LINER LT337A Negative adjustable regulator Datasheet

LT137A/LM137
LT337A/LM337
Negative Adjustable
Regulator
FEATURES
DESCRIPTION
n
The LT®137A/LT337A negative adjustable regulators will
deliver up to 1.5A output current over an output voltage
range of –1.2V to –37V. Linear Technology has made
significant improvements in these regulators compared to
previous devices, such as better line and load regulation,
and a maximum output voltage error of 1%.
n
n
n
n
Guaranteed 1% Initial Voltage Tolerance
Guaranteed 0.01%/V Line Regulation
Guaranteed 0.5% Load Regulation
Guaranteed 0.02%/W Thermal Regulation
100% Burn-in in Thermal Limit
APPLICATIONS
n
n
n
n
Every effort has been made to make these devices easy
to use and difficult to damage. Internal current and power
limiting coupled with true thermal limiting prevents device
damage due to overloads or shorts, even if the regulator
is not fastened to a heat sink.
Adjustable Power Supplies
System Power Supplies
Precision Voltage/Current Regulators
On-Card Regulators
Maximum reliability is attained with Linear Technology’s
advanced processing techniques combined with a 100%
burn-in in the thermal limit mode. This assures that all
device protection circuits are working and eliminates field
failures experienced with other regulators that receive only
standard electrical testing.
L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. All other
trademarks are the property of their respective owners.
TYPICAL APPLICATION
Negative Regulator
Output Voltage Error
12
+
C2
5μF
SOLID
TANTALUM
–VIN
VIN
LT137A VOUT
137A TA01
*R2 = R1
|
VOUT|
–1
1.25V
+
R1
121Ω
ADJ
1% RESISTORS
2% RESISTORS
11
C3
1μF
SOLID
TANTALUM
R2
–VOUT = 1.25V 1 +
R1
OUTPUT VOLTAGE ERROR (%)
R2*
10
9
8
7
LM337
6
5
4
LT337A
3
2
1
0
1
2
4 6 8 10
20
40
OUTPUT VOLTAGE (V)
100
137A TA01b
137afb
1
LT137A/LM137
LT337A/LM337
ABSOLUTE MAXIMUM RATINGS
(Note 1)
Power Dissipation .......................…….Internally Limited
Input to Output Voltage Differential ..................…….40V
Operating Junction Temperature Range
LT137A/LM137 .................................. –55°C to 150°C
LT337A/LM337 ...................................... 0°C to 125°C
Storage Temperature Range
LT137A/LM137 .................................. –65°C to 150°C
LT337A/LM337 .................................. –65°C to 150°C
Lead Temperature (Soldering, 10 sec.) ................. 300°C
PRECONDITIONING
100% Thermal Limit Burn-In
PIN CONFIGURATION
BOTTOM VIEW
BOTTOM VIEW
ADJ
VOUT
CASE IS INPUT
2
1
CASE
IS VIN
2
3
1
ADJ
VIN
K PACKAGE
2-LEAD TO-3 METAL CAN
θJA = 35°C/W, θJC = 3°C/W
H PACKAGE
3-LEAD TO-39 METAL CAN
θJA = 150°C/W, θJC = 15°C/W
OBSOLETE PACKAGE
Consider the M and T Packages for Alternate Source
OBSOLETE PACKAGE
Consider the M and T Packages for Alternate Source
FRONT VIEW
TAB IS
INPUT
FRONT VIEW
TAB
IS
INPUT
VOUT
3
VOUT
2
VIN
1
ADJ
M PACKAGE
3-LEAD PLASTIC DD
θJA = 30°C/W, θJC = 3°C/W
3
VOUT
2
VIN
1
ADJ
T PACKAGE
3-LEAD PLASTIC TO-220
θJA = 50°C/W, θJC = 4°C/W
ORDER INFORMATION
LEAD FREE FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT337AM#PBF
LT337AM#TRPBF
LT337AM
3-Lead Plastic DD
0°C to 125°C
LT337AT#PBF
LT337AT#TRPBF
LT337AT
3-Lead Plastic TO-220
0°C to 125°C
LM337T#PBF
LM337T#TRPBF
LM337T
3-Lead Plastic TO-220
0°C to 125°C
LEAD BASED FINISH
TAPE AND REEL
PART MARKING*
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LT337AM
LT337AM#TR
LT337AM
3-Lead Plastic DD
0°C to 125°C
LT337AT
LT337AT#TR
LT337AT
3-Lead Plastic TO-220
0°C to 125°C
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2
LT137A/LM137
LT337A/LM337
ORDER INFORMATION
LEAD BASED FINISH
TAPE AND REEL
PART MARKING
PACKAGE DESCRIPTION
TEMPERATURE RANGE
LM337T
LM337T#TR
LM337T
3-Lead Plastic TO-220
0°C to 125°C
Consult LTC Marketing for parts specified with wider operating temperature ranges. *The temperature grade is identified by a label on the shipping container.
