MICREL MIC2605

MIC2605/6
0.5A, 1.2MHz / 2MHz Wide Input Range
Boost Regulator with Integrated Switch
and Schottky Diode
General Description
Features
The MIC2605/6 is a 1.2MHz/2MHz, PWM DC/DC boost
switching regulator available in a 2mm x 2mm MLF®
package. High power density is achieved with the
MIC2605/6’s internal 40V/0.5A switch and schottky diode,
allowing it to power large loads in a tiny footprint.
The
MIC2605/6
implements
constant
frequency
1.2MHz/2MHz PWM current mode control. The MIC2605/6
offers internal compensation that offers excellent transient
response and output regulation performance. The high
frequency operation saves board space by allowing small,
low-profile external components. The fixed frequency
PWM scheme also reduces spurious switching noise and
ripple to the input power source.
The MIC2605/6 is available in an 8-pin 2mm x 2mm MLF®
leadless package. This package has an output overvoltage protection feature.
The MIC2605/6 has an operating junction temperature
range of –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Wide input voltage range: 4.5V to 20V
Output voltage adjustable to 40V
0.5A switch current and schottky diode
MIC2605 operates at 1.2MHz
MIC2606 operates at 2MHz
Programmable soft start
Stable with small size ceramic capacitors
High efficiency
Low input and output ripple
<10µA shutdown current
UVLO
Output over-voltage and over-temperature protection
8-pin 2mm x 2mm MLF® package
–40°C to +125°C junction temperature range
Applications
• TV-tuners
• Broadband communications
• TFT-LCD bias supplies
• Bias supply
• Positive output regulators
• SEPIC converters
• DSL applications
• Local boost regulators
___________________________________________________________________________________________________________
Typical Application
10µH
32V OUT Efficiency
VOUT
32V, 30mA
MIC2605/6
VIN
VIN = 12V
EN
1µF
0.1µF
VDD
SS
SW
OUT
FB
80
12.4K
70
60
50
1µF
PGND
90
499
0.1µF
40
30
20
10
0
20
VIN = 12V
40
60
80
100 120
LOAD CURRENT (mA)
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
September 2009
M9999-090909-B
Micrel, Inc.
MIC2605/6
Ordering Information
(2)
Part Number
Marking
Code(1)
Frequency
Output Over
Voltage Protection
Temperature Range
MIC2605YML
WZ5
1.2MHz
40V
–40° to +125°C
8-Pin 2mm x 2mm MLF®
Pb-Free
–40° to +125°C
®
Pb-Free
MIC2606YML
WZ6
2MHz
40V
Lead Finish
Package
8-Pin 2mm x 2mm MLF
Notes
1.
Overbar (
2.
MLF is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
) symbol my not be to scale.
®
Pin Configuration
VOUT
1
8
PGND
VIN
2
7
SW
VDD
3
6
FB
EN
4
5
SS
8-Pin 2mm x 2mm MLF® (ML)
Pin Description
Pin Number
Pin Name
1
VOUT
2
VIN
Supply (Input): 4.5V to 20V input voltage.
3
VDD
Internal regulated supply. VDD should be connected to VIN when VIN ≤ 7V.
4
EN
Enable (Input): Logic high enables regulator. Logic low shuts down regulator.
5
SS
Soft start
6
FB
Feedback (Input): 1.25V output voltage sense node. VOUT = 1.25V (1 + R1/R2).
7
SW
Switch Node (Input): Internal power BIPOLAR collector.
8
PGND
Power ground
EP
EPAD
Exposed backside pad for thermal cooling.
September 2009
Pin Function
Output Pin: Connect to the output capacitor.
2
M9999-090909-B
Micrel, Inc.
MIC2605/6
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) .......................................................22V
Switch Voltage (VSW)....................................... –0.3V to 40V
Enable Voltage (VEN)......................................... –0.3V to VIN
FB Voltage (VFB)............................................................. VDD
Ambient Storage Temperature (Ts) ...........–65°C to +150°C
Lead Temperature (soldering 10sec)......................... 260°C
ESD Rating(3) (MIC2605)................................................ 2kV
ESD Rating(3) (MIC2606)............................................. 1.5kV
Supply Voltage (VIN).......................................... 4.5V to 20V
Junction Temperature (TJ) ........................ –40°C to +125°C
Junction Thermal Resistance
2mm x 2mm MLF-8 (θJA) ...................................90°C/W
2mm x 2mm MLF-8 (θJC) ...................................45°C/W
Electrical Characteristics(4)
TA = 25°C, VIN = VEN = 12V; unless otherwise noted. Bold values indicate –40°C ≤ TJ ≤ +125°C.
