MI
KRON
JS
C
ht
t
p
:
//ww
w
.mikron.ru
17 Dec
e
mb
e
r
2
0
0
3
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
1
DATA SHEET
17 D
ECEMBER
2003
N
O
. 00021
R
EV
1-03
CONTENTS
Page
DESCRIPTION
1
FEATURES
1
APPLICATIONS
1
BASIC FUNCTIONAL DIAGRAM
2
PIN DESCRIPTION
2
BLOCK DIAGRAM
2
ABSOLUTE MAXIMUM RATINGS
2
ELECTRICAL CHARACTERISTICS
3
TYPICAL CHARACTERISTICS
4
DROPOUT VOLTAGE
4
SHORT-CIRCUIT CURRENT
4
LOAD REGULATION
4
RIPPLE REJECTION
4
MINIMUM OPERATING CURRENT
4
TEMPERATURE STABILITY
4
ADJUST PIN CURRENT
4
RIPPLE REJECTION vs. CURRENT
5
LOAD TRANSIENT RESPONSE
5
LINE TRANSIENT RESPONSE
5
TYPICAL APPLICATIONS
6
CONTENTS
Page
1.2V TO 15V ADJUSTABLE REGULATOR
6
5V REGULATOR WITH SHUTDOWN
6
7.5A VARIABLE REGULATOR
6
REMOTE SENSING
6
HIGH EFFICIENCY REGULATOR WITH
SWITCHING PREREGULATOR
6
PARALLELING REGULATORS
6
IMPROVING RIPPLE REJECTION
6
APPLICATION INFORMATION
7
STABILITY
7
PROTECTION DIODES
7
OVERLOAD RECOVERY
7
PHYSICAL DIMENSIONS and MARKING
DIAGRAMS
9
TO-220-3
9
TO-263-3
9
ORDERING INFORMATION
10
RIPPLE REJECTION
8
OUTPUT VOLTAGE
8
LOAD REGULATION
8
THERMAL CONSIDERATIONS
8
DESCRIPTION
The MIK1083/MIK1084/MIK1085 series of positive
adjustable regulators are designed to provide
7.5A, 5A and 3A with higher efficiency than
currently available devices. All internal circuitry is
designed to operate down to 1V input to output
differential and the dropout voltage is fully
specified as a function of load current. Dropout is
guaranteed at a maximum of 1.5 V at maximum
output current. On-chip trimming adjusts the
reference voltage to 1%. Current limit is also
trimmed, minimizing the stress on both the
regulator and power source circuitry under
overload conditions.
The MIK1083/MIK1084/MIK1085 devices are pin
compatible with older 3 terminal regulators. A
10F output capacitor is required on these new
devices; however, this is usually included in most
regulator designs.
FEATURES
Three Terminal Adjustable
Output Current of 3A, 5A or 7.5A
Operates Down to 1V dropout
Guaranteed Dropout Voltage at Multiple Current
Levels
0.015% Line Regulation
0.1% Load Regulation
100% Thermal Limit Burn-In
APPLICATIONS
High Efficiency Linear Regulators
Post Regulators for Switching Supplies
Constant Current Regulators
Battery Chargers
REPLACEMENT OF:
LT108
X
SERIES
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
2
Design by Vladimir F.Lityaghin / E-mail: lityaghin@mail.ru / Tel: +7(095)532-64-54
MI
KRON
JS
C
h
ttp
:
/
/www.
m
i
kr
o
n
.
r
u
02 Oc
to
ber
20
03
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
MIK108x series
MIK108x
CT
MIK108x
CS
1 -- ADJ
2 -- V
OUT
3 -- V
IN
tab -- V
OUT
TO-220-3
TO-263-3
!
!
!
!
V
IN
V
OUT
V
ADJ
THERMAL
LIMIT
!
!
!
PIN DESCRIPTION
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
BASIC FUNCTIONAL DIAGRAM
!
INPUT
OUTPUT
ADJUST
(
)
Substrate
1.25
Band Gap
!
!
!
2
1
3
tab
tab
2
1
3
SYMBOL
PARAMETER
MAXIMUM
UNIT
P
D
Power Dissipation
Internally Limited
W
V
IN
Input to Output Voltage Differential
30 V
Operating Junction Temperature Range
Control Section
0 to 125
T
J
Power Transistor
0 to 150
o
C
T
STG
Storage Temperature
-65 to 150
o
C
T
LEAD
Lead Temperature (Soldering, 10 sec)
300
o
C
MI
KRON
JS
C
ht
t
p
:
//ww
w
.mikron.ru
17 Dec
e
mb
e
r
2
0
0
3
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
3
Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Load
and line regulation are measured at a constant junction temperature by low duty cycle pulse
testing.
