MIC5256-2.85YM5 [MICREL]
150mA μCap LDO with Error Flag; 150毫安μCap LDO具有错误标志
| 型号： | MIC5256-2.85YM5 |
| 厂家： | 
MICREL SEMICONDUCTOR |
| 描述： | 150mA μCap LDO with Error Flag |
| 文件： | 总13页 (文件大小：542K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
MIC5256
150mA µCap LDO with Error Flag
General Description
Features
The MIC5256 is an efficient, precise CMOS voltage
regulator. It offers better than 1% initial accuracy,
extremely low-dropout voltage (typically 135mV at 150mA)
and low ground current (typically 90µA) over load. The
MIC5256 features an error flag that indicates an output
fault condition such as overcurrent, thermal shutdown and
dropout.
• Input voltage range: 2.7V to 6.0V
• Thin SOT package: 1mm height
• Error flag indicates fault condition
• Stable with ceramic output capacitor
• Ultralow dropout: 135mV @ 150mA
• High output accuracy:
Designed specifically for handheld and battery-powered
devices, the MIC5256 provides a TTL-logic-compatible
enable pin. When disabled, power consumption drops
nearly to zero.
–
–
1.0% initial accuracy
2.0% over temperature
• Low quiescent current:90µA
• Tight load and line regulation
• Thermal-shutdown and current-limit protection
• “Zero” off-mode current
The MIC5256 also works with low-ESR ceramic
capacitors, reducing the amount of board space necessary
for power applications, critical in hand-held wireless
devices.
• TTL logic-controlled enable input
Key features include current limit, thermal shutdown, faster
transient response, and an active clamp to speed up
device turnoff. Available in 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 MIC5256 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
Low-Noise Regulator Application
IttyBitty is a registered trademark of Micrel, 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
M9999-080510
August 2010
1
Micrel, Inc.
MIC5256
Ordering Information
Part Number
Marking
Standard
Junction Temperature
Range
Voltage**
Package
Standard
Pb-Free
Pb-Free*
LX15
LX18
LX25
LX26
LX27
LX28
LX2J
LX29
LX30
LX31
LX33
NX2J
MIC5256-1.5BM5
MIC5256-1.8BM5
MIC5256-2.5BM5
MIC5256-2.6BM5
MIC5256-2.7BM5
MIC5256-2.8BM5
MIC5256-2.85BM5
MIC5256-2.9BM5
MIC5256-3.0BM5
MIC5256-3.1BM5
MIC5256-3.3BM5
MIC5256-2.85BD5
MIC5256-1.5YM5
MIC5256-1.8YM5
MIC5256-2.5YM5
MIC5256-2.6YM5
MIC5256-2.7YM5
MIC5256-2.8YM5
MIC5256-2.85YM5
MIC5256-2.9YM5
MIC5256-3.0YM5
MIC5256-3.1YM5
MIC5256-3.3YM5
MIC5256-2.85YD5
LX15
LX18
LX25
LX26
LX27
LX28
LX2J
LX29
LX30
LX31
LX33
NX2J
1.5V
1.8V
2.5V
2.6V
2.7V
2.8V
2.85V
2.9V
3.0V
3.1V
3.3V
2.85V
–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 SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin SOT23
5-Pin TSOT23
Notes:
Under bar symbol ( _ ) may not be to scale.
*
** Other Voltage available. Contact Micrel for details.
Pin Configuration
MIC5256-x.xBM5
5-Pin SOT23
MIC5256-x.xBD5
5-Pin Thin SOT23
MIC5256-x.xYM5
5-Pin SOT23
MIC5256-x.xYD5
5-Pin Thin SOT23
M9999-080510
August 2010
2
Micrel, Inc.
MIC5256
Pin Description
Pin Number
Pin Name Pin Name
1
2
IN
Supply Input.
Ground.
GND
Enable/Shutdown (Input): CMOS compatible input. Logic high = enable; logic low = shutdown. Do not
leave open.
3
EN
4
5
FLG
OUT
Error Flag (Output): Open-drain output. Active low indicates an output undervoltage condition.
