MICREL MIC5250

MIC5250
Micrel
MIC5250
Dual 150mA µCap CMOS LDO Regulator
OBSOLETE
General Description
Features
The MIC5250 is an efficient, precise dual CMOS voltage
regulator optimized for ultra-low-noise applications. The
MIC5250 offers better than 1% initial accuracy, extremely low
dropout voltage (typically 150mV at 150mA) and constant
ground current over load (typically 100µA). The MIC5250
provides a very-low-noise output, ideal for RF applications
where quiet voltage sources are required. A noise bypass pin
is also available for further reduction of output noise.
• Ultralow dropout—100mV @ 100mA
• Ultralow noise—30µV(rms)
• Stability with ceramic, tantalum, or aluminum electrolytic
capacitors
• Load independent, ultralow ground current
• 150mA output current
• Current limiting
• Thermal Shutdown
• Tight load and line regulation
• “Zero” off-mode current
• Fast transient response
• TTL-Logic-controlled enable input
Designed specifically for hand-held and battery-powered
devices, the MIC5250 provides TTL logic compatible enable
pins. When disabled, power consumption drops nearly to
zero.
The MIC5250 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in hand-held wireless devices.
Key features include current limit, thermal shutdown, pushpull outputs for faster transient response, and active clamps
to speed up device turnoff. Available in the 10-lead MSOP
(micro-shrink-outline package), the MIC5250 also offers a
range of fixed output voltages.
Applications
•
•
•
•
•
•
•
•
Cellular phones and pagers
Cellular accessories
Battery-powered equipment
Laptop, notebook, and palmtop computers
PCMCIA VCC and VPP regulation/switching
Consumer/personal electronics
SMPS post-regulator/dc-to-dc modules
High-efficiency linear power supplies
Ordering Information
Part Number
Voltage
Junction Temp. Range
Package
MIC5250-2.7BMM
2.7V
–40°C to +125°C
10-lead MSOP
MIC5250-2.8BMM
2.8V
–40°C to +125°C
10-lead MSOP
MIC5250-3.0BMM
3.0V
–40°C to +125°C
10-lead MSOP
MIC5250-3.3BMM
3.3V
–40°C to +125°C
10-lead MSOP
Other voltages available. Contact Micrel for details.
Typical Application
MIC5250-3.3BMM
VINA
2
ENABLE
SHUTDOWN
VINB
ENABLE
SHUTDOWN
9
7
5
10
INA
ENA
OUTA
BYPA
GNDA
INB
OUTB
8
BYPB
GNDB
4
ENB
3.3V
1
3
6
CBYPA
(optional)
COUTA
3.3V
CBYPB
(optional)
COUTB
ENA may be connected directly to INA.
ENB may be connected directly to INB.
GNDA and GND B may be connected to
isolated grounds or the same ground.
Dual Ultra-Low-Noise Regulator Circuit
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
June 2003
1
MIC5250
MIC5250
Micrel
Pin Configuration
BYPA 1
10 OUTA
ENA 2
9 INA
GNDA 3
8 OUTB
BYPB 4
7 INB
ENB 5
6 GNDB
MIC5250-x.xBMM
Pin Description
Pin Number
Pin Name
Pin Function
9/7
INA / B
Supply Input*
3/6
GNDA / B
2/4
ENA / B
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
1/4
BYPA / B
Reference Bypass: Connect external 0.01µF capacitor to GND to reduce
output noise. May be left open.
10 / 8
OUTA / B
Regulator Output
Ground*
* Supply inputs and grounds are fully isolated.
Absolute Maximum Ratings (Note 1)
Operating Ratings (Note 2)
Supply Input Voltage (VIN) .................................. 0V to +7V
Enable Input Voltage (VEN) ................................. 0V to +7V
Junction Temperature (TJ) ...................................... +150°C
Storage Temperature ............................... –65°C to +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD, Note 3
Input Voltage (VIN) ......................................... +2.7V to +6V
Enable Input Voltage (VEN) .................................. 0V to VIN
Junction Temperature (TJ) ....................... –40°C to +125°C
Thermal Resistance (θJA)...................................... 200°C/W
MIC5250
2
June 2003
MIC5250
Micrel
Electrical Characteristics
Each regulator: VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.
