MPQ2490
The Future of Analog IC Technology
Industrial Grade, 1.5A, 36V, 700kHz
Step-Down Converter
with Programmable Output Current Limit
DESCRIPTION
The MPQ2490 is a monolithic step-down switch
mode converter with programmable output
current limit. It achieves 1.5A continuous output
current over a wide input supply range with
excellent load and line regulation.
The maximum output current can be
programmed by sensing current through the
inductor DC resistance (DCR) or an accurate
sense resistor.
Fault
condition
protection
includes
cycle-by-cycle current limiting and thermal
shutdown.
The MPQ2490 requires a minimum number of
readily available standard external components.
The MPQ2490 is available in QFN (3x 3mm)
package.
FEATURES
Wide 4.5V to 36V Operating Input Range
Programmable up to 1.5A Output Current
Output Adjustable from 0.8V to 15V
Programmable Output Current Limit without
power loss
0.25Ω Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic
Capacitors
95% Efficiency @ 500mA (Vo=5V)
Fixed 700kHz Frequency
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Available in QFN10 Package
APPLICATIONS
Industrial and Car Power Supplies
USB Power Supplies
Automotive Cigarette Lighter Adapters
Power Supply for Battery Chargers
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
U1
VIN
GND
EN
3
EN
8
PGOOD
8V-36V
1
VIN
6
ISN
MPQ2490
ISP
BST
SW
7
9
C9
10
10nF
R6
2k
D1
SMA/3A/40V
R1
300k
1%
5V
VOUT
GND
SS
5
SS
GND
2
FB
4
R2
57.6k
1%
MPQ2490 Rev. 1.03
www.MonolithicPower.com
9/30/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
1
MPQ2490 – INDUSTRIAL GRADE, 1.5A, 36V, 700kHz STEP-DOWN WITH PROGRAMMABLE OUTPUT CURRENT LIMIT
ORDERING INFORMATION
Part Number
MPQ2490DQ
Package
Top Marking
Free-Air Temperature (T
A
)
QFN10 (3mm x 3mm)
T6
-40°C to +85°C
*
For Tape & Reel, add suffix –Z (e.g. MPQ2490DQ–Z);
For RoHS compliant packaging, add suffix –LF; (e.g. MPQ2490DQ–LF–Z)
PACKAGE REFERENCE
TOP VIEW
VIN
GND
EN
FB
SS
1
2
3
4
5
10
9
8
7
6
SW
BST
PGOOD
ISP
ISN
EXPOSED PAD
ON BACKSIDE
CONNECT TO GND
QFN10 (3mm X 3mm)
ABSOLUTE MAXIMUM RATINGS
(1)
Supply Voltage V
IN
....................................... 40V
V
SW
....................................... –0.3V to V
IN
+ 0.3V
V
BST
................................................... V
SW
+ 6.5V
V
ISN,
v
ISP
................................................0V to15V
All Other Pins ..............................–0.3V to +6.5V
Junction Temperature ...............................150C
(2)
Continuous Power Dissipation (T
A
= +25°C)
QFN10 (3mm x 3mm) ................................ 2.5W
Lead Temperature ....................................260C
Storage Temperature.............. –65C to +150C
Thermal Resistance
(4)
QFN10 (3mm x 3mm) .............50 ...... 12 ...
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 T
J
(MAX), the junction-to-
ambient thermal resistance
θ
JA
, 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
)/θ
JA
. 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 is not guaranteed to function outside of its
operating conditions.
4) Measured on approximately 1” square of 1 oz copper.
θ
JA
θ
JC
Recommended Operating Conditions
(3)
Supply Voltage V
IN
...........................4.5V to 36V
Output Voltage V
OUT
(V
IN
>16.5V) .....0.8V to 15V
Output Voltage V
OUT
(V
IN
≤16.5V)
........................
........................................0.8V to (V
IN
–1.5) V
Operating Junction Temp. (T
J
). -40°C to +125°C
MPQ2490 Rev. 1.03
www.MonolithicPower.com
9/30/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
2
MPQ2490 – INDUSTRIAL GRADE, 1.5A, 36V, 700kHz STEP-DOWN WITH PROGRAMMABLE OUTPUT CURRENT LIMIT
ELECTRICAL CHARACTERISTICS
V
IN
= 12V, T
A
= -40°C to +85°C. Typical values are at T
A
=25°C, unless otherwise noted.