Note 2: Line and load regulation are guaranteed up to the maximum power dissipation (30W for the
MIK1083 /MIK1084 /MIK1085). Power dissipation is determined by the input/output differential
and the output current. Guaranteed maximum power dissipation will not be available over the full
input/output voltage range.
Note 3: I
FILL LOAD
is defined in the current limit curves. I
FILL LOAD
curve is defined as the minimum value of
current limit as a function of input to output voltage.
Note 4: Dropout voltage is specified over the full output current range of the device.
ELECTRICAL CHARACTERISTICS
(
T
HE
DENOTES
THE
SPECIFICATIONS
WHICH
APPLY
OVER
THE
FULL
OPERATING
TEMPERATURE
RANGE
,
OTHERWISE
SPECIFICATIONS
ARE
AT
T
A
= 25C)
SYMBOL
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX UNIT
I
OUT
= 10mA,
(
V
IN
-
V
OUT
) = 3V
1.238 1.250 1.262
V
REF
Reference Voltage
10mA
I
OUT
I
FULL LOAD
1.5V (
V
IN
-
V
OUT
) 25V (Note 3)
1.225 1.250 1.270
V
0.015
0.2
I
LOAD
=10mA,
1.5 (
V
IN
-
V
OUT
) 15V
0.035
0.2
R
LINE
Line Regulation
15V (
V
IN
-
V
OUT
) 30V (Notes 1,2)
0.05 0.5
%
0.1
0.3
R
LOAD
Load Regulation
(
V
IN
-
V
OUT
) = 3V
10mA
I
OUT
I
FULL LOAD
(Notes 1,2,3)
0.2
0.4
%
V
DROP
Dropout Voltage
V
REF
=
1%,
I
OUT
=
I
FULL LOAD
(Note 4)
1.3
1.5
V
Current Limit
(
V
IN
-
V
OUT
) = 5V
8.0 9.5
MIK108
3
(
V
IN
-
V
OUT
) = 25V
0.4 1.0
(
V
IN
-
V
OUT
) = 5V
5.5 6.5
MIK108
4
(
V
IN
-
V
OUT
) = 25V
0.3 0.6
(
V
IN
-
V
OUT
) = 5V
3.2 4.0
V
REFCLIM
MIK108
5
(
V
IN
-
V
OUT
) = 25V
0.2
0.5
A
Minimum Load Current
(
V
IN
-
V
OUT
) = 25V
5 10
mA
Thermal Regulation
MIK108
3
0.002 0.010
MIK108
4
0.003 0.015
MIK108
5
T
A
= 25
C, 30ms pulse
0.004 0.020
%/W
RR
Ripple Rejection
f = 120Hz, C
ADJ
= 25F,
C
OUT
= 25F Tantalum,
I
OUT
=
I
FULL LOAD
,
(
V
IN
-
V
OUT
) = 3V
60 75 dB
55
I
ADJ
Adjust Pin Current
T
j
= 25
C
120
A
I
ADJCH
Adjust Pin Current Change 10mA I
OUT
I
FULL LOAD
,
1.5V (
V
IN
-
V
OUT
) = 25V
0.2 5 A
Temperature Stability
0.5 %
Long Term Stability
T
A
= 125
C, 1000Hrs
0.3 1 %
RMS Output Noise
(% of V
OUT
)
T
A
= 25
C, 10Hz
f 10kHz
0.003
%
4
Design by Vladimir F.Lityaghin / E-mail: lityaghin@mail.ru / Tel: +7(095)532-64-54
MI
KRON
JS
C
h
ttp
:
/
/www.
m
i
kr
o
n
.
