MP2459GJ [MPS]
0.5A, 55V, 480kHz Step-Down Converter in a TSOT23-6;
| 型号： | MP2459GJ |
| 厂家： | 
MONOLITHIC POWER SYSTEMS |
| 描述： | 0.5A, 55V, 480kHz Step-Down Converter in a TSOT23-6 |
| 文件： | 总13页 (文件大小：886K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MP2459
0.5A, 55V, 480kHz
StepꢀDown Converter in a TSOT23ꢀ6
DESCRIPTION
FEATURES
The MP2459 is a monolithic, stepꢀdown, switchꢀ
mode converter with a builtꢀin power MOSFET.
It achieves a 0.5A peakꢀoutput current over a
wide input supply range with excellent load and
•
•
•
0.5A Peak Output Current
1ꢁ Internal Power MOSFET
Stable with LowꢀESR Ceramic Output
Capacitors
Up to 90% Efficiency
0.1ꢂA Shutdown Mode
Fixed 480kHz Frequency
Thermal Shutdown
CycleꢀbyꢀCycle OverꢀCurrent Protection
Wide 4.5Vꢀtoꢀ55V Operating Input Range
Output Adjustable from 0.81V to 0.95*VIN
Available in a TSOT23ꢀ6 Package
line
regulation.
Currentꢀmode
operation
•
•
•
•
•
•
•
•
provides a fast transient response and eases
loop stabilization. Fault condition protections
include cycleꢀbyꢀcycle current limiting and thermal
shutdown.
The MP2459 requires a minimal number of
readilyꢀavailable external components. The
MP2459 is available in a TSOT23ꢀ6 package.
APPLICATIONS
•
•
•
•
•
Power Meters
Distributed Power Systems
Battery Chargers
PreꢀRegulator for Linear Regulators
WLED Drivers
All MPS parts are leadꢀfree and adhere to the RoHS directive. For MPS green
status, please visit MPS website under Products, Quality Assurance page.
“MPS” and “The Future of Analog IC Technology” are registered trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
100
90
80
70
60
50
40
BST
VIN
IN
MP2459
U1
L1
GND
SW
VOU T
GND
D1
EN
EN
FB
30
0.0 0.1 0.2 0.3 0.4 0.5 0.6
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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© 2013 MPS. All Rights Reserved.
1
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
ORDERING INFORMATION
Part Number*
Package
Top Marking
TSOT23ꢀ6
MP2459GJ
AEQ
* For Tape & Reel, add suffix –Z (eg. M2459GJ–Z);
PACKAGE REFERENCE
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance (4)
θJA θJC
Supply Voltage VIN ........................ −0.3V to 60V
VSW ........................................−0.3V to VIN+0.3V
VBS.......................................................VSW + 6V
All Other Pins................................ −0.3V to +6V
Continuous Power Dissipation (TA = +25°C) (2)
TSOT23ꢀ6..............................................0.568W
Junction Temperature..............................150°C
Lead Temperature ...................................260°C
Storage Temperature.............. −65°C to +150°C
Recommended Operating Conditions (3)
Supply Voltage VIN .......................... 4.5V to 55V
Output Voltage VOUT............... 0.81V to 0.95×VIN
Operating Junction Temp........ −40°C to +125°C
TSOT23ꢀ6 ..............................220 ...110 °C/W
Notes:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature TJ(MAX), the junctionꢀtoꢀ
ambient thermal resistance θJA, and the ambient temperature
TA. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by PD(MAX)=(TJ(MAX)ꢀ
TA)/θJA. Exceeding the maximum allowable power dissipation
will cause excessive die temperature, and the regulator will go
into thermal shutdown. Internal thermal shutdown circuitry
protects the device from permanent damage.
3) The device function is not guaranteed outside of the
recommended operating conditions.
4) Measured on JESD51ꢀ7, 4ꢀlayer PCB..
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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© 2013 MPS. All Rights Reserved.
