MICREL MIC5253

MIC5253
Micrel
MIC5253
100mA Low Noise µCap Teeny™ LDO
General Description
Features
The MIC5253 is an efficient, CMOS voltage regulator optimized for ultra-low-noise applications. It offers 1.5% initial
accuracy, extremely low dropout voltage (165mV at 100mA),
and low ground current (typically 95µA at full load). The
MIC5253 provides a very low noise output, ideal for RF
applications where a clean voltage source is required. A
noise bypass pin is also available for further reduction of
output noise.
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Designed specifically for handheld and battery-powered devices, the MIC5253 provides a TTL-logic-compatible enable
pin. When disabled, power consumption drops nearly to zero.
Input voltage range: 2.7V to 5.5V
Teeny™ SC-70-5 package
Ultra-low output noise: 30µV(rms)
100mA continuous output current, 150mA peak current
Stability with ceramic output capacitors
Ultralow dropout: 165mV @ 100mA
High output accuracy:
1.5% initial accuracy
3.0% over temperature
Low ground current: 95µA
TTL-Logic-controlled enable input
“Zero” off-mode current
Thermal shutdown and current limit protection
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The MIC5253 also works with low-ESR ceramic capacitors,
reducing the amount of board space necessary for power
applications, critical in handheld wireless devices.
Applications
Available in the Teeny™ SC-70-5 package, the MIC5253
offers a wide range of output voltages. Key features include
current limit, thermal shutdown, faster transient response,
and an active clamp to speed up device turn-off.
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Cellular phones and pagers
Cellular accessories
Battery-powered equipment
Laptop, notebook, and palmtop computers
Consumer/personal electronics
Ordering Information
Part Number
Marking
Voltage
Junction Temp. Range*
Package
MIC5253-1.8BC5
LCN
1.8V
–40°C to +125°C
SC-70-5
MIC5253-1.85BC5
L71J
1.85V
–40°C to +125°C
SC-70-5
MIC5253-2.6BC5
LCP
2.6V
–40°C to +125°C
SC-70-5
MIC5253-2.9BC5
L729
2.9V
–40°C to +125°C
SC-70-5
MIC5253-3.0BC5
LCG
3.0V
–40°C to +125°C
SC-70-5
MIC5253-3.3BC5
L733
3.3V
–40°C to +125°C
SC-70-5
Other voltages available. Contact Micrel for details.
Typical Application
CIN = 1.0µF
Ceramic
Enable
Shutdown
VIN
MIC5253-x.xBC5
1
5
VOUT
2
3
4
COUT = 1.0µF
Ceramic
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
CBYP = 0.01µF
Ultra-Low-Noise Regulator Application
Teeny is a trademark of Micrel, Inc.
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
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Pin Configuration
EN GND IN
3
2
1
LCxx
4
5
BYP
OUT
SC-70-5 (C5)
Pin Description
Pin Number
Pin Name
Pin Function
1
IN
Supply Input.
2
GND
3
EN
4
BYP
Reference Bypass: Connect external 0.01µF ≤ CBYP ≤ 1.0µF capacitor to GND to reduce output
noise. May be left open.
5
OUT
Regulator Output.
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Ground.
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown.
Do not leave open.
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Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Input Voltage (VIN) .................................. 0V to +7V
Enable Input Voltage (VEN) ................................. 0V to +7V
Power Dissipation (PD) ........................ Internally Limited(3)
Junction Temperature (TJ) ....................... –40°C to +125°C
Storage Temperature ............................... –65°C to +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD Rating(4) ................................................................................ 2kV
Input Voltage (VIN) ...................................... +2.7V to +5.5V
Enable Input Voltage (VEN) .................................. 0V to VIN
Junction Temperature (TJ) ....................... –40°C to +125°C
Thermal Resistance
SC-70-5 (θJA) .................................................... 400°C/W
Electrical Characteristics(5)
VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless otherwise noted.