r
u
02 Oc
to
ber
20
03
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
MIK108x series
TYPICAL CHARACTERISTICS
DROPOUT VOLTAGE
MIK108
3
MIK108
4
MIK108
5
SHORT-CIRCUIT CURRENT
MIK108
3
MIK108
4
MIK108
5
LOAD REGULATION
MIK108
3
MIK108
4
MIK108
5
RIPPLE REJECTION
MIK108
3
MIK108
4
MINIMUM OPERATING CURRENT
TEMPERATURE STABILITY
ADJUST PIN CURRENT
MIK108
5
M
I
N
I
M
U
M
I
N
PU
T/
O
U
TPU
T
D
I
FF
ER
EN
TI
A
L
(V)
OUTPUT CURRENT (A)
T
J
= 25C
0C 1
T
J
25C
1
2
0
1
2
3
4
5
6
7
8
9
10
M
I
N
I
M
U
M
I
N
PUT/
O
U
T
P
UT DI
F
F
ERE
N
TI
AL
(V)
OUTPUT CURRENT (A)
T
J
= 25C
0C 1
T
J
25C
1
2
0
1
2
3
4
5
6
M
I
NI
M
U
M
I
N
PUT/
OU
T
P
U
T
DI
F
F
EREN
T
I
AL
(V
)
OUTPUT CURRENT (A)
T
J
= 25C
0C 1
T
J
25C
1
2
0
1
2
3
4
INPUT/OUTPUT DIFFERENTIAL (V)
SHOR
T
-
CI
RCU
I
T
C
URRENT
(A
)
25C
I
FULL
LOAD
GUARANTEED
12
10
8
6
4
2
5
10
15
20
25
30
0
INPUT/OUTPUT DIFFERENTIAL (V)
S
H
ORT
-
CI
RCUI
T
CURRE
NT
(A
)
25C
I
FULL
LOAD
GUARANTEED
10
7
9
8
6
4
5
2
3
1
5
10
15
20
25
30
0
INPUT/OUTPUT DIFFERENTIAL (V)
S
H
O
R
T
-
CI
RCU
I
T
C
U
RRE
NT
(A
)
25C
I
FULL
LOAD
GUARANTEED
6
4
5
2
3
1
5
10
15
20
25
30
0
OU
T
P
U
T
V
O
L
T
A
GE
D
E
V
I
A
T
I
O
N
(%
)
TEMPERATURE (C)
I = 7.5A
-0.20
-0.15
-0.10
-0.05
0.05
0.10
0
25
-25
50
75
0
OUT
P
UT
VOL
T
AGE
DEV
I
A
T
I
O
N
(%
)
TEMPERATURE (C)
I = 5A
-0.20
-0.15
-0.10
-0.05
0.05
0.10
0
25
-25
50
75
0
OUT
P
U
T
V
O
L
T
A
GE
DEV
I
A
T
I
O
N
(%
)
TEMPERATURE (C)
I = 3A
-0.20
-0.15
-0.10
-0.05
0.05
0.10
0
25
-25
50
75
0
REF
E
REN
C
E V
O
L
T
A
G
E
(V
)
TEMPERATURE (C)
1.23
1.24
1.25
1.26
1.27
25
-25
50
75
0
INPUT/OUTPUT DIFFERENTIAL (V)
MI
NI
M
U
M
OPE
R
A
T
I
N
G
CUR
RENT
(m
A)
T
J
= 25C
1
2
3
4
5
6
7
8
9
10
5
10
15
20
25
30
0
AD
J
U
ST PI
N
CU
R
R
EN
T
(
A)
TEMPERATURE (C)
10
20
30
40
50
60
70
80
90
100
0
25
-25
50
75
0
RI
P
P
L
E
R
E
J
E
CT
I
O
N
(d
B
)
FREQUENCY (Hz)
10
20
30
40
50
60
70
80
90
100
0
10
100
1k
10k
100k
(
-
)
3V
V
V
IN
OUT
V
RIPPLE
0.5
V
P-P
V
RIPPLE
3V
P-P
(
-
)
V
V
IN
OUT
V
DROPOUT
C
ADJ
= 200F at Frequencies < 60Hz
C
I
ADJ
OUT
= 25F at Frequencies > 60Hz
= 7A
RI
PP
L
E
RE
J
E
CT
I
O
N
(d
B
)
FREQUENCY (Hz)
10
20
30
40
50
60
70
80
90
100
0
10
100
1k
10k
100k
(
-
)
3V
V
V
IN
OUT
V
RIPPLE
0.5
V
P-P
V
RIPPLE
3V
P-P
(
-
)
V
V
IN
OUT
V
DROPOUT
C
ADJ
= 200F at Frequencies < 60Hz
C
I
ADJ
OUT
= 25F at Frequencies > 60Hz
= 5A
RI
PPL
E REJ
E
CTI
O
N
(d
B
)
FREQUENCY (Hz)
10
20
30
40
50
60
70
80
90
100
0
10
100
1k
10k
100k
(
-
)
3V
V
V
IN
OUT
V
RIPPLE
0.5
V
P-P
V
RIPPLE
3V
P-P
(
-
)
V
V
IN
OUT
V
DROPOUT
C
ADJ
