MIC38150

MIC38150
HELDO®
1.5A High Efficiency Low Dropout
Regulator
General Description
®
HELDO
The MIC38150 is a 1.5A continuous output current step
down converter. This is a follow on product in the new
®
Features
HELDO (High Efficiency Low DropOut Regulators) family,
that provide the benefits of an LDO with respect to ease of
• Output current up to 1.5A
use, fast transient performance, high PSRR and low noise
• Input voltage range: 3.0V to 5.5V
while offering the efficiency of a switching regulator.
• Adjustable output voltage down to 1.0V
As output voltages move lower, the output noise and
• Output noise less than 5mV
transient response of a switching regulator become an
• Ultra fast transient performance
increasing challenge for designers. By combining a
switcher whose output is slaved to the input of a high
• Unique switcher plus LDO architecture
performance LDO, high efficiency is achieved with a clean
• Fully integrated MOSFET switches
low noise output. The MIC38150 is designed to provide
• Micro-power shutdown
less than 5mV of peak-to-peak noise and over 70dB of
• Easy upgrade from LDO as power dissipation
PSRR at 1kHz. Furthermore, the architecture of the
becomes an issue
MIC38150 is optimized for fast load transients allowing the
output to maintain less than 30mV of output voltage
• Thermal shutdown and current limit protection
®
deviation even during ultra fast load steps. This makes the
• 4mm × 6mm × 0.9mm MLF package
MIC38150 an ideal choice for low voltage ASICs and other
digital ICs.
Applications
The MIC38150 features a fully integrated switching
regulator and LDO combination, operates with input
• Point-of-load applications
voltages from 3.0V to 5.5V input and offers adjustable
• Networking, server, industrial power
output voltages down to 1.0V.
• Wireless base-stations
The MIC38150 is offered in the small 28-pin 4mm × 6mm
• Sensitive RF applications
®
× 0.9mm MLF package and can operate from –40°C to
+125°C.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com
___________________________________________________________________________________________________________
LOAD CURRENT
(1A/div)
OUTPUT VOLTAGE
(50mV/div)
Typical Application
HELDO is a registered trademark of Micrel, Inc.
MLF and MicroLeadFrame are registered trademark of Amkor Technologies
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel +1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
June 2010
M9999-061010-C
Micrel, Inc.
MIC38150
Ordering Information
Output
Current
Part Number
MIC38150HYHL
1.5A
Voltage
(1)
Junction
Temperature Range
ADJ
-40°C to +125°C
Package
PB-Free 28-Pin 4x6 MLF
®
Note: For additional voltage options, contact Micrel.
Pin Configuration
®
28-Pin 4mm x 6mm MLF (ML)
(Top View)
Pin Description
Pin Number
Pin Name
1, 2, 3, 4, 5
SWO
6, 23, 24, 25,
26, 27, 28
SW
7, 22
ePAD
Exposed heat-sink pad. Connect externally to PGND.
8
AVIN
Analog Supply Voltage: Supply for the analog control circuitry. Requires
bypass capacitor to ground. Nominal bypass capacitor is 1µF.
9
LPF
Low Pass Filter: Attach external resistor from SW to increase hysteretic
frequency.
10
AGND
11
FB
Feedback: Input to the error amplifier. Connect to the external resistor
divider network to set the output voltage.
12, 13
LDOOUT
LDO Output: Output of voltage regulator. Place capacitor to ground to
bypass the output voltage. Nominal bypass capacitor is 10µF.
14, 15
LDOIN
LDO Input: Connect to SW output. Requires a bypass capacitor to ground.
Nominal bypass capacitor is 10µF.
16, 17
PVIN
Input Supply Voltage (Input): Requires bypass capacitor to GND. Nominal
bypass capacitor is 10µF.
18
EN
Enable (Input): Logic low will shut down the device, reducing the quiescent
current to less than 50µA. This pin can also be used as an under-voltage
lockout function by connecting a resistor divider from EN pin-to-VIN and
GND. It should be not left open.
19, 20, 21
PGND
June 2010
Pin Name
Switch (Output): This is the output of the PFM Switcher.
Switch Node: Attach external resistor from LPF to increase hysteretic
frequency.