Consult LTC Marketing for information on non-standard lead based finish parts.
For more information on lead free part marking, go to: http://www.linear.com/leadfree/
For more information on tape and reel specifications, go to: http://www.linear.com/tapeandreel/
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 3)
LT137A
SYMBOL PARAMETER
VREF
Reference Voltage
CONDITIONS
|VIN – VOUT| = 5V, IOUT = 10mA, Tj = 25°C
3V ≤ |VIN – VOUT| ≤ 40V
MIN
TYP
LM137
MAX
MIN
TYP
MAX
–1.238 –1.250 –1.262 –1.225 –1.250 –1.275
l –1.220
–1.250 –1.280 –1.200 –1.250 –1.300
UNITS
V
V
10mA ≤ IOUT ≤ IMAX, P ≤ PMAX
ΔVOUT
ΔIOUT
ΔVOUT
ΔVIN
Load Regulation
Line Regulation
10mA ≤ IOUT ≤ IMAX, (Note 4)
Tj = 25°C, |VOUT| ≤ 5V
5
25
15
25
mV
Tj = 25°C, |VOUT| ≥ 5V
|VOUT| ≤ 5V
0.1
0.5
0.3
0.5
%
l
10
50
20
50
mV
l
0.2
1
0.3
1
%
l
0.005
0.01
0.01
0.03
0.01
0.02
0.02
0.05
|VOUT| ≥ 5V
3V ≤ |VIN – VOUT| ≤ 40V (Note 4)
Tj = 25°C
Ripple Rejection
Thermal Regulation
VOUT = –10V, f = 120Hz
CADJ = 0
CADJ = 10μF
l
60
70
Tj = 25°C, 10ms Pulse
66
80
66
60
77
%/V
%/V
dB
dB
0.002
0.02
0.002
0.02
%/W
l
65
100
65
100
μA
IADJ
Adjust Pin Current
ΔIADJ
Adjust Pin Current Change
10mA ≤ IOUT ≤ IMAX
3V ≤ |VIN – VOUT| ≤ 40V
l
l
0.2
1
2
5
0.5
2
5
5
μA
μA
Minimum Load Current
|VIN – VOUT| ≤ 40V
|VIN – VOUT| ≤ 10V
|VIN – VOUT| ≤ 15V,
l
2.5
5
2.5
5
mA
l
1.2
3
1.2
3
mA
ISC
Current Limit
K and T Package (Note 7)
H Package
|VIN – VOUT| = 40V,
K and T Package
Tj = 25°C
H Package
l
l
l
ΔVOUT
ΔTemp
Temperature Stability of
Output Voltage (Note 6)
TMIN ≤ T ≤ TMAX
ΔVOUT
ΔTime
Long Term Stability
TA = 125°C, 1000 Hours
en
RMS Output Noise
(% of VOUT)
TA = 25°C, 10Hz ≤ f ≤ 10kHz
θJC
Thermal Resistance Junction
to Case
H Package
K Package
1.5
0.5
2.2
0.8
1.5
0.5
2.2
0.8
A
A
0.24
0.15
0.4
0.25
0.24
0.15
0.4
0.25
A
A
%
0.6
1.5
0.6
0.3
1
0.3
0.003
12
2.3
1
0.003
15
3
12
2.3
%
%
15
3
°C/W
°C/W
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3
LT137A/LM137
LT337A/LM337
ELECTRICAL CHARACTERISTICS
The l denotes the specifications which apply over the full operating
temperature range, otherwise specifications are at TA = 25°C. (Notes 2, 3)
LT337A
SYMBOL PARAMETER
