MIC5308
Low V
IN
/V
OUT
150mA High PSRR
ULDO™ with Ultra-Low IQ
ULDO is a trademark of Micrel, Inc.
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
May 2008
M9999-051508-D
General Description
The MIC5308 is a high performance, µCap low dropout
regulator, offering ultra-low operating current while
maintaining very fast transient response. The MIC5308
can source up to 150mA of output current and can
regulate down from a low input supply voltage to increase
system efficiency.
Ideal for battery operated applications; the MIC5308 offers
extremely low dropout voltage 45mV typically @ 150mA,
and low ground current at all load conditions (typically
23µA). The MIC5308 can also be put into a zero-off-mode
current state, drawing virtually no current when disabled.
The MIC5308 is available in fixed output voltages in the
tiny 6-pin 1.6mm x 1.6mm thin MLF
®
leadless package as
well as the 6-pin TSOT-23 for cost sensitive applications.
Data sheets and support documentation can be found on
Micrel’s web site at: www.micrel.com.
Features
• Input voltage range: 1.6V to 5.5V
• Guaranteed 150mA over temperature
• Ultra Low dropout voltage of 45mV at 150mA
• High PSRR, up to 90dB @ 1kHz
• Output Voltage range: 0.8V to 2.0V
• Very low ground current – 23µA under full load
• Bias supply voltage range: 2.5V to 5.5V
• Stable with 1µF ceramic output capacitor
• 150mA maximum output current at 1.6V input voltage
• Very fast transient response – ideal for digital loads
• Thermal shutdown and current limit protection
• Tiny 6-pin 1.6mm x 1.6mm Thin MLF
®
package
• Cost effective 6-pin TSOT-23 package
Applications
• Mobile Phones
• PDAs
• GPS Receivers
• Portable Electronics
___________________________________________________________________________________________________________
Typical Application
VOUT
BIAS
VIN
MIC5308
EN
BYP
GND
C
BYP
10nF
C
OUT
1µF
C
IN
1µF
C
BIAS
1µF
MIC23050
DC-to-DC
Converter
Li-Ion
2.7V to 4.2V
1.2V / 150mA
Micrel, Inc. MIC5308
May 2008
2 M9999-051508-D
Ordering Information
Part Number Voltage Marking Codes Temperature Range Package
MIC5308-1.2YMT 1.2V
▲
1R2 –40° to +125°C 6-Pin 1.6mm x 1.6mm Thin MLF
®
MIC5308-1.5YMT 1.5V
▲
1R5 –40° to +125°C 6-Pin 1.6mm x 1.6mm Thin MLF
®
MIC5308-1.8YMT 1.8V
▲
1R8 –40° to +125°C 6-Pin 1.6mm x 1.6mm Thin MLF
®
MIC5308YMT Adj.
▲
ARA –40° to +125°C 6-Pin 1.6mm x 1.6mm Thin MLF
®
MIC5308-1.2YD6 1.2V QR12 –40° to +125°C 6-Pin TSOT-23
MIC5308-1.5YD6 1.5V QR15 –40° to +125°C 6-Pin TSOT-23
MIC5308-1.8YD6 1.8V QR18 –40° to +125°C 6-Pin TSOT-23
MIC5308YD6 Adj. QRAA –40° to +125°C 6-Pin TSOT-23
Notes
For other voltage options. Contact Micrel Marketing for details.
Pin 1 identifier =
▲
.
MLF
®
is a GREEN RoHS compliant package. Lead finish is NiPdAu. Mold compound is Halogen Free.
Pin Configuration
1BIAS
GND
VIN
6 BYP/ADJ
EN
VOUT
5
4
2
3
BIAS GND
BYP/ADJ VOUT
VIN
31
6
2
45
EN
6-Pin 1.6mm x 1.6mm Thin MLF
®
(MT) 6-Pin TSOT-23 (D6)
Pin Description
Pin Number
Thin MLF-6
Pin Number
TSOT-23-6
Pin Name Pin Function
3 1 VIN Power Input for LDO.
2 2 GND Ground
1 3 BIAS Bias Input Voltage.
BYP Bypass: Connect a capacitor to ground to reduce noise and
reduce ripple rejection.
6 4
ADJ Adjustable: Feedback input from external resistor divider.
5 5 EN
Enable Input: Active High Input. Logic High = On;
Logic Low = Off; Do not leave floating.
4 6 VOUT Output of regulator.
