Micrel MIC2205-1.3YML 2mhz pwm synchronous buck regulator with ldo standby mode Datasheet

MIC2205
2MHz PWM Synchronous Buck
Regulator with LDO Standby Mode
General Description
Features
The Micrel MIC2205 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 MIC2205
allows an ultra-low noise, small size, and high
efficiency solution for portable power applications.
In PWM mode, the MIC2205 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 the output
voltage 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 MIC2205 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 MIC2205 is available in the 3mm x 3mm MLF10L 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.
• 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
• Adjustable output voltage option down to 1V
Fixed output voltage options available
• 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
C1
1µF
LowQ
C2
0.1µF
8
VIN
SW
9
4
AVIN
LDO
2
6
EN
FB
5
7
LOWQ
3
BIAS
2.2µH
VOUT
R1
100k
R2
125k
C3
100pF
C4
2.2µF
PGND AGND
GND
10
1
GND
VIN = 3V
VIN = 3.6V
85
80
VIN = 4.2V
75
70
65
60
55
50
Adjustable Output Buck Regulator with LOWQ™ Mode
1.8V OUT Efficiency
100
95
90
EFFICIENCY (%)
MIC2205
V IN
2.7V to 5.5V
0
100 200 300 400 500 600
OUTPUT CURRENT (mA)
Patent Pending
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
April 2005
M9999-041105
www.micrel.com
Micrel, Inc.
MIC2205
Ordering Information
Part Number
Output Voltage(1)
Junction Temp. Range
Package
Lead Finish
MIC2205-1.3YML
1.3V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205-1.38YML
1.38V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205-1.5YML
1.5V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205-1.58YML
1.58V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205-1.8YML
1.8V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205-1.85YML
1.85V
–40° to +125°C
3x3 MLF-10L
Pb-free
MIC2205YML
Adj.
–40° to +125°C
3x3 MLF-10L
Pb-free
Note:
1. Other Voltage options available. Contact Micrel for details.
Pin Configuration
10 PGND
AGND 1
LDO 2
9 SW
BIAS 3
8 VIN
AVIN 4
7 LOWQ
FB 5
EP
6 EN
3mm x 3mm MLF-10L (ML)
Pin Description
Pin Number
Pin Name
1
AGND
2
LDO
LDO Output (Output): Connect to VOUT for LDO mode operation.
3
BIAS
Internal circuit bias supply. Must be de-coupled to signal ground with a 0.1µF
capacitor and should not be loaded.
4
AVIN
Analog Supply Voltage (Input): Supply voltage for the analog control circuitry and
LDO input power. Requires bypass capacitor to GND.
5
FB
Feedback. Input to the error amplifier. For the Adjustable option, connect to the
external resistor divider network to set the output voltage. For fixed output
voltage options, connect to VOUT and an internal resistor network sets the output
voltage.
6
EN
Enable (Input). Logic low will shut down the device, reducing the quiescent
current to less than 5µA.
7
_____
LOWQ
8
VIN
Supply Voltage (Input): Supply voltage for the internal switches and drivers.
9
SW
Switch (Output): Internal power MOSFET output switches.
10
PGND
EP
GND
April 2005
Pin Function
Analog (signal) Ground.
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.
Power Ground.
Ground, backside pad.