VREF
Reference Voltage
CONDITIONS
MIN
|VIN – VOUT| = 5V, IOUT = 10mA, Tj = 25°C
3V ≤ |VIN – VOUT| ≤ 40V
TYP
LM337
MAX
MIN
TYP
MAX
–1.238 –1.250 –1.262 –1.213 –1.250 –1.287
l –1.220
–1.250 –1.280 –1.200 –1.250 –1.300
UNITS
V
V
10mA ≤ IOUT ≤ IMAX, P ≤ PMAX
ΔVOUT
ΔIOUT
ΔVOUT
ΔVIN
Load Regulation
Line Regulation
Thermal Regulation
ΔIADJ
ISC
Tj = 25°C, |VOUT| ≤ 5V
5
25
15
50
mV
Tj = 25°C, |VOUT| ≥ 5V
|VOUT| ≤ 5V
0.1
0.5
0.3
1
%
l
10
50
20
70
mV
l
0.2
1
0.3
1.5
%
l
0.005
0.01
0.01
0.03
0.01
0.02
0.04
0.07
%/V
%/V
|VOUT| ≥ 5V
3V ≤ |VIN – VOUT| ≤ 40V (Note 4)
Tj = 25°C
Ripple Rejection
IADJ
10mA ≤ IOUT ≤ IMAX, (Notes 4 and 5)
VOUT = –10V, f = 120Hz
CADJ = 0
CADJ = 10μF
l
60
70
Tj = 25°C, 10ms Pulse
66
80
66
60
77
dB
dB
0.002
0.02
0.003
0.04
%/W
Adjust Pin Current
l
65
100
65
100
μA
Adjust Pin Current Change
10mA ≤ IOUT ≤ IMAX
3V ≤ |VIN – VOUT| ≤ 40V
l
l
0.2
1
2
5
0.5
2
5
5
μA
μA
Minimum Load Current
|VIN – VOUT| ≤ 40V
|VIN – VOUT| ≤ 10V
|VIN – VOUT| ≤ 15V,
l
2.5
5
2.5
10
mA
l
1.2
3
1
6
mA
Current Limit
K, M and T Package
H Package
|VIN – VOUT| = 40V,
K, M and T Package
Tj = 25°C
H Package
l
l
l
ΔVOUT
ΔTemp
Temperature Stability of
Output Voltage (Note 6)
ΔVOUT
ΔTime
Long Term Stability
TA = 125°C, 1000 Hours
en
RMS Output Noise
(% of VOUT)
TA = 25°C, 10Hz ≤ f ≤ 10kHz
θJC
Thermal Resistance Junction
to Case
H Package
K Package
M and T Package
Note 1: Stresses beyond those listed under Absolute Maximum Ratings
may cause permanent damage to the device. Exposure to any Absolute
Maximum Rating condition for extended periods may affect device
reliability and lifetime.
Note 2: The shaded electrical specifications indicate those parameters
which have been improved or guaranteed test limits provided for the first
time.
Note 3: Unless otherwise indicated, these specifications apply: |VIN
– VOUT| = 5V; and IOUT = 0.1A for the H package, IOUT = 0.5A for the K, M,
and T packages. Power dissipation is internally limited. However, these
specifications apply for power dissipation up to 2W for the H package and
20W for the K and T packages. IMAX = 1.5A for the K, M, and T packages,
and 0.2A for the H package.
