LT1036
Logic Controlled Regulator
DESCRIPTIO
FEATURES
s
s
s
s
s
s
Two Regulated Outputs:
12V at 3A
5V at 75mA
2% Output Voltage Tolerance
60dB Ripple Rejection
0.7% Load Regulation
TTL and CMOS Compatible Logic Control
100% Thermal Burn-In on All Devices
The LT
®
1036 features two positive regulators in the same
package. The 12V main regulator offers excellent
performance while supplying load currents up to 3A, and
the 5V auxiliary regulator provides similar performance
while supplying lighter loads of 75mA. The main regulator
has the additional feature of being under the shutdown
control of a logic signal. When the enable pin is taken to a
low logic level, the main regulator shuts down and its
output voltage goes to near 0V. During this command, the
auxiliary output is unaffected by the main regulator’s
condition and continues to provide a 5V output.
The main output has current and power limiting combined
with thermal shutdown to make it virtually blowout proof.
The auxiliary output is not affected by the thermal
shut down mechanism or the state of the main output,
allowing it to be used as a back-up in case of overloads or
shorts on the main supply.
The logic input of the LT1036 (enable pin) has a 1.6V
threshold and can be driven from a high source
impedance. This allows it to be driven by most logic
families, including TTL and CMOS.
For a dual 5V version of the LT1036, please see the LT1035
data sheet.
, LTC and LT are registered trademarks of Linear Technology Corporation.
APPLICATIO S
s
s
s
s
Power Supply Sequencing
Remote On/Off Power Control
Selective System Power During Emergency
Power Operation
Memory Power Supply with Back-Up
TYPICAL APPLICATIO
Functional Diagram
12V
V
IN
5
IN
LT1036
ENABLE
LOGIC
2
EN
GND
3
AUX
4
5V
OUT
1
OV
CURRENT (A)
Guaranteed Load Current,
12V Output
5
4.5
4
3.5
3
2.5
2
1.5
LT1036M/1036C • FD01
1
0.5
0
14
16
18
20 22 24 26
INPUT VOLTAGE (V)
28
30
LT1036M/1036C • FD02
U
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U
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1
LT1036
ABSOLUTE
AXI U
RATI GS
(Note 1)
Operating Junction Temperature
LT1036M
(OBSOLETE)
..................... – 55°C to 150°C
LT1036C ................................................ 0°C to 125°C
Storage Temperature Range ................. – 65°C to 150°C
Lead Temperature (Soldering, 10 sec).................. 300°C
Power Dissipation
Continuous (Note 6) ........................................... 24W
Fault Conditions .............................. Internally Limited
Input Voltage (V
IN
) .................................................. 30V
Enable Voltage (V
EN
) ............................................... 30V
PRECO DITIO I G
100% Burn-In in Thermal Limit
PACKAGE/ORDER I FOR ATIO
BOTTOM VIEW
V
IN
5
1
2
V
O
ORDER PART
NUMBER
CASE
IS GND
LT1036MK
LT1036CK
4
AUX
V
EN
K PACKAGE
4-LEAD TO-3 METAL CAN
T
JMAX
= 125°C,
θ
JC
= 3°C/W
OBSOLETE PACKAGE
Consider the T Package as an Alternate Source
Consult LTC Marketing for parts specified with wider operating temperature ranges.
ELECTRICAL CHARACTERISTICS
SYMBOL
V
O
PARAMETER
Output Voltage
High
Low
∆V
O
∆I
O
∆V
O
∆V
IN
Load Regulation
(Note 7)
Line
Regulation
Ripple Rejection
Thermal Regulation
I
O
I
SC
V
IN
Available Load Current
(Note 7)
Short Circuit
Current
Input Voltage to
Maintain Regulation
(Dropout Voltage)
CONDITIONS
T
J
= 25°C
The
q
denotes the specifications which apply over the full operating
temperature range. Main regulator (Note 2) V
IN
= 15V unless otherwise noted.
MIN
11.76
q
q
q
15V
≤
V
IN
≤
30V,
I
OUT
≤
I
MAX
(Note 7)
7V
≤
V
IN
≤
30V
V
IN
= 16V
0
≤
I
O
≤
3A (Note 3)
15V
≤
V
IN
≤
30V
(Note 3)
50Hz
≤
f
≤
500Hz (Note 9)
∆P
D =
20W (Note 5)
15V
≤
V
IN
≤
20V
V
IN
= 25V
V
IN
= 15V
V
IN
= 25V
(Note 6)
I
O
= 1A
I
O
= 3A
2
U
U
W
W W
U
UU
W
U
FRONT VIEW
5
4
3
2
1
T PACKAGE
5-LEAD PLASTIC TO-220
T
JMAX
= 150°C,
θ
JC
= 2.5°C/W
T
JMAX
= 125°C,
θ
JC
= 2.5°C/W
V
O
GND
V
EN
V
IN
AUX
ORDER PART
NUMBER
LT1036CT
TYP
12
MAX
12.24
12.48
UNITS
V
V
V
mV
mV/V
dB
11.52
0.1
10
1
50
60
0.003
0.3
80
4
0.012
%/W
A
A
q
q
3
2
4
2.7
2.3
1
4
2
14.5
15
A
A
V
V
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q
q
13.8
14.4
LT1036
ELECTRICAL CHARACTERISTICS
SYMBOL
I
Q
θ
JC
PARAMETER
Quiescent
Current
Thermal Resistance,
Junction to Case
CONDITIONS
Output High
Output Low
TO-220
The
q
denotes the specifications which apply over the full operating
temperature range. Main Regulator (Note 2) V
IN
= 15V unless otherwise noted.
