MIC23250
4MHz Dual 400mA Synchronous Buck
Regulator with HYPER LIGHT LOAD™
General Description
The MIC23250 is a high efficiency 4MHz dual 400mA
synchronous buck regulator with Hyper Light Load™. Hyper
Light Load™ provides all the advantages of standard light
load modes, such as low quiescent current and high
efficiency but also allows the use of very small output
capacitors to maintain low output ripple voltage throughout
the entire load range. This benefit is not possible with other
light load mode types as they trade off control speed for low
standby currents. With Hyper Light Load™, the output
capacitor can be reduced by up to a factor of 20 saving cost
and valuable board space. The tiny package (2mm x 2mm
Thin MLF
®
) of MIC23250 also saves crucial board space by
using only six external components while regulating two
independent outputs up to 400mA each.
The device is designed for use with a 1µH inductor and a
4.7µF output capacitor that enables a sub-1mm height.
The MIC23250 has a very low quiescent current of 35µA
and can achieve over 85% efficiency at 1mA. At higher
loads the MIC23250 provides a constant switching
frequency around 4MHz while providing peak efficiencies up
to 94%.
The MIC23250 fixed output voltage option is available in a
10-pin 2mm x 2mm Thin MLF
®
with a junction operating
range from –40°C to +125°C. The adjustable output voltage
option will soon be available in Q2/Q3 2008.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
Input voltage range: 2.7V to 5.5V
•
Dual output current 400mA/400mA
•
Hyper Light Load™ mode
– 35µA dual quiescent current
– 1µH inductor with a 4.7µF capacitor
•
4MHz in PWM operation
•
Ultra fast transient response
•
Low voltage output ripple
– 20mVpp in Hyper Light Load™ mode
– 3mV output voltage ripple in full PWM mode
•
Up to 94% peak efficiency and 85% efficiency at 1mA
•
Fully integrated MOSFET switches
•
Micropower shutdown
•
Thermal shutdown and current limit protection
•
Fixed output:10-pin 2mm x 2mm Thin MLF
®
•
Adjustable output:12-pin 2.5mm x 2.5mm Thin MLF
®
(Available in Q2/Q3 2008)
•
–40°C to +125°C junction temperature range
Applications
•
Mobile handsets
•
Portable media players
•
Portable navigation devices (GPS)
•
WiFi/WiMax/WiBro modules
•
Digital cameras
•
Wireless LAN cards
•
USB Powered Devices
___________________________________________________________________________________________________________
Typical Application
Efficiency V
OUT
= 1.8V
100
VIN = 3.0V
90
VIN = 2.7V
80
70
VIN = 4.2V
60
50
40
30
20
10
0
1
L = 1µH
C
OUT
= 4.7µF
10
100
LOAD (mA)
1000
VIN = 3.6V
Hyper Light Load is a trademark of Micrel, Inc.
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
December 2007
M9999-121707-A
Micrel, Inc.
MIC23250
Ordering Information
Part Number
Marking
Nominal
Output
Voltage 1
1.575V
1.8V
1.0V
1.1V
1.6V
ADJ
Nominal
Output
Voltage 2
1.8V
1.2V
1.2V
0.9V
1.2V
ADJ
Junction
Temp. Range
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
Package
Lead
Finish
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
Pb-Free
MIC23250-GFHYMT
MIC23250-G4YMT
MIC23250-C4YMT
MIC23250-3BYMT
MIC23250-W4YMT
MIC23250-Adj*
Note:
* Available Q2/Q3 2008
WV1
WV5
WV2
WV3
WV4
TBD
10-Pin 2mm x 2mm
Thin MLF
®
10-Pin 2mm x 2mm
Thin MLF
®
10-Pin 2mm x 2mm
Thin MLF
®
10-Pin 2mm x 2mm
Thin MLF
®
10-Pin 2mm x 2mm
Thin MLF
®
12-Pin 2.5mm x
2.5mm Thin MLF
®
Pin Configuration
SNS1
EN1
AGND
SW1
PGND
1
2
3
4
5
10 SNS2
9
8
7
6
EN2
AVIN
SW2
VIN
10-Pin 2mm x 2mm Thin MLF
®
(MT)
(Top View)
Pin Description
Pin Number
1
2
3
4
5
6
7
8
9
10
Pin Name
SNS1
EN1
AGND
SW1
PGND
VIN
SW2
AVIN
EN2
SNS2
Pin Name
Sense 1 (Input): Error amplifier input. Connect to feedback resistor network to
set output 1 voltage.