2
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MIC2205
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) ............................................ +6V
Output Switch Voltage (VSW) ............................... +6V
Output Switch Current (ISW) ................................... 2A
Logic Input Voltage (VEN,VLOWQ) .............. -0.3V to VIN
Storage Temperature (Ts)................ -60°C to +150°C
ESD Rating(3) ....................................................... 3kV
Supply Voltage (VIN)............................+2.7V to +5.5V
Logic Input Voltage (VEN,VLOWQ) .............. -0.3V to VIN
Junction Temperature (TJ) .............. –40°C to +125°C
Junction Thermal Resistance
3x3 MLF-10L (θJA) ................................... 60°C/W
Electrical Characteristics (4)
VIN = VEN = VLOWQ =3.6V; L = 2.2µH; COUT = 2.2µF; TA = 25°C, unless noted. Bold values indicate –40°C< TJ < +125°C
Parameter
Condition
Min
2.7
Supply Voltage Range
Under-Voltage Lockout
Threshold
Typ
(turn-on)
2.45
UVLO Hysteresis
2.55
Max
Units
5.5
V
2.65
V
100
mV
Quiescent Current, PWM
mode
VFB = 0.9 * VNOM (not switching)
690
900
µA
Quiescent Current, LDO
mode
VLOWQ = 0V;IOUT = 0mA
16
29
µA
Shutdown Current
VEN = 0V
0.01
5
µA
[Adjustable] Feedback
Voltage
± 1%
± 2% (over temperature)
0.99
0.98
1
1.01
1.02
V
[Fixed Output] Voltages
Nominal VOUT tolerance
-1
-2
+1
+2
%
FB pin input current
1
0.75
1
nA
1.85
Current Limit in PWM Mode
VFB = 0.9 * VNOM
Output Voltage Line
Regulation
VOUT > 2V; VIN = VOUT+300mV to 5.5V; ILOAD= 100mA
VOUT < 2V; VIN = 2.7V to 5.5V; ILOAD= 100mA
0.13
A
Output Voltage Load
Regulation, PWM Mode
20mA < ILOAD < 300mA
0.2
0.5
%
Output Voltage Load
Regulation, LDO Mode
100µA < ILOAD < 50mA
VLOWQ = 0V
0.1
0.2
%
Maximum Duty Cycle
VFB ≤ 0.4V
PWM Switch ONResistance
ISW = 50mA VFB = 0.7VFB_NOM (High Side Switch)
ISW = -50mA VFB = 1.1VFB_NOM (Low Side Switch)
%
100
%
0.4
Ω
0.4
Oscillator Frequency
1.8
2
2.2
MHz
LOWQ threshold voltage
0.5
0.85
1.3
V
0.1
2
µA
0.85
1.3
V
0.1
2
µA
LOWQ Input Current
0.5
Enable Threshold
Enable Input Current
LDO Dropout Voltage
April 2005
IOUT = 50mA Note 5
110
3
mV
M9999-041105
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MIC2205
Parameter
Condition
Min
Output Voltage Noise
LOWQ = 0V; COUT = 2.2μF, 10Hz to 100kHz
LDO Current Limit
LOWQ = 0V; VOUT = 0V (LDO Mode)
Typ
Max
Units
75
µVrms
120
mA
Over-Temperature
Shutdown
160
°C
Over-Temperature
Hysteresis
20
°C
60
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.
5.
Dropout voltage is defined as the input-to-output differential at which the output voltage drops 2% below its nominal value that is
initially measured at a 1V differential. For outputs below 2.7V, the dropout voltage is the input-to-output voltage differential with a
minimum input voltage of 2.7V.
April 2005
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MIC2205
Typical Characteristics – PWM Mode
Bode Plot
85
70
65
60
50
70
65
60
100
200
300
400
OUTPUT CURRENT (mA)
1.0V OUT Efficiency
VIN = 4.2V
70
65
60
55
50
0
60
1.95
1.9
1.85
VIN = 3.6V
1.8
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
April 2005
VIN = 3.6V
80
VIN = 4.2V
75
70
65
60
50
100
200
300
400
OUTPUT CURRENT (mA)
0
100
200
300
400
OUTPUT CURRENT (mA)
Quiescent Current
vs. Supply Voltage
900
1.006
1.004
1.002
1.000
0.998
0.996
0.994
VIN = 3.6V
LowQ = VIN
0.992
0
800
700
600
500
400
300
200
100
0
2.7
100
200
300
400
OUTPUT CURRENT (mA)
Peak Current Limit
vs. Supply Voltage
CURRENT LIMIT (mA)
FREQUENCY (MHz)
2
0
VIN = 3.6V
VF B = 0.9V
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
5.5
Enable Threshold
vs. Supply Voltage
1.5
1200
2.15
2.05
VIN = 3V
85
55
1.008
Frequency
vs. Temperature
2.2
2.1
VIN = 4.2V
65
0.990
100 200 300 400 500 600
OUTPUT CURRENT (mA)
100 200 300 400 500 600
OUTPUT CURRENT (mA)
1.2V OUT Efficiency
Load Regulation
FEEDBACK VOLTAGE (V)
VIN = 3.6V
0
90
VIN = 3.6V
1.010
VIN = 3V
75
50
95
70
50
80
65
60
VIN = 3V
75
50
85
70
100
200
300
400
OUTPUT CURRENT (mA)
80
55
90
75
1.38V OUT Efficiency
85
55
0
0
90
EFFICIENCY (%)
75
VIN = 4.2V
55
95
VIN = 4.2V
VIN = 3.6V
80
55
VIN = 3.6V
80
EFFICIENCY (%)
75
-18
-36
1E+6
1M
90
85
EFFICIENCY (%)
36
18
0
VIN = 4.2V
80
VIN = 3V
95
VIN = 3.6V
QUIESCENT CURRENT (µA)
72
54
VIN = 3V
90
EFFICIENCY (%)
90
85
1.8V OUT Efficiency
100
VIN = 3V
95
1.5V OUT Efficiency
95
EFFICIENCY (%)
108
90
2.5V OUT Efficiency
ENABLE THRESHOLD (V)
30
20 VIN = 3.6V
10 VOUT = 1.8V
0 L = 2.2 H
Gain
COUT = 2.2 F
-10 C = 120pF
FF
-20
1E+2
1E+3
1E+4
1E+5
100
1k
10k
100k
FREQUENCY (Hz)
100
EFFICIENCY (%)
Phase
60
50
40
144
126
PHASE (°)
GAIN (dB)
80
70
1000
800
600
400
200
LowQ = VIN
0
2.7
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
5
5.5
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6 LowQ = V
IN
0.5
2.7
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
5.5
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MIC2205
Typical Characteristics – PWM Mode (cont.)
