may also suffice.
The input capacitor value should be greater
than 10µF. The capacitor can be electrolytic,
tantalum or ceramic. However since it absorbs
the input switching current it requires an
adequate ripple current rating. Its RMS
current rating should be greater than
approximately 1/2 of the DC load current.
For insuring stable operation C
placed as close to the IC as possible.
Alternately a smaller high quality ceramic
0.1uF capacitor may be placed closer to the IC
and a larger capacitor placed further away. If
using this technique, it is recommended that
the larger capacitor be a tantalum or
electrolytic type. All ceramic capacitors should
be places close to the MP1410.
Output Capacitor
The output capacitor is required to maintain
the DC output voltage. Low ESR capacitors
are preferred to keep the output voltage ripple
low.
should be
IN
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MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Application Information (Continued)
The characteristics of the output capacitor also
effect the stability of the regulation control
system. Ceramic, tantalum, or low-ESR
electrolytic capacitors are recommended.
In the case of ceramic capacitors, the
impedance at the switching frequency is
dominated by the capacitance, and so the
output voltage ripple is mostly independent of
the ESR. The output voltage ripple is
estimated to be:
V
Where V
is the input voltage, f
frequency of the LC filter, f
frequency.
In the case of tantalum or low-ESR electrolytic
capacitors, the ESR dominates the impedance
at the switching frequency, and so the output
ripple is calculated as:
V
Where V
inductor ripple current, and R
series resistance of the output capacitors.
Output Rectifier Diode
The output rectifier diode supplies the current
to the inductor when the high-side switch is off.
To reduce losses due to the diode forward
voltage and recovery times, use a Schottky
rectifier.
Choose a rectifier who’s maximum reverse
voltage rating is greater than the maximum
input voltage, and who’s current rating is
greater than the maximum load current.
Table 1 provides a list of manufacturer’s and
their websites.
~= 1.4 * VIN * (fLC/fSW)^2
RIPPLE
is the output ripple voltage, VIN
RIPPLE
RIPPLE
~= %I * R
is the output voltage ripple, %I is the
RIPPLE
ESR
is the resonant
LC
is the switching
SW
is the equivalent
ESR
Table 1: Schottky Diode Manufacturers
# Manufacturer Website
1 Diodes, Inc. www.diodes.com
2 Fairchild Semiconductor www.fairchildsemi.com
3 General Semiconductor www.gensemi.com
4 International Rectifier www.irf.com
5 On Semiconductor www.onsemi.com
6 Pan Jit International www.panjit.com.tw
Compensation
The output of the transconductance error
amplifier is used to compensate the regulation
system. Typically compensation capacitors,
C
sets the dominant pole. The compensation
C
resistor sets a zero that should have the same
frequency as the pole set by the load
resistance and the output capacitor. If the
output capacitor is not ceramic type, then there
may need to be another capacitor from COMP
to GND (C
produced by the output capacitor and its ESR.
One of the critical parameters is the DC loop gain. This can be determined by the equation:
A
= (VFB / V
VL
Where A
threshold, 1.22V, V
voltage, A
A
is the current sense gain, and RL is the
CS
load resistance, or V
Simplifying the equation:
= AEA * ACS * (VFB / I
A
VL
I
LOAD(MAX)
Another critical parameter is the desired crossover frequency.
) to compensate for the zero
CA
) * AEA * ACS * RL
OUT
is the loop gain, VFB is the feedback
VL
is the regulated output
OUT
is the error amplifier voltage gain,
EA
OUT
/ I
.
LOAD
LOAD(MAX)
) ~= 1663 /
MP1410 Rev 1.0_ 05/29/02 www.monolithicpower.com 5
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MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Application Information (Continued)
This should be approximately one-fifth of the
switching frequency or approximately f
=
C
75kHz. This and the loop gain determines the
frequency of the dominant pole, f
The dominant pole occurs when G
* C
= AEA, where GM is the error amplifier
C
= fC / AVL.
P1
/ 2* & * fP1
M
transconductance. This CC can be
determined by:
~= 306 * AVL / fC ~= 6.8 / I
C
C
LOAD(MAX)
(nF).
The zero of the compensation network is
determined by the compensation resistor RC.
RC should be at the same frequency as the
pole due to the output capacitor and the load
resistor. Or:
* CC = RL * C
R
C
OUT
Solving for RC:
RC = RL * C
/ CC = V
OUT
OUT
* C
OUT
/ I
LOAD(MAX)
* C
C
If non-ceramic capacitors are used, the second
compensation capacitor is required to
compensate for the zero formed from the
capacitor and its ESR. The second
compensation capacitor can be determined by:
* CCA = C
R
C
OUT
* R
ESR
Solving for C
CA
:
= C
C
CA
OUT
* R
ESR
/ RC.
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. Choose an inductor
that will not saturate under the worst-case load
conditions.
Table 2 provides a list of manufacturer’s and
their websites.
Table 2: Inductor Manufacturers
# Manufacturer Website
1 Sumida Corporation www.sumida.com
2 Toko, Inc. www.toko.com
3 Coilcraft, Inc. www.coilcraft.com
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 load current. Also, make sure that
the peak inductor current (the load current plus
half the peak-to-peak inductor ripple current) is
below the 2.4A minimum current limit.
The inductance value can be calculated by the
equation:
L = (V
) * (VIN-V
OUT
Where VOUT is the output voltage, VIN is the
input voltage, f is the switching frequency, and
%I is the peak-to-peak inductor ripple current.
Table 3 gives a list of inductors for the various
inductor manufacturers.
