Page 1
MIC5208 Micrel
MIC5208
Dual 50mA LDO Voltage Regulator
Preliminary Information
General Description
The MIC5208 is a dual linear voltage regulator with very low
dropout voltage (typically 20mV at light loads and 250mV at
50mA), very low ground current (225µA at 10mA output), and
better than 3% initial accuracy. It also features individual
logic-compatible enable/shutdown control inputs.
Designed especially for hand-held battery powered devices,
the MIC5208 can be switched by a CMOS or TTL compatible
logic signal, or the enable pin can be connected to the supply
input for 3-terminal operation. When disabled, power consumption drops nearly to zero. Dropout ground current is
minimized to prolong battery life.
Key features include current limiting, overtemperature shutdown, and protection against reversed battery.
The MIC5208 is available in 3.0V, 3.3V, 3.6V, 4.0V and 5.0V
fixed voltage configurations. Other voltages are available;
contact Micrel for details.
Ordering Information
Features
• Micrel Mini 8™ MSOP package
• Guaranteed 50mA output
• Low quiescent current
• Low dropout voltage
• Wide selection of output voltages
• Tight load and line regulation
• Low temperature coefficient
• Current and thermal limiting
• Reversed input polarity protection
• Zero off-mode current
• Logic-controlled electronic enable
Applications
• Cellular telephones
• Laptop, notebook, and palmtop computers
• Battery powered equipment
• Bar code scanners
• SMPS post regulator/dc-to-dc modules
• High-efficiency linear power supplies
Typical Application
Output A
Output B
Part Number Voltage Accuracy Junction Temp. Range* Package
MIC5208-3.0BMM 3.0 3% –40°C to +125°C 8-lead MSOP
MIC5208-3.3BMM 3.3 3% –40°C to +125°C 8-lead MSOP
MIC5208-3.6BMM 3.6 3% –40°C to +125°C 8-lead MSOP
MIC5208-4.0BMM 4.0 3% –40°C to +125°C 8-lead MSOP
MIC5208-5.0BMM 5.0 3% –40°C to +125°C 8-lead MSOP
Other voltages available. Contact Micrel for details.
1µF
1µF
MIC5208
1
2
3
4
Enable may be connected to V
8
7
6
Enable A
5
Enable B
IN
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MIC5208 Micrel
Pin Configuration
OUTA
GND
OUTB
GND
Pin Description
Pin Number Pin Name Pin Function
1 OUTA Regulator Output A
2, 4 GND Ground: Both pins must be connected together.
3 OUTB Regulator Output B
5 ENB Enable/Shutdown B (Input): CMOS compatible input. Logic high = enable,
6 INB Supply Input B
7 ENA Enable/Shutdown A (Input): CMOS compatible input. Logic high = enable,
8 INA Supply Input A
1
2
3
4
8
INA
7
ENA
6
INB
ENB
5
MIC5208BMM
logic low or open = shutdown. Do not leave floating.
logic low or open = shutdown. Do not leave floating.
3
1997 3-169
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MIC5208 Micrel
Absolute Maximum Ratings
Supply Input Voltage (VIN) ............................ –20V to +20V
Enable Input Voltage (VEN) ........................... –20V to +20V
Power Dissipation (PD) ............................ Internally Limited
Storage Temperature Range ................... –60°C to +150°C
Recommended Operating Conditions
Supply Input Voltage (VIN) ............................... 2.5V to 16V
Enable Input Voltage (VEN) ................................. 0V to 16V
Junction Temperature (TJ) ....................... –40°C to +125°C
8-lead MSOP (θJA) ................................................... Note 1
Lead Temperature (soldering, 5 sec.) ....................... 260°C
Electrical Characteristics
VIN = V
for one-half of dual MIC5208; unless noted.
Symbol Parameter Conditions Min Typical Max Units
V
O
∆V
O
∆V
O/VO
∆V
O/VO
V
– V
IN
I
Q
I
GND
I
GNDDO
I
LIMIT
∆VO/∆P
Control Input
V
IL
V
IH
I
IL
I
IH
General Note: Devices are ESD protected, however, handling precautions are recommended.