Regulator Output.
M9999-080510
August 2010
3
Micrel, Inc.
MIC5256
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 (θJA)..................................................235°C/W
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
IOUT = 100µA
–1
–2
1
2
%
%
VO
Output Voltage Accuracy
ΔVLNR
ΔVLDR
Line Regulation
Load Regulation
VIN = VOUT + 1V to 6V
0.02
1.5
0.1
90
0.05
2.5
5
%/V
%
I
OUT = 0.1mA to 150mA(6)
IOUT = 100µA
IOUT = 100mA
IOUT = 150mA
mV
mV
VIN
–
150
Dropout Voltage(7)
VOUT
135
200
250
mV
mV
IQ
Quiescent Current
VEN ≤ 0.4V (shutdown)
IOUT = 0mA
0.2
90
1
µA
µA
µA
dB
dB
150
IGND
Ground Pin Current(8)
IOUT = 150mA
117
60
f = 10Hz, VIN = VOUT + 1V; COUT = 1.0µF
f = 100Hz, VIN = VOUT + 0.5V; COUT
1.0µF
=
60
PSRR
Ripple Rejection
f = 10kHz, VIN = VOUT + 0.5V
VOUT = 0V
45
dB
mV
ILIM
en
Current Limit
160
425
TBD
Output Voltage Noise
µV(rms)
Enable Input
VIL
Enable Input Logic-Low Voltage VIN = 2.7V to 5.5V, regulator shutdown
0.4
V
V
Enable Input Logic-High
Voltage
VIN = 2.7V to 5.5V, regulator enabled
1.6
VIH
VIL ≤ 0.4V, regulator shutdown
0.01
0.01
500
µA
µA
Ω
IEN
Enable Input Current
V
IH ≥ 1.6V, regulator enabled
Shutdown Resistance
Discharge
M9999-080510
August 2010
4
Micrel, Inc.
MIC5256
Electrical Characteristics(5) (Continued)
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
Error Flag
Low Threshold
High Threshold
% of VOUT (Flag ON)
% of VOUT (Flag OFF)
90
%
%
VFLG
96
VOL
IFL
Output Logic-Low Voltage
Flag Leakage Current
IL = 100µA, fault condition
flag off, VFLG = 6V
0.02
0.01
0.1
V
µA
Thermal Protection
Thermal-Shutdown
Temperature
150
10
°C
°C
Thermal-Shutdown Hysteresis
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.
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 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 1Vdifferential.
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.
Test Circuit
M9999-080510
August 2010
5
Micrel, Inc.
MIC5256
Typical Characteristics
Ground Pin Current
130
125
120
115
110
105
VIN = VOUT + 1V
100
0.1
1
10
100
1000
OUTPUT CURRENT (mA)
Ground Pin Current
Dropout Characteristics
140
120
100
80
3.5
3
ILOAD = 100µA
2.5
2
ILOAD = 150mA
60
1.5
1
40
20
0.5
0
ILOAD = 150mA
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
Dropout Voltage
Dropout Voltage
180
180
T = –40C
160
140
120
100
80
160
140
120
100
80
T = 25C
T = 125C
60
60
40
40
20
20
ILOAD = 150mA
0
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
0
20 40 60 80 100120140160
OUTPUT CURRENT (mA)
M9999-080510
August 2010
6
Micrel, Inc.
MIC5256
Typical Characteristics (Continued)
Short Circuit Current
600
500
400
300
200
100
0
3
3.5
4
4.5
5
5.5
6
INPUT VOLTAGE (V)
M9999-080510
August 2010
7
Micrel, Inc.
MIC5256
Functional Characteristics
M9999-080510
August 2010
8
Micrel, Inc.
MIC5256
Functional Diagram
M9999-080510
August 2010
9
Micrel, Inc.
MIC5256
drain transistor to indicate a fault. This prevents
chattering or inadvertent triggering of the error flag. The
error flag must be pulled-up using a resistor from the flag
pin to either the input or the output.
Application Information
Enable/Shutdown
The MIC5256 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.
