MIC5255-2.7BM5TR [ROCHESTER]
2.7 V FIXED POSITIVE LDO REGULATOR, 0.25 V DROPOUT, PDSO5, SOT-23, 5 PIN;
| 型号： | MIC5255-2.7BM5TR |
| 厂家： | 
Rochester Electronics |
| 描述： | 2.7 V FIXED POSITIVE LDO REGULATOR, 0.25 V DROPOUT, PDSO5, SOT-23, 5 PIN 光电二极管 输出元件 电源电路 线性稳压器IC 调节器 |
| 文件： | 总14页 (文件大小：1605K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC5255
150mA Low Noise µCap CMOS LDO
General Description
Features
The MIC5255 is an efficient, precise CMOS voltage
regulator optimized for ultra-low-noise applications. It
offers 1% initial accuracy, extremely-low dropout voltage
(135mV at 150mA) and low ground current (typically
90µA). The MIC5255 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.
• Input voltage range: 2.7V to 6.0V
• Thin SOT package: 1mm height SOT-23-5
• Ultra-low output noise: 30µV(rms)
• Stability with ceramic output capacitors
• Ultra-low dropout: 135mV @ 150mA
• High output accuracy:
–
–
1.0% initial accuracy
2.0% over temperature
Designed specifically for handheld and battery-powered
devices, the MIC5255 provides a TTL-logic-compatible en-
able pin. When disabled, power consumption drops nearly
to zero.
• Low quiescent current: 90µA
• Tight load and line regulation
• TTL-Logic-controlled enable input
• “Zero” off-mode current
The MIC5255 also works with low-ESR ceramic
capacitors, reducing the amount of board space necessary
for power applications, critical in handheld wireless
devices.
• Thermal shutdown and current limit protection
Key features include current limit, thermal shutdown, faster
transient response, and an active clamp to speed up
device turn-off. Available in the 6-pin 2mm × 2mm MLF®
package, the IttyBitty® SOT-23-5 package and the new
Thin SOT-23-5, which offers the same footprint as the
standard IttyBitty® SOT-23-5, but only 1mm tall. The
MIC5255 offers a range of output voltages.
Applications
• Cellular phones and pagers
• Cellular accessories
• Battery-powered equipment
• Laptop, notebook, and palmtop computers
• Consumer/personal electronics
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
___________________________________________________________________________________________________________
Typical Application
MIC5255-x.x_M5
VIN
VOUT
CIN = 1.0µF
Ceramic
1
2
3
5
COUT = 1.0µF
Ceramic
4
Enable
Shutdown
EN
EN (pin 3) may be
connected directly
to IN (pin 1).
C
BYP = 0.01µF
Ultra-Low-Noise Regulator Application
IttyBitty is a registered 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
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Micrel, Inc.
MIC5255
Ordering Information
Part Number
Standard
Marking
Standard
Junction
Temp. Range
Voltage*
Package
Pb-Free
Pb-Free**
NW25
KW25
NW26
KW26
NW27
KW27
KW2H
NW28
KW28
W28***
NW2J
KW2J
W2J***
NW29
KW29
NW30
KW30
W30***
KW31
KW32
NW33
KW33
W33***
KW35
MIC5255-2.5BD5
MIC5255-2.5BM5
MIC5255-2.6BD5
MIC5255-2.6BM5
MIC5255-2.7BD5
MIC5255-2.7BM5
MIC5255-2.75BM5
MIC5255-2.8BD5
MIC5255-2.8BM5
MIC5255-2.8BML
MIC5255-2.85BD5
MIC5255-2.85BM5
MIC5255-2.85BML
MIC5255-2.9BD5
MIC5255-2.9BM5
MIC5255-3.0BD5
MIC5255-3.0BM5
MIC5255-3.0BML
MIC5255-3.1BM5
MIC5255-3.2BM5
MIC5255-3.3BD5
MIC5255-3.3BM5
MIC5255-3.3BML
MIC5255-3.5BM5
Notes:
MIC5255-2.5YD5
MIC5255-2.5YM5
MIC5255-2.6YD5
MIC5255-2.6YM5
MIC5255-2.7YD5
MIC5255-2.7YM5
MIC5255-2.75YM5
MIC5255-2.8YD5
MIC5255-2.8YM5
MIC5255-2.8YML
MIC5255-2.85YD5
MIC5255-2.85YM5
MIC5255-2.85YML
MIC5255-2.9YD5
MIC5255-2.9YM5
MIC5255-3.0YD5
MIC5255-3.0YM5
MIC5255-3.0YML
MIC5255-3.1YM5
MIC5255-3.2YM5
MIC5255-3.3YD5
MIC5255-3.3YM5
MIC5255-3.3YML
MIC5255-3.5YM5
NW25
LW25
NW26
LW26
NW27
LW27
LW2H
NW28
LW28
W28
2.5V
2.5V
2.6V
2.6V
2.7V
2.7V
2.75V
2.8V
2.8V
2.8V
2.85V
2.85V
2.85V
2.9V
2.9V
3.0V
3.0V
3.0V
3.1V
3.2V
3.3V
3.3V
3.3V
3.5V
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
–40° to +125°C
5-Pin TSOT-23
5-Pin SOT-23
5-Pin TSOT-23
5-Pin SOT-23
5-Pin TSOT-23
5-Pin SOT-23
5-Pin SOT-23
5-Pin TSOT-23
5-Pin SOT-23
6-Pin 2x2 MLF®
5-Pin TSOT-23
5-Pin SOT-23
6-Pin 2x2 MLF®
5-Pin TSOT-23
5-Pin SOT-23
5-Pin TSOT-23
5-Pin SOT-23
6-Pin 2x2 MLF®
5-Pin SOT-23
5-Pin SOT-23
5-Pin TSOT-23
5-Pin SOT-23
6-Pin 2x2 MLF®
5-Pin SOT-23
NW2J
LW2J
W2J
NW29
LW29
NW30
LW30
W30
LW31
LW32
NW33
LW33
W33
LW35
*
Other Voltage available. Contact Micrel for details.
