MICREL MIC2225

MIC2225
2MHz 600mA Synchronous Buck
Regulator with 300mA LDO
General Description
Features
The Micrel MIC2225 is a dual output regulator featuring a
high efficiency 2MHz PWM synchronous buck (step-down)
regulator and a 300mA LDO. The MIC2225 is an ultra-low
noise, small size, and high efficiency solution for portable
power applications, providing core and I/O supply rails for
applications like application processors, camera DSPs and
multimedia chipsets.
In PWM mode, the MIC2225 operates with a constant
2MHz frequency. The MIC2225 switching regulator
operates from 2.7V to 5.5V input and features internal
power MOSFETs that can supply up to 600mA output
current in PWM mode.
The MIC2225 is available in the 10-pin 2mm x 2mm Thin
MLF® 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.
DC-DC Converter
• 2.7 to 5.5V supply voltage
• 2MHz PWM mode
• Output current to 600mA
• >95% efficiency
• 100% maximum duty cycle
• Fixed output voltage option down to 1V
• Ultra-fast transient response
• Stable with 2.2µF ceramic output capacitor
• Fully integrated MOSFET switches
• Micropower shutdown (1mA in shutdown)
• Thermal shutdown and current limit protection
• Pb-free 10-pin 2mm x 2mm Thin MLF® package
• –40°C to +125°C junction temperature range
LDO
• VIN range 2.7V to 5.5V
• 300mA output current
• Output voltage down to 0.8V
• Thermal shutdown protection
• Current limit protection
Applications
• Cellular phones
• PDAs
• USB peripherals
___________________________________________________________________________________________________________
Typical Application
1.8V Efficiency @ 25°C
100
90
2.7VIN
80
70
60
50
3.6VIN
5.5VIN
40
30
20
10
0
0
0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6
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
October 2007
M9999-101107-B
Micrel, Inc.
MIC2225
Ordering Information
Part Number
Voltage
Temperature Range
Package
MIC2225-4MYMT
1.2V/2.8V
–40° to +125°C
10-Pin 2x2 Thin MLF®
Pb-Free
–40° to +125°C
10-Pin 2x2 Thin MLF
®
Pb-Free
®
Pb-Free
Pb-Free
MIC2225-4SYMT
1.2V/3.3V
Lead Finish
MIC2225-G4YMT
1.8V/1.2V
–40° to +125°C
10-Pin 2x2 Thin MLF
MIC2225-GFYMT
1.8V/1.5V
–40° to +125°C
10-Pin 2x2 Thin MLF®
Note:
1. For other voltages available. Contact Micrel Marketing for details.
Pin Configuration
AGND
1
10 PGND
LDO
2
9
SW
BIAS
3
8
VIN
AVIN
4
7
ENLDO
FB
5
6
EN
10-Pin 2mm x 2mm Thin MLF® (MT)
Pin Description
Pin Number
Pin Name
1
AGND
Pin Function
Analog (signal) Ground.
2
LDO
LDO Output (Output): Connect to a 2.2µF output capacitor.
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 switching regulator reducing the
quiescent current to less than 5µA.
7
ENLDO
8
VIN
9
SW
10
PGND
October 2007
Enable LDO (Input): Logic low will shut down the LDO, reducing the quiescent
current to less than 5µA.
Supply Voltage (Input): Supply voltage for the internal switches and drivers.
Switch (Output): Internal power MOSFET output switches.
Power Ground.
2
M9999-101107-B
Micrel, Inc.
MIC2225
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) .......................................................+6V
Output Switch Voltage (VSW) ..........................................+6V
Output Switch Current (ISW)..............................................1A
Logic Input Voltage (VEN,VLOWQ)........................ –0.3V to VIN
Storage Temperature (Ts) .........................–60°C to +150°C
ESD Rating(3) .................................................................. 2kV
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
Thin MLF-10L (θJA) ............................................90°C/W
Electrical Characteristics DC/DC(4)
VEN = VIN = 3.6V, L = 2.2µH; COUTDC/DC = 2.2µF, CLDO = 2.2µF; IOUTDC/DC = 100mA; CBIAS = 0.1µF
VENLDO = 0V; TJ = 25°C, bold values indicate –40°C < TJ < +125°C; unless noted.
