MIC29311
Micrel
MIC29311
3A Fast-Response LDO Regulator for USB
Preliminary Information
General Description
The MIC29311 is a 3A, fast response, low-dropout (LDO)
voltage regulator. Using Micrel’s proprietary Super
βeta
PNP™ process, the MIC29311 offers exceptional dropout
(600mV at 3A) and low ground current (60mA at 3A). Fast
transient response allows it to recover quickly from large load
changes while maintaining a steady output. The device can
be sent into a “zero-current” off mode when the TTL compat-
ible enable is brought low.
Designed specifically for Universal Serial Bus (USB) applica-
tions, the MIC29311 works with USB power switches to
provide an economical solution for self-powered hubs. The
5.1V output voltage is optimized to work with lower-cost high
on-resistance USB power switches (300mΩ) to provide a
minimum of 4.75V at 500mA to downstream ports. Used with
MIC2527 quad USB power switches, the MIC29311 can
power up to 6 downstream ports.
Features of the MIC29311 include thermal shutdown, current
limit, reversed-battery and reversed-lead insertion protec-
tion. An overvoltage clamp is available to maintain a safe
output when the input voltage exceeds 8V. An error flag is
also available to indicate of the output falls out of regulation,
or when an overcurrent condition occurs.
The MIC29311 is available in a 5-pin TO-220 or TO-263
package with a fixed 5.1V output voltage.
For other high current, low-dropout voltage regulators, please
see the MIC29150/300/500/750 and the MIC29310,
MIC29510, MIC29710.
Features
•
•
•
•
•
•
•
•
•
•
Fast transient response
3A output current over full temperature range
600mV dropout voltage at full load
Low ground current
3% total accuracy
“Zero” off-mode current
Thermal Shutdown
Current Limiting
Reversed battery protection
Fixed 5.1V Output
Applications
•
•
•
•
Self-powered USB hubs
USB power switching
High-efficiency linear power supplies
High-efficiency switching supply post-regulator
Typical Application
MIC29311-5.1
LDO Regulator
AC
Line
6.3Vac
3A
47µF
MIC5207-3.3
100mA
LDO Regulator
max.
IN
OUT
GND
4.7
µF
D+
D–
10k
0.01µF
33µF
GND
V
BUS
D+
D–
GND
Downstream
USB
Port 6
4.75V min
500mA max.
1.0
µF
3.3V USB Controller
V+
ON/OFF
OVERCURRENT
33µF
0.01µF
5.8V @ 3A
10k
IN
EN
OUT
FLAG
GND
33µF
5.1V
0.01µF
33µF
Ferrite
Bead
V
BUS
D+
D–
GND
Downstream
USB
Port 1
4.75V min
500mA max.
V
BUS
D+
D–
GND
Upstream
USB Port
V
BUS
D+
D–
GND
Downstream
USB
Port 2
4.75V min
500mA max.
Bold
lines indicate
0.1" wide, 1-oz. copper
high-current traces.
Simple USB Stand-Alone 6-Port Self-Powered Hub
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 944-0970 • http://www.micrel.com
December 1998
1
MIC29311
MIC29311
Micrel
Absolute Maximum Ratings
(Note 1)
Input Voltage (V
IN
) ........................................ –20V to +12V
Enable Voltage (V
EN
) .................................... –20V to +12V
Error Output Voltage (V
ERR
) ............................. 0V to +12V
Lead Temperature (soldering, 5 sec.) ....................... 260°C
ESD Rating,
Note 3
Operating Ratings
(Note 2)
Input Voltage (V
IN
) ........................................................ +8V
Maximum Power Dissipation (P
D(max)
).....................
Note 4
Junction Temperature (T
J
) ........................... 0°C to +125°C
Package Thermal Resistance
TO-220-5
(θ
JA
) .................................................... 55°C/W
TO-220-5
(θ
JC
) ...................................................... 2°C/W
TO-263-5
(θ
JC
) ...................................................... 2°C/W
Electrical Characteristics
T
A
= 25°C,
bold
values indicate 0°C
≤
T
J
≤
+125°C; unless noted.
Parameter
Output Tolerange
Line Regulation
Load Regulation
Output Voltage Temperature
Coefficient
Dropout Voltage,
Note 6
Condition
10mA
≤
I
OUT
< 3A, (V
OUT
+ 1V)
≤
V
IN
≤
8V
I
OUT
= 10mA, (V
OUT
+ 1V)
≤
V
IN
≤
8V
V
IN
= V
OUT
+ 1V, 10mA
≤
I
OUT
3A
Note 5
I
OUT
= 100mA
I
OUT
= 750mA
I
OUT
= 1.5A
I
OUT
= 3A
Ground Current,
Note 7
V
IN
= 6.1V, I
OUT
= 750mA
V
IN
= 6.1V, I
OUT
= 1.5A
V
IN
= 6.1V, I
OUT
= 3A
Dropout Ground Current
Current Limit
Minimum Load Current
Output Noise Voltage
C
LOAD
= 10µF
C
LOAD
= 33µF
Error Flag Output
Output Leakage Current
Output Low Voltage
V
IN
= 6.1V, V
ERR
= 8V
V
IN
= 4.1V, I
ERR
= 250µA
0.1
220
1
2
300
400
µA
µA
mV
mV
V
IN
= 4.6V, I
OUT
= 10mA
V
IN
= 3V, V
OUT
= 0V
3.0
Min
–3
0.06
0.2
20
80
220
330
600
5
15
60
2
3.8
7
400
260
10
150
3
1000
20
Typ
Max
+3
0.5
1
100
200
Units
%
%
%
ppm/°C
mV
mV
mV
mV
mA
mA
mA
mA
A
mA
µV(rms)
µV(rms)
December 1998
3
MIC29311
MIC29311
Parameter
Enable Input
Logic Low Voltage
Logic High Voltage
Enable Input Current
regulator shutdown
regulator enabled
V
EN
= V
IN
V
EN
= 0.8V
Regulator Output Current
Note 1.
Note 2.
Note 3.
Note 4.
Note 5.
Note 6.
Note 7.
Note 8.
Micrel
Condition
Min
Typ
Max
Units
0.8
2.4
15
30
75
2
4
10
20
V
V
µA
µA
µA
µA
µA
V
IN
=
≤8V,
V
EN
≤
0.8V (shutdown), V
OUT
= 0V,
Note 8
Exceeding the absolute maximum rating may damage the device.
The device is not guaranteed to function outside its operating rating.
Devices are ESD sensitive. Handling precautions recommended.
P
D(max)
= (T
J(max)
– T
A
)
÷ θ
JA
, where
θ
JA
depends upon the printed curcuit board layout. See “Applications Information.”
Output voltage temperature coefficient is defined as the
∆V
OUT(worst case)
÷
(T
J(max)
– T
J(min)
) where T
J(max)
is +125°C and T
J(min)
is 0°C.
V
DO
= V
IN
– V
OUT
when V
OUT
decreases to 99% of its nominal output voltage with V
IN
= V
OUT
+ 1V.
I
GND
is the quiescent current. I
IN
= I
GND
+ I
OUT
.
V
EN
≤
0.8V and V
IN
≤
8V, V
OUT
= 0.
MIC29311
4
December 1998
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