Analog Ground.
Power Ground.
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M9999-061010-C
Micrel, Inc.
MIC38150
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN) .........................................................6V
Output Switch Voltage (VSW) ...........................................6V
Logic Input Voltage (VEN) ..................................-0.3V to VIN
(3)
Power Dissipation .................................. Internally Limited
Storage Temperature (TS)................... -65°C ≤ TJ ≤ +150°C
Lead Temperature (soldering, 10sec) ........................ 260°C
(4)
ESD Rating .............................................................. 1.5kV
Supply voltage (VIN) ...................................... 3.0V to 5.5V
Enable Input Voltage (VEN) ................................. 0V to VIN
Junction Temperature Range .........–40°C ≤ TJ ≤ +125°C
Package Thermal Resistance
4mm × 6mm MLF-28 (θJA) .............................24°C/W
Electrical Characteristics(5)
TA = 25°C with VIN = VEN = 5V; IOUT = 10mA, VOUT = 1.8V. Bold values indicate –40°C ≤ TJ ≤ +125°C, unless noted.
Parameter
Conditions
Min
3.0
Supply Voltage Range
Under-Voltage Lockout Threshold
Typ
Turn-on
UVLO Hysteresis
Max
Units
5.5
V
2.85
V
100
mV
1
mA
Quiescent Current
IOUT = 0A, Not switching, Open Loop
Turn-on Time
VOUT to 95% of nominal
200
500
µs
Shutdown Current
VEN = 0V
30
50
µA
Feedback Voltage
±2.5%
1
1.025
V
0.975
Feedback Current
Dropout Voltage (VIN – VOUT)
5
ILOAD = 1.5A; VOUT = 3V
0.85
1.75
nA
1.2
V
Current Limit
VFB = 0.9×VNOM
Output Voltage Load Regulation
VOUT = 1.8V, 10mA to 1.5A
0.1
3
1
%
A
Output Voltage Line Regulation
VOUT = 1.8V, VIN from 3.0V to 5.5V
0.35
0.5
%/V
Output Ripple
ILOAD = 1.5A, COUTLDO = 20µF, COUTSW = 20µF
LPF=25kΩ
2
mV
Over-Temperature Shutdown
150
°C
Over-Temperature Shutdown Hysteresis
15
°C
(6)
Enable Input
Enable Input Threshold
Regulator enable
Enable Hysteresis
0.90
1
1.1
V
20
100
200
mV
0.03
1
µA
Enable Input Current
Notes:
1.
Exceeding the absolute maximum rating may damage the device.
2.
The device is not guaranteed to function outside its operating rating.
3.
The maximum allowable power dissipation of any TA (ambient temperature) is PD(max) = (TJ(max) – TA) / θJA. Exceeding the maximum allowable power
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown.
4.
Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
5.
Specification for packaged product only.
6.
Enable pin should not be left open.
June 2010
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Micrel, Inc.
MIC38150
Typical Characteristics
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted
1.86
70
1.84
PSRR (dB)
60
50
40
30
20
1.80
1.78
1.76
1.74
0
1.72
1000
10000
FREQUENCY (Hz)
1.8
1.82
10
100
2.0
100000
VIN = 3.3V
VOUT = 1.8V
0
1.0
0.6
0.4
0.3
0.6
0.9
1.2
LO AD CURRENT (A)
0
1.5
90
80
1.6
1.82
1.80
1.78