2
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
ELECTRICAL CHARACTERISTICS
VIN = 12V, TA = +25°C, unless otherwise noted.
Parameters
Symbol Condition
Min
Typ
Max
0.832
0.1
Units
V
Feedback Voltage
VFB
IFB
0.792
0.812
4.5V ≤ VIN ≤ 55V
Feedback Current
VFB = 0.85V
ꢂA
ꢁ
SwitchꢀOn Resistance
Switch Leakage
RDS(ON)
1
ISW_LKG VEN = 0V, VSW = 0V
ILIM
fSW
fSW_F
1
ꢂA
A
Current Limit
1.0
1.25
480
150
93.5
100
3.3
1.5
580
Oscillator Frequency
Foldback Frequency
Maximum Duty Cycle
Minimum ONꢀTime
VFB = 0.6V
VFB = 0V
380
kHz
kHz
%
DMAX
VFB = 0.6V
90
τON
ns
V
UnderꢀVoltage Lockout Threshold, Rising
UnderꢀVoltage Lockout Threshold, Falling
VUVLO_R
VUVLO_F
2.9
3.7
2.65
3.05
3.45
V
UnderꢀVoltage Lockout Threshold,
Hysteresis
VUVLO_HYS
250
mV
EN Threshold, Rising
EN Threshold, Falling
EN Threshold, Hysteresis
VEN_R
VEN_F
1.35
1.17
180
3.1
V
V
VEN_HYS
mV
VEN = 2V
EN Input Current
IEN
ꢂA
VEN = 0V
0.1
Supply Current (Shutdown)
Supply Current (Quiescent)
Thermal Shutdown
IS
IQ
VEN = 0V
0.1
1.0
ꢂA
mA
°C
VEN = 2V, VFB = 1V
0.73
165
20
0.85
TSD
Thermal Shutdown Hysteresis
TSD_HYS
°C
MP2459 Rev. 1.0
www.MonolithicPower.com
3
3/4/2013
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© 2013 MPS. All Rights Reserved.
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
TYPICAL CHARACTERISTICS
VIN=12V, VOUT=5V, IOUT=0.5A, L=15ꢁH, TA=25°C, unless otherwise noted.
80
60
180
120
60
80
60
180
120
60
1.3
1.1
0.9
0.7
0.5
0.3
40
40
20
20
0
0
0
0
-20
-40
-60
-80
-20
-40
-60
-60
-120
-60
-120
-180
-180 -80
1000 10000 1000001000000 100
100
1000 10000 1000001000000
5
15 25 35 45 55 65
Conduction EMI
Radiation EMI
80
70
60
50
40
30
20
60
55
50
EN 55022ElectricFieldStrength3m QP
EN 55022VoltageonMainsQP
45
40
EN 55022VoltageonMainsAV
35
30
25
20
15
10
5
0
30M
10
0
150k 300
8001M 2M 3M 5M 810M 20M 30M
5060 80100M
200 300400500 8001G
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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© 2013 MPS. All Rights Reserved.
4
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
TYPICAL PERFORMANCE CHARACTERISTICS
VIN=12V, VOUT=5V, L=22ꢁH, TA=25°C, unless otherwise noted.