= 200F at Frequencies < 60Hz
C
I
ADJ
OUT
= 25F at Frequencies > 60Hz
= 3A
MI
KRON
JS
C
ht
t
p
:
//ww
w
.mikron.ru
17 Dec
e
mb
e
r
2
0
0
3
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
5
TYPICAL CHARACTERISTICS
(CONTINUED)
RIPPLE REJECTION vs. CURRENT
MIK108
3
MIK108
4
MIK108
5
LOAD TRANSIENT RESPONSE
MIK108
3
MIK108
4
LINE TRANSIENT RESPONSE
MIK108
3
MIK108
4
MIK108
5
MIK108
5
RI
P
P
L
E
RE
J
E
CT
I
O
N
(d
B
)
OUTPUT CURRENT (A)
10
20
30
40
50
60
70
80
90
100
0
1
2
4
5
6
7
8
3
f
R
= 120Hz,
3
V
V
RIPPLE P-P
f
R
= 20kHz,
0.5
V
V
RIPPLE P-P
V
C
OUT
= 5V
25F
C
ADJ
OUT
= 25F
=
RIP
P
L
E
RE
J
E
C
T
IO
N
(d
B
)
OUTPUT CURRENT (A)
10
20
30
40
50
60
70
80
90
100
0
1
2
4
5
3
f
V
V
R RIPPLE
P-P
= 20kHz,
0.5
f
V
V
R RIPPLE
P-P
= 120Hz,
3
V
C
C
OUT
ADJ
OUT
= 5V
= 25F
= 25F
RI
PPL
E
R
E
J
E
CT
I
O
N
(d
B
)
OUTPUT CURRENT (A)
10
20
30
40
50
60
70
80
90
100
0
1.0
0.5
1.5
2.5
2.0
3.0
f
V
V
R RIPPLE
P-P
= 20kHz,
0.5
f
V
V
R RIPPLE
P-P
= 120Hz,
3
V
C
C
OUT
ADJ
OUT
= 5V
= 25F
= 25F
LO
AD
CURRE
N
T
(A
)
O
U
T
P
UT
V
O
L
T
AG
E
DE
VI
A
T
I
O
N
(m
V)
2
4
6
8
-0.4
-0.2
0.2
0.4
0.6
0
0
50 60 70 80 90 100
10 20 30 40
= 0
C
ADJ
= 1F
= 10F Tantalum
C
C
IN
OUT
= 1F
C
ADJ
V
V
OUT
IN
= 1 0V,
= 13V
= 100mA
PRELOAD
TIME (s)
LO
AD
CU
RRE
NT
(A
)
OU
T
P
U
T
V
O
L
T
A
GE
D
EVI
A
T
I
O
N
(mV
)
2
4
6
-0.4
-0.6
-0.2
0.2
0.4
0.6
0
0
50 60 70 80 90 100
10 20 30 40
= 0
C
ADJ
= 1F
= 10F Tantalum
C
C
IN
OUT
= 1F
C
ADJ
V
V
OUT
IN
= 1 0V,
= 13V
= 100mA
PRELOAD
TIME (s)
LO
A
D
C
URR
E
N
T
(A)
OUT
P
UT
V
O
L
T
AGE
DEVI
A
T
I
O
N
(m
V
)
1
2
3
-0.2
-0.3
-0.1
0.1
0.2
0.3
0
0
50 60 70 80 90 100
10 20 30 40
= 0
C
A DJ
= 1F
= 10F Tantalum
C
C
IN
OUT
= 1F
C
A DJ
V
V
OUT
IN
= 10V,
= 13V
= 100mA
PRELOAD
TIME (s)
IN
P
U
T
DE
V
I
A
T
I
O
N
(V
)
O
U
TP
UT
V
O
L
T
AG
E
DE
V
I
A
T
I
O
N
(m
V
)
12
13
14
-150
-100
-50
50
100
150
0
0
100 120 140 160 180
20 40 60 80
200
= 0
C
A D J
= 1F
C
A D J
V
OUT
= 10V
I
C
C
OUT
IN
IN
= 10F
= 0.2A
= 1F
TIME (s)
100 120 140 160 180
20 40 60 80
200
= 0
C
ADJ
= 1F
C
ADJ
V
OUT
= 10V
I
C
C
OUT
IN
IN
= 10F
= 0.2A
= 1F
TIME (s)
IN
P
U
T
DE
V
I
A
T
I
O
N
(V
)
O
U
T
P
UT
V
O
L
T
AG
E
D
EVI
A
T
I
O
N
(m
V
)
12
13
14
-60
-40
-20
20
40
60
0
0
100 120 140 160 180
20 40 60 80
200
= 0
C
A D J
= 1F
C
A D J
V
OUT
= 10V
I
C
C
OUT
IN
IN
= 10F
= 0.2A
= 1F
TIME (s)
IN
P
U
T
DE
V
I
A
T
I
O
N
(V
)
O
U
TP
UT
V
O
L
T
AG
E
D
EVI
A
T
I
O
N
(m
V)
12
13
14
-60
-40
-20
20
40
60
0
0
6
Design by Vladimir F.Lityaghin / E-mail: lityaghin@mail.ru / Tel: +7(095)532-64-54
MI
KRON
JS
C
h
ttp
:
/
/www.