Turn-On Time
vs. Supply Voltage
100
TURN-ON DELAY (µs)
90
80
70
60
50
40
30
20
10 V = 3.6V
IN
0
2.7
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
April 2005
5.5
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MIC2205
Typical Characteristics - LDO Mode
PSRR
vs. Output Current
80
60
60
40
4.2V
3V
20 IOUT = 50mA
VOUT = 1.8V
3.6V
COUT = 2.2 F
0
1E-2
1E+1
1
10 1E+2
1k
0.01 1E-1
100 1E+3
0.1 1E+0
FREQUENCY (Hz)
20 VIN = 3.6
VOUT = 1.8V
COUT = 2.2 F I
OUT = 50mA
0
1E-2
1E+1
1
10 1E+2
1k
0.01 1E-1
100 1E+3
0.1 1E+0
FREQUENCY (Hz)
250
200
150
100
50
VOUT = 3.3V
0
Dropout Voltage
vs. Temperature
80
120
140
70
80
60
40
20
LowQ = 0V
0
2.7
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
120
100
80
60
40
VOUT = 3.3V
IOUT = 50mA
LowQ = 0V
20
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
5.5
Dropout Voltage
vs. Temperature
50
40
30
20
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Dropout Voltage
vs. Temperature
Output Voltage
vs. Temperature
35
8
1.827
25
20
15
5
VOUT = 3.3V
IOUT = 10mA
LowQ = 0V
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
5
4
3
2
1
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Enable Threshold Voltage
vs. Supply Voltage
1.4
90
TURN-ON DELAY (µs)
100
1.1
1.0
0.9
0.8
0.7
0.6
0.5
2.7
April 2005
3.4
4.1
4.8
SUPPLY VOLTAGE (V)
5.5
1.800
1.791
1.782
1.773
LowQ = 0V
1.764
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
60
50
40
30
20
0
2.7
Quiescent Current
vs. Temperature
25
80
70
10
LowQ = 0V
1.809
Turn-On Time
vs. Supply Voltage
1.5
1.3
1.2
VOUT = 3.3V
IOUT = 1mA
LowQ = 0V
1.818
VIN = 3.6V
LowQ = 0V
3.4
4.1
4.8
5.5
SUPPLY VOLTAGE (V)
7
QUIESCENT CURRENT (µA)
10
6
OUTPUT VOLTAGE (V)
1.836
7
VOUT = 3.3V
IOUT = 25mA
LowQ = 0V
10
9
30
20
40
60
80
100
OUTPUT CURRENT (mA)
60
40
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
160
100
0
Dropout Voltage
vs. Temperature
140
DROPOUT VOLTAGE (mV)
CURRENT LIMIT (mA)
IOUT = 100 A
40
Current Limit
vs. Supply Voltage
ENABLE THRESHOLD (V)
IOUT = 0A
Dropout
vs. Output Current
DROPOUT VOLTAGE (mV)
80
PSRR (dB)
PSRR (dB)
PSRR
vs. Input Voltage
IOUT = 50mA
20
15
IOUT = 1mA
IOUT = 100 A
10
5
VIN = 3.6V
LowQ = 0V
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
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MIC2205
Typical Characteristics – LDO Mode (cont.)
