MP2494
2A, 55V, 100kHz Step-Down Converter The Future of Analog IC Technology
DESCRIPTIONglg
The MP2494 is a monolithic step-down switch mode converter. It achieves 2A continuous output current over a wide input supply range with excellent load and line regulation.
MP2494 achieves low EMI signature with well controlled switching edges.
Fault condition protection includes cycle-by-cycle current limiting and thermal shutdown.
The MP2494 requires a minimum number of readily available standard external components. The MP2494 is available in SOIC8 and SOIC8E package. FEATURES
•Wide 4.5V to 55V Operating Input Range •Output Adjustable from 0.8V to 15V
• 0.25Ω Internal Power MOSFET Switch •Stable with Low ESR Output Ceramic Capacitors
•Fixed 100kHz Frequency
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•Low EMI signature
• Thermal Shutdown
•Cycle-by-Cycle Over Current Protection •Available in SOIC8 and SOIC8E packages APPLICATIONS
•USB Power Supplies
•Automotive Cigarette Lighter Adapters “MPS” and “The Future of Analog IC Technology” are Registered Trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
ORDERING INFORMATION
Part Number Package Top Marking Free Air Temperature (T A) MP2494DS* SOIC8 MP2494DS
pullin–40°C to +85°C
MP2494DN** SOIC8E MP2494DN
–40°C to +85°C
* For Tape & Reel, add suffix –Z (e.g. MP2494DS–Z);
For RoHS, compliant packaging, add suffix –LF (e.g. MP2494DS–LF–Z).
** For Tape & Reel, add suffix –Z (e.g. MP2494DN–Z);
For RoHS, compliant packaging, add suffix –LF (e.g. MP2494DN–LF–Z).
PACKAGE REFERENCE
ABSOLUTE MAXIMUM RATINGS (1) Input Voltage 60V –0.3V to V IN + 0.3V .V SW + 6.5V All .–0.3V to +6.5V 150°C 260°C –65°C to +150°C Continuous Power Dissipation (T A = +25°C) (2) 1.2.5W Recommended Operating Conditions (3) Input Voltage .4.5V to 55V Output Voltage 0.8V to 15V Operating Junct. Temp. (T J)....–40°C to +125°C Thermal Resistance (4)θJA θJC
<.90......45...°C/50......10...°C/W Notes:
1) Exceeding the ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature T J (MAX), the junction-to-ambient thermal resistance θJA, and the ambient temperature T A. The maximum allowable continuous power dissipation at any ambient temperature is calculated by P D (MAX) = (T J (MAX)-T A)/θJA. Exceeding the maximum allowable power dissipation will cau excessive die temperature, and the regulator will go into thermal shutdown. Internal thermal shutdown circuitry protects the device from permanent damage.
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
ELECTRICAL CHARACTERISTICS (5)
V IN = 12V, T A = +25°C, unless otherwi noted.
Max
Units
Typ
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Parameters Symbol
Feedback Voltage V FB 4.5V ≤ V IN≤ 55V 0.78 0.8 0.82 V
Feedback Bias Current I BIAS(FB)V FB = 0.8V 10 nA
Switch On Resistance R DS(ON)0.25 Ω
Switch Leakage V EN = 0V, V SW = 0V 0.1 10 µA
A Current Limit(5) 3.5
Oscillator Frequency f SW V FB = 0.6V 80 100 120 kHz
Boot-Strap Voltage V BST - V SW 4.3 V
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Minimum On Time (5)t ON V FB = 1V 100 ns
=2A 50 ns
SW rising edge tri V IN =12V, V OUT =5V, I OUT
SW falling edge tfall V IN =12V, V OUT =5V, I OUT =2A 50 ns
EN Input Low Voltage 0.4 V
EN Input High Voltage 1.8 V
EN Input Bias Current V EN
10
µA
-2
=0-6V -10
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Under Voltage Lockout
3.0 3.3 3.6 V
Threshold Rising
Under Voltage Lockout
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Threshold Hysteresis
Supply Current (Shutdown) V EN
10
µA =0V
4
Supply Current (Quiescent) V EN= 2V, V FB = 1V 500 800 µA
Thermal Shutdown (5)150 °C
Notes:
5) Guaranteed by design
PIN FUNCTIONS
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Package Pin #
Name Description
1 VIN
Supply Voltage. The MP2494 operates from a +4.5V to +55V unregulated input. CIN is needed to prevent large voltage spikes from appearing at the input. Put CIN as clo to
the IC as possible. It is the drain of the internal power device and power supply for the whole chip.
2 GND Ground. This pin is the voltage reference for the regulated output voltage. For this reason
care must be taken in its layout. This node should be placed outside of the D1 to CIN
ground path to prevent switching current spikes from inducing voltage noi into the part.
3 EN On/Off Control Input.
4 FB
An external resistor divider from the output to GND tapped to the FB pin ts the output
voltage. It is pulled up to 4V power supply internally by a 2Meg resistor.
5 SS Connect to an external capacitor ud for Soft-Start.
6 VO Connect to ground.
7 BST Bootstrap. This capacitor is needed to drive the power switch’s gate above the supply voltage. It is connected between SW and BST pins to form a floating supply across the
power switch driver. An on-chip regulator is ud to charge up the external boot-strap
capacitor. If the on-chip regulator is not strong enough, one optional diode can be connected from IN or OUT to charge the external boot-strap capacitor. 8
SW
Switch Output. It is the source of power device.
TYPICAL PERFORMANCE CHARACTERISTICS
C 1 =220uF, C 2 =2.2uF, C 3 =39uF, C 4 =22uF, L =39uH, T A =25°C, unless otherwi noted.
I L C U R R E N T (A )
E F F I C I E N C Y (%)
V O U T (V )tere
Efficiency vs. Load Current
V OUT =5V Efficiency vs. Load Current
V OUT =3.3V Efficiency vs. Load Current
V OUT =2.5V 0%
20%
40%
60%
80%
100%
0.1iji
1
10
100
1000
-50
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