Note 1: Absolute maximum ratings indicate limits beyond which damage to the component may occur. Electrical specifications do not apply when
Note 2: Output voltage temperature coefficient is defined as the worst case voltage change divided by the total temperature range.
Note 3: Regulation is measured at constant junction temperature using low duty cycle pulse testing. Changes in output voltage due to heating effects
Note 4: Dropout voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
Note 5: Ground pin current is the regulator quiescent current plus pass transistor base current. The total current drawn from the supply is the sum of
Note 6: Thermal regulation is defined as the change in output voltage at a time “t” after a change in power dissipation is applied, excluding load or line
+ 1V; IL = 1mA; CL = 1µF, and V
OUT
Output Voltage variation from nominal V
Accuracy –4 4 %
≥ 2.0V; TJ = 25°C, bold values indicate –40°C to +125°C;
EN
OUT
–3 3 %
/∆T Output Voltage Note 2 50 200 ppm/°C
Temperature Coeffcient
Line Regulation VIN = V
+1V to 16V 0.008 0.3 %
OUT
0.5 %
Load Regulation IL = 0.1mA to 50mA, Note 3 0.08 0.3 %
0.5 %
O
Dropout Voltage, Note 4 IL = 100µA20mV
= 20mA 200 350 mV
I
L
IL = 50mA 250 500 mV
Quiescent Current VEN ≤ 0.4V (shutdown) 0.01 10 µA
Ground Pin Current VEN ≥ 2.0V (enabled), IL = 100µA 180 µA
Note 5 I
= 20mA 225 750 µA
L
IL = 50mA 850 1200 µA
Ground Pin Current at Dropout VIN = 0.5V less than designed V
Current Limit V
D
Thermal Regulation Note 6 0.05 %/W
= 0V 180 250 mA
OUT
Note 5 200 300 µA
OUT,
Input Voltage Level
Logic Low shutdown 0.6 V
Logic High enabled 2.0 V
Control Input Current VIL ≤ 0.6V 0.01 1 µA
VIH ≥ 2.0V 15 50 µA
operating the device outside of its rated operating conditions. The maximum allowable power dissipation is a function of the maximum
junction temperature, T
power dissipation at any ambient temperature is calculated using: P
dissipation will result in excessive die temperature, and the regulator will go into thermal shutdown. θJA of the 8-lead MSOP is 200°C/W,
mounted on a PC board.
are covered by the thermal regulation specification.
differential.
the load current plus the ground pin current.
regulation effects. Specifications are for a 50mA load pulse at VIN = 16V for t = 10ms.
, the junction-to-ambient thermal resistance, θJA, and the ambient temperature, TA. The maximum allowable
J(max)
MAX
= (T
– TA) / θJA. Exceeding the maximum allowable power
J(max)
3-170 1997
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MIC5208 Micrel
0
100
200
300
400
-60 -30 0 30 60 90 120 150
DROPOUT VOLTAGE (mV)
TEMPERATURE (°C)
0.0
0.5
1.0
1.5
2.0
01234567
GROUND CURRENT (mA)
SUPPLY VOLTAGE (V)
0
20
40
60
80
100
120
140
160
01234567
SHORT CIRCUIT CURRENT (mA)
INPUT VOLTAGE (V)
3.3
3.4
3.5
-60 -30 0 30 60 90 120 150
MIN. SUPPLY VOLTAGE (V)
TEMPERATURE (°C)
Typical Characteristics
Dropout Voltage
1000
DROPOUT VOLTAGE (V)