Quiescent Current
vs. Temperature
Quiescent Current
vs. Supply Voltage
20
IOUT = 60mA
IOUT = 0A
15
10
5
0
LowQ = 0V
1
2
3
4
5
SUPPLY VOLTAGE (V)
0
25
24
23
22
21
20
19
18
17
16
15
2.7
IOUT = 100 A
LowQ = 0V
3.4
4.1
4.8
5.5
SUPPLY VOLTAGE (V)
QUIESCENT CURRENT (µA)
25
IOUT = 100 A
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
25
Quiescent Current
vs. Output Current
24
23
22
21
20
19
18
17
16
15
0
VIN = 3.6V
LowQ = 0V
20
40
60
80
100
OUTPUT CURRENT (mA)
Output Voltage
vs. Output Current
OUTPUT VOLTAGE (V)
1.836
1.827
1.818
1.809
1.8
1.791
1.782
1.773
1.764
0
April 2005
VIN = 3.6V
VOUT =1.8V
LowQ = 0V
20
40
60
80
100
OUTPUT CURRENT (mA)
8
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MIC2205
Functional Diagram
VIN
AVIN
P-Channel
Current Limit
6
BIAS
HSD
SW
PWM
Control
VOUT
Anti-Shoot
Through
COUT
LSD
N-Channel
Current Limit
R1
EN
Enable and
Control Logic
LOWQ
Bias,
UVLO,
Thermal
Shutdown
FB
Soft
Start
EA
R2
1.0V
LDO Block
LDO
Current
Limit
EA
1.0V
LDO
PGND
SGND
MIC2205 Block Diagram
April 2005
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MIC2205
Functional Characteristics
Load Transient PWM Mode
Output Voltage
AC Coupled
(50mV/div)
Output Current
(100mA/div)
LowQ = VIN
Time 20 s/div
Enable Transient PWM Mode
VOUT
(50mV/div)
ENABLE
(1V/div)
LowQ = 0V
Time 40 s/div
April 2005
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MIC2205
Functional Characteristics
April 2005
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MIC2205
Functional Description
for bypassing.
VIN
VIN provides power to the MOSFETs for the switch
mode regulator section, along with the current
limiting sensing. Due to the high switching speeds, a
1µF capacitor is recommended close to VIN and the
power ground (PGND) pin for bypassing. Please
refer to layout recommendations.
FB
The feedback pin (FB) provides the control path to
control the output. For adjustable versions, a resistor
divider connecting the feedback to the output is used
to adjust the desired output voltage. The output
voltage is calculated as follows:
⎛ R1 ⎞
VOUT = VREF × ⎜
+ 1⎟
⎝ R2 ⎠
AVIN
Analog VIN (AVIN) provides power to the LDO
section and the bias through an internal 6 Ohm
resistor. AVIN and VIN must be tied together.
Careful layout should be considered to ensure high
frequency switching noise caused by VIN is reduced
before reaching AVIN.
where VREF is equal to 1.0V.
A feedforward capacitor is recommended for most
designs using the adjustable output voltage option.
To reduce battery current draw, a 100K feedback
resistor is recommended from the output to the FB
pin (R1). Also, a feedforward capacitor should be
connected between the output and feedback (across
R1). The large resistor value and the parasitic
capacitance of the FB pin can cause a high
frequency pole that can reduce the overall system
phase margin. By placing a feedforward capacitor,
these effects can be significantly reduced.
Feedforward capacitance (CFF) can be calculated as
follows:
LDO
The LDO pin is the output of the linear regulator and
should be connected to the output. In LOWQ mode
(LOWQ<1.5V), the LDO provides the output voltage.
In PWM mode (LOWQ>1.5V) the LDO pin is high
impedance.
EN
The enable pin provides a logic level control of the
output. In the off state, supply current of the device
is greatly reduced (typically <1µA). Also, in the off
state, the output drive is placed in a "tri-stated"
condition, where both the high side P-channel
Mosfet and the low-side N-channel are in an “off” or
non-conducting state. Do not drive the enable pin
above the supply voltage.
