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MIC5256
Datasheet (Micrel)
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Datasheet MIC5256 Datasheet (Micrel)

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MIC5256 Micrel
查询MIC5256-2.6BM5供应商
MIC5256
150mA µCap LDO with Error Flag
Final Information
General Description
The MIC5256 is an efficient, precise CMOS voltage regula­tor. It offers better than 1% initial accuracy, extremely low­dropout 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.
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.
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.
Features
• 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:
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
• TTL logic-controlled enable input
Applications
• Cellular phones and pagers
• Cellular accesories
• Battery-powered equipment
• Laptop, notebook, and palmtop computers
• Consumer/personal electronics
T ypical Application
Ordering Information
Part Number Marking Voltage Junction Temp. Range Package
MIC5256-2.6BM5 LX26 2.6V –40°C to +125°C SOT-23-5 MIC5256-2.7BM5 LX27 2.7V –40°C to +125°C SOT-23-5 MIC5256-2.8BM5 LX28 2.8V –40°C to +125°C SOT-23-5 MIC5256-2.85BM5 LX2J 2.85V –40°C to +125°C SOT-23-5 MIC5256-3.0BM5 LX30 3.0V –40°C to +125°C SOT-23-5 MIC5256-3.3BM5 LX33 3.3V –40°C to +125°C SOT-23-5 MIC5256-2.85BD5 NX2J 2.85V –40°C to +125°C TSOT-23-5
Other voltages available. Contact Micrel for details.
MIC5256-x.xBM5
IN
15
2 34
V
OUT
C
= 1.0µF
OUT
Ceramic
FLG
= 1.0µF
C
IN
Ceramic
Enable
Shutdown
EN (pin 3) may be connected directly to IN (pin 1).
Low-Noise Regulator Application
V
EN
IttyBitty is a trademark of Micrel, Inc.
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 MIC5256
MIC5256 Micrel
Pin Configuration
GND
2
IN
13
EN
LXxx
45
FLG
OUT
MIC5256-x.xBM5
(SOT-23-5)
Pin Description
Pin Number Pin Name Pin Function
1 IN Supply Input. 2 GND Ground. 3 EN Enable/Shutdown (Input): CMOS compatible input. Logic high = enable;
4 FLG Error Flag (Output): Open-drain output. Active low indicates an output
5 OUT Regulator Output.
EN
MIC5256-x.xBD5
logic low = shutdown. Do not leave open.
undervoltage condition.
IN
GND
13
2
NWxx
45
OUTBYP
(TSOT-23-5)
MIC5256 2 June 2003
MIC5256 Micrel
Absolute Maximum Ratings (Note 1)
Supply Input Voltage (V Enable Input Voltage (V Power Dissipation (P
Junction Temperature (TJ) ....................... –40°C to +125°C
) .................................. 0V to +7V
IN
) ................................. 0V to +7V
EN
) ............... Internally Limited, Note 3
D
Operating Ratings (Note 2)
Input Voltage (V
Enable Input Voltage (VEN) .................................. 0V to V
Junction Temperature (TJ) ....................... –40°C to +125°C
Thermal Resistance
SOT-23 (θJA) .....................................................235°C/W
) ......................................... +2.7V to +6V
IN
Storage Temperature ............................... –65°C to +150°C
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD, Note 4..................................................................2kV
Electrical Characteristics
VIN = V
Symbol Parameter Conditions Min Typical Max Units
V
O
∆V
LNR
∆V
LDR
VIN – V
I
Q
I
GND
PSRR Power Supply Rejection f = 10Hz, VIN = V
I
LIM
e
n
Enable Input
V
IL
V
IH
I
EN
Error Flag
V
FLG
V
OL
I
FL
Thermal Protection
+ 1V, VEN = V
OUT
Output Voltage Accuracy I
Line Regulation VIN = V Load Regulation I
OUT
Dropout Voltage, Note 6 I
Quiescent Current VEN ≤ 0.4V (shutdown) 0.2 1 µA Ground Pin Current, Note 7 I
Current Limit V Output Voltage Noise tbd
Enable Input Logic-Low Voltage VIN = 2.7V to 5.5V, regulator shutdown 0.4 V Enable Input Logic-High Voltage VIN = 2.7V to 5.5V, regulator enabled 1.6 V Enable Input Current VIL ≤ 0.4V, regulator shutdown 0.01 µA
Shutdown Resistance Discharge 500 Ω
Low Threshold % of V High Threshold % of V
Output Logic-Low Voltage IL = 100µA, fault condition 0.02 0.1 V Flag Leakage Current flag off, V
Thermal Shutdown Temperature 150 °C Thermal Shutdown Hysteresis 10 °C
= 100µA; TJ = 25°C, bold values indicate –40°C ≤ TJ ≤ +125°C; unless noted.