** Under bar / Over bar symbol may not be to scale.
*** Over bar symbol located after Pin 1 identifier.
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MIC5255
Pin Configuration
EN GND IN
EN GND IN
3
2
1
3
2
1
6
5
4
BYP
NC
EN
GND
IN
1
2
3
Wxx
LWxx
NWxx
4
5
4
5
OUT
BYP
BYP
OUT
OUT
MIC5255-x.xBM5
5-Pin SOT23 (M5)
MIC5255-x.xBD5
5-Pin Thin SOT23 (D5)
MIC5255-x.xBML
6-Pin 2x2 MLF® (ML)
EN GND IN
EN GND IN
3
2
1
3
2
1
6
5
4
BYP
NC
EN
GND
IN
1
2
3
Wxx
KWxx
NWxx
4
5
4
5
OUT
BYP
BYP
OUT
OUT
MIC5255-x.xYM5
5-Pin SOT23 (M5)
MIC5255-x.xYD5
5-Pin Thin SOT23 (D5)
MIC5255-x.xYML
6-Pin 2x2 MLF® (ML)
Pin Description
Pin Number
Pin Number
6-MLF
Pin Name Pin Name
SOT23-5
TSOT23-5
1
2
3
3
2
1
IN
GND
EN
Supply Input.
Ground.
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
logic low = shutdown. Do not leave open.
4
6
BYP
Reference Bypass: Connect external 0.01µF ≤ CBYP ≤ 1.0µF capacitor
to GND to reduce output noise. May be left open.
5
–
–
4
5
OUT
NC
Regulator Output.
No internal connection.
EP
GND
Ground: Internally connected to the exposed pad. Connect externally to
GND pin.
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MIC5255
Absolute Maximum Ratings(1)
Operating Ratings(2)
Supply Voltage (VIN)............................................. 0V to +7V
Enable Voltage (VEN)............................................ 0V to +7V
Power Dissipation (PD)...........................Internally Limited(3)
Junction Temperature (TJ) ........................–40°C to +125°C
Storage Temperature (Ts) .........................–60°C to +150°C
Lead Temperature (soldering, 5 sec.)........................ 260°C
EDS Rating(4)..................................................................2kV
Supply Voltage (VIN)........................................ +2.7V to +6V
Enable Voltage (VEN).............................................. 0V to VIN
Junction Temperature (TJ) ........................–40°C to +125°C
Thermal Resistance
SOT23-5 (
θ
JA)..................................................235°C/W
JA) .................................................90°C/W
2x2 MLF-6 (
θ
Electrical Characteristics(5)
VIN = VOUT + 1V, VEN = VIN; IOUT = 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.