m
i
kr
o
n
.
r
u
02 Oc
to
ber
20
03
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
MIK108x series
TYPICAL APPLICATIONS
1.2V TO 15V ADJUSTABLE REGULATOR
5V REGULATOR WITH SHUTDOWN*
C1 needed if device is far from filter capacitor
V
OUT
= 1.25V x (1 + R2 / R1)
* OUTPUT shuts down to 1.3V
7.5A VARIABLE REGULATOR
* 1% FILM RESISTOR
L : DALE TO-5 TYPE
T2: STANCOR 11Z-2003
GENERAL PURPOSE REGULATOR WITH SCR PREREGULATOR
TO LOWER POWER DISSIPATION. ABOUT 1.7V DIFFERENTIAL
IS MAINTAINED ACROSS THE MIK1083 INDEPENDENT OF
OUTPUT VOLTAGE AND LOAD CURRENT
REMOTE SENSING
HIGH EFFICIENCY REGULATOR WITH SWITCHING
PREREGULATOR
PARALLELING REGULATORS
IMPROVING RIPPLE REJECTION
V
OUT
= 1.25V x (1+R2/R1)
I
OUT
= 0A to 15A
*
THE #18 WIRE ACTS AS BALLAST
RESISTANCE INSURING CURRENT
SHARING BETWEEN BOTH DEVICES
* C1 IMPROVES RIPPLE REJECTION.
X
C
SHOULD BE < R1 AT RIPPLE FREQUENCY
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
120
2 FEET #18 WIRE*
0.015
R1
R2
!
!
C1
10F
C2
100F
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
R1
90.9
R2
1k
!
!
!
100F
10F
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
= 5V
365
1%
121
1%
1k
1k
2N3904
TTL
!
!
!
1F
100pF
0.1F
1F
50,000F
LT1011
NC
2N390
1N4148
1N4003
LT1004-1.2
LT1004-1.2
1N914
T2
T1
TRIAD
F-269U
1N4003
1N4003
C30B
C30B
L
1MH
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
11k*
10k
82k
11k*
200k
560
20
20
15k
15k
10k
16k*
16k*
750
OUTPUT
ADJUST
0V to 35V
0A to 7.5A
2k
1.5k
100F
2.7k
+15V
+15V
+15V
+15V
-15V
-15V
-15V
-15V
~110V
2
2
2
8
8
8
4
4
4
7
7
7
6
1
1
1
3
3
3
LT1011
LM301A
2
1
3
!
!
!
!
!
!
!
!
!
!
!
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
OUT
=5V
V
IN
V
IN
121
25
25
365
100F
100F
100pF
5F
1k
RETURN
RETURN
7
2
8
4
6
1
3
LM301A
R
L
R
P
(Max Drop 300mV)
!
!
!
!
!
10,000F
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
1k
1M
10k
10k
470
1mH
240
10k
2k
28V
28V
28V
LT1011
4N28
1N914
MR1122
1N914
!
!
!
!
150F
10F
C1 *
25F
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
= 5V
R1
121
1%
R2
365
1%
!
!
MI
KRON
JS
C
ht
t
p
:
//ww
w
.mikron.ru
17 Dec
e
mb
e
r
2
0
0
3
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
7
The MIK1083 family of three-terminal adjustable
regulators is easy to use and has all the protection
features that are expected in high performance voltage
regulators. They are short-circuit protected, and have
safe area protection as well as thermal shutdown to turn
off the regulator should the junction temperature
exceed about 165C.
These regulators are pin compatible with older three-
terminal adjustable devices, offer lower dropout voltage
and more precise reference tolerance. Further, the
reference stability with temperature is improved over
older types of regulators. The only circuit difference
between using the MIK1083 family and older regulators is
that this new family requires an output capacitor for
stability.