Symbol
Parameter
VIN
Input Voltage Range
Condition
Min
Typ
4.5
VDD
Internal Regulated Voltage
Note 5
VULVO
Under-voltage Lockout
For VDD
Max
Units
20
V
2.4
V
5.8
1.8
2.1
V
IQ
Quiescent Current
VFB = 2V (not switching)
4.2
6
mA
ISD
Shutdown Current
VEN = 0V, Note 6
0.1
10
µA
VFB
Feedback Voltage
(±2%)
1.225
1.25
1.275
V
(±3%) (over temperature)
1.212
IFB
Feedback Input Current
1.288
VFB = 1.25V
–550
Line Regulation
8V ≤ VIN ≤ 14V, VOUT = 18V
0.04
Load Regulation
5mA ≤ IOUT ≤ 40mA, VOUT = 18V, Note 7
Maximum Duty Cycle
MIC2605
MIC2606
85
80
ISW
Switch Current Limit
Note 7
0.5
VSW
Switch Saturation Voltage
ISW = 0.5A
ISW
Switch Leakage Current
VEN = 0V, VSW = 18V
VEN
Enable Threshold
Turn ON
Turn OFF
IEN
Enable Pin Current
fSW
Oscillator Frequency (MIC2605)
Oscillator Frequency (MIC2606)
DMAX
1
%
1.5
%
%
%
0.8
A
600
mV
0.01
5
µA
0.3
V
V
20
40
µA
1.02
1.2
1.38
MHz
1.7
2
2.3
MHz
1.5
VEN = 12V
VD
Schottky Forward Drop
ID = 1mA
ID = 150mA
IRD
Schottky Leakage Current
VR = 30V
VOVP
Output Over-voltage Protection
15% Over programmed VOUT
TJ
Over-temperature Threshold
Shutdown
Hysteresis
V
nA
450
850
10
mV
mV
0.1
4
µA
15
20
%
150
°C
10
°C
Notes:
1. Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when operating
the device outside of its operating ratings. The maximum allowable power dissipation is a function of the maximum junction temperature, TJ(Max), the
junction-to-ambient thermal resistance, θ JA, and the ambient temperature, TA. The maximum allowable power dissipation will result in excessive die
temperature, and the regulator will go into thermal shutdown.
2. The device is not guaranteed to function outside its operating rating.
3. IC devices are inherently ESD sensitive. Handling precautions required. Human body model rating: 1.5k in series with 100pF.
4. Specification for packaged product only.
5. Connect VDD pin to VIN pin when VIN ≤ 7V.
6. ISD = IVIN.
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
7. Guaranteed by design.
September 2009
4
M9999-090909-B
Micrel, Inc.