IN; IOUT
= 100µA –1+1%
OUT
+ 1V to 6V 0.02 0.05 %/V
OUT
= 0.1mA to 150mA, Note 5 1.5 2.5 %
OUT
= 100µA 0.1 5.0 mV
OUT
I
= 100mA 90 150 mV
OUT
= 150mA 135 200 mV
I
OUT
= 0mA 90 150 µA
OUT
I
= 150mA 117 µA
OUT
+ 1V; C
OUT
f = 100Hz, VIN = V f = 10kHz, VIN = V
= 0V 160 425 mA
OUT
+ 0.5V; C
OUT
+ 0.5V 45 dB
OUT
= 1µF60dB
OUT
= 1µF60dB
OUT
VIH ≥ 1.6V, regulator enabled 0.01 µA
(Flag ON) 90 %
OUT
(Flag OFF) 96 %
OUT
= 6V 0.01 µA
FLG
–2+2%
250 mV
µV(rms)
IN
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. The maximum allowable power dissipation of any TA (ambient temperature) is P
D(max)
= T
J(max)–TA/θJA
. Exceeding the maximum allowable
June 2003 3 MIC5256
MIC5256 Micrel
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).
Note 4. Devices are ESD sensitive. Handling precautions recommended. Note 5. Regulation is measured at constant junction temperature using low duty cycle pulse testing. Parts are tested for load regulation in the load
Note 6. 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 7. 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
range from 0.1mA to 150mA. Changes in output voltage due to heating effects are covered by the thermal regulation specification.
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.
pin current.
MIC5256 4 June 2003
MIC5256 Micrel
)
)
0
10
20
30
40
50
60
70
0 200 400 600 800 1000
PSRR (dB)
VOLTAGE DROP (mV)
PSRR vs. Voltage Drop
I
LOAD
= 150mA
I
LOAD
= 100µA
C
OUT
= 1µF
95
100
105
110
115
120
125
-40 -20 0 20 40 60 80 100120140
GROUND CURRENT (µA)
TEMPERATURE (°C)
Ground Pin Current
I
LOAD
= 150mA
0
0.5
1
1.5
2
2.5
3
3.5
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
OUTPUT VOLTAGE (V)
INPUT VOLTAGE (V)
Dropout Characteristics
I
LOAD
= 150mA
I
LOAD
= 100µA
0
20
40
60
80
100
120
140
160
180
0 20 40 60 80 100 120 140 160
DROPOUT VOLTAGE (mV)
OUTPUT CURRENT (mA)
Dropout Voltage
T = –40C
T = 25C
T = 125C
Typical Characteristics
Power Supply Rejection Ratio
70 60 50
100µA*
40
50mA*
30
PSRR (dB)
130
125
120
115
110
105
GROUND CURRENT (µA)
100
100mA* 150mA*
20
*I
LOAD
10
C
= 1.0µF Ceramic
OUT
0
10
100
1000
10000
FREQUENCY (Hz
Ground Pin Current
VIN = V
0.1 1 10 100 1000
OUTPUT CURRENT (mA)
OUT
+ 1V
100000
1000000
Power Supply Rejection Ratio
70 60 50 40 30
PSRR (dB)
20 10
115 113 111 109 107 105 103 101
99
GROUND CURRENT (µA)
97 95
100µA* 50mA* 100mA* 150mA*
*I
LOAD
C
= 4.7µF Ceramic
OUT
0
10
100
1000
10000
FREQUENCY (Hz
Ground Pin Current
I
= 100µA
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
LOAD
100000
1000000
June 2003 5 MIC5256
Ground Pin Current
140 120 100
80 60 40 20
GROUND CURRENT (µA)
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
0.14
0.12
0.08
0.06
0.04
0.02
DROPOUT VOLTAGE (mV)
Dropout Voltage
0.1
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