1.76
VIN = 3.3V
IOUT = 10mA
1.2
1.0
0.8
0.6
0.4
VIN = 3.3V
VOUT = 1.8V
0.2
-40
10
Dropout Voltage
v s. Load Current
50
40
30
VIN = 5.0V
VOUT = 3.3V
RLPF = 25kΩ
10
60
110
160
T EMPERAT URE (°C)
0
210
0
0.3
0.6
0.9
1.2
LO AD CURRENT (A)
1.5
Current Lim it
v s. Input Voltage
Dropout Voltage
v s. Temperature
0.9
5
60
20
0.0
20 40 60 80 100 120
T EM PERAT URE (°C)
2
3
4
INPUT VOLTAGE (V)
70
1.4
EFFICIENCY (%)
O UTPUT VO LTAG E (V)
1.84
1
MIC38150 Efficiency
1.8
0
VOUT = 1.8V
0.2
2.0
-20
IOUT = 1.5A
0.8
1.86
-40
1.0
4.0
3.8
0.8
0.6
0.5
0.4
0.3
0.2
0.1
3.6
0.8
0.6
0.4
0.2
VOUT = 3.3V
IOUT = 1.5A
VOUT = 3.3V
0.0
CURRENT LIM IT (A)
0.7
DROPO UT VO LTAGE (V)
DROPO UT VO LTAGE (V)
1.2
Therm al Shutdown
1.72
0.5
1
LOAD CURRENT (A)
1.5
3.4
3.2
3.0
2.8
2.6
VOUT= 1.8V
COUT = 20µF
RLPF = 25kΩ
2.4
2.2
0.0
0
2.0
-40
-20
0
20 40 60 80 100 120
T EM PERAT URE (°C)
3
3.5
4
4.5
5
INPUT VO LT AG E (V)
5.5
Operating Current
vs. Input Voltage
Enable Threshold
1.20
60
OPERATING CURRENT (mA)
1.15
ENABLE VOLTAGE (V)
1.4
1.88
1.74
IOUT = 10mA
1.6
0.0
Output Voltage
v s. Temperature
OUTPUT VO LTAGE (V)
OUTPUT VOLTAGE (V)
1.88
80
O UTPUT VO LTAG E (V)
90
10
Output Voltage
vs. Input Voltage
Load Regulation
MIC38150 PSRR
1.10
1.05
1.00
0.95
0.90
0.85
VOUT = 1.8V
0.80
50
40
30
20
VOUT = 1.8V
COUT = 20µF
10
0
3
June 2010
3.5
4
4.5
5
INPUT VOLTAGE (V)
5.5
3
3.5
4
4.5
5
INPUT VOLTAGE (V)
4
5.5
M9999-061010-C
Micrel, Inc.
MIC38150
Typical Characteristics
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, RLPF = 25kΩ, IOUT = 100mA, unless noted
Switch Frequency v s.
RLPF Resistance (3.3V-1.0V)
Switch Frequency v s.
RLPF Resistance (3.3V-1.8V)
3
3
SW FREQUENCY (M Hz)
SW FREQUENCY (MHz)
2.5
500mA
2
1.5
10mA
1
3
1.5A
0.5
0
2.5
1.5A
SW FREQUENCY (MHz)
1A
2.5
500mA
2
1.5
10mA
1
1A
0.5
0
10
100
RLPF (kΩ)
1000
10
Switch Frequency vs.
RLPF Resistance (5.0V-1.8V)
100
RLPF (kΩ)
1000
1.5A
1A
2
1.5
1
10mA
500mA
0.5
0
10
100
RLPF (kΩ)
1000
Switch Frequency v s.
RLPF Resistance (5.0V-2.5V)
3
3
1.5A
1.5A
2.5
2.5
1A
SW FREQUENCY (MHz)
SW FREQUENCY (M Hz)
Switch Frequency v s.
RLPF Resistance (5.0V-1.0V)
2
1.5
10mA
500mA
1
0.5
0
500mA
2
1.5
10mA
1
1A
0.5
0
10
June 2010
100
RLPF (kΩ)
1000
10
100
RLPF (kΩ)
5
1000
M9999-061010-C
Micrel, Inc.
MIC38150
Functional Characteristics
LOAD CURRENT
(1A/div)
OUTPUT VOLTAGE
(50mV/div)
VIN = 3.3V, VOUT = 1.8V, COUT = 10µF, Inductor = 470nH; RLPF = 25kΩ, IOUT = 100mA, unless noted
June 2010
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Micrel, Inc.
MIC38150
EMI Performance
VOUT =1.8V, IOUT =1.2A
EMI Test – Horizontal Front
EMI Test – Vertical Front
Additional components to MIC38150 Evaluation Board:
1. Input Ferrite Bead Inductor. Part number: BLM21AG102SN1D
2. 0.1µF and 0.01µF ceramic bypass capacitors on PVIN, SW, SWO, and LDOOUT pins.
June 2010
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Micrel, Inc.