Symbol
Parameter
Condition
Min
Typ
Max
Units
VO
Output Voltage Accuracy
IOUT = 100µA
–1
–2
1
2
%
%
∆VLNR
Line Regulation
Load Regulation
Dropout Voltage(7)
VIN = VOUT + 1V to 6V
I
OUT = 0.1mA to 150mA(6)
0.02
1.5
0.1
90
0.05
2.5
5
%/V
%
∆VLDR
VIN – VOUT
IOUT = 100µA
IOUT = 100mA
IOUT = 150mA
mV
mV
150
135
200
250
mV
mV
IQ
Quiescent Current
Ground Pin Current(8)
VEN ≤ 0.4V (shutdown)
IOUT = 0mA
0.2
90
1
µA
µA
IGND
150
IOUT = 150mA
117
60
µA
PSRR
Ripple Rejection
f = 10Hz, COUT = 1.0µF, CBYP = 0.01µF
f = 100Hz, VIN = VOUT +1
f = 10kHz, VIN = VOUT +1
VOUT = 0V
dB
60
dB
50
dB
ILIM
en
Current Limit
160
425
30
mV
Output Voltage Noise
C
OUT = 1.0µF, CBYP = 0.01µF,
µV(rms)
f = 10Hz to 100kHz
Enable Input
VIL
VIH
IEN
Enable Input Logic-Low Voltage
Enable Input Logic-High Voltage
Enable Input Current
VIN = 2.7V to 5.5V, regulator shutdown
VIN = 2.7V to 5.5V, regulator enabled
VIL ≤ 0.4V, regulator shutdown
0.4
V
V
1.6
0.01
0.01
500
µA
µA
Ω
V
IH ≥ 1.6V, regulator enabled
Shutdown Resistance Discharge
Thermal Protection
Thermal Shutdown Temperature
Thermal Shutdown Hysteresis
150
10
°C
°C
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MIC5255
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. The θJA of the MIC5255-x.xBM5 (all versions) is
235°C/W on a PC board. See “Thermal Considerations” section for further details.
4. Devices are ESD sensitive. Handling precautions recommended. Human body model, 1.5k in series with 100pF.
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 1.0mA to 150mA. 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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MIC5255
Typical Characteristics
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MIC5255
Typical Characteristics
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MIC5255
Functional Characteristics
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MIC5255
Functional Diagram
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MIC5255
large capacitor on the bypass pin without significantly
slowing turn-on time. Refer to the “Typical Character-
istics” section for performance with different bypass
capacitors.
Application Information
Enable/Shutdown
The MIC5255 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-mode-current 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.
Active Shutdown
The MIC5255 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.
No-Load Stability
The MIC5255 will remain stable and in regulation with no
load unlike many other voltage regulators. This is
especially important in CMOS RAM keep-alive
applications.
Input Capacitor
The MIC5255 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.
Thermal Considerations
Low-ESR
ceramic
capacitors
provide
optimal
The MIC5255 is designed to provide 150mA of
continuous current in a very small package. Maximum
power dissipation can be calculated based on the output
current and the voltage drop across the part. To
determine the maximum power dissipation of the
package, use the junction-to-ambient thermal resistance
of the device and the following basic equation:
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 MIC5255 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 300mꢀ. 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.
T
− TA
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
J(max)
PD(max)
=
θJA
TJ(max) is the maximum junction temperature of the die,
125°C, and TA is the ambient operating temperature. θJA
is layout dependent; Table 1 shows examples of
junction-to-ambient thermal resistance for the MIC5255.
Package
θ
JA Recommended
Minimum Footprint
θ
JA 1” Square
Copper Clad
θJC
X7R/X5R dielectric-type ceramic capacitors are recom-
mended 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.
SOT23-5
(M5 or D5)
235°C/W
185°C/W
145°C/W
Table 1. SOT-23-5 Thermal Resistance
The actual power dissipation of the regulator circuit can
be determined using the equation:
PD = (VIN – VOUT) IOUT + VIN IGND
Substituting PD(max) for PD and solving for the operating
conditions that are critical to the application will give the
maximum operating conditions for the regulator circuit.
For example, when operating the MIC5255-3.0BM5 at
50°C with a minimum footprint layout, the maximum
input voltage for a set output current can be determined
as follows:
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 MIC5255 to drive a
125°C − 50°C
235°C/W
⎛
⎜
⎞
⎟
PD(max)
=
⎝
⎠
P
D(max) = 315mW
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MIC5255
The junction-to-ambient thermal resistance for the
minimum footprint is 235°C/W, from Table 1. The
maximum power dissipation must not be exceeded for
proper operation. Using the output voltage of 3.0V and
an output current of 150mA, the maximum input voltage
can be determined. 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:
Therefore, a 3.0V application at 150mA of output current
can accept a maximum input voltage of 5.4V in a SOT-
23-5 package. For a full discussion of heat sinking and
thermal effects on voltage regulators, refer to the “Reg-
ulator Thermals” section of Micrel’s Designing with Low-
Dropout Voltage Regulators handbook.
315mW = (VIN – 3.0V) 150mA
315mW = VIN × 150mA – 450mW
810mW = VIN × 150mA
VIN(max) = 5.4V
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Micrel, Inc.
MIC5255
Package Information
5-Pin SOT (M5)
5-Pin Thin SOT (D5)
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Micrel, Inc.
MIC5255
6-Pin MLF® (ML)
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.
© 2004 Micrel, Incorporated.
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