Parameter
Condition
Min
Typ
Max
UVLO Threshold
Rising input voltage during turn-on
2.45
2.55
2.65
UVLO Hysteresis
70
Units
V
mV
Switcher Ground Pin Current
ENLDO = 0V, VFB = GND ; IL=0mA
850
1100
µA
LDO Ground Pin Current
EN = 0V
67
110
µA
Ground Pin Current in
Shutdown
EN +ENLDO = 0V
0.2
5
µA
Over-temperature Shutdown
160
°C
Over-temperature Shutdown
Hysteresis
23
°C
Enable Input Voltage
Logic Low
Logic High
Enable Input Current
0.2
V
V
1.0
VIL < 0.2V
0.1
1
µA
VIH > 1.0V
0.1
1
µA
Turn-on Time
ILOAD = 5mA
50
Fixed Output Voltages
Nominal VOUT tolerance Io=50mA
Current Limit in PWM Mode
VFB = 0.9*VNOM
Output Voltage Line Regulation
VIN = 2.7V to 5.5V, ILOAD= 100mA
Output Voltage Load Regulation
20mA < ILOAD < 300mA
Maximum Duty Cycle
VFB ≤ 0.4V
PWM Switch ON-Resistance
ISW = 150mA; VFB = 0.7VFB_NOM
ISW = -150mA; VFB = 1.1VFB_NOM
0.675
+2
+3
%
%
0.12
1
%
%
0.2
1.5
%
0.95
A
100
%
Ω
Ω
0.4
0.4
Oscillator Frequency
October 2007
–2
–3
µs
1.8
3
2
2.2
MHz
M9999-101107-B
Micrel, Inc.
MIC2225
Electrical Characteristics LDO(4)
COUTLDO = 2.2µF, IOUTLDO = 100µA; TJ = 25°C, bold values indicate –40°C < TJ < +125°C; unless noted.
Parameter
Input Voltage
Output Voltage Accuracy
Line Regulation
Turn-on Time
Load Regulation
Dropout Voltage, Note 5
Ripple Rejection
Current Limit
Output Voltage Noise
Condition
Min
Variation from nominal VOUT
Variation from nominal VOUT; –40°C to +125°C
VIN = VOUT +1V to 5.5V; IOUT = 100µA
ILOAD = 300mA
IOUT = 100µA to 300mA @ VIN = VOUT + 1
IOUT = 300mA @ VIN = 2.7V
f = 1kHz; COUT = 2.2µF
f = 20kHz; COUT = 2.2µF
VOUT = 0V
COUT = 2.2µF, 10Hz to 100kHz
Typ
2.7
–2.0
–3.0
0.2
30
0.70
210
43
17
400
470
Max
Units
5.5
+2.0
+3.0
V
%
%
%
µs
%
mV
dB
dB
mA
µVRMS
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, 1.5k 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.
October 2007
4
M9999-101107-B
Micrel, Inc.
MIC2225
Typical Characteristics (DC-DC)
1.2V Efficiency @ –40°C
100
90
2.7VIN
3.6VIN
80
1.2V Efficiency @ 25°C
100
90
70
60
5.5VIN
50
40
50
40
30
30
20
10
20
10
150
0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6
Quiescent Current
vs. Input Voltage
0
0
1200
125
1000
100
800
75
600
50
VOUT = 1.2V
LOAD = 0
ENLDO = 0V
EN = VIN
25
0
2.5
100
90
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
5.5
Turn-On Time
vs. Input Voltage
3.6VIN
5.5VIN
0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6
Quiescent Current
vs. Load Current
VOUT = 1.19V
VLDO = 2.8V
ENLDO = 5V
20
10
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
October 2007
5.5
5.5VIN
0.1 0.2 0.3 0.4 0.5
LOAD CURRENT (A)
0.6
Enable Threshold
vs. Input Voltage
1.0
0.8
0.6
VOUT = 1.2V
EN = VIN
ENLDO = 0V
30 40 50 60
LOAD CURRENT (mA)
Peak Current Limit
vs. Input Voltage
0.4
VOUT = 1.19V
ENLDO = 5V
0.2
0
2.5
2.9
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
5.5
Frequency
vs. Input Voltage
2.7
2.5
2.3
2.1
0.3
0.2
0.1
0
2.5
3.6VIN
1.2
0.5
0.4
40
30
10
0
0
1.4
0.7
0.6
60
50
2.7VIN
40
30
20
200
0
90
80
70
60
50
400
1.0
0.9
0.8
80
70
0
2.5
100
2.7VIN
80
70
60
0
0
1.2V Efficiency @ 70°C
1.9
VOUT = 1.2V
EN = ENLDO = VIN
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
5
5.5
VOUT = 1.2V
LOAD = 0
ENLDO = VIN
1.7
1.5
2.5
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
5.5
M9999-101107-B
Micrel, Inc.
