MIC5156/5157/5158
Micrel
MIC5156/5157/5158
Super LDO™ Regulator Controller
General Description
The MIC5156, MIC5157, and MIC5158 Super Low-Dropout
(LDO) Regulator Controllers are single IC solutions for high-
current low-dropout linear voltage regulation. Super LDO™
Regulators have the advantages of an external N-channel
power MOSFET as the linear pass element.
The MIC5156/7/8 family features a dropout voltage as low as
the R
DS(ON)
of the external power MOSFET multiplied by the
output current. The output current can be as high as the
largest MOSFETs can provide.
The MIC5156/7/8 family operates from 3V to 36V. The
MIC5156 requires an external gate drive supply to provide the
higher voltage needed to drive the gate of the external
MOSFET. The MIC5157 and MIC5158 each have an internal
charge pump tripler to produce the gate drive voltage. The
tripler is capable of providing enough voltage to drive a logic-
level MOSFET to 3.3V output from a 3.5V supply and is
clamped to 17.5V above the supply voltage. The tripler
requires three external capacitors.
The regulator output is constant-current limited when the
controller detects 35mV across an optional external sense
resistor. An active-low open-collector flag indicates a low
voltage of 8% or more below nominal output. A shutdown
(low) signal to the TTL-compatible enable control reduces
controller supply current to less than 1µA while forcing the
output voltage to ground.
The MIC5156-3.3 and MIC5156-5.0 controllers have inter-
nally fixed output voltages. The MIC5156 [adjustable] output
is configured using two external resistors. The MIC5157 is a
fixed output controller which is externally configured to select
either 3.3V, 5.0V, or 12V. The MIC5158 can be configured as
a fixed 5V controller or programmed to any voltage from 1.3V
to 36V using two external resistors.
The MIC5156 is available in an 8-pin DIP or SOP. The
MIC5157 and MIC5158 are available in a 14-pin DIP or SOP
which operate from –40°C to +85°C.
Features
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4.5mA typical operating current
<1µA typical standby current
Low external parts count
Optional current limit (35mV typical threshold)
1% initial output voltage tolerance in most configurations
2% output voltage tolerance over temperature
Fixed output voltages of 3.3V, 5.0V (MIC5156)
Fixed output voltages of 3.3V, 5.0V, 12V (MIC5157)
Programmable (1.3 to 36V) with 2 resistors (MIC5156/8)
Internal charge pump voltage tripler (MIC5157/8)
Enable pin to activate or shutdown the regulator
Internal gate-to-source protective clamp
All versions available in DIP and SOP
Ultrahigh current ultralow dropout voltage regulator
Constant high-current source
Low parts count 5.0V to 3.3V computer supply
Low noise/low-dropout SMPS post regulator
High-current, current-limited switch
Applications
Typical Applications
+12V
0.1µF
1.0µF
Enable
Shutdown
0.1µF
7
C2+
4
V
P
3
GND
2
FLAG
1
EN
6
C2–
5
V
CP
4
GND
FLAG
3
3.3V
S
2
1
5V
EN
MIC5156-3.3
C1+
C1–
V
DD
G
D
S
MIC5157
V
DD
G
D
5
6
7
8
8
0.1µF
9
10
11
12 13
14
V
IN
5V
47µF
R
S
= 0.035V / I
LIMIT
3mΩ
R
S
C
L
*
47µF
V
OUT
3.3V, 10A
V
IN
(3.61V min.)
3mΩ
47µF
R
S
Enable
Shutdown
C
L
*
47µF
V
OUT
3.3V, 10A
SMP60N03-10L
* Improves transient
response to load changes
R
S
= 0.035V / I
LIMIT
IRLZ44 (Logic Level MOSFET)
* Improves transient
response to load changes
10A 5V to 3.3V Desktop Computer Regulator
Super LDO
is a trademark of Micrel, Inc.
10A Low-Dropout Voltage Regulator
3-112
March 1999
MICREL [ MICREL SEMICONDUCTOR ]