CFF =
For fixed options A feed forward capacitor from the
output to the FB pin is required. Typically a 100pF
small ceramic capacitor is recommended
SW
The switch (SW) pin connects directly to the inductor
and provides the switching current nessasary to
operate in PWM mode. Due to the high speed
switching on this pin, the switch node should be
routed away from sensitive nodes.
LOWQ
The LOWQ pin provides a logic level control
between the internal PWM mode and the low noise
linear regulator mode. With LOWQ pulled low
(<0.5V), quiescent current of the device is greatly
reduced by switching to a low noise linear regulator
mode that has a typical IQ of 18µA. In linear (LDO)
mode the output can deliver 60mA of current to the
output. By placing LOWQ high (>1.5V), this
transitions the device into a constant frequency
PWM buck regulator mode. This allows the device
the ability to efficiently deliver up to 600mA of output
current at the same output voltage.
PGND
Power ground (PGND) is the ground path for the
high current PWM mode. The current loop for the
power ground should be as small as possible and
separate from the Analog ground (AGND) loop.
Refer to the layout considerations for more details.
SGND
Signal ground (SGND) is the ground path for the
biasing and control circuitry. The current loop for the
signal ground should be separate from the Power
ground (PGND) loop. Refer to the layout
considerations for more details.
BIAS
The BIAS pin supplies the power to the internal
power to the control and reference circuitry. The bias
is powered from AVIN through an internal 6Ω
resistor. A small 0.1µF capacitor is recommended
April 2005
1
2π × R1× 160kHz
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MIC2205
Applications Information
Output Capacitor
The MIC2205 is a 600mA PWM power supply that
utilizes a LOWQ™ light load mode to maximize
battery efficiency in light load conditions. This is
achieved with a LOWQ control pin that when pulled
low, shuts down all the biasing and drive current for
the PWM regulator, drawing only 18µA of operating
current. This allows the output to be regulated
through the LDO output, capable of providing 60mA
of output current. This method has the advantage of
producing a clean, low current, ultra low noise output
in LOWQ™ mode. During LOWQ™ mode, the SW
node becomes high impedance, blocking current
flow. Other methods of reducing quiescent current,
such as pulse frequency modulation (PFM) or
bursting techniques, create large amplitude, low
frequency ripple voltages that can be detrimental to
system operation.
When more than 60mA is required, the LOWQ pin
can be forced high, causing the MIC2205 to enter
PWM mode. In this case, the LDO output makes a
"hand-off" to the PWM regulator with virtually no
variation in output voltage. The LDO output then
turns off allowing up to 600mA of current to be
efficiently supplied through the PWM output to the
load.
Even though the MIC2205 is optimized for a 2.2µF
output capacitor, output capacitance can be varied
from 1µF to 4.7µF. The MIC2205 utilizes type III
internal compensation and utilizes an internal high
frequency zero to compensate for the double pole
roll off of the LC filter. For this reason, larger output
capacitors can create instabilities. X5R or X7R
dielectrics are recommended for the output
capacitor. Y5V dielectrics lose most of their
capacitance over temperature and are therefore, not
recommended.
In addition to a 2.2µF, a small 10nF is recommended
close to the load for high frequency filtering. Smaller
case size capacitors are recommended due to there
lower ESR and ESL.
Inductor Selection
The MIC2205 is designed for use with a 2.2µH
inductor. Proper selection should ensure the
inductor can handle the maximum average and peak
currents required by the load. Maximum current
ratings of the inductor are generally given in two
methods; permissible DC current and saturation
current. Permissible DC current can be rated either
for a 40°C temperature rise or a 10% to 20% loss in
inductance. Ensure that the inductor selected can
handle the maximum operating current. When
saturation current is specified, make sure that there
is enough margin that the peak current will not
saturate the inductor. Peak inductor current can be
calculated as follows:
Input Capacitor
A minimum 1µF ceramic is recommended on the
VIN pin for bypassing. X5R or X7R dielectrics are
recommended for the input capacitor. Y5V
dielectrics lose most of their capacitance over
temperature and are therefore, not recommended.
A minimum 1µF is recommended close to the VIN
and PGND pins for high frequency filtering. Smaller
case size capacitors are recommended due to their
lower ESR and ESL. Please refer to layout
recommendations for proper layout of the input
capacitor.
April 2005
IPK = IOUT
13
⎛
V
VOUT ⎜⎜1 − OUT
VIN
⎝
+
2× f ×L
⎞
⎟
⎟
⎠
M9999-041105
www.micrel.com
Micrel, Inc.