MIC2225
Typical Characteristics (LDO)
PSRR
70
90
60
80
100mA
78
76
74
72
70
60
40 300mA
30
40
30
20
VIN = 1.7V
10 VOUT = 2.8V
COUT = 2.2µF
0
100
1K
10K
FREQUENCY (Hz)
100
10
100K
0
0
3.00
2.95
ENLDO = VIN
1
2
3
4
INPUT VOLTAGE (V)
5
Output Voltage
vs. Load Current
2.80
2.75
2.75
2.70
1mA
2.65
25
VIN = 3.6V
ENLDO = VIN
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Output Voltage
vs. Temperature
2.86
2.60
2.55
VIN = 3.6V
ENLDO = VIN
2.50
0.025 0.075 0.125 0.175 0.225 0.275
LOAD CURRENT (A)
0.20
0.18
2.84
2.82
Dropout Voltage
vs. Load Current
2.70
2.65
2.60
50
40
30
2.76
0.12
0.10
2.74
2.72
0.08
0.06
20
VIN = 3.6V
ENLDO = VIN
Load = 10mA
2.70
2.68
2.66
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
2.0
1.8
Peak Current Limit
vs. Input Voltage
50
45
1.6
40
1.4
1.2
35
30
1.0
0.8
25
20
0.6
15
0.4
0.2
10
5
0
2.5
EN = ENLDO = VIN
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
October 2007
5.5
0
2.5
Dropout Voltage
vs. Temperature
ENLDO = VIN
50mA
0.04
0.02
0
0
VIN = 3.6V
ENLDO = VIN
Load = 1mA
2.55
2.50
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
0.16
0.14
2.8
2.78
Output Voltage
vs. Temperature
3.00
2.85
2.80
100mA
VIN = 3.6V
62
ENLDO = VIN
60
0.025 0.075 0.125 0.175 0.225 0.275
LOAD CURRENT (A)
2.95
2.90
2.85
2.90
50mA
50
68
66
64
0mA
20
Quiescent Current
vs. Temperature
125
100mA
50
10mA
Quiescent Current
vs. Load Current
80
60mA
70
50
75
Quiescent Current
vs. Input Voltage
VIN = 3.6V
ENLDO = VIN
0.05 0.1 0.15 0.2 0.25 0.3
LOAD CURRENT (A)
Turn-On Time
vs. Input Voltage
25mA
10mA
10
1mA
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
1.4
Enable Threshold
vs. Input Voltage
1.2
1.0
0.8
0.6
0.4
0.2
ENLDO = VIN
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
6
5.5
0
2.5
3
LDO = 2.8V
3.5
4
4.5
5
5.5
INPUT VOLTAGE (V)
M9999-101107-B
Micrel, Inc.
MIC2225
Typical Characteristics (LDO) continued
3.0
Output Noise
Spectral Density
VIN = 3.6V
VOUT = 3.3V
COUT = 2.2µF
CBYP = 0.1µF
2.5
2.0
Noise(10Hz–100kHz) = 169µVRMS
1.5
1.0
0.5
0
10
100
1K
10K 100K
FREQUENCY (Hz)
October 2007
1M
7
M9999-101107-B
Micrel, Inc.
MIC2225
Functional Characteristics
October 2007
8
M9999-101107-B
Micrel, Inc.
MIC2225
Functional Diagram
VIN
AVIN
P-Channel
Current Limit
6
BIAS
HSD
PWM
Control
SW
VOUT1
Anti-Shoot
Through
COUT1
LSD
N-Channel
Current Limit
EN
ENLDO
Enable and
Control Logic
Bias,
UVLO,
Thermal
Shutdown
Soft
Start
FB
EA
1.0V
LDO
LDO Block
LDO
Current
Limit
EA
VOUT2
COUT2
1.0V
SGND
PGND
MIC2225 Block Diagram
October 2007
9
M9999-101107-B
Micrel, Inc.