I
LOAD
I
LOAD
= 100µA
= 100µA
Ground Pin Current
140 120 100
80 60 40 20
GROUND CURRENT (µA)
0
0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5
INPUT VOLTAGE (V)
180 160 140 120 100
DROPOUT VOLTAGE (mV)
Dropout Voltage
80 60 40 20
0
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
I
LOAD
I
LOAD
= 150mA
= 150mA
MIC5256 Micrel
Short Circuit Current
600
500
400
300
200
100
SHORT CIRCUIT CURRENT (mA)
0
3 3.5 4 4.5 5 5.5 6
INPUT VOLTAGE (V)
1.25
1.15
1.05
0.95
0.85
ENABLE THRESHOLD VOLTAGE (V)
500 490 480 470 460 450 440 430 420 410
SHORT CIRCUIT CURRENT (mA)
400
-40 -20 0 20 40 60 80 100120140
Enable Threshold
vs. Temperature
1.3
1.2
1.1
1
0.9 I
= 100µA
0.8
-40 -20 0 20 40 60 80 100120140
TEMPERATURE (°C)
LOAD
Short Circuit Current
VIN = V
+ 1V
OUT
TEMPERATURE (°C)
3.05
3.04
3.03
3.02
3.01
3.00
2.99
2.98
2.97
OUTPUT VOLTAGE (V)
2.96
2.95
-40 -20 0 20 40 60 80 100120140
Error Flag Pull-Up Resistor
4.5 Power Good
4
3.5
3
2.5
2
1.5
1
FLAG VOLTAGE (V)
0.5
0
0.1 1 10 100 1000 10000
RESISTANCE (kΩ)
VIN = 4V
Power Fail
Output Voltage vs.
Temperature
I
= 100µA
LOAD
TEMPERATURE (°C)
Test Circuits
1.0µF*
Ceramic
0V
* CIN = C
ON OFF
OUT
= 1µF
MIC5256
47k
0.01µF
Figure 1. Test Circuit
1.0µF* Ceramic
Error Flag Output
MIC5256 6 June 2003
MIC5256 Micrel
Functional Characteristics
(50mV/div)
Output Voltage
100µA
(100mA/div)
Output Current
(1V/div)
Enable Voltage
Load Transient Response
CIN = 1µF Ceramic
C
OUT
150mA
TIME (4µs/div)
Enable Pin Delay
CIN = 1µF Ceramic
= 1µF Ceramic
C
OUT
I
OUT
= 1µF Ceramic
V
= 100µA
IN
= 4V
(1V/div)
Input Voltage
(50mV/div)
Output Voltage
(1V/div)
Enable Voltage
Line Transient Response
C
IN
C
OUT
TIME (400µs/div)
Shutdown Delay
CIN = 1µF Ceramic
= 1µF Ceramic
C
OUT
= 1µF Ceramic
= 1µF Ceramic
= 100µA
I
OUT
= 100µA
I
L
(1V/div)
Output Voltage
TIME (10µs/div)
(1V/div)
Output Voltage
Error Flag Start-up*
(2V/div)
Enable Voltage
(2V/div)
Output Voltage
(2V/div)
Error Flag
TIME (400µs/div)
(2V/div)
Enable Voltage
(2V/div)
Output Voltage
(2V/div)
Error Flag
* See Test Circuit Figure 1 * See Test Circuit Figure 1
TIME (400µs/div)
Error Flag Shutdown*
TIME (400µs/div)
June 2003 7 MIC5256
MIC5256 Micrel
Block Diagram
IN
EN
Reference
Voltage
Thermal
Sensor
Under-
voltage
Lockout
Overcurrent
Dropout
Detection
Startup/
Shutdown
Control
FAULT
Quickstart
Error
Amplifier
Current
Amplifier
ACTIVE SHUTDOWN
Out of
Regulation
Detection
OUT
FLG
GND
MIC5256 8 June 2003
MIC5256 Micrel
P
TT
D(max)
J(max) A
JA
=
−
 
 
θ
Applications 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-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 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 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 recom-
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.