1.5
0.5
2.2
0.8
1.5
0.5
2.2
0.8
A
A
0.24
0.15
0.5
0.25
0.15
0.1
0.4
0.17
A
A
%
0.6
1.5
0.6
0.3
1
0.3
0.003
12
2.3
3
1
0.003
15
3
5
12
2.3
3
%
%
15
3
5
°C/W
°C/W
°C/W
Note 4: Testing is done using a pulsed low duty cycle technique. See
thermal regulation specifications for output changes due to heating effects.
Load regulation is measured on the output pin at a point 1/8" below the
base of the K and H package and at the junction of the wide and narrow
portion of the lead on the M and T package.
Note 5: Load regulation for the LT337AT is the same as for LM337T.
Note 6: Guaranteed on LT137A and LT337A, but not 100% tested in
production.
Note 7: ISC is tested at the ambient temperatures of 25°C and –55°C. ISC
cannot be tested at the maximum ambient temperature of 150°C due to the
high power level required. ISC specification at 150°C ambient is guaranteed
by characterization and correlation to 25°C testing.
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4
LT137A/LM137
LT337A/LM337
TYPICAL PERFORMANCE CHARACTERISTICS
Dropout Voltage
Temperature Stability
3.0
Minimum Load Current
1.270
1.8
Tj = 25°C
1.8
Tj = 150°C
1.4
Tj = –55°C
1.4
1.260
CURRENT (mA)
Tj = –55°C
2.2
REFERENCE VOLTAGE (V)
INPUT-OUTPUT DIFFERENTIAL
1.6
2.6
1.250
1.240
1.2
1.0
Tj = 25°C
0.8
0.6
Tj = 150°C
0.4
0.2
1.0
0.4
0.8
1.2
1.6
OUTPUT CURRENT (A)
2.0
1.230
–75 –50 –25
0
0 25 50 75 100 125 150
TEMPERATURE (°C)
137A G01
Ripple Rejection
CADJ = –10μF
CADJ = 0
40
|V – VOUT| = 5V
20 I IN
L = 500mA
f = 120Hz
Tj = 25°C
0
–10
–20
–30
0
OUTPUT VOLTAGE (V)
–40
137A G04
Ripple Rejection
100
100
80
80
60
CADJ = 10μF
40
CADJ = 0
V = –15V
20 VIN = –10V
OUT
IL = 500mA
Tj = 25°C
0
10
100
40
137A G03
Ripple Rejection
RIPPLE REJECTION (dB)
RIPPLE REJECTION (dB)
60
10
20
30
INPUT-OUTPUT DIFFERENTIAL (V)
137A G02
100
80
0
RIPPLE REJECTION (dB)
0
1k
10k
FREQUENCY (Hz)
100k
1M
137A G05
60
CADJ = 10μF
CADJ = 0
40
V = –15V
20 VIN = –10V
OUT
f = 120Hz
Tj = 25°C
0
0.1
1
0.01
OUTPUT CURRENT (A)
10
137A G06
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5
LT137A/LM137
LT337A/LM337
TYPICAL PERFORMANCE CHARACTERISTICS
Output Impedance
Line Transient Response
CADJ = 0
Load Transient Response
0.6
0.6
0.4
0.4
OUTPUT VOLTAGE
DEVIATION (V)
0.8
CADJ = 0
0.2
0
CADJ = 10μF
–0.2
CADJ = 10μF
10–3
10
100
1k
10k
FREQUENCY (Hz)
100k
1M
VOUT = –10V
IL = 50mA
CL = 1μF
Tj = 25°C
0
–0.5
–1.0
0
10
20
TIME (μs)
30
137A G07
–0.4
40
–1.0
–1.5
0
OUTPUT CURRENT (A)
–0.2
10
20
TIME (μs)
2
30
40
137A G09
Adjustment Current
Tj = –55°C
Tj = 25°C
Tj = 150°C
0.4
0
VIN = –15V
VOUT = –10V
INL = 50mA
CL = 1μF
Tj = 25°C
0
–0.5
Current Limit
3
0.2
CADJ = 10μF
137A G08
Load Regulation*
OUTPUT VOLTAGE DEVIATION (%)
0
–0.2