The error flag circuit was designed essentially to work
with a capacitor to ground to act as a power-on reset
generator, signaling a power-good situation once the
regulated voltage was up and/or out of a fault condition.
This capacitor delays the error signal from pulling high,
allowing the down stream circuits time to stabilize. When
the error flag is pulled-up to the input without using a
pull-down capacitor, then there can be a glitch on the
error flag upon start up of the device. This is due to the
response time of the error flag circuit as the device starts
up. When the device comes out of the “zero” off mode
current state, all the various nodes of the circuit power
up before the device begins supplying full current to the
output capacitor. The error flag drives low immediately
and then releases after a few microseconds. The
intelligent circuit that triggers an error detects the output
going into current limit AND the output being low while
charging the output capacitor. The error output then pulls
low for the duration of the turn-on time. A capacitor from
the error flag to ground will filter out this glitch. The glitch
does not occur if the error flag pulled up to the output.
Input Capacitor
The MIC5256 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 MIC5256 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.
Active Shutdown
The MIC5256 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 MIC5256 will remain stable and in regulation with no
load unlike many other voltage regulators. This is
especially important in CMOS RAM keep-alive
applications.
X7R/X5R dielectric-type ceramic capacitors are
recommended
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.
Thermal Considerations
The MIC5256 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:
Error Flag
T
− TA
⎛
⎜
⎜
⎝
⎞
⎟
⎟
⎠
J(max)
The error flag output is an active-low, open-drain output
that drives low when a fault condition AND an under-
voltage detection occurs. Internal circuitry intelligently
monitors overcurrent, overtemperature and dropout
conditions and ORs these outputs together to indicate
some fault condition. The output of that OR gate is
ANDed with an output voltage monitor that detects an
undervoltage condition. That output drives the open-
PD(max)
=
θJA
M9999-080510
August 2010
10
Micrel, Inc.
MIC5256
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 MIC5256.
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.
315mW = (VIN – 3.0V) 150mA
315mW = VIN·•150mA – 450mW
810mW = VIN·•150mA
θ
JA Recommended
Minimum Footprint
θJA 1” Square
Package
θJC
Copper Clad
SOT23-5
(M5 or D5)
235°C/W
185°C/W
145°C/W
VIN(max) = 5.4V
Table 1. SOT-23-5 Thermal Resistance
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
“Regulator Thermals” section of Micrel’s Designing with
Low-Dropout Voltage Regulators handbook.
The actual power dissipation of the regulator circuit can
be determined using the equation:
PD = (VIN – VOUT) IOUT + VIN IGND
Fixed Regulator Applications
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 MIC5256-3.0BM5 at
50°C with a minimum footprint layout, the maximum
input voltage for a set output current can be determined
as follows:
Figure 1. Low-Noise Fixed Voltage Application
125°C − 50°C
235°C/W
⎛
⎜
⎞
⎟
PD(max)
=
⎝
⎠
PD(max) = 315mW
Figure 1 shows a standard low-noise configuration with a
47kꢀ pull-up resistor from the error flag to the input
voltage and a pull-down capacitor to ground for the
purpose of fault indication. EN (Pin 3) is connected to IN
(Pin 1) for an application where enable/shutdown is not
required. COUT = 1.0µF minimum.
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
M9999-080510
August 2010
11
Micrel, Inc.
MIC5256
Package Information
5-Pin SOT (M5)
M9999-080510
August 2010
12
Micrel, Inc.
MIC5256
Package Information (Continued)
5-Pin Thin SOT (D5)
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.
© 2003 Micrel, Incorporated.
M9999-080510
August 2010
13
相关型号：
MIC5256-2.8BM5TR
Fixed Positive LDO Regulator, 2.8V, 0.25V Dropout, CMOS, PDSO5, SOT-23, 5 PIN
MICROCHIP
MIC5256-2.9BM5TR
Fixed Positive LDO Regulator, 2.9V, 0.25V Dropout, CMOS, PDSO5, SOT-23, 5 PIN
MICROCHIP
©2020 ICPDF网 联系我们和版权申明