MIC2205
Layout Recommendations
VOUT
L1
CBIAS
GND
VIN
LowQ
MIC2205
EN
CFF
R1
R2
Top
L1
VOUT
CBIAS
GND
VIN
LowQ
MIC2205
EN
CFF
R1
R2
Bottom
Note:
The above figures demonstrate the recommended layout for the MIC2205 adjustable option.
April 2005
14
M9999-041105
www.micrel.com
Micrel, Inc.
MIC2205
MIC2205
V IN
2.7V to 5.5V
C1
1µF
LowQ
8
VIN
SW
9
4
AVIN
LDO
2
6
EN
FB
5
7
LOWQ
3
BIAS
C2
0.1µF
2.2µH
VOUT
R1
100k
C3
100pF
C4
2.2µF
R2
125k
PGND AGND
10
GND
1
GND
Adjustable Output
MIC2205
V IN
2.7V to 5.5V
C1
1µF
LowQ
C2
0.1µF
8
VIN
SW
9
4
AVIN
LDO
2
6
EN
FB
5
7
LOWQ
3
BIAS
2.2µH
VOUT
C3
100pF
C4
2.2µF
PGND AGND
GND
10
1
GND
Fixed Output
Item
Part Number
Description
Manufacturer
C1
06036D105MAT2
GRM185R60J105KE21D
1µF Ceramic Capacitor X5R, 6.3V 0603
1µF Ceramic Capacitor X5R, 6.3V 0603
AVX
(4)
Murata
1
C4
06036D225MAT2
GRM188R61A225KE34
2.2µF Ceramic Capacitor X5R, 10V 0603
2.2µuF Ceramic Capacitor X5R, 10V 0603
AVX
(4)
Murata
1
C3
VJ0402A101KXAA
100pF Ceramic Capacitor
Vishay
1
C2
0201ZD103MAT2
GRM033R10J103KA01D
10nF Ceramic Capacitor 6.3V 0201
10nF Ceramic Capacitor 6.3V 0201
AVX
(4)
Murata
1
L1
LQH32CN2R2M53K
CDRH2D14-2R2
2.2µH Inductor 97mΩ 3.2mmx2.5mmx1.55mm
2.2µH Inductor 94mΩ 3.2mmx3.2mmx1.55mm
Murata
(2)
Sumida
CRCW04021002F
100kΩ 1% 0402
Vishay Dale
Vishay Dale
(3)
Vishay Dale
(3)
Vishay Dale
(3)
Vishay Dale
(3)
Vishay Dale
(1)
R1
(1)
(3)
Qty
(4)
1
(3)
1
(3)
R2
CRCW04026652F
CRCW04021243F
CRCW04022003F
CRCW04024023F
66.5 kΩ 1% 0402 For 2.5VOUT
124 kΩ 1% 0402 For 1.8 VOUT
200 kΩ 1% 0402 For 1.5 VOUT
402 kΩ 1% 0402 For 1.2 VOUT
Open
For 1.0 VOUT
U1
MIC2205BML
2MHz Synchronous Buck Regulator with LOWQ
Mode
TM
Micrel, Inc.
(5)
1
Notes:
1. For adjustable version only.
2. Sumida Tel: 408-982-9660
3. Murata Tel: 949-916-4000
4. Vishay Tel: 402-644-4218
5. Micrel, Inc. Tel: 408-944-0800
April 2005
15
M9999-041105
www.micrel.com
Micrel, Inc.
MIC2205
Package Information
10-Lead MLF™ (ML)
MICREL, INC. 2180 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL +1 (408) 944-0800 FAX +1 (408) 474-1000 WEB http:/www.micrel.com
The information furnished by Micrel in this data sheet is believed to be accurate and reliable. However, no responsibility is assumed by Micrel
for its use. Micrel reserves the right to change circuitry and specifications at any time without notification to the customer.
Micrel Products are not designed or authorized for use as components in life support appliances, devices or systems where malfunction of a
product can reasonably be expected to result in personal injury. Life support devices or systems are devices or systems that (a) are intended
for surgical implant into the body or (b) support or sustain life, and whose failure to perform can be reasonably expected to result in a
significant injury to the user. A Purchaser’s use or sale of Micrel Products for use in life support appliances, devices or systems is a
Purchaser’s own risk and Purchaser agrees to fully indemnify Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
April 2005
16
M9999-041105
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