MIC3775
750mA µCap Low-Voltage
Low-Dropout Regulator
General Description
The MIC3775 is a 750mA low-dropout linear voltage
regulators that provides low-voltage, high-current output
from an extremely small package. Utilizing Micrel’s
proprietary Superβeta PNP
®
pass element, the MIC3775
offers extremely low-dropout (typically 280mV at 750mA)
and low ground current (typically 7.5mA at 750mA).
The MIC3775 is ideal for PC add-in cards that need to
convert from standard 5V to 3.3V or 3.0V, 3.3V to 2.5V or
2.5V to 1.8Vor 1.65V. A guaranteed maximum dropout
voltage of 500mV over all operating conditions allows the
MIC3775 to provide 2.5V from a supply as low as 3.0V and
1.8V or 1.5V from a supply as low as 2.25V.
The MIC3775 is fully protected with overcurrent limiting,
thermal shutdown, and reversed-leakage protection. Fixed
and adjustable output voltage options are available with an
operating temperature range of –40°C to +125°C.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
•
Fixed and adjustable output voltages to 1.24V
•
280mV typical dropout at 750mA
–
Ideal for 3.0V to 2.5V conversion
–
Ideal for 2.5V to 1.8V or 1.65V conversion
•
Stable with ceramic capacitor
•
750mA minimum guaranteed output current
•
1% initial accuracy
•
Low ground current
•
Current limiting and thermal shutdown
•
Reversed-leakage protection
•
Fast transient response
•
Low-profile power MSOP-8 package
Applications
•
•
•
•
•
•
•
•
Fiber optic modules
LDO linear regulator for PC add-in cards
PowerPC™ power supplies
High-efficiency linear power supplies
SMPS post regulator
Multimedia and PC processor supplies
Battery chargers
Low-voltage microcontrollers and digital logic
___________________________________________________________________________________________________________
Typical Application
1.25V/750mA Adjustable Regulator
PowerPC is a trademark of IBM Corp.
Super
βeta
PNP 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
December 2006
1
M9999-121906
Micrel, Inc.
MIC3775
Absolute Maximum Ratings
(1)
Supply Voltage (V
IN
) ......................................................6.5V
Enable Voltage (V
EN
).....................................................6.5V
Lead Temperature (soldering, 5 sec.)........................ 260°C
Storage Temperature (T
s
) .........................–65°C to +150°C
EDS Rating................................................................
Note 3
Operating Ratings
(2)
Supply Voltage (V
IN
)...................................... +2.25V to +6V
Enable Voltage (V
EN
)............................................ 0V to +6V
Maximum Power Dissipation (P
D(MAX)
) ......................
Note 4
Junction Temperature (T
J
) ........................ –40°C to +125°C
Package Thermal Resistance
MSOP-8 (θ
JA
) .....................................................80°C/W
Electrical Characteristics
(5)
V
IN
= V
OUT
+ 1V; V
EN
= 2.25V; T
J
= 25°C,
bold
values indicate –40°C< T
J
< +125°C, unless noted.
Symbol
V
OUT
Parameter
Output Voltage
Line Regulation
Load Regulation
∆V
OUT
/∆T
V
DO
Output Voltage Temp.
Coefficient,
Note 6
Dropout Voltage,
Note 7
I
OUT
= 100mA,
∆V
OUT
= –1%
I
OUT
= 500mA,
∆V
OUT
= –1%
I
OUT
= 750mA,
∆V
OUT
= –1%
I
GND
Ground Current,
Note 8
I
OUT
= 100mA, V
IN
= V
OUT
+ 1V
I
OUT
= 500mA, V
IN
= V
OUT
+ 1V
I
OUT
= 750mA, V
IN
= V
OUT
+ 1V
I
OUT(lim)
V
EN
I
EN
Current Limit
Enable Input Voltage
Enable Input Current
V
OUT
= 0V, V
IN
= V
OUT
+ 1V
logic low (off)
logic high (on)
V
EN
= 2.25V
V
EN
= 0.8V
Flag Output
I
FLG(leak)
V
FLG(do)
V
FLG
Output Leakage Current
Output Low Voltage
Low Threshold
High Threshold
Hysteresis
Adjustable Output Only
Reference Voltage
Adjust Pin Bias Current
1.227
1.215
1.240
40
1.252
1.265
80
120
V
V
nA
nA
V
OH
= 6V
V
IN
= 2.250V, I
OL
, = 250µA
% of V
OUT
% of V
OUT
1
93
99.2
0.01
250
1
2
500
µA
µA
mV
%
%
%
2.25
1
10
30
2
4
Enable Input
0.8
V
V
µA
µA
µA
Condition
10mA
10mA
≤
I
OUT
≤
750mA, V
OUT
+ 1V
≤
V
IN
≤
6V
I
OUT
= 10mA, V
OUT
+ 1V
≤
V
IN
≤
6V
V
IN
= V
OUT
+ 1V, 10mA
≤
I
OUT
≤
750mA
Min
–1
–2
0.06
0.2
40
125
210
280
700
3.7
7.5
1.6
15
2.5
500
200
250
Typ
Max
1
2
0.5
1
Units
%
%
%
%
ppm/°C
mV
mV
mV
mV
µA
mA
mA
A
December 2006
3
M9999-121906
Micrel, Inc.
MIC3775
Notes:
1. Exceeding the absolute maximum rating may damage the device.
2. The device is not guaranteed to function outside its operating rating.
3. Devices are ESD sensitive. Handling precautions recommended.
4. P
D(max)
= (T
J(max)
– T
A
) ÷
θ
JA
, where
θ
JA
depends upon the printed circuit layout. See “Applications Information.”
5. Specification for packaged product only.
6. Output voltage temperature coefficient is
∆V
OUT(worst case)
÷ (T
J(max)
– T
J(min)
) where T
J(max)
is +125°C and T
J(min)
is –40°C.
7. V
DO
= V
IN
– V
OUT
when V
OUT
decreases to 98% of its nominal output voltage with V
IN
= V
OUT
+ 1V. For output voltages below 1.75V, dropout voltage is
the input-to-output voltage differential with the minimum input voltage being 2.25V. Minimum input operating voltage is 2.25V.
8. I
GND
is the quiescent current. I
IN
= I
GND
+ I
OUT
.
December 2006
4
M9999-121906
嵌入式系统
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