HS Pad – EPAD Exposed heatsink pad connected to ground internally.
Micrel, Inc. MIC5308
May 2008
3
M9999-051508-D
Absolute Maximum Ratings(1)
Supply Voltage (V
IN
)............................................ 0V to V
BIAS
Bias Supply Voltage (V
BIAS
).................................. 0V to +6V
Enable Voltage (V
EN
)........................................... 0V to V
BIAS
Power Dissipation, ................................ Internally Limited
(3)
Lead Temperature (soldering, 10µsec.)..................... 260°C
Storage Temperature (T
s
) .........................–65°C to +150°C
ESD Rating
(4)
.................................................................. 3kV
Operating Ratings(2)
Supply Voltage (V
IN
)........................................+1.6V to
V
BIAS
Bias Supply Voltage (V
BIAS
).......................... +2.5V to +5.5V
Enable Input Voltage (V
EN
)...................................0V to
V
BIAS
Junction Temperature (T
J
) ........................ –40°C to +125°C
Junction Thermal Resistance
1.6x1.6 MLF-6 (θ
JA
) ...........................................90°C/W
TSOT-23-6 (θ
JA
)...............................................235°C/W
Electrical Characteristics
V
BIAS
= 3.6V; V
IN
= V
OUT
+ 1V; V
IN
≤ V
BIAS
; C
OUT
= 1.0µF; I
OUT
= 100µA; T
J
= 25°C, bold values indicate –40°C to +125°C,
unless noted.
Parameter Condition Min Typ Max Units
Output Voltage Accuracy Variation from nominal V
OUT
–
2.0
+2.0
%
Reference Voltage ADJ pin voltage
0.7595
0.775
0.7905
V
V
BIAS
Line Regulation V
BIAS
= 3.6 to 5.5V,
V
IN
= V
OUT
+ 1V
0.01
0.3
%/V
V
IN
Line Regulation
V
IN
= V
OUT
+ 1V,
V
BIAS
= 5.5V 0.02
0.2
%/V
Load Regulation I
OUT
= 100µA to 150mA 0.2
1
%
Dropout Voltage I
OUT
= 150mA 45
150
mV
Ground Pin Current
(5)
I
OUT
= 100µA to 150mA 23
35
µA
Ground Pin Current in
Shutdown
V
EN
≤ 0.2V 0.01 2.0 µA
f = up to 1kHz; C
OUT
= 1.0µF; no C
BYP
70 dB
f = up to 1kHz;C
OUT
= 1.0µF; C
BYP
= 10nF 50 90 dB
V
IN
Ripple Rejection
f = 20kHz; C
OUT
= 1.0µF; C
BYP
= 10nF 80 dB
Current Limit f = up to 1kHz;C
OUT
= 1.0µF; C
BYP
= 10nF 180 325 mA
Output Voltage Noise f = 20kHz; C
OUT
= 1.0µF; C
BYP
= 10nF 28 µV
RMS
Enable Inputs (EN)
Logic Low
0.2
V Enable Input Voltage
Logic High
1.2
V
V
IL
≤ 0.2V 0.17
1
µA Enable Input Current
V
IH
≥ 1.2V 1.5
1
µA
Turn-on Time C
OUT
= 1.0µF; C
BYP
= 10nF 150
500
µs
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 T
A
(ambient temperature) is P
D(max)
= T
J(max)
– T
A
) / θ
JA
. 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, 1.5kΩ in series with 100pF.
5. I
GND
= I
IN
+ I
BIAS
– I
OUT
.
