MP2370
1.2A, 24V, 1.4MHz Step-Down
White LED Driver
The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP2370 is a monolithic step-down white
LED driver with a built-in power MOSFET. It
achieves 1.2A peak 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-by-cycle current limiting and thermal
shutdown.
The MP2370 requires a minimum number of
readily available standard external components.
The MP2370 is available in a TSOT23-6 package
and a TQFN-6 (2mmx2mm) package.
1.2A Peak Output Current
0.35Ω Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic
Capacitors
Also Work with Cap-less Configuration
Up to 87% Efficiency
0.1μA Shutdown Mode
Fixed 1.4MHz Frequency
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Wide 4.5V to 24V Operating Input Range
0.15V Sense Voltage
Available in a TSOT23-6 Package and a
TQFN-6 (2mmx2mm) package
APPLICATIONS
WLED Drivers
Distributed Power Systems
Battery Charger
Pre-Regulator for Linear Regulators
All MPS parts are lead-free, halogen free, and adhere to the RoHS
directive. For MPS green status, please visit MPS website under Quality
Assurance.
“MPS” and “The Future of Analog IC Technology” are Registered
Trademarks of Monolithic Power Systems, Inc.
TYPICAL APPLICATION
Efficiency vs
Output Current
EFFICIENCY (%)
100
90
80
Circuit as Figure 1
VIN=12V
VIN=8V
VIN=20V
70
60
0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
OUTPUT CURRENT (A)
MP2370 Rev. 1.1
7/29/2019
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1
MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
ORDERING INFORMATION
Part Number*
MP2370DJ
MP2370DGT
Package
TSOT-6
TQFN-6 (2mmx2mm)
Top Marking
See below
See below
* For Tape & Reel, add suffix –Z (e.g. MP2370DJ-Z);
For RoHS compliant packaging, add suffix –LF (eg. MP2370DJ-LF-Z)
* For Tape & Reel, add suffix –Z (e.g. MP2370DGT-Z);
For RoHS compliant packaging, add suffix –LF (eg. MP2370DGT-LF-Z)
TOP MARKING (TSOT-6)
P5: product code of MP2370DJ;
Y: year code;
W: week code:
TOP MARKING (TQFN-6)
P5: product code of MP2370DGT;
Y: year code;
LLL: lot number;
PACKAGE REFERENCE
TOP VIEW
BST
1
Top View
6
SW
SW 1
GND
2
5
IN
FB
3
4
EN
TSOT-6
MP2370 Rev. 1.1
7/29/2019
6 BST
IN
2
5 GND
EN
3
4 FB
TQFN-6 (2mmx2mm)
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2
MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
ABSOLUTE MAXIMUM RATINGS (1)
Thermal Resistance (3)
Supply Voltage VIN ........................................ 26V
VSW .............................. -1.2V(25ns) to VIN + 0.3V
VBST........................................................ VSW + 6V
All Other Pins ................................. –0.3V to +6V
Junction Temperature ............................... 150C
Lead Temperature .................................... 260C
Storage Temperature ............... –65C to +150C
TSOT23-6 .............................. 220 ..... 110 .. C/W
TQFN-6 (2mmx2mm) .............. 80 ....... 16 ... C/W
Recommended Operating Conditions (2)
Supply Voltage VIN ........................... 4.5V to 24V
Output Voltage VOUT ....................... 0.15V to 15V
Ambient Temperature ................ –40C to +85C
MP2370 Rev. 1.1
7/29/2019
θJA
θJC
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 junction-toambient 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) Measured on JESD51-7, 4-layer PCB.
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MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
ELECTRICAL CHARACTERISTICS
VIN = 12V, TA = +25C, unless otherwise noted.
Parameters
Symbol Condition
Feedback Voltage
Feedback Current
Switch-On Resistance (4)
Switch Leakage
Current Limit (4)
Oscillator Frequency
Fold-back Frequency
Maximum Duty Cycle
Minimum On-Time (4)
Under Voltage Lockout Threshold Rising
Under Voltage Lockout Threshold Hysteresis
EN Input Low Voltage
EN Input High Voltage
VFB
IFB
RDS(ON)
Typ
Max
Units
0.145
0.155
0.165
V
0.1
0.35
VEN = 0V, VSW = 0V
fSW
VFB = 0.13V
VFB = 0V
VFB = 0.13V
10
1.2
tON
2.5
1.8
1.4
700
87
100
2.8
150
1.7
3.1
0.4
1.5
VEN = 2V
VEN = 0V
EN Input Current
Minimum PWM DIM On-Time on EN Pin
4.5V VIN 24V
VFB = 0.15V
Min
TMIN_ON
Supply Current (Shutdown)
IS
Supply Current (Quiescent)
IQ
VOUT=4.5V 25C
VOUT=4.5V
-40C ~125C(5)
VEN = 0V
VEN = 2V, VFB =
0.2V
Thermal Shutdown (4)
2.1
0.1
μA
Ω
μA
A
MHz
KHz
%
ns
V
mV
V
V
μA
200
μs
240
μs
0.1
1.0
μA
0.8
1.0
mA
150
°C
Note:
4) Guaranteed by design.