MIC2605/6
Typical Characteristics
Frequency
vs. Input Voltage
2.0
Quiescent Current
vs. Input Voltage
7
97
6
96
5
95
1.6
4
94
1.4
3
93
2
92
MIC2606
1.8
1.2
1.0
468
10 12 14 16
INPUT VOLTAGE (V)
18
Switch Saturation Voltage
vs. Input Voltage
1100
1000
900
800
700
600
500
400
300
200
100
0
46
–50mA
–0.25A
–0.45A
–0.65A
–0.85A
–0.1A
–0.3A
–0.5A
–0.7A
91
1
MIC2605
–0.15A
–0.35A
–0.55A
–0.75A
–0.2A
–0.4A
–0.6A
–0.8A
81 01 21 41 61 82 0
INPUT VOLTAGE (V)
0
13579
1100
1000
900
800
700
600
500
400
300
200
100
0
–4.5V –5V –6V –7V –8V –9V
–10V –11V –12V –15V –20
32.9
Load = 40mA
10 12 14 16 18
INPUT VOLTAGE (V)
0.85
0.75
0.70
0.65
0.60
46
SWITCH CURRENT (mA)
32V OUT Efficiency
12VIN
Feedback Voltage
vs. Temperature
1.264
90
80
70
4.5VIN
60
50
40
40
30
30
20
20
10
10
1.00
12 16 20 24 28 32 36 40
LOAD CURRENT (mA)
Switch Current Limit
vs. Temperature
0
20
1000
0.95
1.258
1.256
VIN = 12V
40
60
80
100 120
LOAD CURRENT (mA)
VSAT
vs. Temperature
ISW=750mA
1.262
1.260
EN = VIN
81 01 21 41 61 82 0
INPUT VOLTAGE (V)
32V OUT Efficiency
50
0
48
Switch Current Limit
vs. Input Voltage
0.80
60
33.0
1.00
EN = VIN
81 01 21 41 61 82 0
INPUT VOLTAGE (V)
0.95
70
33.1
90
46
0.90
80
33.2
1.266
11 13 15 17 19
INPUT VOLTAGE (V)
90
33.3
32.8
468
No Switching FB Pin @ 2V
Switch Saturation Voltage
vs. Switch Current
Line Regulation
33.4
Max Duty Cycle
vs. Input Voltage
0.90
ISW=400mA
0.85
100
0.80
1.254
VIN = 12V
Load = 100mA
1.250
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
1.252
September 2009
0.75
VIN = 12V
0.70
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
5
ISW=100mA
10
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
M9999-090909-B
Micrel, Inc.
MIC2605/6
Typical Characteristics (continued)
1.270
Enable Threshold ON
vs. Temperature
1.265
100
98
Max Duty Cycle
vs. Temperature
2.0
MIC2606
96
1.8
1.260
94
92
1.6
1.255
90
88
1.4
1.250
86
1.245
VIN = 12V
1.240
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
25
24
Frequency
vs. Temperature
Enable Current
vs. Temperature
1.2
84
82
1.0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Shutdown Current
vs. Temperature
Quiescent Current
vs. Temperature
0.100
0.090
22
21
4.22
4.20
0.085
20
19
0.080
18
0.075
17
16
0.070
VIN = 12V
15
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
4.30
4.28
4.26
4.24
0.095
23
MIC2605
VIN = 12V
80
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
4.18
4.16
4.14
VIN = 12V
0.065
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
4.12
VIN = 12V
4.10
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Thermal Derating
400
350
300
250
200
150
100
50 VIN = 12V
VOUT = 18V
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
Functional Characteristics
September 2009
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Micrel, Inc.
MIC2605/6
Functional Diagram
VIN
VDD
FB
VOUT
OVP CMP
Regulator
EN
OVP
CL
THERMAL
UVLO
BANDGAP
5.8V
Bandgap
SW
OSC
EA
1.25V
S
PWM
CMP
R
SS
+
1.2/2MHz
Oscillator
OSC
+
Ramp
Generator
CA
PGND
Figure 1. MIC2605/6 Block Diagram
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
Functional Description
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 <0.1µA). Also, in the off state,
the output drive is placed in a "tri-stated" condition,
where bipolar output transistor is in an “off” or nonconducting state. Do not drive the enable pin above the
supply voltage.
The MIC2605/6 is a constant frequency, PWM current
mode boost regulator. The block diagram is shown in
Figure 1. The MIC2605/6 is composed of an oscillator,
slope compensation ramp generator, current amplifier,
gm error amplifier, PWM generator, and a 0.5A bipolar
output transistor. The oscillator generates a 1.2MHz/
2MHz clock. The clock’s two functions are to trigger the
PWM generator that turns on the output transistor and to
reset the slope compensation ramp generator. The
current amplifier is used to measure the switch current
by amplifying the voltage signal from the internal sense
resistor. The output of the current amplifier is summed
with the output of the slope compensation ramp
generator. This summed current-loop signal is fed to one
of the inputs of the PWM generator.
The gm error amplifier measures the feedback voltage
through the external feedback resistors and amplifies the
error between the detected signal and the 1.25V
reference voltage. The output of the gm error amplifier
provides the voltage-loop signal that is fed to the other
input of the PWM generator. When the current-loop
signal exceeds the voltage-loop signal, the PWM
generator turns off the bipolar output transistor. The next
clock period initiates the next switching cycle,
maintaining the constant frequency current-mode PWM
control.