MIN
TYP
4
3
2
MAX
5.5
4.5
3
UNITS
mA
mA
°C/W
Auxiliary Regulator (Note 2)
SYMBOL
V
O
PARAMETER
Output Voltage
CONDITIONS
T
J
= 25°C
7.2V
≤
V
IN
≤
30V
0mA
≤
I
O
≤
75mA
∆V
O
∆I
O
∆V
O
∆V
IN
Load
Regulation
Line
Regulation
Ripple Rejection
I
SC
V
IN
Short Circuit
Current (Note 8)
Input Voltage to
Maintain Regulation
(Dropout Voltage)
7.2V
≤
V
IN
≤
30V
0mA
≤
I
O
≤
75mA (Note 3)
7.2V
≤
V
IN
≤
30V
(Note 3)
50Hz
≤
f
≤
500Hz
7.0V
≤
V
IN
≤
30V
(Note 6)
I
O
≤
10mA
I
O
= 75mA
q
q
MIN
4.9
4.8
TYP
5.0
5.0
5
0.2
74
140
MAX
5.1
5.2
15
1
2
UNITS
V
V
mV
mV/V
mV/V
dB
250
mA
q
q
6.2
6.8
6.5
7.2
V
V
Logic Control (Note 2)
SYMBOL
V
EN
PARAMETER
Enable Threshold Voltage
Enable Pin Current
CONDITIONS
7.0V
≤
V
IN
≤
30V
T
J
= 25°C
V
EN
≤
1V (Note 4)
V
EN
≤
2.4V
q
q
q
MIN
1.45
1.3
0
TYP
1.6
1.6
1.5
0
MAX
1.7
1.8
12
6
UNITS
V
V
µA
µA
Note 1:
Absolute Maximum Ratings are those values beyond which the life
of a device may be impaired.
Note 2:
Unless otherwise indicated, these specifications apply for
V
IN
= 15V, I
O
= 0mA, and T
J
= 25°C.
Note 3:
Line and load regulation is measured using a low duty cycle pulse,
causing little change in the junction temperature. Effects due to thermal
gradients and device heating must be taken into account separately.
Note 4:
When the enable pin is at a low logic level, current flows out of the
enable pin.
Note 5:
Pulse length for this measurement is 20ms.
Note 6:
Input voltage is reduced until output drops by 100mV from its
initial value.
Note 7:
See “Guaranteed Load Current” graph.
Note 8:
Continuous shorts on the auxiliary output are not allowed unless
adequate heat sinking is used to maintain junction temperature below
150°C.
Note 9:
Guaranteed but not tested.
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LT1036
TYPICAL PERFOR A CE CHARACTERISTICS
Minimum Input-Output
Differential of Main Output
2.6
2.4
INPUT-OUTPUT VOLTAGE (V)
OUTPUT
VOLTAGE CHANGE (mV)
2.2
2.0
1.8
1.6
T
J
= 25°C
1.4
1.2
1.0
0
0.5
T
J
= 150°C
2.0
1.5
OUTPUT CURRENT (A)
1.0
2.5
3.0
INPUT-OUTPUT VOLTAGE (V)
T
J
= –55°C
INPUT
TRANSIENT (V)
LT1036M/1036C • TPC01
Maximum Available Load
Current, 12V Output
5
T
J
= 25°C
4
8
7
T
J
= 25°C
6
5
4
12V OUTPUT “ON”
MAIN OUTPUT (V)
SUPPLY CURRENT (mA)
CURRENT (A)
3
DEVICE OUT OF REGULATION
BELOW 14V
AUXILIARY OUTPUT (V)
2
1
1
0
0
4
8
12 16 20 24
INPUT VOLTAGE (V)
28
32
0
0
3
6
9 12 15 18 21 24 27 30
INPUT VOLTAGE (V)
LT1036M/1036C • TPC05
LT1036M/1036C • TPC04
Load Transient Response,
12V Output
50
OUTPUT VOLTAGES
CHANGE (V)
0
–50
50
C
OUT
= 1µF TANTALUM
CURRENT (µA)
0
–50
C
OUT
= 10µF TANTALUM
LOAD TRANSIENT
0.2
0
I
OUT
= 1A
∆
I
OUT
= 0.2A
0
2
4
6
8
TIME (µs)
10
12
14
0.6
0.8
1.0
1.2
T
J
= 25°C
THRESHOLD (V)
LOAD
TRANSIENT (A)
LT1036M/1036C • TPC07
4
U W
Minimum Input-Output
Differential of Auxiliary Output
2.6
2.4
2.2
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0
20
60
80
40
OUTPUT CURRENT (mA)
100
T
J
= 150°C
T
J
= 25°C
T
J
= –55°C
Line Transient Response,
12V Output
20
0
–20
20
0
–20
1
0
V
IN
= 18V
0
2
4
6
8
TIME (µs)
10
12
14
∆
V
IN
= 1V
C
OUT
= 10µF TANTALUM
C
OUT
= 1µF TANTALUM
LT1036M/1036C • TPC02
LT1036M/1036C • TPC03
Quiescent Current
12.2
12.1
12.0
11.9
11.8
Output Voltage vs Temperature
3
12V OUTPUT “OFF”
2
5.1
5.0
4.9
4.8
4.7
–50 –25
0
25 50 75 100 125 150
TEMPERATURE (°C)