Symbol
Parameter
Conditions
Min
VO
Output Voltage Accuracy
IOUT = 100µA
–1.5
–3
∆VLNR
Line Regulation
VIN = VOUT + 1V to 6V
∆VLDR
Load Regulation
VIN – VOUT
Dropout Voltage(7)
Typical
Max
Units
1.5
3
%
%
0.035
0.05
%/V
IOUT = 0.1mA to 100mA, Note 6
1.5
2.5
%
IOUT = 50mA
80
150
mV
IOUT = 100mA
165
300
mV
IQ
Quiescent Current
VEN ≤ 0.4V (shutdown)
0.2
1
µA
IGND
Ground Pin Current(8)
IOUT = 0mA
75
100
µA
IOUT = 100mA
90
150
µA
f = 100Hz, COUT = 1.0µF, CBYP = 0.1µF
66
dB
f = 1kHz, VIN = VOUT +1, CBYP = 0.1µF
70
dB
f = 10kHz, VIN = VOUT +1, CBYP = 0.1µF
65
dB
PSRR
Ripple Rejection
30
150
µs
250
450
mA
tON
Turn-On Time
ILIM
Current Limit
VOUT = 0V
en
Output Voltage Noise
COUT = 1.0µF, CBYP = 0.01µF,
f = 10Hz to 100kHz
VIL
Enable Input Logic-Low Voltage
VIN = 2.7V to 5.5V, regulator shutdown
VIH
Enable Input Logic-High Voltage
VIN = 2.7V to 5.5V, regulator enabled
IEN
Enable Input Current
VIL ≤ 0.4V, regulator shutdown
0.01
µA
VIH ≥ 1.6V, regulator enabled
0.01
µA
Thermal Shutdown Temperature
150
°C
Thermal Shutdown Hysteresis
10
°C
150
µV(rms)
30
Enable Input
0.4
1.6
V
V
Thermal Protection
Notes:
1. Exceeding the absolute maximum ratings may damage the device.
2. The device is not guaranteed to function outside its operating ratings.
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. The θJA of the MIC5253-x.xBC5 (all versions) is
400°C/W on a PC board (see ”Thermal Considerations” section for further details).
4. Devices are ESD sensitive. Handling precautions recommended.
5. Specification for packaged product only.
6. 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 100mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
7. 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.
For outputs below 2.7V, dropout voltage is the input-to-output voltage differential with the minimum input voltage 2.7V. Minimum input operating voltage
is 2.7V.
8. 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.
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Typical Characteristics
Power Supply Rejection Ratio
70
70
60
60
1mA
30
10mA
100mA
VOUT = 1.8V COUT = 1µF
10 V = 2.8V
CBYP = 0.1µF
IN
0
1k
10k
100k
100
FREQUENCY (Hz)
20
1M
100µA
1mA
30
10mA
100mA
20
V
= 1.8V COUT = 1µF
10 OUT
CBYP = 0.01µF
VIN = 2.8V
0
10k
100k
1k
100
FREQUENCY (Hz)
40
OUTPUT VOLTAGE (mV)
GROUND CURRENT (µA)
60
50
40
30
20
= 100mA
5
250
150
–40°C
25°C
100
125°C
50
VIN = 3.6V
VOUT = 2.6V
0
0
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25 50 75 100 125 150
OUTPUT CURRENT (mA)
25 50 75 100 125 150
OUTPUT CURRENT (mA)
78
76
74
72
I
= 100µA
LOAD
70
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
60
50
40
30
20
10
0
0
ILOAD = 100µA
1
2
3
4
INPUT VOLTAGE (V)
5
Dropout Voltage
250
ILOAD = 100mA
1.4
ILOAD = 100µA
1.2
1
0.8
0.6
0.4
0.2
VOUT = 1.85V
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
200
150
100
50
VIN = 3.6V
VOUT = 2.6V
ILOAD = 100mA
0
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
Output Voltage
vs. Temperature
Short Circuit Current
SHORT CIRCUIT CURRENT (mA)
DROPOUT VOLTAGE (mV)
300
VOUT =1.8V
VIN = VOUT + 1V
Ground Pin Current
80
Dropout Voltage
350
200
81
0
1M
70
1.8
1.6
70
LOAD
82
82
80
I
83
80
2
1
2
3
4
INPUT VOLTAGE (V)
84
Dropout Characteristics
Ground Pin Current
0
0
85
84
90
10
86
Ground Pin Current
90
88
86
84
82
80
78
76
74
72
I
= 100mA
LOAD
70
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
GROUND CURRENT (µA)
GROUND CURRENT (µA)
Ground Pin Current
87
GROUND CURRENT (µA)
40
50
DROPOUT VOLTAGE (mV)
100µA
2.7
290
OUTPUT VOLTAGE (V)
50
Ground Pin Current
88
GROUND CURRENT (µA)
80
PSRR (dB)
PSRR (dB)
Power Supply Rejection Ratio
80
270
250
230
210
190
170
150
2.5 2.7 2.9 3.1 3.3 3.5 3.7 3.9
INPUT VOLTAGE (V)
4
2.65
2.6
2.55
ILOAD = 100µA
VOUT = 2.6V
VIN = 3.6V
2.5
-40 -20 0 20 40 60 80 100 120
TEMPERATURE (°C)
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Functional Characteristics
Load Transient Response
Output Voltage
(20mV/div)
Input Voltage
(1V/div)
Line Transient Response
5V
4V
CIN = 1µF Ceramic
COUT = 1µF Ceramic
CBYP = 0.01µF
IOUT = 100µA
Output Current
(50mA/div)
Output Voltage
(50mV/div)
100mA
Enable Pin Delay
Shutdown Delay
Enable Voltage
(1V/div)
TIME (5µs/div)
Enable Voltage
(1V/div)
TIME (500µs/div)
CIN = 1µF Ceramic
COUT = 1µF Ceramic
CBYP = 0.01µF
VIN = 4V
Output Voltage
(500mV/div)
Output Voltage
(500mV/div)
CIN = 1µF Ceramic
COUT = 1µF Ceramic
CBYP = 0.01µF
IOUT = 100µA
TIME (5µs/div)
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100µA
CIN = 1µF Ceramic
COUT = 1µF Ceramic
CBYP = 0.01µF
VIN = 4V
TIME (500µs/div)
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Block Diagram
IN
Reference
Voltage
Startup/
Shutdown
Control
Quickstart/
Noise
Cancellation
EN
BYP
Thermal
Sensor
FAULT
Error
Amplifier
Undervoltage
Lockout
Current
Amplifier
OUT
ACTIVE SHUTDOWN
GND
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No-Load Stability
The MIC5253 will remain stable and in regulation with no load
unlike many other voltage regulators. This is especially
important in CMOS RAM keep-alive applications.