Efficiency vs. Load Load Regulation
Line Regulation
I =0.5A
OUT
100
90
80
70
60
50
40
30
2.0
1.6
1.2
0.8
0.4
0.0
2.0
1.6
1.2
0.8
0.4
0.0
-0.4
-0.8
-1.2
-1.6
-2.0
-0.4
-0.8
-1.2
-1.6
-2.0
0.0
0.2
0.4
0.6
0.8
1.0
0.00.10.20.30.40.50.60.70.8
6
16
26
36
46
56
LOAD CURRENT ( A )
LOAD CURRENT ( A )
INPUT VOLTAG ( V )
Load Regulation
=3.3V
V
OUT
2.0
1.6
100
90
80
70
60
50
40
30
2.0
1.6
1.2
1.2
0.8
0.8
0.4
0.4
0.0
0.0
-0.4
-0.8
-1.2
-1.6
-0.4
-0.8
-1.2
-1.6
-2.0
-2.0
6
16
26
36
46
56
0.00.10.20.30.40.50.60.70.8
0.0 0.2 0.4 0.6 0.8 1.0
LOAD CURRENT ( A )
LOAD CURRENT ( A )
INPUT VOLTAG ( V )
2.0
850
830
810
790
770
750
600
1.7
1.4
1.1
0.8
0.5
560
520
480
440
400
-40 -10 20 50 80 110 140
-40 -10 20 50 80 110 140
-40 -10 20 50 80 110 140
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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© 2013 MPS. All Rights Reserved.
5
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN=12V, VOUT=5V, L=22ꢁH, TA=25°C, unless otherwise noted.
Steady State
V =8V, I =0.8A
IN OUT
Steady State
I =0.15A
OUT
LoadTransient
I =0.2A to 0A.7
OUT
V
V
V
IN
10V/dvi.
IN
10V/dvi.
IN
5V/dvi.
V
10V/dvi.
SW
V
10V/dvi.
V
5V/dvi.
SW
SW
V
200mV/div.
OUT
V
5V/dvi.
V
5V/dvi.
OUT
OUT
I
L
I
L
I
L
1A/dvi.
500mA/div.
500mA/div.
Steady State
V =6V, V =3.3V, I =0.1A
IN OUT OUT
Steady State
V =60V, V =3.3V, I =0.9A
LoadTransient
V =3.3V, I =0.2A to 0A.7
OUT OUT
IN
OUT
OUT
V
V
IN
10V/dvi.
IN
5V/dvi.
V
IN
50V/dvi.
V
10V/dvi.
SW
V
5V/dvi.
SW
V
50V/dvi.
SW
V
200mV/div.
OUT
V
2V/dvi.
V
2V/dvi.
OUT
OUT
I
L
I
L
I
L
200mA/div.
500mA/div.
1A/dvi.
Power Ramp Up
V =60V, I =0.5A
IN OUT
Power Ramp Down
V =60V, I =0.5A
IN OUT
Short Output
I =0.65A
OUT
V
V
V
IN
50V/dvi.
IN
50V/dvi.
IN
10V/dvi.
V
10V/dvi.
SW
V
50V/dvi.
SW
V
SW
50V/dvi.
V
5V/dvi.
V
5V/dvi.
OUT
V
OUT
OUT
5V/dvi.
I
L
I
500mA/div.
OUT
I
OUT
500mA/div.
1A/dvi.
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
6
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
TYPICAL PERFORMANCE CHARACTERISTICS (continued)
VIN=12V, VOUT=5V, L=22ꢁH, TA=25°C, unless otherwise noted.
Enable On Enable Off
Short Output Recover
I
I
=0.5A
I
=0.5A
=0.65A
OUT
OUT
OUT
V
V
V
IN
10V/dvi.
EN
2V/dvi.
EN
2V/dvi.
V
10V/dvi.
V
10V/dvi.
V
10V/dvi.
SW
SW
SW
V
5V/dvi.
V
5V/dvi.
V
5V/dvi.
OUT
OUT
OUT
I
L
I
L
I
L
1A/dvi.
500mA/div.
500mA/div.
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
7
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
PIN FUNCTIONS
Pin # Name Description
Bootstrap. Connect a capacitor between the SW and BS pins to form a floating supply across
the power switch driver. This capacitor drives the power switch’s gate above the supply voltage.
1
2
BST
Ground. Voltage reference for the regulated output voltage. Requires special layout
GND considerations. Isolate this node from the D1 to C1 ground path to prevent switching current
spikes from inducing.
Feedback. Sets the output voltage. Connect to the tap of an external resistor divider from the
3
FB
output to GND. The frequency foldback comparator lowers the oscillator frequency when the FB
voltage is below 250mV to prevent currentꢀlimit runaway during a shortꢀcircuit fault.