vs. Output Current
CIN = 10µF
C
= 1µF
OUT
100
10
1
0.01 0.1 1 10 100
OUTPUT CURRENT (mA)
Ground Current
2000
1500
1000
GROUND CURRENT (µA)
vs. Output Current
500
VIN = V
0
0 1020304050607080
OUTPUT CURRENT (mA)
OUT
+ 1V
Dropout Voltage
vs. Temperature
CIN = 10µF
C
= 1µF
OUT
IL = 50mA
IL = 1mA
Ground Current
vs. Supply Voltage
IL = 50mA
IL = 100µA
IL = 100µA
V
= 3.3V
OUT
Dropout Characteristics
4
3
2
1
OUTPUT VOLTAGE (V)
0
(MIC5208-3.3)
IL = 100µA
IL = 50mA
CIN = 10µF
C
= 1µF
OUT
01234567
SUPPLY VOLTAGE (V)
Ground Current
3.0
2.5
2.0
1.5
1.0
0.5
GROUND CURRENT (mA)
0.0
vs. Temperature
CIN = 10µF
C
= 1µF
OUT
IL = 50mA
IL = 100µA
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
3
4.0
3.5
3.0
2.5
CIN = 10µF
C
2.0
OUT
1.5
1.0
OUTPUT VOLTAGE (V)
0.5
0.0
0 50 100 150 200
4.0
3.8
3.6
3.4
3.2
1997 3-171
3.0
2.8
OUTPUT VOLTAGE (V)
2.6
2.4
-60 -30 0 30 60 90 120 150
Output Voltage
vs. Output Current
= 1µF
OUTPUT CURRENT (mA)
Output Voltage
vs. Temperature
CIN = 10µF
C
= 1µF
OUT
3 DEVICES
HI / AVG / LO
CURVES APPLICABLE
AT 100µA AND 50mA
TEMPERATURE (°C)
Short Circuit Current
vs. Input Voltage
CIN = 10µF
C
= 1µF
OUT
Short Circuit Current
200
180
160
140
120
OUTPUT CURRENT (mA)
100
vs. Temperature
CIN = 10µF
C
= 1µF
OUT
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
Thermal Regulation
60
40
20
-20
-40
∆ OUTPUT (mV)
-60
100
50
LOAD (mA)
-50
(MIC5208-3.3)
0
0
CL = 1µF
-2 0 2 4 6 8 10 12 14 16
TIME (ms)
Minimum Supply Voltage
vs. Temperature
IL = 1mA
V
= 3.3V
OUT
CIN = 10µF
C
= 1µF
OUT
Page 5
MIC5208 Micrel
Typical Characteristics
1000
Output Impedance
100
IL = 100µA
10
IL = 1mA
1
0.1
OUTPUT IMPEDANCE (Ω)
0.01
0
0
0
1x10
10x10
100x10
FREQUENCY (Hz)
Ripple Voltage
0
IL = 100µA
C
V
0
10x10
vs. Frequency
= 1µF
L
= V
+ 1
IN
OUT
0
3
1x10
100x10
FREQUENCY (Hz)
100
80
60
40
20
RIPPLE VOLTAGE (dB)
IL = 50mA
3
1x10
3
10x10
3
10x10
3
100x10
3
100x10
6
1x10
6
1x10
200
Load Transient
0
C
-200
∆ OUTPUT (mV)
100
-400
= 1µF
OUT
V
= V
IN
OUT
50
0
OUTPUT (mA)
-50
-1 012345678
TIME (ms)
Line Transient
(MIC5208-3.3)
3
2
1
0
-1
∆ OUTPUT (V)
8
-2
6
4
INPUT (V)
2
-0.2 0.0 0.2 0.4 0.6 0.8 1.0
CL = 1µF
I
= 1mA
L
TIME (ms)
+ 1
100
Load Transient
0
C
= 10µF
-100
∆ OUTPUT (mV)
100
-200
OUT
V
= V
IN
OUT
50
0
OUTPUT (mA)
-50
-5 0 5 10 15 20
TIME (ms)
Line Transient
(MIC5208-3.3)
2
1
0
∆ OUTPUT (V)
8
-1
6
4
INPUT (V)
2
-0.2 0.0 0.2 0.4 0.6 0.8 1.0
CL = 11µF
I
= 1mA
L
TIME (ms)
+ 1
Ripple Voltage
0
IL = 1mA
C
V
0
10x10
vs. Frequency
= 1µF
L
= V
+ 1
IN
OUT
0
3
1x10
100x10
FREQUENCY (Hz)
100
80
60
40
20
RIPPLE VOLTAGE (dB)
Ripple Voltage
0
IL = 50mA
C
V
0
10x10
vs. Frequency
= 1µF
L
= V
+ 1
IN
OUT
0
3
1x10
100x10
FREQUENCY (Hz)
100
80
60
40
20
RIPPLE VOLTAGE (dB)
3
10x10
3
10x10
3
100x10
3
100x10
6
1x10
6
1x10
Enable Characteristics
4.0
3.0
2.0
1.0
0.0
OUTPUT (V)
-1.0
ENABLE (V)
(MIC5208-3.3)
CL = 1µF
I
= 100µA
4
2
0
-2
-2 0246810
L
TIME (µs)
Enable Voltage
1.50
1.25
1.00
0.75
ENABLE VOLTAGE (mV)
0.50