Enable 1 (Input): Logic low will shut down output 1. Logic high powers up
output 1. Do not leave unconnected.
Analog Ground. Must be connected externally to PGND.
Switch Node 1 (Output): Internal power MOSFET output.
Power Ground.
Supply Voltage (Power Input): Requires close bypass capacitor to PGND.
Switch Node 2 (Output): Internal power MOSFET output.
Supply Voltage (Power Input): Analog control circuitry. Connect to VIN.
Enable 2 (Input): Logic low will shut down output 2. Logic high powers up
output 2. Do not leave unconnected.
Sense 2 (Input): Error amplifier input. Connect to feedback resistor network to
set output 2 voltage.
December 2007
2
M9999-121707-A
Micrel, Inc.
MIC23250
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) .........................................................6V
Output Switch Voltage (V
SW
) ............................................6V
Logic Input Voltage (V
EN
) .................................. –0.3V to V
IN
Storage Temperature Range (T
s
)..............–65°C to +150°C
ESD Rating
(3)
.................................................................. 2kV
Operating Ratings
(2)
Supply Voltage (V
IN
)......................................... 2.7V to 5.5V
Logic Input Voltage (V
EN
) .................................. –0.3V to V
IN
Junction Temperature (T
J
) ..................–40°C
≤
T
J
≤
+125°C
Thermal Resistance
2mm x 2mm Thin MLF
®
-10 (θ
JA
)........................70°C/W
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
= V
EN
= 3.6V; L = 1µH; C
OUT
= 4.7µF; I
OUT
= 20mA; only one channel power is enabled, unless
otherwise specified.
Bold
values indicate –40°C< T
J
< +125°C.
Parameter
Supply Voltage Range
Under-Voltage Lockout Threshold
UVLO Hysteresis
Quiescent Current,
Hyper LL mode
Shutdown Current
Output Voltage Accuracy
Current Limit in PWM Mode
Output Voltage Line Regulation
Output Voltage Load Regulation
Maximum Duty Cycle
PWM Switch ON-Resistance
Frequency
Soft Start Time
Enable Threshold
Enable Input Current
Over-temperature Shutdown
Over-temperature Shutdown
Hysteresis
Condition
(turn-on)
V
OUT1, 2 (both Enabled)
, I
OUT1, 2
= 0mA , SNS1, 2 >1.2 * V
OUT1, 2
Nominal
V
EN1, 2
= 0V; V
IN
= 5.5V
V
IN
= 3.6V, I
LOAD
= 20mA
SNS = 0.9*V
OUT NOM
V
IN
= 3.0V to 5.5V, I
LOAD
= 20mA
20mA < I
LOAD
< 400mA, V
IN
= 3.6V
SNS
≤
V
NOM
, V
OUT
= 1.8V, V
IN
= 2.7V
I
SW
= 100mA PMOS
I
SW
= -100mA NMOS
I
LOAD
= 120mA
V
OUT
= 90%
Min
2.7
2.45
Typ
2.55
60
35
0.01
–2.5
0.410
0.65
0.4
0.5
86
0.6
0.8
4
260
0.8
0.1
160
40
50
4
+2.5
1
Max
5.5
2.65
Units
V
V
mV
µA
µA
%
A
%/V
%
%
Ω
Ω
MHz
µs
V
µA
°C
°C
80
3.4
0.5
4.6
1.2
2
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended. Human body model: 1.5kΩ in series with 100pF.
4. Specification for packaged product only.
December 2007
3
M9999-121707-A
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