On/Off. Pull EN above 1.2V to turn the device ON. For automatic enable, connect to VIN using a
100kꢁ resistor.
4
5
6
EN
IN
Supply Voltage. The MP2459 operates from a 4.5Vꢀtoꢀ55V unregulated input. Requires C1 to
prevent large voltage spikes from appearing at the input.
SW Switch Output.
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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© 2013 MPS. All Rights Reserved.
8
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
OPERATION
The MP2459 is a current mode buck regulator.
That is, the EA output voltage is proportional to
the peak inductor current.
If the sum of the Current Sense Amplifier output
and the Slope Compensation signal does not
exceed the EA output for a whole cycle, then
the falling edge of the CLK resets the FlipꢀFlop.
At the beginning of a cycle, M1 is off. The EA
output voltage is higher than the current sense
amplifier output, and the current comparator’s
output is low. The rising edge of the 480kHz
CLK signal sets the RS FlipꢀFlop. Its output
turns on M1 thus connecting the SW pin and
inductor to the input supply.
The output of the Error Amplifier integrates the
voltage difference between the feedback and
the 0.81V bandgap reference. The polarity is
such that lower than 0.81V FB pin voltage
increases the EA output voltage. Since the EA
output voltage is proportional to the peak
inductor current, an increase in its voltage also
increases current delivered to the output.
The increasing inductor current is sensed and
amplified by the Current Sense Amplifier. Ramp
compensation is summed to the Current Sense
Amplifier output and compared to the Error
Amplifier output by the PWM Comparator.
When the sum of the Current Sense Amplifier
output and the Slope Compensation signal
exceeds the EA output voltage, the RS Flipꢀ
Flop is reset and M1 is turned off. The external
Schottky rectifier diode (D1) conducts the
inductor current.
Figure 1: Functional Block Diagram
MP2459 Rev. 1.0
3/4/2013
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© 2013 MPS. All Rights Reserved.
9
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
APPLICATION INFORMATION
Setting Output Voltage
Selecting the Input Capacitor
The external resistor divider sets the output
voltage (see the Typical Application schematic).
Table 1 lists resistors for common output
voltages. The feedback resistor (R1) also sets
the feedback loop bandwidth with the internal
compensation capacitor (see Figure 1). R2 is:
The input capacitor reduces the surge current
drawn from the input supply and the switching
noise from the device. The input capacitor
impedance at the switching frequency should be
less than the input source impedance to prevent
highꢁfrequencyꢁswitching current from passing
through the input. Use ceramic capacitors with
X5R or X7R dielectrics for their low ESRs and
small temperature coefficients. For most
applications, a 4.7µF capacitor will sufficient.
R1
VOUT
R2 =
− 1
0.81V
Table 1: Resistor Selection for Common
Output Voltages
Selecting the Output Capacitor
The output capacitor keeps the output voltage
ripple small and ensures feedback loop stability.
The output capacitor impedance should be low
at the switching frequency. Use ceramic
capacitors with X5R or X7R dielectrics for their
low ESR characteristics. For most applications,
a 22µF ceramic capacitor will sufficient.
VOUT (V)
1.8
R1 (kꢂ)
80.6 (1%)
49.9 (1%)
49.9 (1%)
49.9 (1%)
R2 (kꢂ)
64.9 (1%)
23.7 (1%)
16.2 (1%)
9.53 (1%)
2.5
3.3
5
Selecting the Inductor
PCB Layout Guide
Use an inductor with a DC current rating at
least 25% percent higher than the maximum
load current for most applications. For best
efficiency, the inductor’s DC resistance should
be less than 200mꢀ. Refer to Table 2 for
suggested surfaceꢁmount inductors. For most
designs, the required inductance value can be
derived from the following equation.
PCB layout is very important to stability. Please
follow these guidelines and use Figure 2 as
reference.