SS
The SS pin is the soft start pin which allows the
monotonic buildup of output when the MIC2605/6 comes
up during turn on. The SS pin gives the designer the
flexibility to have a desired soft start by placing a
capacitor SS to ground. A 0.1µF capacitor is used for in
the circuit.
FB
The feedback pin (FB) provides the control path to
control the output. For fixed output controller output is
directly connected to feedback (FB) pin.
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 and high
voltage associated with this pin, the switch node should
be routed away from sensitive nodes.
Pin Description
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.
VIN
VIN provides power to the MOSFETs for the switch
mode regulator section. 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.
VOUT
VOUT pin is the cathode of pin of internal schottky
diode. This pin is connected to output cap. At least 1µF
cap is recommended very close to the VOUT pin and
PGND.
VDD
The VDD pin supplies the power to the internal power to
the control and reference circuitry. The VDD is powered
from VIN. A small 0.1µF capacitor is recommended for
bypassing.
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
Component Selection
Inductor
Inductor selection is a balance between efficiency,
stability, cost, size, and rated current. For most
applications, a 10µH is the recommended inductor
value; it is usually a good balance between these
considerations. Large inductance values reduce the
peak-to-peak ripple current, affecting efficiency. This has
an effect of reducing both the DC losses and the
transition losses. There is also a secondary effect of an
inductor’s DC resistance (DCR). The DCR of an inductor
will be higher for more inductance in the same package
size. This is due to the longer windings required for an
increase in inductance. Since the majority of input
current (minus the MIC2605/6 operating current) is
passed through the inductor, higher DCR inductors will
reduce efficiency. To maintain stability, increasing
inductor size will have to be met with an increase in
output capacitance. This is due to the unavoidable “right
half plane zero” effect for the continuous current boost
converter topology. The frequency at which the right half
plane zero occurs can be calculated as follows:
Application Information
DC-to-DC PWM Boost Conversion
The MIC2605/6 is a constant frequency boost converter.
It operates by taking a DC input voltage and regulating a
higher DC output voltage. Figure 2 shows a typical
circuit. Boost regulation is achieved by turning on an
internal switch, which draws current through the inductor
(L1). When the switch turns off, the inductor’s magnetic
field collapses, causing the current to be discharged into
the output capacitor through an internal Schottky diode.
Voltage regulation is achieved through pulse-width
modulation (PWM).
10µH
VOUT
32V, 30mA
MIC2605/6
VIN
VIN = 12V
EN
1µF
0.1µF
VDD
SS
SW
OUT
FB
12.4K
1µF
PGND
499
0.1µF
FRHPZ =
Figure 2. Typical Application Circuit
Duty Cycle Considerations
Duty cycle refers to the switch on-to-off time ratio and
can be calculated as follows for a boost regulator:
D = 1−
2 ⋅ π ⋅ L ⋅ IO
The right half plane zero has the undesirable effect of
increasing gain, while decreasing phase. This requires
that the loop gain is rolled off before this has significant
effect on the total loop response. This can be
accomplished by either reducing inductance (increasing
RHPZ frequency) or increasing the output capacitor
value (decreasing loop gain).
VIN
VOUT
The duty cycle required for voltage conversion should be
less than the maximum duty cycle of 85%. Also, in light
load conditions where the input voltage is close to the
output voltage, the minimum duty cycle can cause pulse
skipping. This is due to the energy stored in the inductor
causing the output to overshoot slightly over the
regulated output voltage. During the next cycle, the error
amplifier detects the output as being high and skips the
following pulse. This effect can be reduced by increasing
the minimum load or by increasing the inductor value.
Increasing the inductor value reduces peak current,
which in turn reduces energy transfer in each cycle.
Output Capacitor
Output capacitor selection is also a trade-off between
performance, size, and cost. Increasing output
capacitance will lead to an improved transient response,
but also an increase in size and cost. X5R or X7R
dielectric ceramic capacitors are recommended for
designs with the MIC2605/6. Y5V values may be used,
but to offset their tolerance over temperature, more
capacitance is required.