M, T AND K
PACKAGES
1
H
PACKAGE
80
ADJUSTMENT CURRENT (μA)
10–2
CADJ = 0
0.2
–0.6
–0.4
LOAD CURRENT (A)
10–1
OUTPUT VOLTAGE
DEVIATION (V)
VIN = –15V
VOUT = –10V
IL = 500mA
CL = 1μF
100
Tj = 25°C
INPUT VOLTAGE
CHANGE (V)
OUTPUT IMPEDANCE (Ω)
101
75
70
65
60
55
–0.4
0
0.4
0.8
1.2
1.6
OUTPUT CURRENT (A)
2.0
137A G10
0
0
10
20
30
INPUT-OUTPUT DIFFERENTIAL (V)
40
137A G11
50
–75 –50 –25
0 25 50 75 100 125 150
TEMPERATURE (°C)
137A G12
*THE LT137A/LT337A HAS LOAD REGULATION
COMPENSATION WHICH MAKES THE TYPICAL
UNIT READ CLOSE TO ZERO. THIS BAND
REPRESENTS THE TYPICAL PRODUCTION
SPREAD.
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LT137A/LM137
LT337A/LM337
APPLICATIONS INFORMATION
Output Voltage
EXAMPLES:
The output voltage is determined by two external resistors, R1 and R2 (see Figure 1). The exact formula for the
output voltage is:
1. A precision 10V regulator to supply up to 1A load
current.
⎛ R2 ⎞
VOUT = VREF ⎜ 1+ ⎟ + IADJ (R2)
⎝ R1⎠
b. Calculate R2 =
Where: VREF = Reference Voltage, IADJ = Adjustment Pin
Current. In most applications, the second term is small
enough to be ignored, typically about 0.5% of VOUT. In
more critical applications, the exact formula should be
used, with IADJ equal to 65μA. Solving for R2 yields:
R2 =
VOUT – VREF
VREF
+I
R1 ADJ
The maximum value for the operating current, which must
be absorbed, is 5mA for the LT137A. If input-output voltage differential is less than 10V, the operating current that
must be absorbed drops to 3mA.
+
C1
10μF
R2
+
IADJ
C2
5μF
VREF
ADJ
–VIN
VIN
VOUT – VREF 10 V – 1.25V
=
= 696.4Ω
VREF
1.25V
+ 65μA
+ IADJ
100Ω
R1
Use R2 = 698Ω
2. A 15V regulator to run off batteries and supply
50mA. VIN MAX = 25V
a. To minimize battery drain, select R1 as high as
possible
Smaller values of R1 and R2 will reduce the influence
of IADJ on the output voltage, but the no-load current
drain on the regulator will be increased. Typical values
for R1 are between 100Ω and 300Ω, giving 12.5mA and
4.2mA no-load current respectively. There is an additional
consideration in selecting R1, the minimum load current
specification of the regulator. The operating current of the
LT137A flows from input to output. If this current is not
absorbed by the load, the output of the regulator will rise
above the regulated value. The current drawn by R1 and
R2 is normally high enough to absorb the current, but
care must be taken in no-load situations where R1 and
R2 have high values.
+
a. Select R1 = 100Ω to minimize effect of IADJ
LT137A VOUT
137A F01
Figure 1
C3
1μF
R1
–VOUT
R1=
1.25V
= 417Ω, use 402Ω, 1%
3mA
b. The high value for R1 will exaggerate the error due
to IADJ, so the exact formula to calculate R2 should
be used.