Symbol
Parameter
Conditions
Min
VO
Output Voltage Accuracy
IOUT = 0mA
–1
–2
∆VLNR
Line Regulation
VIN = VOUT + 1V to 6V
Max
Units
1
2
%
%
0
0.3
%/V
∆VLDR
Load Regulation
IOUT = 0.1mA to 150mA, Note 4
2.0
3.0
%
VIN – VOUT
Dropout Voltage, Note 5
IOUT = 100µA
1.5
5
mV
IOUT = 50mA
50
85
mV
IOUT = 100mA
100
150
mV
IOUT = 150mA
150
200
250
mV
mV
–0.3
Typical
IQ
Quiescent Current
VEN ≤ 0.4V (shutdown)
0.2
1
µA
IGND
Ground Pin Current, Note 6
IOUT = 0mA
100
150
µA
IOUT = 150mA
100
µA
50
dB
300
mA
µV(rms)
PSRR
Power Supply Rejection
f = 120Hz, COUT = 10µF, CBYP = 0.01µF
ILIM
Current Limit
VOUT = 0V
en
Output Voltage Noise
COUT = 10µF, CBYP = 0.01µF,
f = 10Hz to 100kHz
30
VIL
Enable Input Logic-Low Voltage
VIN = 2.7V to 5.5V, regulator shutdown
0.8
VIH
Enable Input Logic-High Voltage
VIN = 2.7V to 5.5V, regulator enabled
IEN
Enable Input Current
160
Enable Input
V
1
V
VIL ≤ 0.4V
0.17
µA
VIH ≥ 2.0V
1.5
µA
500
Ω
Thermal Shutdown Temperature
150
°C
Thermal Shutdown Hysteresis
10
°C
Shutdown Resistance Discharge
2.0
0.4
Thermal Protection
Note 1.
Exceeding the absolute maximum rating may damage the device.
Note 2.
The device is not guaranteed to function outside its operating rating.
Note 3.
Devices are ESD sensitive. Handling precautions recommended.
Note 4.
Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
Dropout Voltage is defined as the input to output differential at which the output voltage drops 2% below its nominal value measured at 1V
differential.
Ground pin current is the regulator quiescent current. The total current drawn from the supply is the sum of the load current plus the ground
pin current.
Note 5.
Note 6.
June 2003
3
MIC5250
MIC5250
Micrel
Typical Characteristics
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
100
60
40
VIN = 4V
VOUT = 3V
IOUT = 100mA
80 COUT = 1µF tant
PSRR (dB)
IOUT = 10mA
80 COUT = 1µF tant
PSRR (dB)
60
40
VIN = 4V
VOUT = 3V
60
40
20
20
20
0
1E+1
1k 1E+4
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
1E+1
1k 1E+4
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
0
1E+1
1k 1E+4
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
100
80
80
60
40
PSRR (dB)
100
VIN = 4V
VOUT = 3V
PSRR (dB)
IOUT = 150mA
80 COUT = 1µF tant
60
40
IOUT = 100µA
COUT = 10µF cer.
CBYP = 0.01µF
0
1E+1
1k 1E+4
10k 1E+5
1M 1E+7
10M
10 1E+2
100k 1E+6
100 1E+3
FREQUENCY (Hz)
20 V = 4V
IN
VOUT = 3V
0
1E+1
100 1E+3
1k 1E+4
10k 1E+5
100k 1E+6
1M 1E+7
10M
10 1E+2
FREQUENCY (Hz)
Power Supply
Rejection Ratio
Power Supply
Rejection Ratio
100
100
60
40
IOUT = 100mA
COUT = 10µF cer.
CBYP = 0.01µF
20
60
40
IOUT = 150mA
COUT = 10µF cer.
CBYP = 0.01
20
Power Supply Ripple Rejection
vs. Voltage Drop
10mA
30
20
10
0
0
MIC5250
100µA
COUT = 10µF cer.
CBYP = 0.01µF
200 400 600 800 1000
VOLTAGE DROP (mV)
70
100µA
10mA
60
50
40
30
150mA
20
IOUT = 100mA
10
0
0
COUT = 1µF
200 400 600 800 1000
VOLTAGE DROP (mV)
Noise Performance
10
IL = 100µA
IL = 100µA
IOUT = 100mA
NOISE (µV/√Hz)
RIPPLE REJECTION (dB)
100mA
50
40
Power Supply Ripple Rejection
vs. Voltage Drop
10
70
60
0
1E+1
100 1E+3
1k 1E+4
10k 1E+5
100k 1E+6
1M 1E+7
10M
10 1E+2
FREQUENCY (Hz)
Noise Performance
80
IOUT = 10mA
COUT = 10µF cer.