MIC2225
Functional Description
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 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, it is
recommended that an 1µF capacitor be placed 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 fixed output, the controller
output is directly connected to the feedback (FB) pin.
AVIN
Analog VIN (AVIN) provides power to the LDO section
and the bias through an internal 6Ω 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.
SW
The switch (SW) pin connects directly to the inductor
and provides the switching current necessary to operate
in PWM mode. Due to the high speed switching on this
pin, the switch node should be routed away from
sensitive nodes.
LDO
The LDO pin is the output of the linear regulator and
needs to be connected to a 2.2µF output capacitor.
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.
EN
The enable pin provides a logic level control of the
output. In the off state, the 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,
wherein 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.
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.
ENLDO
The enable pin provides a logic level control of the LDO
output. In the off state, supply current of the device is
greatly reduced (typically <1µA). Do not drive the enable
pin above the supply voltage.
October 2007
10
M9999-101107-B
Micrel, Inc.
MIC2225
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.
Application Information
The MIC2225 is a 600mA PWM and 300mA LDO dual
power supply. Both PWM output and LDO outputs are
independent and are controlled by EN and ENLDO pins
respectively. These enable pins are logic level
compatible.
Inductor Selection
The MIC2225 is designed for use with a 2.2µH inductor.
Proper selection should ensure that the inductor can
handle the maximum average and peak currents
required by the load. Maximum current ratings for 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 so 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 loose most of
their capacitance over temperature and are therefore,
not recommended.
A minimum 1µF is recommended for placement 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.
Output Capacitor
Even though the MIC2225 is optimized for a 2.2µF
output capacitor, output capacitance can be varied from
1µF to 10µF. The MIC2225 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,
October 2007
IPK = IOUT
11
⎛
V
VOUT ⎜⎜1 − OUT
VIN
⎝
+
2× f ×L
⎞
⎟⎟
⎠
M9999-101107-B
Micrel, Inc.
MIC2225
PCB Layout Recommendations
Top Layer
Bottom Layer
Note:
The above figures demonstrate the recommended layout for the MIC2225 fixed output option.
October 2007
12
M9999-101107-B
Micrel, Inc.
MIC2225
8
R1
10k
1
2
JP1
1X2
L1
0.47µH / 2.2µH
MIC2225
J1
VIN
5.5V Max
J7
ENLDO
J6
EN
C1
2.2µF/
6.3V
R2
10k
C2
0.1µF/
6.3V
J2
GND
VIN
SW
9
4
AVIN
FB
5
6
EN
7
ENLDO
LDO
2
3
BIAS
PGND AGND
10
R3
0
C3
2.2µF/
6.3V
J3
VO1
C4
2.2µF/
6.3V
J4
VO2
J5
GND
1
Schematic Diagram
Bill of Materials
Item
C1
C2
Part Number
C1608X5R0J225K
VJ0402Y104KXQCW1BC
Manufacturer
TDK
(1)
Vishay Vitramon
2.2µF/6.3V, X5R
1
2.2µF/6.3V, X5R
1
(2)
10k, 0603, 1/16W, 1%
1
(2)
10k, 0603, 1/16W, 1%
1
0, 0805, 1/8W, 1%
1
2.2µH, 1.1A (Isat)
1
2Mhz PWM Synchronous Buck Regulator
with 300mA LDO
1
TDK
C1608X5R0J225K
TDK(1)
Vishay Dale
R2
CRCW06031002FKEYE3
Vishay Dale
R3
CRCW08050000FKEYE3
Vishay Dale(2)
CDRH2D11/HPNP-2R2NC
U1
MIC2225-XYMT
1
1
C1608X5R0J225K
L1
2.2µF/6.3V, X5R
0.1µF/6.3V, X7R
C4
CRCW06031002FKEYE3
Qty.
(1)
C3
R1
(2)
Description
Sumida
(3)
(4)
Micrel, Inc.
Notes:
1. TDK: www.tdk.com
2. Vishay: www.vishay.com
3. Sumida: www.sumida.com
4. Micrel, Inc.: www.micrel.com
October 2007
13
M9999-101107-B
Micrel, Inc.
MIC2225
Package Information
10-Pin Thin MLF® (MT)
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.
© 2007 Micrel, Incorporated.
October 2007
14
M9999-101107-B