S
TABILITY
The circuit design used in the MIK1083 family requires
the use of an output capacitor as part of the device
frequency compensation. For all operating conditions,
the addition of 150mF aluminium electrolytic or a 22mF
solid tantalum on the output will ensure stability.
Normally, capacitors much smaller than this can be used
with the MIK1083. Many different types of capacitors
with widely varying characteristics are available. These
capacitors differ in capacitor tolerance (sometimes
ranging up to 100%), equivalent series resistance, and
capacitance temperature coefficient. The 150mF or
22mF values given will ensure stability.
When the adjustment terminal is bypassed to improve
the ripple rejection, the requirement for an output
capacitor increases. The value of 22mF tantalum or
150mF aluminum covers all cases of bypassing the
adjustment terminal. Without bypassing the adjustment
terminal, smaller capacitors can be used with equally
good results and the table below shows approximately
what size capacitors are needed to ensure stability.
Normally, capacitor values on the order of 100mF are
used in the output of many regulators to ensure good
transient response with heavy load current changes.
Output capacitance can be increased without limit and
larger values of output capacitor further improve
stability and transient response of the MIK1083
regulators. Another possible stability problem that can
occur in monolithic IC regulators is current limit
oscillations. These can occur because, in current limit,
the safe area protection exhibits a negative impedance.
The safe area protection decreases the current limit as
the input-to-output voltage increases. That is the
equivalent of having a negative resistance since
increasing voltage causes current to decrease. Negative
resistance during current limit is not unique to the
MIK1083 series and has been present on all power IC
regulators. The value of the negative resistance is a
function of how fast the current limit is folded back as
input-to-output voltage increases. This negative
resistance can react with capacitors or inductors on the
input to cause oscillation during current limiting.
Depending on the value of series resistance, the overall
circuitry may end up unstable. Since this is a system
problem, it is not necessarily easy to solve; however, it
does not cause any problems with the IC regulator and
can usually be ignored.
P
ROTECTION
D
IODES
In normal operation, the MIK1083 family does not need
any protection diodes. Older adjustable regulators
required protection diodes between the adjustment pin
and the output and from the output to the input to
prevent overstressing the die. The internal current paths
on the MIK1083 adjustment pin are limited by internal
resistors. Therefore, even with capacitors on the
adjustment pin, no protection diode is needed to ensure
device safety under short-circuit conditions.
Diodes between input and output are usually not
needed. The internal diode between the input and the
output pins of the MIK1083 family can handle
microsecond surge currents of 50A to 100A. Even with
large output capacitances, it is very difficult to get
those values of surge currents in normal operations. Only
with a high value of output capacitors, such as 1000mF
to 5000mF and with the input pin instantaneously
shorted to ground, can damage occur. A crowbar circuit
at the input of the MIK1083 can generate those kinds of
currents, and a diode from output to input is then
recommended. Normal power supply cycling or even
plugging and unplugging in the system will not generate
current large enough to do any damage.
The adjustment pin can be driven on a transient basis
25V, with respect to the output without any device
degradation. Of course, as with any IC regulator,
exceeding the maximum input to output voltage
differential causes the internal transistors to break down
and none of the protection circuitry is functional.
O
VERLOAD
R
ECOVERY
Like any of the IC power regulators, the MIK1083 has
safe area protection. The safe area protection decreases
the current limit as input-to-output voltage increases
and keeps the power transistor inside a safe operating
region for all values of input-to-output voltage. The
MIK1083 protection is designed to provide some output
current at all values of input-to-output voltage up to the
device breakdown.
When power is first turned on, as the input voltage rises,
the output follows the input, allowing the regulator to
start up into very heavy loads. During the start-up, as
the input voltage is rising, the input-to-output voltage
differential remains small, allowing the regulator to
supply large output currents. With high input voltage, a
problem can occur wherein removal of an output short
will not allow the output voltage to recover. Older
regulators, such as the 7800 series, also exhibited this
phenomenon, so it is not unique to the MIK1083.
The problem occurs with a heavy output load when the
input voltage is high and the output voltage is low, such
APPLICATION INFORMATION
INPUT
OUTPUT
ADJUSTMENT
10F 10F Tantalum, 50F Aluminum
None
10F 22F Tantalum, 150F Aluminum
20F
R
ECOMMENDED
C
APACITOR
V
ALUES
R1
In
Out
Adj
MIK1084
V
IN
V
OUT
R2
C
OUT
150F
C
ADJ
10F
D1
1N4002
(Optional)
!
!