CBYP = 0.01µF
20
0
1E+1
1E+7
100 1E+3
1k 1E+4
10k 1E+5
100k 1E+6
1M 10M
10 1E+2
FREQUENCY (Hz)
0
1E+1
100 1E+3
1k 1E+4
10k 1E+5
100k 1E+6
1M 1E+7
10M
10 1E+2
FREQUENCY (Hz)
40
80
VIN = 4V
VOUT = 3V
80
PSRR (dB)
80
VIN = 4V
VOUT = 3V
VIN = 4V
VOUT = 3V
60
RIPPLE REJECTION (dB)
20
1
VIN = 4V
0.1 V
OUT = 3V
COUT = 1µF cer.
CBYP = 0.01µF
0.01
10 1E+2
100 1E+3
1k 1E+4
10k 100k
1M
1E+1
1E+5 1E+6
FREQUENCY (Hz)
4
NOISE (µV/√Hz)
PSRR (dB)
VIN = 4V
VOUT = 3V
100
PSRR (dB)
100
100
IOUT = 100µA
80 COUT = 1µF tant
PSRR (dB)
Power Supply
Rejection Ratio
1
VIN = 4V
0.1 VOUT = 3V
COUT = 10µF cer.
CBYP = 0.01µF
0.01
1k 1E+4
10 1E+2
1M
10k 1E+5
100 1E+3
100k 1E+6
1E+1
FREQUENCY (Hz)
June 2003
MIC5250
Micrel
Ground Pin Current
Ground Pin Current
200
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
95
VIN = 4V
VOUT = 3V
90
85
0.1
1
10
100
LOAD CURRENT (mA)
VOUT = 3V
75
50
25
IOUT = 100µA
50
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
0
Dropout Characteristics
RL = 30Ω
1.0
0.5
1
2
3
4
INPUT VOLTAGE (V)
ILOAD = 100µA
6
4
2
Dropout Voltage
TA = 25°C
100
TA = -40°C
25 50 75 100 125 150
OUTPUT CURRENT (mA)
IOUT = 150mA
1
2
3
4
INPUT VOLTAGE (V)
5
200
150
100
50
Output Voltage
vs. Temperature
3.05
500
400
300
200
IL = 150mA
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
VIN = 3.5V
VEN = 3V
100
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
5
OUTPUT VOLTAGE (V)
TA = 125°C
250
Short Circuit Current
OUTPUT CURRENT (mA)
DROPOUT VOLTAGE (mV)
25
Dropout Voltage
600
250
June 2003
50
300
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
5
300
0
0
75
0
0
5
DROPOUT VOLTAGE (mV)
DROPOUT VOLTAGE (mV)
OUTPUT VOLTAGE (V)
RL = 30kΩ
1.5
50
1
2
3
4
INPUT VOLTAGE (V)
VOUT = 3V
Dropout Voltage
VOUT = 3V
2.0
150
0
8
3.5
200
Ground Pin Current
100
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
QUIESCENT CURRENT (µA)
VIN = 4V
VOUT = 3V
IOUT = 150mA
0
0
IOUT = 100µA
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
Ground Pin Current
75
2.5
50
100
100
3.0
100
500
Ground Pin Current
150
125
150
VIN = 4V
VOUT = 3V
VIN = 4V
TYPICAL 3V DEVICE
3.00
2.95
2.90
ILOAD = 100µA
2.85
-50
0
50
100
TEMPERATURE (°C)
150
MIC5250
MIC5250
Micrel
Enable Pin Bias Current
4
THRESHOLD VOLTAGE (V)
ENABLE PIN CURRENT (µA)
2.0
1.5
VIN = 4.0V
1.0
0.5
VEN = 100mV
Enable Threshold Voltage
3
2
VIN = 4.0V
1
0
-40 -20 0 20 40 60 80 100
TEMPERATURE (°C)
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
Functional Characteristics
Load Transient Response
∆ OUTPUT VOLTAGE
(100mV/div.)
OUTPUT CURRENT
6V
VOUT = 3V
COUT = 10µF
CBYP = 0.01µF
IOUT = 100µA
4V
VIN = 4V
VOUT = 3V
COUT = 10µF cer.
CBYP = 0.01µF
Enable Pin Delay
Shutdown Delay
100µA
OUTPUT VOLTAGE
(1V/div.)
OUTPUT VOLTAGE
(1V/div.)
ENABLE VOLTAGE
(2V/div.)
TIME (100µs/div.)
VIN = 4V
VOUT = 3V
COUT = 10µF
CBYP = 0.01µF
IOUT = no load
TIME (20µs/div.)
MIC5250
150mA
TIME (10ms/div.)
ENABLE VOLTAGE
(1V/div.)
INPUT VOLTAGE
(2V/div.)