R2 =
VOUT – VREF 15V – 1.25V
=
= 4331Ω
VREF
1.25V
+ 65μA
+I
R1 ADJ 402Ω
Use R2 = 4320Ω
Capacitors and Protection Diodes
An output capacitor, C3, is required to provide proper frequency compensation of the regulator feedback loop. A 1μF
or larger solid tantalum capacitor is generally sufficient for
this purpose if the 1MHz impedance of the capacitor is 2Ω
or less. High Q capacitors, such as Mylar, are not recommended because they tend to reduce the phase margin at
light load currents. Aluminum electrolytic capacitors may
also be used, but the minimum value should be 10μF to
ensure a low impedance at 1MHz. The output capacitor
should be located within a few inches of the regulator to
keep lead impedance to a minimum. The following caution
should be noted: if the output voltage is greater than 6V
and an output capacitor greater than 20μF has been used,
it is possible to damage the regulator if the input voltage
137afb
7
LT137A/LM137
LT337A/LM337
APPLICATIONS INFORMATION
becomes shorted, due to the output capacitor discharging
into the regulator. This can be prevented by using the diode
D1 (see Figure 2) between the input and the output.
The input capacitor, C2, is only required if the regulator is
more than 4 inches from the raw supply filter capacitor.
Bypassing the Adjustment Pin
The adjustment pin of the LT137A may be bypassed with a
capacitor to ground, C1, to reduce output ripple, noise, and
impedance. These parameters scale directly with output
voltage if the adjustment pin is not bypassed. A bypass
capacitor reduces ripple, noise, and impedance to that of
a 1.25V regulator. In a 15V regulator, for example, these
parameters are improved by 15V/1.25V = 12 to 1. This
improvement holds only for those frequencies where the
impedance of the bypass capacitor is less than R1. Ten
microfarads is generally sufficient for 60Hz power line
applications where the ripple frequency is 120Hz since
XC = 130Ω. The capacitor should have a voltage rating at
least as high as the output voltage of the regulator. Values
larger than 10μF may be used, but if the output is larger
than 25V, a diode, D2, should be added between the output
and adjustment pins (see Figure 2).
Proper Connection of Divider Resistors
The LT137A has an excellent load regulation specification
of 0.5% and is measured at a point 1/8" from the bottom
of the package. To prevent degradation of load regulation,
the resistors which set output voltage, R1 and R2, must be
connected as shown in Figure 3. Note that the positive side
of the load has a true force and sense (Kelvin) connection,
but the negative side of the load does not.
R1 should be connected directly to the output lead of the
regulator, as close as possible to the specified point 1/8"
from the case. R2 should be connected to the positive
side of the load separately from the positive (ground)
connection to the raw supply. With this arrangement, load
regulation is degraded only by the resistance between the
regulator output pin and the load. If R1 is connected to
the load, regulation will be degraded.
LEAD RESISTANCE HERE DOES
NOT AFFECT LOAD REGULATION
R2
LOAD
R1
ADJ
+
–VIN
R2
C1
LT137A VOUT
137A F03
+
+
C3
C2
R1
ADJ
–VIN
VIN
VIN
LT137A VOUT
D2**
1N4002
–VOUT
CONNECT R1
DIRECTLY TO
REGULATOR PIN
LEAD RESISTANCE HERE
DEGRADES LOAD REGULATION.
MINIMIZE THE LENGTH OF
THIS LEAD.
Figure 3
137A F02
D1*
1N4002
*D1 PROTECTS THE REGULATOR FROM INPUT SHORTS TO GROUND. IT IS
REQUIRED ONLY WHEN C3 IS LARGER THAN 20μF AND VOUT IS LARGER THAN 6V.
**D2 PROTECTS THE ADJUST PIN OF THE REGULATOR FROM OUTPUT SHORTS
IF C2 IS LARGER THAN 10μF AND VOUT IS LARGER THAN –25V.
