MIC2206
2MHz PWM Synchronous Buck
Regulator with LOWQ Mode and Voltage
Scaling
General Description
The Micrel MIC2206 is a high efficiency 2MHz PWM
synchronous buck (step-down) regulator that
features a
LOWQ™
LDO standby mode that draws
only 18µA of quiescent current. The MIC2206
allows an ultra-low noise, small size, and high
efficiency solution for portable power applications.
In PWM mode, the MIC2206 operates with a
constant frequency 2MHz PWM control. Under light
load conditions, such as in system sleep or standby
modes, the PWM switching operation can be
disabled to reduce switching losses. In this light
load
LOWQ™
mode, the LDO maintains an output
voltage of 1V and draws only 18µA of quiescent
current. The LDO mode of operation saves battery
life while not introducing spurious noise and high
ripple as experienced with pulse skipping or bursting
mode regulators.
The MIC2206 operates from 2.7V to 5.5V input and
features internal power MOSFETs that can supply
up to 600mA output current in PWM mode. It can
operate with a maximum duty cycle of 100% for use
in low-dropout conditions.
The MIC2206 is available in the 3mm x 3mm MLF-
10L package 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
•
2.7 to 5.5V supply voltage
•
Light load
LOWQ™
LDO mode
18µA quiescent current
Low noise, 75µVrms
•
2MHz PWM mode
Output current to 600mA
>95% efficiency
100% maximum duty cycle
•
Output Voltage Scaling (1V output in LOWQ
Mode)
•
Ultra-fast transient response
•
Stable with 1µF ceramic output capacitor
•
Fully integrated MOSFET switches
•
Micropower shutdown
•
Thermal shutdown and current limit protection
•
Pb-free 3mm x 3mm MLF-10L package
•
–40°C to +125°C junction temperature range
Applications
•
Cellular phones
•
PDAs
•
USB peripherals
____________________________________________________________________________________________________
Typical Application
MIC2206
VIN
AVIN
V
IN
Li Ion
Battery
C
IN
4.7µF
0.1µF
EN
LDO
SW
FB
100pF
2.2µH
V
OUT
1.8V/600mA
C
OUT
2.2µF
Ceramic
LOWQ PGND
BIAS
AGND
Fixed Output Buck Regulator with
LOWQ™
Mode
LOWQ
is a trademark of Micrel, 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
October 2005
M9999-102105
www.micrel@micrel.com
Micrel, Inc.
MIC2206
Ordering Information
Part Number
(Pb-Free)
MIC2206-1.8YML
MIC2206-1.2YML
Note:
1. Other Voltage options available. Contact Micrel for details.
Output Voltage
(1)
(PWM/LDO)
1.8V/1.0V
1.2V/1.0V
Junction Temp. Range
–40° to +125°C
–40° to +125°C
Package
3x3 MLF-10L
3x3 MLF-10L
Pin Configuration
AGND 1
LDO 2
BIAS 3
AVIN
4
EP
10 PGND
9 SW
8 VIN
7 LOWQ
6 EN
FB 5
3mm x 3mm MLF-10L (ML)
Pin Description
Pin Number
1
2
3
4
5
6
Pin Name
AGND
LDO
BIAS
AVIN
FB
EN
_____
LOWQ
VIN
SW
PGND
GND
Pin Function
Analog (signal) Ground.
LDO Output (Output): Connect to V
OUT
for LDO mode operation.
Internal circuit bias supply. Must be de-coupled to signal ground with a 0.1µF
capacitor and should not be loaded.
Analog Supply Voltage (Input): Supply voltage for the analog control circuitry and
LDO input power. Requires bypass capacitor to GND.
Feedback. Input to the error amplifier and internal feedback resistors. Place a
100pF ceramic capacitor from FB to the output.
Enable (Input). Logic low will shut down the device, reducing the quiescent
current to less than 5µA.
Enable LDO Mode (Input): Logic low enables the internal LDO and disables the
PWM operation. Logic high enables the PWM mode and disables the LDO
mode.
Supply Voltage (Input): Supply voltage for the internal switches and drivers.
Switch (Output): Internal power MOSFET output switches.
Power Ground.
Ground, backside pad.
7
8
9
10
EP
October 2005
2
M9999-102105
www.micrel.com
Micrel, Inc.
MIC2206
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
LOWQ
) .............. -0.3V to V
IN
Storage Temperature (T
s
)................ -60°C to +150°C
ESD Rating
(3)
.......................................................
3kV
Operating Ratings
(2)
Supply Voltage (V
IN
)............................+2.7V to +5.5V
Logic Input Voltage (V
EN
,V
LOWQ
) .............. -0.3V to V
IN
Junction Temperature (T
J
) .............. –40°C to +125°C
Junction Thermal Resistance
3x3 MLF-10L (θ
JA
) ................................... 60°C/W
Electrical Characteristics
(4)
V
IN
= V
EN
= V
LOWQ
=3.6V; L = 2.2µH; C
OUT
= 2.2µF; T
A
= 25°C, unless noted.
Bold
values indicate –40°C< T
J
< +125°C
Parameter
Supply Voltage Range
Under-Voltage Lockout
Threshold
UVLO Hysteresis
Quiescent Current, PWM
mode
Quiescent Current, LDO
mode
Shutdown Current
[Fixed Output] Voltages
Current Limit in PWM Mode
Output Voltage Line
Regulation
Output Voltage Load
Regulation, PWM Mode
Output Voltage Load
Regulation, LDO Mode
Maximum Duty Cycle
PWM Switch ON-
Resistance
Oscillator Frequency
LOWQ threshold voltage
LOWQ Input Current
Enable Threshold
Enable Input Current
0.5
V
FB
= 0.9 * V
NOM
(not switching)
V
LOWQ
= 0V;I
OUT
= 0mA
V
EN
= 0V
Nominal V
OUT
tolerance
V
FB
= 0.9 * V
NOM
V
OUT
> 2V; V
IN
= V
OUT
+300mV to 5.5V; I
LOAD
= 100mA
V
OUT
< 2V; V
IN
= 2.7V to 5.5V; I
LOAD
= 100mA
20mA < I
LOAD
< 300mA
100µA < I
LOAD
< 50mA
V
LOWQ
= 0V
V
FB
≤
0.4V
I
SW
= 50mA V
FB
= 0.7V
FB_NOM
(High Side Switch)
I
SW
= -50mA V
FB
= 1.1V
FB_NOM
(Low Side Switch)
1.8
0.5
100
0.4
0.4
2
0.85
0.1
0.85
0.1
2.2
1.3
2
1.3
2
-1
-2
0.75
1
0.13
0.2
0.2
0.5
0.5
(turn-on)
Condition
Min
2.7
2.45
2.55
100
690
16
0.1
900
29
5
+1
+2
1.85
Typ
Max
5.5
2.65
Units
V
V
mV
µA
µA
µA
%
A
%
%
%
%
Ω
MHz
V
µA
V
µA
October 2005
3
M9999-102105
www.micrel.com
微控制器 MCU
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