Input capacitor
A minimum 1μF ceramic capacitor is recommended for
designing with the MIC2605/6. Increasing input
capacitance will improve performance and greater noise
immunity on the source. The input capacitor should be
as close as possible to the inductor and the MIC2605/6,
with short traces for good noise performance.
Overvoltage Protection
For the MIC2605/6 there is an over voltage protection
function. If the output voltage overshoots the set voltage
by 15% when feedback is high during input higher than
output, turn on, load transients, line transients, load
disconnection etc. the MIC2605/6 OVP ckt will shut the
switch off saving itself and other sensitive circuitry
downstream.
September 2009
(D )2 ⋅ VO
10
M9999-090909-B
Micrel, Inc.
MIC2605/6
Feedback Resistors
The MIC2605/6 utilizes a feedback pin to compare the
output to an internal reference. The output voltage is
adjusted by selecting the appropriate feedback resistor
network values. The R2 resistor value must be less than
or equal to 1kΩ (R2 ≤ 1kΩ). The desired output voltage
can be calculated as follows:
September 2009
⎛ R1
⎞
VOUT = VREF ⋅ ⎜
+ 1⎟
R
2
⎝
⎠
where VREF is equal to 1.25V.
11
M9999-090909-B
Micrel, Inc.
MIC2605/6
L1
10µH
1
2
U1 MIC2605/6-YML
J1
VIN 4.5V to 12V
2
C1
1µF/25V
J2
GND
J3
EN
SW
FB
VDD
SS
PGND
3
J4
VOUT 32V
R1
12.4k
EN
6
C4
1µF/50V
C5
N.U.
5
C3
0.1µF/50V
R2
J5
GND
8
C2
0.1µF/50V
7
1
VOUT
4
R3
10k
VIN
Bill of Materials
Item
Part Number
C1608X5R1E105K
06033D105MAT
C1
08055D105MAT
VJ0603Y104KXAAT
C2
06035C104MAT
GRM188R71C104KA01D
VJ0603Y104KXAAT
C3
06035C104MAT
GRM188R71C104KA01D
C4
08055D105MAT
C5
N.U.
L1
Manufacturer
Description
(1)
Capacitor, 1µF, 25V, X5R, Size 0603
(2)
Capacitor, 1µF, 25V, X5R, Size 0603
(2)
Capacitor, 1µF, 50V, X5R, Size 0805
TDK
AVX
AVX
(3)
Vishay
Capacitor, 0.1µF, 16V, X7R, 0603
(3)
Capacitor, 0.1µF, 50V, X7R, 0603
Murata
Vishay
(2)
AVX
Capacitor, 0.1µF, 16V, X7R, 0603
Murata
(2)
AVX
----(4)
TDK
1
Capacitor, 0.1µF, 50V, X7R, 0603
(4)
VLCF4020T-100MR85
1
Capacitor, 0.1µF, 50V, X7R, 0603
(4)
Murata
1
Capacitor, 0.1µF, 50V, X7R, 0603
AVX(2)
LQH43CN100K03
Qty.
Capacitor, 1µF, 50V, X5R, Size 0805
1
-----
1
10µH, 0.65mA, DCR 240mΩ
(1)
1
10uH, 0.85A-1.22A, DCR 120mΩ
R1
CRCW06031242FKEA
Vishay Dale(3)
Resistor, 12.4k, 1%, 1/10W, Size 0603
1
R2
CRCW06034990FKEA
Vishay Dale(3)
Resistor, 499Ω, 1%, 1/10W, Size 0603
1
R3
CRCW060310K0FKEA
(3)
Resistor, 10k, 1%, 1/10W, Size 0603
1
U1
MIC2605/6-YML
0.5A, 1.2MHz/2MHz Wide Input Range Integrated
Switch Boost Regulator
1
Vishay Dale
Micrel, Inc.(5)
Notes:
1. TDK: www.tdk.com
2. AVX: www.avx.com
3. Vishay: www.vishay.com
4. Murata: www.murata.com
6. Micrel, Inc.: www.micrel.com
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
PCB Layout Recommendations
Top Layer
Bottom Layer
September 2009
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M9999-090909-B
Micrel, Inc.
MIC2605/6
Package Information
8-Pin 2mm x 2mm 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.
© 2008 Micrel, Incorporated.
September 2009
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M9999-090909-B