8
Design by Vladimir F.Lityaghin / E-mail: lityaghin@mail.ru / Tel: +7(095)532-64-54
MI
KRON
JS
C
h
ttp
:
/
/www.
m
i
kr
o
n
.
r
u
02 Oc
to
ber
20
03
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
MIK108x series
APPLICATION INFORMATION
(CONTINUED)
as immediately after removal of a short. The load line
for such a load may intersect the output current curve at
two points. If this happens, there are two stable output
operating points for the regulator. With this double
intersection, the power supply may need to be cycled
down to zero and brought up again to make the output
recover.
R
IPPLE
R
EJECTION
The typical curves for ripple rejection reflect values for
a bypassed adjustment pin. This curve will be true for all
values of output voltage. For proper bypassing and ripple
rejection approaching the values shown, the impedance
of the adjust pin capacitor at the ripple frequency
should be less than the value of R1, (normally 100W to
120W). The size of the required adjust pin capacitor is a
function of the input ripple frequency. At 120Hz the
adjust pin capacitor should be 25mF if R1 = 100W. At
10kHz only 0.22mF is needed.
For circuits without an adjust pin bypass capacitor, the
ripple rejection will be a function of output voltage. The
output ripple will increase directly as a ratio of the
output voltage to the reference voltage (
V
OUT
/
V
REF
). For
example, with the output voltage equal to 5V and no
adjust pin capacitor, the output ripple will be higher by
the ratio of 5V/1.25V or four times larger. Ripple
rejection will be degraded by 12dB from the value shown
on the typical curve.
O
UTPUT
V
OLTAGE
The MIK1083 develops a 1.25V reference voltage
between the output and the adjust terminal (see Figure
1). By placing a
r e s i s t o r R 1
between these
two terminals, a
constant current
is caused to flow
through R1 and
down through R2
to set the overall
output voltage.
Normally this
current is the
specified minimum load current of 10mA. Because I
ADJ
is
very small and constant when compared with the current
through R1, it represents a small error and can usually
be ignored.
L
OAD
R
EGULATION
Because the MIK1083 is a three-terminal device, it is not
possible to provide true remote load sensing. Load
regulation will be limited by the resistance of the wire
connecting the regulator to the load. The data sheet
specification for load regulation is measured at the
bottom of the package. Negative side sensing is a true
Kelvin connection, with the bottom of the output divider
returned to the negative side of the load. Although it
may not be immediately obvious, best load regulation is
obtained when the top of the resistor divider R1 is
connected directly to the case not to the load. This is
illustrated in Figure 2. If R1 were connected to the load,
the effective resistance between the regulator and the
load would be:
Connected as
shown,
R
P
is not
multiplied by
t he divi der
ratio.
R
P
is
about 0.004W
per foot using
16-gauge wire.
This translates
to 4mV/ft at 1A
load current, so
it is important
to keep the
positive lead
between regulator and load as short as possible and use
large wire or PC board traces.
T
HERMAL
C
ONSIDERATIONS
The MIK1083 series of regulators have internal power
and thermal limiting circuitry designed to protect the
device under overload conditions. For continuous normal
load conditions however, maximum junction
temperature ratings must not be exceeded. It is
important to give careful consideration to all sources of
thermal resistance from junction to ambient. This
includes junction-to-case, case-to-heat sink interface,
and heat sink resistance itself. New thermal resistance
specifications have been developed to more accurately
reflect device temperature and ensure safe operating
temperatures. The data section for these new regulators
provides a separate thermal resistance and maximum
junction temperature for both the Control Section and
the Power Transistor. Previous regulators, with a single
junction-to-case thermal resistance specification, used
an average of the two values provided here and
therefore could allow excessive junction temperatures
under certain conditions of ambient temperature and
heat sink resistance. To avoid this possibility,
calculations should be made for both sections to ensure
that both thermal limits are met.
Junction-to-case thermal resistance is specified from the
IC junction to the bottom of the case directly below the
die. This is the lowest resistance path for heat flow.
Proper mounting is required to ensure the best possible
thermal flow from this area of the package to the heat
sink. Thermal compound at the case-to-heat sink
interface is strongly recommended. If the case of the
device must be electrically isolated, a thermally
conductive spacer can be used, as long as its added
contribution to thermal resistance is considered. Note
that the case of all devices in this series is electrically
connected to the output.
(
)
Resistance
Line
Parasitic
,
=
+
P
P
R
R
R1
R1
R2
R1
50A
R2
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
V
OUT
I
ADJ
!
!