MIC38150
Block Diagram
June 2010
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Micrel, Inc.
MIC38150
Adjustable Regulator Design
Application Information
Enable Input
The MIC38150 features a TTL/CMOS compatible
positive logic enable input for on/off control of the device.
High enables the regulator while low disables the
regulator. In shutdown the regulator consumes very little
current (only a few microamperes of leakage). For
simple applications the enable (EN) can be connected to
VIN (IN).
Input Capacitor
PVIN provides power to the MOSFETs for the switch
mode regulator section and the gate drivers. Due to the
high switching speeds, a 10µF capacitor is
recommended close to PVIN and the power ground
(PGND) pin for bypassing.
Analog VIN (AVIN) provides power to the analog supply
circuitry. AVIN and PVIN must be tied together
externally. Careful layout should be considered to
ensure high frequency switching noise caused by PVIN
is reduced before reaching AVIN. A 1µF capacitor as
close to AVIN as possible is recommended.
Output Capacitor
The MIC38150 requires an output capacitor for stable
operation. As a µCap LDO, the MIC38150 can operate
with ceramic output capacitors of 10µF or greater.
Values of greater than 10µF improve transient response
and noise reduction at high frequency. X7R/X5R
dielectric-type ceramic capacitors are recommended
because of their superior temperature performance.
X7R-type capacitors change capacitance by 15% over
their operating temperature range and are the most
stable type of ceramic capacitors. Larger output
capacitances can be achieved by placing tantalum or
aluminum electrolytics in parallel with the ceramic
capacitor. For example, a 100µF electrolytic in parallel
with a 10µF ceramic can provide the transient and high
frequency noise performance of a 100µF ceramic at a
significantly lower cost. Specific undershoot/overshoot
performance will depend on both the values and
ESR/ESL of the capacitors.
For less than 5mV noise performance at higher current
loads, 20µF capacitors are recommended at LDOIN and
LDOOUT.
Low Pass Filter Pin
The MIC38150 features a Low Pass Filter (LPF) pin for
adjusting the switcher frequency. By tuning the
frequency, the user can further improve output ripple.
Adjusting the frequency is accomplished by connecting a
resistor between the LPF and SW pins. A small value
resistor would increase the frequency while a larger
value resistor decreases the frequency. Recommended
RLPF value is 25kΩ.
June 2010
Adjustable Regulator with Resistors
The adjustable MIC38150 output voltage can be
programmed from 1V to 5.0V using a resistor divider
from output to the FB pin. Resistors can be quite large,
up to 100kΩ because of the very high input impedance
and low bias current of the sense amplifier. For large
value resistors (>50kΩ), R1 should be bypassed by a
small capacitor (CFF = 0.1µF bypass capacitor) to avoid
instability due to phase lag at the ADJ/SNS input.
The output resistor divider values are calculated by:
R1
+ 1)
R2
Efficiency Considerations
Efficiency is defined as the amount of useful output
power, divided by the amount of power supplied.
VOUT = 1V × (
Efficiency(%) =
VOUT × IOUT
× 100
VIN × IIN
Maintaining high efficiency serves two purposes. It
reduces power dissipation in the power supply, reducing
the need for heat sinks and thermal design
considerations and it reduces consumption of current for
battery powered applications. Reduced current draw
from a battery increases the devices operating time and
is critical in hand held devices.
There are two types of losses in switching converters;
DC losses and switching losses. DC losses are simply
2
the power dissipation of I R. Power is dissipated in the
high side switch during the on cycle. Power loss is equal
to the high side MOSFET RDSON multiplied by the Switch
2
Current . During the off cycle, the low side N-channel
MOSFET conducts, also dissipating power. Device
operating current also reduces efficiency. The product of
the quiescent (operating) current and the supply voltage
is another DC loss.
Over 100mA, efficiency loss is dominated by MOSFET
RDSON and inductor losses. Higher input supply voltages
will increase the Gate to Source threshold on the internal
MOSFETs, reducing the internal RDDSON. This improves
efficiency by reducing DC losses in the device. As the
inductors are reduced in size, the inductor losses are
mainly caused by the DC resistance (DCR).