OUT
) / V
* f * %I
IN
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MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Table 3: Inductor Selection Guide
Package Dimensions
Value
Vendor/Model
Sumida
CR75 10 2.3 0.070 Open Ferrite
CR75 15 1.8 0.090 Open Ferrite
CR75 22 1.5 0.110 Open Ferrite
CDH74 10 2.75 0.056 Open Ferrite
CDH74 15 2.1 0.083 Open Ferrite
CDH74 22 1.7 0.130 Open Ferrite
CDRH5D28 6.8 1.6 0.053 Shielded Ferrite
CDRH5D28 10 1.3 0.065 Shielded Ferrite
CDRH5D28 15 1.1 0.103 Shielded Ferrite
CDRH6D28 6.8 2.3 0.031 Shielded Ferrite
CDRH6D28 10 1.7 0.065 Shielded Ferrite
CDRH6D28 15 1.6 0.057 Shielded Ferrite
CDRH6D28 22 1.3 0.096 Shielded Ferrite
CDRH6D38 6.8 2.3 0.031 Shielded Ferrite
CDRH6D38 10 2.0 0.038 Shielded Ferrite
CDRH6D38 15 1.6 0.057 Shielded Ferrite
CDRH6D38 22 1.3 0.096 Shielded Ferrite
CDRH104R 6.8 4.8 0.027 Shielded Ferrite
CDRH104R 10 4.4 0.035 Shielded Ferrite
CDRH104R 15 3.6 0.050 Shielded Ferrite
CDRH104R 22 2.9 0.073 Shielded Ferrite
(uH)
Max
IDC (A)
Max
DCR (Ω)
Core
Type
Core
Material
Toko
D53LC Type A 6.8 2.01 0.068
D53LC Type A 10 1.77 0.090
D53LC Type A 15 1.40 0.142
D53LC Type A 22 1.15 0.208
D75C 6.8 1.79 0.050
D75C 10 1.63 0.055
D75C 15 1.33 0.081
D75C 22 1.09 0.115
D104C 10 4.3 0.0265
D104C 16 3.3 0.0492
D104C 22 2.5 0.0265
D10FL 10 2.26 0.051
D10FL 15 2.00 0.066
D10FL 22 1.83 0.100
Coilcraft
DO3308 10 2.4 0.030
DO3308 15 2.0 0.040
DO3308 22 1.6 0.050
DO3316 10 3.8 0.030
DO3316 15 3.0 0.040
DO3316 22 2.6 0.050
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Shielded
Open
Open
Open
Open
Open
Open
Open
Open
Open
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
Ferrite
(mm)
W L H
7.0 7.8 5.5
7.0 7.8 5.5
7.0 7.8 5.5
7.3 8.0 5.2
7.3 8.0 5.2
7.3 8.0 5.2
5.5 5.7 5.5
5.5 5.7 5.5
5.5 5.7 5.5
6.7 6.7 3.0
6.7 6.7 3.0
6.7 6.7 3.0
6.7 6.7 3.0
6.7 6.7 4.0
6.7 6.7 4.0
6.7 6.7 4.0
6.7 6.7 4.0
10.1 10.0 3.0
10.1 10.0 3.0
10.1 10.0 3.0
10.1 10.0 3.0
5.0 5.0 3.0
5.0 5.0 3.0
5.0 5.0 3.0
5.0 5.0 3.0
7.6 7.6 5.1
7.6 7.6 5.1
7.6 7.6 5.1
7.6 7.6 5.1
10.0 10.0 4.3
10.0 10.0 4.3
10.0 10.0 4.3
9.7 11.5 4.0
9.7 11.5 4.0
9.7 11.5 4.0
9.4 13.0 3.0
9.4 13.0 3.0
9.4 13.0 3.0
9.4 13.0 5.1
9.4 13.0 5.1
9.4 13.0 5.1
MP1410 Rev 1.0_ 05/22/02 www.monolithicpower.com 7
Page 8
MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Figure 3. MP1410 with Murata 22uF/10V Ceramic Output Capacitor
MP1410 Rev 1.0_ 05/22/02 www.monolithicpower.com 8
Page 9
MP1410
2A Step-Down
Monolithic Power Systems
Switch-Mode Regulator
PRELIMINARY
Packaging
SOIC 8 Pin
0.053(1.350)
0.068(1.730)
0.189(4.800)
0.197(5.004)
0.150(3.810)
0.157(4.000)
0.013(0.330)
0.020(0.508)
0.050(1.270)BSC
0.049(1.250)
0.060(1.524)
0.0040(0.102 )
0.0098(0.249 )
PIN 1 IDENT.
SEATING PLANE
SEE DETAIL "A"
o
0o-8
0.229(5.820)
0.244(6.200)
0.016(0.410)
0.050(1.270)
0.011(0.280)
0.020(0.508)
DETAIL "A"
x 45
0.0075(0.191)
0.0098(0.249)
o
NOTE:
1) Control dimension is in inches. Dimension in bracket is millimeters.
PDIP 8 Pin
NOTICE: MPS believes the information in this document to be accurate and reliable. However, it is subject to change
without notice. Please contact the factory for current specifications. No responsibility is assumed by MPS for its use or fit to
any application, nor for infringement of patent or other rights of third parties.
MP1410 Rev 1.0 Monolithic Power Systems, Inc. 9
05/29/02 3777 S tevens Creek Blvd, S ui te 400, Santa Clara, CA 95051-7364 USA
© 2002 MPS, Inc. Tel: (408) 243-0088, Fax: (408) 243-0099, Web: www.monolithicpower.com
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