V
REF
Fig 1. B
ASIC
A
DJUSTABLE
R
EGULATOR
2
1
2
1
R
I
R
R
V
V
ADJ
REF
OUT
+
+
=
R1*
R
L
R
P
PARASITIC LINE
RESISTANCE
R2*
MIK1083
IN
OUT
ADJ
!
3
!
2
!
1
V
IN
!
Fig 2. C
ONNECTIONS
FOR
B
EST
L
OAD
R
EGULATIONS
C
ONNECT
R1
TO
C
ASE
C
ONNECT
R2
TO
L
OAD
MI
KRON
JS
C
ht
t
p
:
//ww
w
.mikron.ru
17 Dec
e
mb
e
r
2
0
0
3
MIK108x series
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
9
PHYSICAL DIMENSIONS
AND
MARKING DIAGRAMS
MIK108
X
YYWW/n
X
-- output current
(see table below)
YY
-- Year
WW
-- Work Week
n
-- assembly location
X
OUTPUT CURRENT
3
7.5 A
4
5.0 A
5
3.0 A
TO-220-3
PACKAGE
TO-220-3
MARKING DIAGRAM
MILLIMETERS
INCHES
DIM
MIN
MAX
MIN
MAX
A
3.75 3.85 0.147 0.151
B
15.24 15.75 0.600 0.620
C
12.47 12.9 0.491 0.508
D
9.05 9.15 0.356 0.360
E
13.00 14.00 0.511 0.551
F
1.14 1.70 0.044 0.067
G
2.40 2.72 0.094 0.107
H
2.40 2.70 0.094 0.106
J
4.40 4.60 0.173 0.181
K
0.61 0.88 0.024 0.034
L
3.50 3.93 0.137 0.154
M
0.49 0.70 0.019 0.027
N
1.23 1.32 0.048 0.051
H
J K L M N
A
B
C
D
E
F
G
MIK108
X
YWW/n
X
-- output current
(see table below)
Y
-- Year
WW
-- Work Week
n
-- assembly location
TO-263-3
PACKAGE
TO-263-3
MARKING DIAGRAM
A
B
C
D
E
F
G
H
J K L M N
MILLIMETERS
INCHES
DIM
MIN
MAX
MIN
MAX
A
1.143 1.397 0.045 0.055
B
9.804 10.236 0.386 0.403
C
11.074 11.506 0.406 0.418
D
9.042 9.347 0.356 0.368
E
0.660 0.914 0.026 0.036
F
4.318 4.572 0.170 0.180
G
0.000 0.254 0.000 0.010
H
2.540 BSC
0.100 BSC
J
1.295 REF
0.051 REF
K
13.691 14.707 0.539 0.579
L
0.457 0.660 0.018
0.026
M
5 REF
5 REF
N
2.235 2.591 0.088 0.102
X
OUTPUT CURRENT
3
7.5 A
4
5.0 A
5
3.0 A
10
Design by Vladimir F.Lityaghin / E-mail: lityaghin@mail.ru / Tel: +7(095)532-64-54
MI
KRON
JS
C
h
ttp
:
/
/www.
m
i
kr
o
n
.
r
u
02 Oc
to
ber
20
03
LOW DROPOUT POSITIVE ADJUSTABLE REGULATORS
MIK108x series
!
Address: 1
ST
Zapadny Proezd 12, Building 1, Zelenograd, Moscow, Russia, 124460
"
Telephone: +7 (095) 535-23-43; 536-85-44
#
Fax: +7 (095) 530-92-01
$
Email: export@mikron.ru
#
Tel/Fax: +86-755-329-7574
%
Voice: +86-755-329-7573
$
Email: miksz@963.net
MIKRON JSC Head Office
MIKRON ShenZhen Office
The information presented in this Data sheet is believed to be accurate and
reliable. Application circuits shown are typical examples illustrating the
operation of the device. MIKRON can assume no responsibility for use of any
application circuits.
In the interest of product improvement, MIKRON reserves the right to change
specifications and data without notice.
ORDERING INFORMATION
NOTE: The form of packing is stipulated in the contract.
ORDERING
NUMBER
OUTPUT
CURRENT
PACKAGE
OPERATING
TEMPERATURE
SHIPPING
MIK 1083 CT 7.5
A
MIK 1084 CT 5.0
A
MIK 1085 CT 3.0
A
TO-220-3
0
C to +70
C
25 units/Rail
MIK 1083 CS 7.5
A
MIK 1084 CS 5.0
A
MIK 1085 CS 3.0
A
TO-263-3
0
C to +70
C
55 units/Rail
2500 units/Reel
PDF 
ZIP