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
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:
mended 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
T
is the maximum junction temperature of the die,
J(max)
125°C, and TA is the ambient operating temperature. θJA is layout dependent; Table 1 shows examples of junction-to­ambient thermal resistance for the MIC5256.
X7R ceramic capacitor to ensure the same minimum capaci­tance over the equivalent operating temperature range.
Package
Error Flag
The error flag output is an active-low, open-drain output that drives low when a fault condition AND an undervoltage
SOT-23-5 235°C/W 185°C/W 145°C/W (M5 or D5)
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-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.
The error flag circuit was designed essentially to work with a capacitor to ground to act as a power-on reset generator,
The actual power dissipation of the regulator circuit can be determined using the equation:
PD = (VIN – V
Substituting P 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:
signaling a power-good situation once the regulated voltage was up and/or out of a fault condition. This capacitor delays
P
the error signal from pulling high, allowing the down stream circuits time to stablilize. When the error flag is pulled-up to
June 2003 9 MIC5256
P
θθ
θJA Recommended
θθ
Minimum Footprint Copper Clad
Table 1. SOT-23-5 Thermal Resistance
) I
OUT
OUT
for PD and solving for the operating
D(max)
125 C 5 C
°− °
D(max)
D(max)
=
235 C/W
= 315mW
0
°
+ VIN I
 
θθ
θJA 1" Square
θθ
GND
θθ
θ
θθ
JC
MIC5256 Micrel
15 2 34
V
OUT
MIC5256-x.xBM5
47kΩ
V
IN
C
OUT
= 1.0µF
Ceramic
C
IN
= 1.0µF
Ceramic
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.
315mW = (VIN – 3.0V) 150mA 315mW = VIN·150mA – 450mW 810mW = VIN·150mA V
IN(max)
= 5.4V
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
lators
handbook.
Designing with Low-Dropout Voltage Regu-
Fixed Regulator Applications
Figure 1. Low-Noise Fixed Voltage Application
Figure 1 shows a standard low-noise configuration with a 47kΩ 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. C
OUT
=
1.0µF minimum.
MIC5256 10 June 2003
MIC5256 Micrel
Package Information
1.90 (0.075) REF
0.95 (0.037) REF
3.02 (0.119)
2.80 (0.110)
2.90BSC
1.90BSC
0.50 (0.020)
0.35 (0.014)
1.90BSC
0.30
0.45
1.75 (0.069)
1.50 (0.059)
1.30 (0.051)
0.90 (0.035)
0.15 (0.006)
0.00 (0.000)
SOT-23-5 (M5)
DIMENSIONS:
Millimeter
3.00 (0.118)
2.60 (0.102)
10°
0°
DIMENSIONS:
MM (INCH)
0.20 (0.008)
0.09 (0.004)
0.60 (0.024)
0.10 (0.004)
0.90
0.80
1.90BSC
0.10
0.01
1.00
0.90
1.60BSC
0.20
0.12
1.60BSC
0.30
0.50
TSOT-23-5 (D5)
MICREL, INC. 1849 FORTUNE DRIVE SAN JOSE, CA 95131 USA
TEL + 1 (408) 944-0800 FAX + 1 (408) 944-0970 WEB http://www.micrel.com
This information is believed to be accurate and reliable, however no responsibility is assumed by Micrel for its use nor for any infringement of patents or
other rights of third parties resulting from its use. No license is granted by implication or otherwise under any patent or patent right of Micrel, Inc.
© 2003 Micrel, Incorporated
June 2003 11 MIC5256
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