Figure 2
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8
LT137A/LM137
LT337A/LM337
TYPICAL APPLICATIONS
A high stability regulator is illustrated in the application
circuit shown to the right. The output stability, load regulation, line regulation, thermal regulation, temperature drift,
long term drift, and noise can be improved by a factor of
6.6 over the standard regulator configuration. This assumes
a zener whose drift and noise is considerably better than
the regulator itself. The LM329B has 20ppm/°C maximum
drift and about 10 times lower noise than the regulator.
In the application shown below, regulators #2 to “N” will
track regulator #1 to within ±24mV initially, and to ±60mV
over all load, line, and temperature conditions. If any
regulator output is shorted to ground, all other outputs will
drop to approximately ≈ –2V. Load regulation of regulators 2 to “N” will be improved by VOUT/1.25V compared
to a standard regulator, so regulator #1 should be the one
which has the lowest load current.
High Stability Regulator
7V
LM329B
+
R3
1.5k
1%
VIN
LT137A VOUT
137A TA03
+VIN
VIN
ADJ
VIN
–VIN
R1**
100Ω
1%
REG #1 VOUT
R4
5k
1%
+
C1
1μF
SOLID
TANTALUM
10μF
ADJ
–VIN
+
+
2μF
1N4002
ADJ
REG #2 VOUT
VIN
1μF
SOLID
TANTALUM
+
2.2μF*
D1
1N4002
2.2μF*
D2
1N4002
+
R5**
100Ω
1%
–VOUT1
137A TA02
– 908Ω
R3
5k
R2
R1
120Ω
|VOUT|
9.08 • 10–3
+VOUT
R2
5k
1%
LT137A
VIN
*R2 =
ADJ
+
1N4002
–VOUT
LT317A VOUT
+
2μF
1μF
SOLID
TANTALUM
Dual Tracking Supply ±1.25V to ±20V
10μF
+
R1
1k
1%
ADJ
–VIN
Multiple Tracking Regulators
C3
10μF
R2*
LT337A VOUT
–VOUT
137A TA04
*SOLID TANTALUM
**R1 OR R5 MAY BE TRIMMED SLIGHTLY TO IMPROVE TRACKING
–VOUT2
Current Regulator
LT137A
137A TA02
+
+
2μF
ADJ
VIN
+
1μF
SOLID
TANTALUM
ADJ
(–)
REG #N VOUT
VIN
LT337A VOUT
137A TA02
(+)
RS
–VOUT3
137A TA05
LT137A
C1
1μF
SOLID TANTALUM
I
I = 65μA +
1.25V
RS
(0.8Ω < RS < 250Ω)
137afb
9
LT137A/LM137
LT337A/LM337
SCHEMATIC DIAGRAM
ADJ
2k
Q1
Q2
2k
D4
Q3
20k
Q4
15pF
Q5
D1
Q6
D2
D3
750Ω
100k
600Ω
800Ω
Q32 Q34
60k
Q7
VOUT
5k
15pF
25pF
220Ω
2k
Q11
Q33
18k
Q12
Q10
Q9
Q8
100k
D5
20Ω
20Ω
Q13
Q25
Q26
4k
6.8k
12k
250Ω
Q23
480Ω
12k
5pF
Q22
Q21
2pF
15k
12k
Q20
Q18
Q24
Q19
150Ω
1k
Q14
Q27
Q28
Q31
Q30
270Ω
Q16
100Ω
0.02Ω
2k
Q17
8k
20k
Q29
6k
Q15
600Ω
10Ω
4.2k
4k
1k
100Ω
1k
2.4k
500Ω
VIN
137A SD
137afb
10
LT137A/LM137
LT337A/LM337
PACKAGE DESCRIPTION
OBSOLETE PACKAGES
H Package
3-Lead TO-39 Metal Can
(Reference LTC DWG # 05-08-1330)
.350 – .370
(8.890 – 9.398)