Thermal Considerations
The MIC5253 is designed to provide 100mA 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 5.0V, the output voltage is 2.9V, and the output
current = 100mA.
The actual power dissipation of the regulator circuit can be
determined using the equation:
PD = (VIN – VOUT) IOUT + VIN IGND
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.
PD = (5.0V – 2.9V) × 100mA
PD = 0.21W
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:
Applications Information
Enable/Shutdown
The MIC5253 comes with an 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-modecurrent state. In this state, current consumed by the regulator
goes nearly to zero. Forcing the enable pin high enables the
output voltage. This part is CMOS and the enable pin cannot
be left floating; a floating enable pin may cause an indeterminate state on the output.
Input Capacitor
The MIC5253 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 performance 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.
Output Capacitor
The MIC5253 requires an output capacitor for stability. The
design requires 1µF or greater on the output to maintain
stability. The design is optimized for use with low-ESR
ceramic chip capacitors. High ESR capacitors may cause
high frequency oscillation. The maximum recommended
ESR is 300mΩ. 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 recommended because of their temperature performance. X7Rtype 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.
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 MIC5253 to drive a large capacitor on the bypass
pin without significantly slowing turn-on time. Refer to the
“Typical Characteristics” section for performance with different bypass capacitors.
Active Shutdown
The MIC5253 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.
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 T (max) − TA 
PD (max) =  J

θ JA


TJ(max) = 125°C, the max. junction temperture of the die
θJA thermal resistance = 400°C/W
Table 1 shows junction-to-ambient thermal resistance for the
MIC5253 in the SC-70 package.
Package
SC-70-5 (C5)
θJA Recommended
Minimum Footprint
θJA 1" Sq.
Copper Clad
θJC
400°C/W
325°C
250°C/W
Table 1. Thermal Resistance
Substituting PD for PD(max) and solving for the ambient
operating temperature will give the maximum operating conditions for the regulator circuit. The junction-to-ambient thermal resistance for the minimum footprint is 400°C/W, from
Table 1. The maximum power dissipation must not be exceeded for proper operation.
For example, when operating the MIC5253-2.9BC5 at an
input voltage of 5.0V and 100mA load with a minimum
footprint layout, the maximum ambient operating temperature TA can be determined as follows:
0.21W =
125°C − TA
400°C/W
TA = 41°C
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Therefore, a 2.9V application at 100mA of output current can
accept an ambient operating temperature of 41°C in a SC-70
package. For a full discussion of heat sinking and thermal
effects on voltage regulators, refer to the “Regulator Thermals”
section of Micrel’s Designing with Low-Dropout Voltage Regulators handbook. This information can be found on Micrel's
website at:
http://www.micrel.com/_PDF/other/LDOBk_ds.pdf
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Package Information
0.65 (0.0256) BSC
1.35 (0.053) 2.40 (0.094)
1.15 (0.045) 1.80 (0.071)
2.20 (0.087)
1.80 (0.071)
DIMENSIONS:
MM (INCH)
1.00 (0.039) 1.10 (0.043)
0.80 (0.032) 0.80 (0.032)
0.10 (0.004)
0.00 (0.000)
0.30 (0.012)
0.15 (0.006)
0.18 (0.007)
0.10 (0.004)
0.30 (0.012)
0.10 (0.004)
5-Pin SC-70-5 (C5)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131
TEL
+ 1 (408) 944-0800
FAX
+ 1 (408) 474-1000
WEB
USA
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 at Purchaser’s own risk and Purchaser agrees to fully indemnify
Micrel for any damages resulting from such use or sale.
© 2004 Micrel, Incorporated.
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