vs. Temperature
CIN = 10µF
C
= 1µF
OUT
I
= 1mA
L
V
OFF
ON
V
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
Enable Characteristics
(MIC5208-3.3)
5
4
3
2
1
0
OUTPUT (V)
4
-1
CL = 1µF
I
= 100µA
L
2
0
ENABLE (V)
-2
-0.2 0.0 0.2 0.4 0.6 0.8 1.0
TIME (ms)
Enable Current
vs. Temperature
40
30
20
10
ENABLE CURRENT (µA)
0
-60 -30 0 30 60 90 120 150
TEMPERATURE (°C)
VEN = 2V
CIN = 10µF
C
= 1µF
OUT
I
= 1mA
L
VEN = 5V
3-172 1997
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MIC5208 Micrel
Applications Information
Supply/Ground
Both MIC5208 GND pins must be connected to the same
ground potential. INA and INB can each be connected to a
different supply.
Enable/Shutdown
ENA (enable/shutdown) and ENB may be enabled separately. Forcing ENA/B high (> 2V) enables the associated
regulator. ENA/B requires a small amount of current, typically
15µA. While the logic threshold is TTL/CMOS compatible,
ENA/B may be forced as high as 20V, independent of VIN.
Input Capacitor
A 0.1µF capacitor should be placed from IN to GND if there is
more than 10 inches of wire between the input and the ac filter
capacitor or if a battery is used as the input.
Output Capacitor
An output capacitor is required between OUT and GND to
prevent oscillation. Larger values improve the regulator’s
transient response. The output capacitor value may be increased without limit.
The output capacitor should have an ESR (effective series
resistance) of about 5Ω or less and a resonant frequency
above 500kHz. Most tantalum or aluminum electrolytic capacitors are adequate; film types will work, but are more
expensive. Since many aluminum electrolytics have electrolytes that freeze at about –30°C, solid tantalums are recommended for operation below –25°C.
At lower values of output current, less output capacitance is
required for output stability. The capacitor can be reduced to
0.22µF for current below 10mA or 0.1µF for currents below
1mA.
No-Load Stability
The MIC5208 will remain stable and in regulation with no load
(other than the internal voltage divider) unlike many other
voltage regulators. This is especially important in CMOS RAM
keep-alive applications.
Thermal Shutdown
Thermal shutdown is independent on both halves of the dual
MIC5208, however, an overtemperature condition in one half
may affect the other half because of proximity.
Thermal Considerations
Multilayer boards having a ground plane, wide traces near the
pads, and large supply bus lines provide better thermal
conductivity.
The MIC5208-xxBMM (8-lead MSOP) has a thermal resistance of 200°C/W when mounted on a FR4 board with
minimum trace widths and no ground plane.
PC Board θ
Dielectric
FR4 200°C
MSOP Thermal Characteristics
For additional heat sink characteristics, please refer to Micrel
Application Hint 17, “Calculating P.C. Board Heat Sink Area
For Surface Mount Packages”.
JA
3
1997 3-173
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