.305 – .335
(7.747 – 8.509)
.050
(1.270)
MAX
.165 – .185
(4.191 – 4.699)
REFERENCE
PLANE
*
.016 – .019**
(0.406 – 0.483)
DIA
.500
(12.700)
MIN
.200
(5.080)
TYP
.100
(2.540)
PIN 1
.029 – .045
(0.737 – 1.143)
.100
(2.540)
.028 – .034
(0.711 – 0.864)
45o
H3(TO-39) 0801
*LEAD DIAMETER IS UNCONTROLLED BETWEEN THE REFERENCE PLANE
AND .050" BELOW THE REFERENCE PLANE
.016 – .024
**FOR SOLDER DIP LEAD FINISH, LEAD DIAMETER IS
(0.406 – 0.610)
K Package
2-Lead TO-3 Metal Can
(Reference LTC DWG # 05-08-1310)
.760 – .775
(19.30 – 19.69)
.320 – .350
(8.13 – 8.89)
.060 – .135
(1.524 – 3.429)
.420 – .480
(10.67 – 12.19)
.038 – .043
(0.965 – 1.09)
1.177 – 1.197
(29.90 – 30.40)
.655 – .675
(16.64 – 17.15)
.210 – .220
(5.33 – 5.59)
.151 – .161
(3.86 – 4.09)
DIA, 2PLCS
.167 – .177
(4.24 – 4.49)
R
.425 – .435
(10.80 – 11.05)
.067 – .077
(1.70 – 1.96)
.490 – .510
(12.45 – 12.95)
R
K2 (TO-3) 0801
137afb
Information furnished by Linear Technology Corporation is believed to be accurate and reliable.
However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights.
11
LT137A/LM137
LT337A/LM337
PACKAGE DESCRIPTION
M Package
3-Lead Plastic DD Pak
(Reference LTC DWG # 05-08-1460)
.060
(1.524)
TYP
.390 – .415
(9.906 – 10.541)
.165 – .180
(4.191 – 4.572)
15° TYP
.045 – .055
(1.143 – 1.397)
.330 – .370
(8.382 – 9.398)
.218 – .252
(5.537 – 6.401)
.520 – .570
(13.208 – 14.478)
.090 – .110
(2.286 – 2.794)
.013 – .023
(0.330 – 0.584)
.050
(1.270)
TYP
.028 – .038
(0.711 – 0.965)
.095 – .115
(2.413 – 2.921)
.420
.080
.420
.276
.325
.350
.205
.565
.565
.320
.090
.090
.100 BSC
.070 TYP
.100 BSC
RECOMMENDED SOLDER PAD LAYOUT
.070 TYP
RECOMMENDED SOLDER PAD LAYOUT
FOR THICKER SOLDER PASTE APPLICATIONS
NOTE:
1. DIMENSIONS IN INCH/(MILLIMETER)
2. DRAWING NOT TO SCALE
M(DD3) (STRAIGHT) 0801
T Package
3-Lead Plastic TO-220
(Reference LTC DWG # 05-08-1420)
.147 – .155
(3.734 – 3.937)
DIA
.390 – .415
(9.906 – 10.541)
.165 – .180
(4.191 – 4.572)
.045 – .055
(1.143 – 1.397)
.230 – .270
(5.842 – 6.858)
.460 – .500
(11.684 – 12.700)
.570 – .620
(14.478 – 15.748)
.330 – .370
(8.382 – 9.398)
.980 – 1.070
(24.892 – 27.178)
.520 – .570
(13.208 – 14.478)
.100
(2.540)
BSC
.218 – .252
(5.537 – 6.401)
.013 – .023
(0.330 – 0.584)
.028 – .038
(0.711 – 0.965)
.050
(1.270)
TYP
.095 – .115
(2.413 – 2.921)
T3 (TO-220) 0801
137afb
12 Linear Technology Corporation
LT 0807 REV B • PRINTED IN USA
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