Micrel, Inc. MIC5308
May 2008
4
M9999-051508-D
Typical Characteristics
0
-20
-40
-60
-80
-100
-120
Power Supply
Rejection Ratio (VIN)
10 100K 1M
FREQUENCY (Hz)
100 1K 10K
V
IN
= V
OUT
+ 1V
V
OUT
= 1.2V
C
OUT
= 1µF
C
BYP
= 0.01µF
100µA 100mA
50mA
100µA
(no byp)
150mA
0
-10
-20
-30
-40
-50
-60
-70
-80
-90
-100
Power Supply
Rejection Ratio (VBIAS)
10 100K 1M
FREQUENCY (Hz)
100 1K 10K
V
IN
= 2.8V
V
OUT
= 1.8V
C
OUT
= 1µF
100µA
150mA
50mA
0
1
2
3
4
6
7
8
9
10
Ground Current (VIN)
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
V
IN
= 2.2V
V
BIAS
= 3.6V
V
OUT
= 1.2V
C
OUT
= 1µF
100µA
150mA
5
0
1
2
3
4
5
6
7
8
9
10
0 25 50 75 100 125 150
OUTPUT CURRENT (mA)
Ground Current (VIN)
vs. Output Current
V
IN
= 2.2V
V
BIAS
= 3.6V
V
OUT
= 1.2V
C
OUT
= 1µF
0
2
4
6
8
10
12
14
16
0 25 50 75 100 125 150
OUTPUT CURRENT (mA)
Ground Current (VBIAS)
vs. Output Current
V
IN
= 2.2V
V
BIAS
= 3.6V
C
OUT
= 1µF
C
BYP
= 1µF
10
12
14
16
18
20
22
24
26
28
30
0 25 50 75 100 125 150
OUTPUT CURRENT (mA)
Ground Current (Total)
vs. Output Current
V
IN
= 2.2V
V
BIAS
= 3.6V
C
OUT
= 1µF
C
BYP
= 1µF
0
1
2
3
4
5
6
7
8
9
10
1.5 2 2.5 3 3.5 4 4.5 5 5.5
VIN (V)
Ground Current (V
IN
)
vs. V
IN
VBIAS = 5.5V
VOUT = 1.8V
COUT = 1µF
100µA
150mA
0
5
10
15
20
25
30
35
40
012345
ENABLE VOLTAGE (V)
Bias Current
vs. Enable Voltage
V
BIAS
= 5.5V
V
OUT
= 1.8V
C
OUT
= 1µF
100µA
150mA
0
10
20
30
40
50
60
70
80
Dropout Voltage
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
150mA
COUT = 1µF
0
5
10
15
20
25
30
35
40
45
50
0 25 50 75 100 125 150
OUTPUT CURRENT (mA)
Dropout Voltage
vs. Output Current
COUT = 1µF
1.10
1.15
1.20
1.25
1.30
Output Voltage
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
VIN = 2.2V
VBIAS = 3.6V
VOUT = 1.2V
COUT = 1µF
IOUT = 100µA
1.10
1.15
1.20
1.25
1.30
Output Voltage
vs. Output Current
50 100
OUTPUT CURRENT (mA)
V
IN
= 2.2V
V
BIAS
= 3.6V
V
OUT
= 1.2V
C
OUT
= 1µF
25 75 125
Micrel, Inc. MIC5308
May 2008
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M9999-051508-D
Typical Characteristics (continued)
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
1.8
2.0
012345
VIN (V)
Output Voltage
vs. V
IN
VBIAS = 5.5V
VOUT = 1.2V
COUT = 1µF
100µA
150mA
0.700
0.725
0.750
0.800
0.825
0.850
0.875
0.900
Reference Voltage
vs. Temperature
20 40 60 80
TEMPERATURE (°C)
VIN = 2.2V
VBIAS = 3.6V
VOUT = 1.2V
COUT = 1µF
IOUT = 100µA
0.775
100
150
200
250
300
350
400
1.5 2 2.5 3 3.5 4 4.5 5 5.5
VIN (V)
Current Limit
vs. V
IN
V
OUT
= 1.8V
V
BIAS
= 3.6V
0.001
0.01
0.1
1
10
Output Noise
Spectral Density
10 100K 1M
FREQUENCY (Hz)
100 1K 10K
COUT = 1µF
CBYP = 0.01µF
ILOAD
Micrel, Inc. MIC5308
May 2008
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M9999-051508-D
Functional Characteristics
Micrel, Inc. MIC5308
May 2008
7
M9999-051508-D
Functional Diagram
MIC5308 Block Diagram
Micrel, Inc. MIC5308
May 2008
8
M9999-051508-D
Applications Information
The MIC5308 is a high performance, low-dropout linear
regulator designed for low current applications requiring
fast transient response. The MIC5308 utilizes two input
supplies, significantly reducing dropout voltage, perfect
for low-voltage, DC-to-DC conversion. The MIC5308
requires a minimum of external components.
The MIC5308 regulator is fully protected from damage
due to fault conditions, offering linear current limiting and
thermal shutdown.
Bias Supply Voltage
V
BIAS
, requiring relatively light current, provides power to
the control portion of the MIC5308. Bypassing on the
bias pin is recommended to improve performance of the
regulator during line and load transients. 1µF ceramic
capacitor from V
BIAS
to ground helps reduce high
frequency noise from being injected into the control
circuitry from the bias rail and is good design practice.
