General Description Features: 2A Step Down DC To DC Converter
General Description Features: 2A Step Down DC To DC Converter
General Description Features: 2A Step Down DC To DC Converter
2A Step Down
DC to DC Converter
MPS
5.0V
90
OUTPUT
ENABLE 2.5V/2A
3.3V
SHUTDOWN MP1410
85
Efficiency (%)
2.5V
80
75
70
0 0 .5 1 1 .5 2
Ou t pu t Cu r r e n t ( A)
Electrical Characteristics (Unless otherwise specified refer to Circuit of Figure 1, VEN=5V, VIN=12V, TA=25 C)
Parameters Condition Min Typ Max Units
Feedback Voltage 4.75V ≤ VIN ≤ 15V 1.184 1.222 1.258 V
Upper Switch On Resistance 0.22 Ω
Lower Switch On Resistance 10 Ω
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 VFB = 0V 42 KHz
Maximum Duty Cycle VFB = 1.0V 90 %
Minimum Duty Cycle VFB = 1.5V 0 %
Enable Threshold 0.7 1.0 1.3 V
Under Voltage Lockout Threshold High Going 2.0 2.5 3.0 V
Under Voltage Lockout Threshold Hysteresis 200 mV
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.
Pin Description
BS 1 8 N/C
IN 2 7 EN
SW 3 6 COMP
GND 4 5 FB
IN 2
Internal
Σ
Regulators Current
Slope Sense
Compensation Amplifier 1 BS
5V
M1
Oscillator
S Q
CLK
40/400KHz
R Q
3 SW
Shutdown Current M2
Comparator Comparator
0.7V 4 GND
1uA
EN 7
1.8V
2.30/2.53V Lockout
Comparator
Frequency
Foldback 0.7V 1.22V
Comparator Error Amplifier
5 FB gm= 630uA/Volt
6 COMP
Functional Description
Inductor
The MP1410 is a current-mode step-down
switch-mode regulator. It regulates input The inductor is required to supply constant
voltages from 4.75V to 15V down to an output current to the output load while being driven by
voltage as low as 1.22V, and is able to supply the switched input voltage. A larger value
up to 2A of load current. The MP1410 uses inductor results in less ripple current that in
current-mode control to regulate the output turn results in lower output ripple voltage.
voltage. The output voltage is measured at FB However, the larger value inductor has a larger
through a resistive voltage divider and physical size, higher series resistance, and/or
amplified through the internal error amplifier. lower saturation current. Choose an inductor
The output current of the transconductance that does not saturate under the worst-case
error amplifier is presented at COMP where a load conditions. A good rule for determining
network compensates the regulation control the inductance is to allow the peak-to-peak
system. The voltage at COMP is compared to ripple current in the inductor to be
the switch current measured internally to approximately 30% of the maximum load
control the output voltage. current. Also, make sure that the peak
inductor current (the load current plus half the
The converter uses an internal n-channel peak-to-peak inductor ripple current) is below
MOSFET switch to step down the input voltage the 2.4A minimum current limit. The
to the regulated output voltage. Since the inductance value can be calculated by the
MOSFET requires a gate voltage greater than equation:
the input voltage, a boost capacitor connected L = (VOUT) * (VIN-VOUT) / VIN * f * ∆I
between SW and BS drives the gate. The
capacitor is internally charged while the switch Where VOUT is the output voltage, VIN is the
is off. An internal 10Ω switch from SW to GND input voltage, f is the switching frequency, and
is used to insure that SW is pulled to GND ∆I is the peak-to-peak inductor ripple current.
when the switch is off to fully charge the BS Table 2 lists a number of suitable inductors
capacitor. from various manufacturers.
if R1 is less than 10KΩ, or if R1 = 10KΩ use R1 ≈ (1.37 x 108) (22 x 10-6)(3.3V) = 9.9KΩ
the following equation: Use the nearest standard value of 10KΩ.
1%
10K
10nF
Packaging
PDIP8
Packaging
SOIC8
0.150(3.810) 0.0075(0.191)
0.157(4.000) 0.0098(0.249)
0.189(4.800)
0.197(5.004) 0o-8o
0.049(1.250)
0.016(0.410)
0.050(1.270)
DETAIL "A"
0.053(1.350)
0.068(1.730) 0.060(1.524)
SEATING PLANE
0.001(0.030)
0.004(0.101)
NOTE:
1) Control dimension is in inches. Dimension in bracket is millimeters.
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.