1) Keep the path of switching current short
and minimize the loop area formed by the
input capacitor, highꢁside MOSFET, and
Schottky diode.
2) Keep the connection from the power
ground→Schottky diode→SW pin as short
and wide as possible.
VOUT × (VIN − VOUT
VIN × ꢀIL × fSW
)
L =
Where ꢂIL is the inductor ripple current.
3) Ensure all feedback connections are short
and direct. Place the feedback resistors
and compensation components as close to
the chip as possible.
Choose the inductor ripple current to be 30% of
the maximum load current. The maximum
inductor peak current is:
4) Route SW away from sensitive analog
areas such as FB.
ꢀIL
IL(MAX) = ILOAD
+
2
5) Connect IN, SW, and especially GND to
large copper areas to cool the chip for
improved thermal performance and longꢁ
term reliability. For single layer PCBs, avoid
soldering the exposed pad
Under lightꢁload conditions (below 100mA), use
a larger inductance to improve efficiency.
.
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
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10
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
R2
R1
External Bootstrap Diode
An external bootstrap diode may enhance
regulator efficiency under the following
conditions:
SGND
ꢀ
ꢀ
VOUT=5V or 3.3V; and
VOUT
High duty cycle: D=
>65%
VIN
L1
In these cases, add an external BST diode from
the output of the voltage regulator to the BST
pin, as shown in Figure 3.
C1
D1
C2
MP2459
PGND
Figure 2: PCB Layout
Figure 3: Optional Bootstrap Diode for Enhanced
Efficiency
The recommended external BST diode is
IN4148, and the BST capacitor is 0.1µFꢁ1µF.
MP2459 Rev. 1.0
3/4/2013
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© 2013 MPS. All Rights Reserved.
11
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
TYPICAL APPLICATION CIRCUIT
U1
D2
NS
1
5
BST
VIN
IN
R6
0
MP2459
FB1
C3
0805
3.3V/0.A5
100nF
GND
6
3
VOU T
SW
FB
D1
DFLS160
4
EN
EN
GND
2
GND
C6
NS
R3
NS
MP2459 Rev. 1.0
3/4/2013
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12
MP2459 – 0.5A, 55V, 480kHz, STEPꢀDOWN CONVERTER IN A TSOT23ꢀ6
PACKAGE INFORMATION
TSOT23ꢀ6
0.95
BSC
0.60
TYP
2.80
3.00
6
4
1.20
TYP
SeeNote7
EXAMPLE
TOPMARK
1.50
1.70
2.60
3.00
2.60
TYP
AAAA
PIN 1
1
3
TOP VIEW
RECOMM ENDED LAND PATTERN
0.84
0.90
1.00MAX
0.09
0.20
SEATING PLANE
0.30
0.50
0.00
0.10
0.95BSC
SEE DETAIL"A"
SIDE VIEW
FRONT VIEW
NOTE:
1)ALLDIMENSIONSAREIN MILLIMETERS.
GAUGEPLANE
0.25BSC
2)PACKAGELENGTH DOESNOTINCLUDEMOLD FLASH,
PROTRUSION OR GATE BURR.
3)PACKAGEWIDTH DOES NOTINCLUDEINTERLEAD FLASH
OR PROTRUSION.
)
4)LEAD COPLANARITY(BOTTOM OFLEADSAFTER FORMING
SHALL BE0.10MILLIMETERSMAX.
0.30
0.50
0o-8o
5)DRAWING CONFORMSTO JEDEC MO-193,VARIATION AB.
6)DRAWING IS NOTTO SCALE.
7)PIN1ISLOWE R LEFTPINWHEN READING TOPMARK FROM
LEFTTO RIGHT,(SEEEXAMPLETOPMARK)
NOTICE: The information in this document is subject to change without notice. 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.
MP2459 Rev. 1.0
3/4/2013
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2013 MPS. All Rights Reserved.
13
相关型号：
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