Input Supply Voltage
V
IN
provides the supply to power the LDO. The minimum
input voltage is 1.6V, allowing conversion from low
voltage supplies.
Output Capacitor
The MIC5308 requires an output capacitor of 1µF or
greater to maintain stability. The design is optimized for
use with low-ESR ceramic chip capacitors. High ESR
capacitors may cause high frequency oscillation. The
output capacitor can be increased, but performance has
been optimized for a 1µF ceramic output capacitor and
does not improve significantly with larger capacitance.
X7R/X5R dielectric-type ceramic capacitors are recomm-
ended because of their temperature performance. X7R-
type capacitors change capacitance by 15% over their
operating temperature range and are the most stable
type of ceramic capacitors. Z5U and Y5V dielectric
capacitors change value by as much as 50% and 60%,
respectively, over their operating temperature ranges. To
use a ceramic chip capacitor with Y5V dielectric, the
value must be much higher than an X7R ceramic
capacitor to ensure the same minimum capacitance over
the equivalent operating temperature range.
Input Capacitor
The MIC5308 is a high-performance, high bandwidth
device. Therefore, it requires a well-bypassed input
supply for optimal performance. A 1µF capacitor is
required from the input to ground to provide stability.
Low-ESR ceramic capacitors provide optimal perform-
ance at a minimum of space. Additional high-frequency
capacitors, such as small-valued NPO dielectric-type
capacitors, help filter out high-frequency noise and are
good practice in any RF-based circuit.
Bypass Capacitor
A capacitor can be placed from the noise bypass pin to
ground to reduce output voltage noise. The capacitor
bypasses the internal reference. A 0.01µF capacitor is
recommended for applications that require low-noise
outputs. The bypass capacitor can be increased, further
reducing noise and improving PSRR. Turn-on time
increases slightly with respect to bypass capacitance. A
unique, quick-start circuit allows the MIC5308 to drive a
large capacitor on the bypass pin without significantly
slowing turn-on time.
Minimum Load Current
The MIC5308, unlike most other regulators, does not
require a minimum load to maintain output voltage
regulation.
Adjustable Regulator Design
The MIC5308 adjustable version allows programming
the output voltage anywhere between 0.8Vand 2V. Two
resistors are used. The resistor values are calculated by:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−×= 1
775.0
V
R2R1
OUT
Where V
OUT
is the desired output voltage.
Enable/Shutdown
The MIC5308 comes with a single active-high enable pin
that allows the regulator to be disabled. Forcing the
enable pin low disables the regulator and sends it into a
“zero” off-mode-current state. In this state, current
consumed by the regulator goes nearly to zero. Forcing
the enable pin high enables the output voltage. The
active-high enable pin uses CMOS technology and the
enable pin cannot be left floating; a floating enable pin
may cause an indeterminate state on the output.
Thermal Considerations
The MIC5308 is designed to provide 150mA of
continuous current in a very small package. Maximum
ambient operating temperature can be calculated based
on the output current and the voltage drop across the
part. Given that the input voltage is 3.3V, the output
voltage is 1.2V and the output current = 150mA. The
actual power dissipation of the regulator circuit can be
determined using the equation:
P
D
= (V
IN
– V
OUT1
) I
OUT
+ V
IN
I
GND
Because this device is CMOS and the ground current is
typically <100µA over the load range, the power
dissipation contributed by the ground current is < 1%
and can be ignored for this calculation.
P
D
= (3.3V – 1.2V) × 150mA
P
D
= 0.315W
Micrel, Inc. MIC5308
May 2008
9
M9999-051508-D
To determine the maximum ambient operating
temperature of the package, use the junction-to-ambient
thermal resistance of the device and the following basic
equation:
⎟
⎟
⎠
⎞
⎜
⎜
⎝
⎛−
=
JA
AJ(max)
D(max)
TT
P
θ
T
J(max)
= 125°C, the maximum junction temperature of
the die θ
JA
thermal resistance = 90°C/W.
Micrel, Inc. MIC5308
May 2008
10
M9999-051508-D
Package Information
6-Pin 1.6mm x 1.6mm Thin MLF
®
(MT)
6-Pin TSOT-23 (D6)
Micrel, Inc. MIC5308
May 2008
11
M9999-051508-D
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.
