MIC23050
4MHz PWM Buck Regulator
with HYPER LIGHT LOAD™
General Description
The Micrel MIC23050 is a high efficiency 500mA PWM
synchronous buck (step-down) regulator featuring Hyper
Light Load™, a patented switching scheme that offers
best-in-class light load efficiency and transient
performance while providing very small external
components and low output ripple at all loads.
The MIC23050 also has a very low typical quiescent
current draw of 20µA and can achieve over 85% efficiency
even at 1mA. The device allows operation with a tiny
inductor ranging from 0.47µH to 2.2µH and uses a small
output capacitor that enables a sub-1mm height.
In contrast to traditional light load schemes Hyper Light
Load™ architecture does not need to trade off control
speed to obtain low standby currents and in doing so the
device only needs a small output capacitor to absorb the
load transient as the powered device goes from light load
to full load.
At higher loads the MIC23050 provides a constant
switching frequency of greater than 4MHz while providing
peak efficiencies greater than 93%.
The MIC23050
comes in fixed output voltage options from
0.72V to 2.5V eliminating external feedback components.
®
The MIC23050 is available in an 8-pin 2mm x 2mm MLF
with a junction operating range from –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
•
•
•
•
•
•
•
•
•
•
•
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Input voltage range: 2.7V to 5.5V
Fixed output voltage options from 0.72V to 2.5V
Output current guaranteed up to 500mA
Ultra fast transient response
20µA typical quiescent current
4MHz in PWM in constant current mode
Hyper light load mode
0.47µH to 2.2µH inductor
Low voltage output ripple
– 25mVpp in hyper light load mode
– 3mV output voltage ripple in full PWM mode
>93% efficiency
~85% at 1mA
Fully integrated MOSFET switches
Micropower shutdown
Thermal shutdown and current limit protection
®
8-pin 2mm x 2mm MLF
–40°C to +125°C junction temperature range
Applications
•
Cellular phones
•
Digital cameras
•
Portable media players
•
Wireless LAN cards
•
WiFi/WiMax/WiBro modules
•
USB Powered Devices
___________________________________________________________________________________________________________
Typical Application
Efficiency V
OUT
= 1.8V
100
80
60
40
20
0
1
V
IN
= 2.7V
V
IN
= 3.3V
V
IN
= 3.6V
V
OUT
= 1.8V
L = 1µH
10
100
LOAD (mA)
1000
Hyper Light Load is a trademark of Micrel, Inc.
MLF and
MicroLeadFrame
are registered trademarks of Amkor Technology, Inc.
Protected by US Patent No. 7064531
M9999-072007-B
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (
408
) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
July 2007
1
Micrel, Inc.
MIC23050
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ........................................................ 6V
Output Switch Voltage (V
SW
) ........................................... 6V
Output Switch Current (I
SW
) ............................................. 2A
Logic Input Voltage (V
EN
, V
LQ
) ...........................V
IN
to –0.3V
Storage Temperature Range (T
s
) ............. –65°C to +150°C
(3)
ESD Rating ..................................................................3kV
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
2x2 MLF-8 (θ
JA
) ................................................. 90°C/W
Electrical Characteristics
(4)
T
A
= 25°C with V
IN
= V
EN
= 3.6V; L = 1µH; C
FF
= 560pF; C
OUT
= 4.7µF; I
OUT
= 20mA unless otherwise specified.
Bold
values indicate –40°C< T
J
< +125°C.
Parameter
Condition
Min
Typ
Max
Units
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 Hysteresis
Enable Input Current
Over-temperature Shutdown
Over-temperature Shutdown
Hysteresis
(turn-on)
I
OUT
= 0mA , V
SNS
> 1.2*V
OUT
nominal
V
IN
= 5.5V; V
EN
= 0V;
V
IN
= 3.0V, I
LOAD
= 20mA
SNS = 0.9*V
NOM
V
IN
= 3.0V to 5.5V, I
LOAD
= 20mA
20mA < I
LOAD
< 500mA,
SNS
≤
V
NOM
I
SW
= 100mA PMOS
I
SW
= -100mA NMOS
I
LOAD
= 120mA
V
OUT
= 90%
(turn-on)
2.7
2.45
2.55
100
20
0.01
5.5
2.65
V
V
mV
µA
µA
%
A
%/V
%
%
Ω
Ω
MHz
µs
V
mV
µA
°
C
°
C
32
4
+2.5
1.7
–2.5
0.65
1
0.5
0.3
80
3.4
0.5
89
0.45
0.5
4
650
0.8
35
0.1
165
20
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.
July 2007
3
M9999-072007-B
嵌入式系统
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