The DCR losses can be calculated as follows:
2
L_PD = IOUT × DCR
Efficiency loss due to DCR is minimal at light loads and
gains significance as the load is increased.
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Micrel, Inc.
MIC38150
input capacitors and IC pins.
PCB Layout Guideline
Warning!!! To minimize EMI and output noise, follow
these layout recommendations.
PCB Layout is critical to achieve reliable, stable and
efficient performance. A ground plane is required to
control EMI and minimize the inductance in power,
signal and return paths.
The following guidelines should be followed to insure
proper operation of the MIC38150.
IC
•
Place the IC close to the point of load (POL).
•
Use fat traces to route the input and output power
lines.
•
The exposed pad (ePAD) on the bottom of the IC
must be connected to the PGND pins of the IC.
•
Use several vias to connect the ePAD to the ground
plane.
•
Signal and power grounds should be kept separate
and connected at only one location.
•
Keep the switch node (SW) away from the feedback
(FB) pin.
Place the input capacitor next.
•
Place the input capacitors on the same side of the
board and as close to the MIC38150 as possible.
•
Keep both the PVIN and PGND connections short.
•
Place several vias to the ground plane close to the
input capacitor ground terminal, but not between the
June 2010
Use either X7R or X5R dielectric input capacitors.
Do not use Y5V or Z5U type capacitors.
•
Do not replace the ceramic input capacitor with any
other type of capacitor. Any type of capacitor can be
placed in parallel with the input capacitor.
•
If a Tantalum input capacitor is placed in parallel
with the input capacitor, it must be recommended for
switching regulator applications and the operating
voltage must be derated by 50%.
•
In “Hot-Plug” applications, a Tantalum or Electrolytic
bypass capacitor must be used to limit the overvoltage spike seen on the input supply with power is
suddenly applied.
•
The 1µF capacitor, which connects to the AVIN
terminal, must be located right at the IC. The AVIN
terminal is very noise sensitive and placement of the
capacitor is very critical. Connections must be made
with wide trace.
Output Capacitor
Input Capacitor
•
•
10
•
Use a wide trace to connect the VSW output
capacitor ground terminal to the PVIN input
capacitor ground terminal.
•
The feedback trace should be separate from the
power trace and connected as close as possible to
the output capacitor.
M9999-061010-C
Micrel, Inc.
MIC38150
Evaluation Board Schematics
Bill of Materials
Item
C1, C3, C4, C5, C6
C2
R1
R2, R4
R3
Part Number
Manufacturer
0805ZD106MAT2A
AVX
LMK212BJ106KG-T
Taiyo Yuden
10uF, 10V, X5R, 0805 Ceramic Capacitor
5
1uF, 10V, X5R, 0805 Ceramic Capacitor
1
(5)
8.06k, 1%, 1/10W, 0603
1
(5)
10k, 1%, 1/10W, 0603
2
(5)
24.9k, 1%, 1/10W, 0603
1
TDK
GRM219R61A106KE44D
Murata
C2012X5R1A105K
TDK
0805ZD105KAT2A
AVX
(1)
Murata
CRCW06038061FRT1
Vishay
U1
MIC38150-HYHL
(4)
(3)
GRM219R61A105MA01D
CRCW06032492FRT1
Qty
(2)
(3)
C2012X5R1A106K
CRCW06031002KEYE3
Description
(1)
(4)
Vishay
Vishay
(6)
Micrel, Inc.
®
HELDO 1.5A High Efficiency Low Dropout
Regulator
1
Notes:
1. AVX: www.avx.com
2. Taiyo Yuden: www.t-yuden.com
3. TDK: www.tdk.com
4. Murata: www.murata.com
5. Vishay: www.vishay.com
6. Micrel, Inc.: www.micrel.com
June 2010
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Micrel, Inc.
MIC38150
PCB Layout
Top Layer
Mid Layer 1
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Micrel, Inc.
MIC38150
Mid Layer 2
Bottom Layer
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Micrel, Inc.
MIC38150
Package Information
®
28-Pin 4mm x 6mm MLF (ML)
June 2010
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Micrel, Inc.
MIC38150
Recommended Landing Pattern
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.
© 2009 Micrel, Incorporated.
June 2010
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