5) Not tested in production, guaranteed by over -temperature correlation.
MP2370 Rev. 1.1
7/29/2019
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© 2019 MPS. All Rights Reserved.
4
MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
PIN FUNCTIONS
TSOT-6
Pin #
QFN-6
Pin #
Name
1
6
BST
2
5
GND
3
4
4
3
FB
EN
5
2
IN
6
1
SW
MP2370 Rev. 1.1
7/29/2019
Description
Bootstrap. A capacitor is connected between SW and BS pins to form a floating
supply across the power switch driver. This capacitor is needed to drive the
power switch’s gate above the supply voltage.
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 C1 ground path to prevent switching current spikes from inducing
voltage noise into the part.
Current Sense Feedback Voltage. Its internal threshold is 0.15V.
On/Off Control Input. Pull EN above 1.2V to turn the device on.
Supply Voltage. The MP2370 operates from a +4.5V to +24V unregulated input.
Input Capacitor is needed to prevent large voltage spikes from appearing at the
input.
Switch Output.
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MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
TYPICAL PERFORMACE CHARACTERISTICS
Circuit as Figure 1, VIN = 12V, Load: one 3 Watt White LED, unless otherwise noted.
Steady State Operation
Enable Start Up
VSW
10V/div
VSW
10V/div
VOUT(AC)
20mV/div
VEN
5V/div
Enable Turn Off
VSW
10V/div
VEN
5V/div
IINDUCTOR
0.5A/div
ILED
0.5A/div
ILED
0.5A/div
400nS/div
40us/div
Output Short
VSW
10V/div
40us/div
Output Short Entry
Output Short Recovery
VSW
10V/div
VSW
10V/div
VOUT
2V/div
IINDUCTOR
0.5A/div
Line Regulation
VOUT = 3.3V
VOUT
2V/div
ILED
0.5A/div
ILED
0.5A/div
1us/div
4us/div
4us/div
Current Limit vs
Duty Cycle
VOUT
2V/div
VSW
10V/div
ILED
0.5A/div
Line Regulation
VOUT = 3.3V
400us/div
MP2370 Rev. 1.1
7/29/2019
0.9
2.0
0.8
1.8
INDUCTOR PEAK CURRENT(A)
VEN
5V/div
OUTPUT CURRENT(A)
I
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
0
40
60
80
20
PWM DIMMING DUTY(%)
100
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
10 20 30 40 50 60 70 80 90
DUTY(%)
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6
MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
OPERATION
The MP2370 is a current mode buck regulator.
That is, the EA output voltage is proportional to
the peak inductor current.
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 1.4MHz
CLK signal sets the RS Flip-Flop. Its output
turns on M1 thus connecting the SW pin and
inductor to the input supply.
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 FlipFlop is reset and M1 is turned off. The external
Schottky rectifier diode (D1) conducts the
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 Flip-Flop.
The output of the Error Amplifier integrates the
voltage difference between the feedback and
the 0.15V bandgap reference. The polarity is
such that a FB pin voltage lower than 0.15V
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 internal floating power MOSFET driver (M1)
is powered by an external bootstrap capacitor.
When M1 turns off and when external Schottky
turns on, the bootstrap capacitor is charged
through the internal diode (D) and regulator. For
application with lower input voltage, connect the
external diode between the IN pin and BST pin
to enhance the floating MOS driver capability.
IN
RAMP
GENERATOR
-+
x20
CURRENT SENSE
AMPLIFIER
D
REGULATOR
BST
EN
REGULATOR
OSCILLATOR
1.4MHz/700KHz
S
+
-1pF
DRIVER
M1
R
CURRENT
LIMIT
COMPARATOR
R
SW
27pF
REFERENCE
0.15V
FB
Q
+EA
--
ERROR
AMPLIFIER
+
--
PWM
COMPARATOR
GND
Figure 1—Functional Block Diagram
MP2370 Rev. 1.1
7/29/2019
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MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
APPLICATION INFORMATION
Setting LED Current
The current sense resistor is inserted between
the anode of WLED and GND. The current
sense resistor value is calculated as:
R1
0.15 V
ILED
For 1A WLED current, choose R1 = 150mΩ
Selecting the Inductor
A 1µH to 10µH inductor with a DC current rating
of at least 25% percent higher than the
maximum load current is recommended for
most applications. For highest efficiency, the
inductor’s DC resistance should be less than
200mΩ. Refer to Table 2 for suggested surface
mount inductors. For most designs, the required
inductance value can be derived from the
following equation.