∆ OUTPUT VOLTAGE
(50mV/div.)
Line Transient Response
VOUT = 3V
COUT = 10µF
CBYP = 0.01µF
IOUT = no load
TIME (1ms/div.)
6
June 2003
MIC5250
Micrel
Crosstalk
Characteristics
OUTPUT VOLTAGE A OUTPUT VOLTAGE B
(100mV/div.)
(20mV/div.)
OUTPUT VOLTAGE A OUTPUT VOLTAGE B
(100mV/div.)
(20mV/div.)
Crosstalk
Characteristics
VOUTB = 3.3V
COUTB = 10µF
CBYPB = 0
ILOAD = 100µA
VOUTA = 3.3V
COUTA = 10µF
CBYPA = 0
VIN = 4.3V
separate supplies
ILOAD = 100µA
ILOAD = 150mA
VOUTB = 3.3V
COUTB = 10µF
CBYPB = 0
ILOAD = 100µA
VOUTA = 3.3V
COUTA = 10µF
CBYPA = 0
VIN = 4.3V
common supply
ILOAD = 100µA
ILOAD = 150mA
TIME (25µs/div.)
TIME (25µs/div.)
Block Diagrams
INA
Reference
Voltage
Startup/
Shutdown
Control
Quickstart/
Noise
Cancellation
ENA
BYPA
PULL
UP
Thermal
Sensor
FAULT
Error
Amplifier
Undervoltage
Lockout
Current
Amplifier
ACTIVE SHUTDOWN
OUTA
PULL
DOWN
GNDA
INB
Reference
Voltage
Startup/
Shutdown
Control
Quickstart/
Noise
Cancellation
ENB
BYPB
PULL
UP
Thermal
Sensor
FAULT
Error
Amplifier
Undervoltage
Lockout
Current
Amplifier
ACTIVE SHUTDOWN
OUTB
PULL
DOWN
GNDB
June 2003
7
MIC5250
MIC5250
Micrel
Thermal Considerations
The MIC5250 is a dual LDO voltage regulator designed to
provide two output voltages from one package. Both regulator outputs are capable of sourcing 150mA of output current.
Proper thermal evaluation needs to be done to ensure that
the junction temperature does not exceed it’s maximum
value, 125°C. Maximum power dissipation can be calculated
based on the output current and the voltage drop across each
regulator. The sum of the power dissipation of each regulator
determines the total power dissipation. The maximum power
dissipation that this package is capable of handling can be
determined using thermal resistance, junction to ambient,
and the following basic equation:
Applications Information
Enable/Shutdown
The MIC5250 comes with active-high enable pins that allows
either regulator to be disabled. Forcing an enable pin low
disables the respective regulator and places it into a “zero”
off-mode-current state. In this state, current consumed by the
regulator goes nearly to zero. Forcing an enable pin high
enables the output voltage. This part is CMOS therefore the
enable pin cannot be left floating; a floating enable pin may
cause an indeterminate state on the output.
Input Capacitor
Input capacitors are not required for stability. A 1µF input
capacitor is recommended for either regulator when the bulk
ac supply capacitance is more than 10 inches away from the
device, or when the supply is a battery.
Output Capacitor
The MIC5250 requires output capacitors for stability. The
design requires 1µF or greater on each output to maintain
stability. Capacitors can be low-ESR ceramic chip capacitors. The MIC5250 has been designed to work specifically
with low-cost, small chip capacitors. Tantalum capacitors can
also be used for improved capacitance over the operating
temperature range. The value of the capacitor can be increased without bounds.
Bypass Capacitor
Capacitors can be placed from each noise bypass pin to their
respective ground to reduce output voltage noise. These
capacitors bypass the internal references. A 0.01µF capacitor is recommended for applications that require low-noise
outputs.
Transient Response
The MIC5250 implements a unique output stage design
which dramatically improves transient response recovery
time. The output is a totem-pole configuration with a Pchannel MOSFET pass device and an N-channel MOSFET
clamp. The N-channel clamp is a significantly smaller device
that prevents the output voltage from overshooting when a
heavy load is removed. This feature helps to speed up the
transient response by significantly decreasing transient response recovery time during the transition from heavy load
(100mA) to light load (100µA).
Active Shutdown
Each regulator also features an active shutdown clamp,
which is an N-channel MOSFET that turns on when the
device is disabled. This allows the output capacitor and load
to discharge, de-energizing the load.
