Texas Instruments UC1838AL883B, UC1838AL, UC1838AJ883B, UC1838AJ Datasheet

UC1838A UC2838A UC3838A
Magnetic Amplifier Controller
FEATURES
Independent 1% Reference
Two Uncommitted, Identical
Operational Amplifiers
100mA Reset Current Source with –120V Capability
5W DIL Package
10VCC
VREF
9
2.5V
REFERENCE
INV. IN
8E/A OUT
3INV. IN
6
7N.I. IN
2
1
N.I. IN
C/L OUT
C/L
E/A
3.5V
15 DR 1
16 DR 2
RESET
14
VM11
5 12 134
GND GND GND GND
201k5k
BLOCK DIAGRAM
04/99
UDG-97174
DESCRIPTION
The UC1838A family of magnetic amplifier controllers contains the circuitry to gen­erate and amplify a low-level analog error signal along with a high volt­age-compliant current source. This source will provide the reset current necessary to enable a magnetic amplifier to regulate and control a power supply output in the range of 2A to 20A.
By controlling the reset current to a magnetic amplifier, this device will define the amount of volt-seconds the magnetic amplifier will block before switching to the conducting state. Magnetic amplifiers are ideal for post-regulators for multi­ple-output power supplies where each output can be independently controlled with efficiencies up to 99%. With a square or pulse-width-modulated input voltage, a magnetic amplifier will block a portion of this input waveform, allowing just enough to pass to provide a regulated output. With the UC1838A, only the magnetic ampli­fier coil, three diodes, and an output L-C filter are necessary to implement a com­plete closed-loop regulator.
The UC1838A contains a precision 2.5V reference, two uncommitted high-gain op amps and a high-gain PNP-equivalent current source which can deliver up to 100mA of magnetic amplifier reset current and with –120 volt capability.
These devices are available in a plastic “bat-wing” DIP for operation over a –20°C to +85°C temperature range and, with reduced power, in a hermetically sealed cerdip for –55°C to +125°C operation.Surface mount versions are also available.
This improved “A”version replaced the non “A” version formerly introduced.
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UC1838A UC2838A UC3838A
ABSOLUTE MAXIMUM RATINGS
Supply Voltage, V
CC
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
40V
Magnetic Amp. Source Voltage, V
M
. . . . . . . . . . . . . . . . . . . . . . . .
40V
Reset Output Voltage, V
R
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
–120V
Total Current Source Voltage, VM-V
R
. . . . . . . . . . . . . . . . . .
–140V
Amplifier Input Range . . . . . . . . . . . . . . . . . . . . . . –0.3V to V
CC
Reset Input Current, I
DR
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
–10mA
Power Dissipation at TA= 25°C
Q, N, DP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2W
J, L Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1W
Power Dissipation at T (leads/case) = 25°C
Q, N, DP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5W
J, L Package. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2W
Operating Temperature Range. . . . . . . . . . . . –55°C to +125°C
Storage Temperature Range . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 sec) . . . . . . . . . . . . . . 300°C
Note: All voltages are with respect to ground pins. All currents are positive into the specified terminal. Consult Packaging section of Databook for thermal limitations and considerations of package.
DR 216
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
DR 1
Reset
Gnd
Gnd
V
M
V
CC
V
REF
C/L Out
C/L N.I. In
C/L INV. In
Gnd
Gnd
E/A Inv.In
E/A N.I. In
E/A Out
CONNECTION DIAGRAMS
DIL-16, SOIC-16 (TOP VIEW) J or N Package, DP Package
3
18 17 16
N/C
122019
15 14
4 5 6 7 8
91110 12 13
C/L Out
C/L N.I. In
DR2 DR1
Reset N/C N/C GND V
M
C/L Inv. In
GND
N/C N/C
E/A Inv. In
V
CC
V
REF
N/C
E/A N.I. In
E/A Out
PLCC-20, LCC-20 (TOP VIEW) Q, L Packages
Note: All four ground pins must be connected to a common ground
TEMPERATURE RANGE PACKAGE
UC1838AJ –55°C to +125°C Ceramic Dip UC1838AL CLCC UC2838ADP –20°C to +85°C Power SOIC UC2838AN Plastic Dip UC2838AQ PLCC UC3838ADP 0°C to +70°C Power SOIC UC3838AN Plastic Dip UC3838AQ PLCC
ORDERING INFORMATION
3
UC1838A UC2838A UC3838A
ELECTRICAL CHARACTERISTICS:
Unless otherwise stated, these specifications apply for TA= –55°C to +125°C for the
UC1838A, –20°C to +85°C for the UC2838A, and 0°C to +70°C for the UC3838A, VCC= 20V, VM= 5V, TA=T
J
.
PARAMETER TEST CONDITIONS
UC1838A / UC2838A UC3838A UNITS
MIN TYP MAX MIN TYP MAX
Reference Section
Supply Current V
CC=VM
= 40V 4 8 4 8 mA
Reference Output T
A
= 25°C 2.47 2.5 2.53 2.45 2.5 2.55 V
Line Regulation V
CC
= 5 to 30V 1 5 1 10 mV
Load Regulation I
O
= 0 to –2mA 5 20 5 20 mV
Short Circuit Current V
REF
= 0V –30 –60 –30 –60 mA
Temperature Stability* Over Operating Temp. Range 15 25 10 25 mV
Amplifier Section (Each Amplifier)
Offset Voltage V
CM
= 2.5V 5 10 mV
Input Bias Current V
IN
= 0V –1 –1
µ
A Input Offset Current 100 100 nA Minimum Output Swing 0.4 18 0.4 18 V Output Sink Current V
O
= 5V 1103011030mA
Output Source Current V
O
= 0V –1 –10 –20 –1 –10 –20 mA
A
VOL
VO= 1 to 11V 100 120 100 120 dB
C
MRR
VIN= 1 to 11V 70 80 70 80 dB
P
SRR
VCC= 10 to 20V 70 100 70 100 dB
Gain Bandwidth* 0.6 0.8 0.6 0.8 MHz
Reset Drive Section
Input Leakage V
DR
= 40V 10 10
µ
A Output Leakage V
R
= –120V –100 –100
µ
A Input Current I
R
= –50mA –1 –2 –1 –2 mA
Maximum Reset Current I
DR
= –3mA –100 –120 –200 –100 –120 –200 mA
Transconductance I
R
= –10 to –50mA .03 .042 .055 .03 .042 .055 A/V
* These parameters are guaranteed by design but not 100% tested in production.
TYPICAL APPLICATION
+12V, 4A output with switching frequency = 50 kHz.
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UC1838A UC2838A UC3838A
APPLICATION INFORMATION
Figure 1. Amplifier open loop response.
Figure 2. Reset driver-input current.
Figure 5. Reset driver-input voltage.
Figure 3. Reset driver-output impedance. Figure 6. Reference temperature coefficient.
UNITRODE CORPORATION 7 CONTINENTAL BLVD. • MERRIMACK, NH 03054 TEL. (603) 424-2410 • FAX (603) 424-3460
Figure 4. Reset driver response.
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Copyright 1999, Texas Instruments Incorporated
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