Parameters
Feedback Voltage
Feedback Bias Current
Switch On Resistance
Switch Leakage
Current Limit
(5)
Oscillator Frequency
Fold-Back Frequency
Boot-Strap Voltage
Minimum On Time
(5)
Under Voltage Lockout
Threshold Rising
Under Voltage Lockout
Threshold Hysteresis
Supply Current (Shutdown)
Supply Current (Quiescent)
Thermal Shutdown
(5)
Current Sense Voltage
V
ISP
–V
ISN
V
ISP
, V
ISN
0.4–15V
0.4–15V
80
–1.5
V
EN
=
0V
V
EN
=
2V, V
FB
= 1V
V
BST
- V
SW
t
ON
V
FB
= 1V
2.9
f
SW
Symbol
V
FB
I
BIAS(FB)
R
DS(ON)
V
EN
= 0V, V
SW
= 0V
Duty Cycle <= 80%
V
FB
= 0.6V
V
FB
= 0V
1.7
500
700
200
5
100
3.3
200
4
500
150
100
0.1
120
+1.5
25
800
3.7
Condition
4.5V
V
IN
36V
V
FB
= 0.8V
T
A
=25C
-40CT
A
85°C
Min
0.785
0.777
0.01
0.25
0.1
10
4.2
950
Typ
0.805
Max
0.825
0.833
1
Units
V
μA
Ω
μA
A
kHz
kHz
V
ns
V
mV
μA
μA
°C
mV
μA
Input Bias Current (ISN, ISP) I
BIAS (ISN,ISP)
V
ISP
, V
ISN
Note:
5) Derived from design and bench characterization. Not tested in production.
MPQ2490 Rev. 1.03
www.MonolithicPower.com
9/30/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
3
MPQ2490 – INDUSTRIAL GRADE, 1.5A, 36V, 700kHz STEP-DOWN WITH PROGRAMMABLE OUTPUT CURRENT LIMIT
PIN FUNCTIONS
QFN10
Pin #
1
Name
Description
2
3
4
5
6
7
8
9
10
Supply Voltage. The MPQ2490 operates from a +4.5V to +36V unregulated input. C
IN
is needed to prevent large voltage spikes from appearing at the input. Put C
IN
as close
VIN
to the IC as possible. It is the drain of the internal power device and power supply for
the whole chip.
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
GND
to C
IN
ground path to prevent switching current spikes from inducing voltage noise into
the part.
EN
On/Off Control Input. (Only available for the MPQ2490DQ)
Feedback. An external resistor divider from the output to GND, tapped to the FB pin
sets the output voltage. To prevent current limit run away during a short circuit fault
FB
condition the frequency-fold-back comparator lowers the oscillator frequency when the
FB voltage is below 250mV.
Connect to an external capacitor used for Soft-Start and compensation for current
SS
limiting loop.
ISN
Negative Current Sense Input for load current limiting.
ISP
Positive Current Sense
Power good signal. When FB is less than 90% of 0.8V, PGOOD is low. It is an open-
PGOOD drain output. Use a high value pull-up resistor externally to pull it up to system power
supply. (Only available for the MPQ2490DQ)
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
BST
power switch driver. An on-chip regulator is used 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.
SW
Switch Output. It is the source of power device.
MPQ2490 Rev. 1.03
www.MonolithicPower.com
9/30/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
4
MPQ2490 – INDUSTRIAL GRADE, 1.5A, 36V, 700kHz STEP-DOWN WITH PROGRAMMABLE OUTPUT CURRENT LIMIT
TYPICAL PERFORMANCE CHARACTERISTICS
C1=C2=4.7μF, C3=C4=10μF, C8=0.1μF, L=12μH, T
A
=25ºC, unless otherwise noted
MPQ2490 Rev. 1.03
www.MonolithicPower.com
9/30/2015
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2015 MPS. All Rights Reserved.
5
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