Cross Talk
When a load transient occurs on one output of the MIC5250,
the second output may couple a small amount of ripple to its
output. This typically comes from a common input source or
from poor grounding. Using proper grounding techniques
such as star grounding as well as good bypassing directly at
the inputs of each regulator will help to reduce the magnitude
of the cross talk. See “Functional Characteristics” for an
example of cross talk performance.
MIC5250
 TJ (max ) − TA 
PD(max ) = 

θJA


TJ(max) is the maximum junction temperature of the die,
125°C and TA is the ambient operating temperature of the die.
θJA is layout dependent. Table 1 shows the typical thermal
resistance for a minimum footprint layout for the MIC5250.
Package
θJA at Recommended
Minimum Footprint
MSOP-10
200° C/W
Table 1. Thermal Resistance
The actual power dissipation of each regulator output can be
calculated using the following simple equation:
(
)
PD = VIN − VOUT IOUT + VIN IGND
Each regulator contributes power dissipation to the overall
power dissipation of the package.
PD (total ) = PD (reg1) + PD (reg 2)
Each output is rated for 150mA of output current, but the
application may limit the amount of output current based on
the total power dissipation and the ambient temperature.
A typical application may call for two 3.0V outputs from a
single Li-ion battery input. This input can be as high as 4.2V.
When operating at high ambient temperatures, the output
current may be limited. When operating at an ambient of
60°C, the maximum power dissipation of the package is
calculated as follows:
 125°C − 60°C 
PD(max) = 

 200°C/W 
PD(max) = 325mW
For the application mentioned above, if regulator 1 is sourcing
150mA, it contributes the following to the overall power
dissipation:
(
)
PD(reg1) = VIN − VOUT IOUT + VIN IGND
PD(reg1) = (4.2V − 3.0V) 150mA + 4.2V × 100µA
PD(reg1) = 180.4mW
8
June 2003
MIC5250
Micrel
Since the total power dissipation allowable is 325mW, the
maximum power dissipation of the second regulator is limited
to:
Fixed Regulator Applications
MIC5250-3.3BMM
10
OUTA
PD(max) = PD(reg1) + PD(reg2)
VINA
325mW = 180.4mW + PD (reg 2)
VINB
PD (reg 2) = 144.6mW
The maximum output current of the second regulator can be
calculated using the same equations but solving for the
output current (ground current is constant over load and
simplifies the equation):
(
9
INA
BYPA
1
2
ENA
GNDA
3
7
INB
OUTB
8
5
ENB
BYPB
GNDB
4
3.3V
0.01µF
1µF
3.3V
6
0.01µF
1µF
Figure 1. Ultra-Low-Noise Dual 3.3V Application
Figure 1 includes 0.01µF capacitors for low-noise operation
and shows EN (pin 3) connected to IN (pin 1) for an applications where enable/shutdown is not required. COUT = 1µF
minimum.
)
PD (reg 2) = VIN − VOUT IOUT + VIN IGND
144.6mW = (4.2V − 3.0V) IOUT + 4.2V × 100µA
MIC5250-3.3BMM
10
OUTA
IOUT = 120.5mA
VINA
The second output is limited to 120mA due to the total power
dissipation of the system when operating at 60°C ambient
temperature.
VINB
9
INA
BYPA
1
2
ENA
GNDA
3
7
INB
ENB
OUTB
BYPB
8
5
GNDB
6
4
3.3V
1µF
3.3V
1µF
Figure 2. Low-Noise Fixed Voltage Application
Figure 2 is an example of a low-noise configuration where
CBYP is not required. COUT = 1µF minimum.
Dual-Supply Operation
When used in dual supply systems where the regulator load
is returned to a negative supply, the output voltage must be
diode clamped to ground.
June 2003
9
MIC5250
MIC5250
Micrel
Package Information
3.15 (0.122)
2.85 (0.114)
DIMENSIONS:
MM (INCH)
4.90 BSC (0.193)
3.10 (0.122)
2.90 (0.114)
1.10 (0.043)
0.94 (0.037)
0.30 (0.012)
0.15 (0.006)
0.50 BSC (0.020)
0.15 (0.006)
0.05 (0.002)
0.26 (0.010)
0.10 (0.004)
6° MAX
0° MIN
0.70 (0.028)
0.40 (0.016)
10-Lead MSOP (MM)
MIC5250
10
June 2003
MIC5250
June 2003
Micrel
11
MIC5250
MIC5250
Micrel
MICREL INC.
TEL
1849 FORTUNE DRIVE SAN JOSE, CA 95131
+ 1 (408) 944-0800
FAX
+ 1 (408) 944-0970
WEB
USA
http://www.micrel.com
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© 2003 Micrel Incorporated
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June 2003