L
VOUT ( VIN VOUT )
VIN IL f SW
Where ∆IL is the inductor ripple current.
Choose the inductor ripple current to be 30% of
the maximum load current. The maximum
inductor peak current is calculated from:
IL(MAX ) ILOAD
IL
2
Under light load conditions below 100mA, a
larger inductance is recommended to improve
efficiency. See Table 2 for suggested inductors.
Selecting the Output Capacitor
The output capacitor keeps the output current
ripple small and ensures feedback loop stability.
The output capacitor impedance should be low
at the switching frequency. Ceramic capacitors
with X5R or X7R dielectrics are recommended
for their low ESR characteristics. For most
applications, a 2.2µF ceramic capacitor will be
sufficient.
The MP2370 can also work properly without
output capacitor by adding a small capacitor in
the feedback loop (see Figure 2). The small
capacitor is recommended 680pF.
PC Board Layout
The high current paths (GND, IN and SW) should
be placed very close to the device with short,
direct and wide traces. The input capacitor needs
to be as close as possible to the IN and GND pins.
The external feedback resistors should be placed
next to the FB pin. Keep the switch node traces
short and away from the feedback network.
External bootstrap diode
To get the full rated output current when
operating at low input voltage (Vin240us
on-time PWM dimming signal.
PWM Dimming
MP2370 has PWM dimming function on EN pin with
dimming signal. The dimming ratio depends on the
dimming
frequency.
The
lower
PWM
Table 2—Suggested Surface Mount Inductors
Manufacturer
Part Number
Inductance(µH)
Max DCR(Ω)
Toko
Sumida
Wurth Electronics
A921CY-4R7M
CDRH4D28C/LD
7440530047
4.7
4.7
4.7
0.027
0.036
0.038
Dimensions
L x W x H (mm3)
6 x 6.3 x 3
5.1 x 5.1 x 3
5.8 x 5.8 x 2.8
Current
Rating (A)
1.66
1.5
2.0
TYPICAL APPLICATION CIRCUITS
6V to 23V
VIN
BS
IN
C3
10nF
MP2370
SW
OFF ON
FB
EN
D1
B130A
GND
L1
WLED
3W
0.75A
C4
680pF
Figure 3—White LED Driver without Output Capacitor
U1
VIN
6V-23V
IN
BST
MP2370
OFF ON
EN
L1
SW
D1
B130A
D2
5.6V
1A
FB
GND
Figure 4—White LED Driver with Over-Voltage Clamp Output
VIN
16V-23V
IN
BST
MP2370
OFF ON
EN
GND
CB
10nF
SW
D1
B130A
FB
LED1
LED2
LED3
Figure 5—Driving 3 White LEDs in Series from 16V- 23V Input Voltage
MP2370 Rev. 1.1
7/29/2019
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9
MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
PACKAGE INFORMATION
TSOT23-6
0.60
TYP
2.80
3.00
6
See Note 7
EXAMPLE
TOP MARK
4
AAAA
PIN 1
1
0.95
BSC
1.20
TYP
1.50
1.70
2.60
TYP
2.60
3.00
3
TOP VIEW
RECOMMENDED LAND PATTERN
0.84
0.90
1.00 MAX
0.09
0.20
SEATING PLANE
0.30
0.50
0.95 BSC
0.00
0.10
SEE DETAIL
FRONT VIEW
SIDE VIEW
NOTE:
GAUGE PLANE
0.25 BSC
0o-8o
DETAIL
MP2370 Rev. 1.1
7/29/2019
0.30
0.50
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) PACKAGE LENGTH DOES NOT INCLUDE MOLD FLASH,
PROTRUSION OR GATE BURR.
3) PACKAGE WIDTH DOES NOT INCLUDE INTERLEAD FLASH
OR PROTRUSION.
4) LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING)
SHALL BE 0.10 MILLIMETERS MAX.
5) DRAWING CONFORMS TO JEDEC MO-193, VARIATION AB.
6) DRAWING IS NOT TO SCALE.
7) PIN 1 IS LOWER LEFT PIN WHEN READING TOP MARK FROM
LEFT TO RIGHT, (SEE EXAMPLE TOP MARK)
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MP2370 – 1.2A, 24V, 1.4MHz STEP-DOWN WHITE LED DRIVER
PACKAGE INFORMATION
TQFN-6 (2mmx2mm)
° TYP.
1) ALL DIMENSIONS ARE IN MILLIMETERS.
2) EXPOSED PADDLE SIZE DOES NOT INCLUDE
MOLD FLASH.
3) LEAD COPLANARITY SHALL BE 0.10
MILLIMETERS MAX.
4) JEDEC REFERENCE IS MO-229,VARIATION
WCCC
5) DRAWING IS NOT TO SCALE.
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.
MP2370 Rev. 1.1
7/29/2019
www.MonolithicPower.com
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© 2019 MPS. All Rights Reserved.
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