LT1036M/1036C • TPC06
Enable Pin Characteristics
1.75
0
–0.2
0.4
Enable Threshold
1.70
1.65
1.60
1.55
1.50
1.45
1.4
1.6
1.8
1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1 20
ENABLE VOLTAGE (V)*
*NOTE SCALE CHANGE
0
LT1036M/1036C • TPC08
1.40
1.35
–50 –25
0
25 50 75 100 125 150
JUNCTION TEMPERATURE (°C)
LT1036M/1036C • TPC09
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LT1036
TYPICAL PERFOR A CE CHARACTERISTICS
Short-Circuit Current, 12V Output
5
OUTPUT VOLTAGE (V)
4
CURRENT (A)
T
J
= 25°C
3
6
3
0
C
OUT
= 10µF
NOISE (µV
RMS
)
2
ENABLE
VOLTAGE (V)
1
0
0
4
8
12 16 20 24
INPUT VOLTAGE (V)
28
32
0
10 20 30 40 50 60 70 80 90
TIME (µs)
LT1036M/1036C • TPC11
LT1036M/1036C • TPC10
APPLICATIO S I FOR ATIO
General Information
The LT1036 is a dual output regulator. The main 12V
output is capable of delivering up to 3A of load current and
can be shut down with a logic signal. The auxiliary 5V
output supplies a minimum of 75mA and is unaffected by
the logic signal. The outputs are trimmed to
±
2% initial
tolerance and exhibit excellent line and load regulation.
The logic control feature makes the LT1036 ideal for many
system applications where it is desirable to power-up a
portion of the system for a period of time, and then power
the system down during a standby operation. Applications
such as multiple power supply sequencing, elimination of
expensive AC and DC power switches, delayed start ap-
plications, switching 12V DC loads, and many others are
now easily accomplished.
Timing functions, such as delayed power-up or power-
down, can also be performed directly at the enable pin.
Because a logic low on the enable pin shuts down the main
regulator, feedback from output to enable can be used to
generate hysteresis or latching functions.
U
W
U W
Output Switching Characteristics
15
12
9
CC
OUT
≤
0.1F
OUT
≤
0.1µF
C
OUT
= 1µF
200
180
160
140
120
100
80
60
40
0
20
Output Voltage Noise
MAIN (12V) OUTPUT
SEE APPLICATION SECTION
FOR FALL TIME INFORMATION
5
AUXILIARY
OUTPUT
300
3k
10k
1k
BANDWIDTH (1 POLE) (Hz)
30k
0
100
LT1036M/1036C • TPC12
U U
The low quiescent current drain of the LT1036 makes it
useful in battery-powered or battery back-up applications.
The enable pin can be used as a “low battery” detector or
to shut down major portions of system power, allowing
memory portions to continue to operate from the auxiliary
output. At low output currents, the auxiliary output will
regulate with input voltage typically as low as 6.2V, giving
maximum battery life.
Good design practice with all regulators is to bypass the
input and output terminals. A 2µF solid tantalum at the
input and at both outputs is suggested. For the applica-
tions which follow, the bypass capacitors are still recom-
mended, but for simplicity are not shown on the diagram.
It is also recommended that for maximum noise immunity
the voltage enable pin be tied high if it is unused. It can be
tied directly to V
IN
, as shown in Figure 1, or to the auxiliary
Output. If the enable pin is left open, it will float to a high
logic level of approximately 1.6V and the main output
regulator will be at 12V.
The enable pin is fully protected against input voltages up
to 30V, even if the power input voltage is zero.
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