ETC UC2836D

UC1835 UC1836
UC2835 UC2836
UC3835 UC3836
High Efficiency Regulator Controller
FEATURES
DESCRIPTION
•
Complete Control for a High Current,
Low Dropout, Linear Regulator
•
Fixed 5V or Adjustable Output Voltage
•
Accurate 2.5A Current Limiting with
Foldback
•
Internal Current Sense Resistor
The UC1835/6 families of linear controllers are optimized for the design of low cost, low dropout, linear regulators. Using an external pass
element, dropout voltages of less than 0.5V are readily obtained.
These devices contain a high gain error amplifier, a 250mA output
driver, and a precision reference. In addition, current sense with foldback provides for a 2.5A peak output current dropping to less than
0.5A at short circuit.
•
Remote Sense for Improved Load
Regulation
•
External Shutdown
•
Under-Voltage Lockout and Reverse
Voltage Protection
•
Thermal Shutdown Protection
•
8 Pin Mini-Dip Package
(Surface Mount also Available)
BLOCK DIAGRAM
Note: Pin numbers refer to 8-Pin DIL Package
8/94
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These devices are available in fixed, 5V, (UC1835), or adjustable,
(UC1836), versions. In the fixed 5 volt version, the only external parts
required are an external pass element, an output capacitor, and a compensation capacitor. On the adjustable version the output voltage can
be set anywhere from 2.5V to 35V with two external resistors.
Additional features of these devices include under-voltage lockout for
predictable start-up, thermal shutdown and short circuit current limiting
to protect the driver device. On the fixed voltage version, a reverse
voltage comparator minimizes reverse load current in the event of a
negative input to output differential.
UC1835 UC1836
UC2835 UC2836
UC3835 UC3836
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Supply Voltage (+VIN) . . . . . . . . . . . . . . . . –1.0V to + 40V
Driver Output Current (Sink or Source) . . . . . . . . . . . . . 600mA
Driver Source to Sink Voltage . . . . . . . . . . . . . . . . . . . . . + 40V
Maximum Current Through Sense Resistor. . . . . . . . . . . . . . 4A
VOUT Sense Input Voltage . . . . . . . . . . . . . . . . . . –.3V to + 40V
Power Dissipation at TA = 25°C (Note 2) . . . . . . . . . . . 1000mW
Power Dissipation at TC = 25°C (Note 2) . . . . . . . . . . . 2000mW
Operating Junction Temperature . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C
Note 1: Voltages are referenced to ground, (Pin 3). Currents are
positive into, negative out of, the specified terminals.
Consult Packaging Section of Databook for thermal
considerations and limitations of packages.
CONNECTION DIAGRAMS
DIL-8, SOIC-8 (TOP VIEW)
N or J Package, D Package
PLCC-20, LCC-20
(TOP VIEW)
Q, L Packages
PACKAGE PIN FUNCTION
FUNCTION
PIN
N/C
+VIN
+VIN
N/C
Compensation/
Shutdown
N/C
Ground
N/C
N/C
Driver Source
N/C
VOUT Sense
N/C
N/C
Driver Sink
N/C
Current Limit (-)
N/C
Sense Resistor Out
Sense Resistor Out
SOIC-16 (TOP VIEW)
DW Package
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, specifications hold for TA = 0°C to + 70°C for the
UC3835/6, –25°C to + 85°C for the UC2835/6, and –55°C to +125°C for the
UC1835/6, +VIN = 6V, Driver Source= 0V, Driver Sink = 5V, TA = TJ.
PARAMETER
Input Supply
Supply Current
TEST CONDITIONS
+VIN = 6V
+VIN = 40V
+VIN Low to High, VOUT Sense = 0V
UVLO Threshold
Threshold Hysteresis
Reverse Current
+VIN = -1.0V, Driver Sink Open
Regulating Voltage and Error Amplifier (UC1835 Family Only)
Driver Current = 10mA, TJ = 25°C
Regulating Level at VOUT Sense (VREG)
Over Temperature
Line Regulation
+VIN = 5.2V + 35V
Load Regulation
Driver Current = 0 to 250mA
VOUT Sense = 5.0V
Bias Current at VOUT Sense
Error Amp Transconductance
±100µA at Compensation/Shutdown Pin
Maximum Compensation Output Current
Sink or Source, Driver Source Open
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MIN.
TYP.
MAX. UNITS
3.9
2.75
3.75
4.4
0.1
6.0
4.0
6.0
4.9
0.35
20
mA
mA
V
V
mA
5.0
5.06
5.1
40
25
210
2.0
260
V
V
mV
mV
µA
mS
µA
4.94
4.9
75
0.8
90
15
6.0
125
1.3
200
UC1835 UC1836
UC2835 UC2836
UC3835 UC3836
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, specifications hold for TA = 0°C to + 70°C for the
UC3835/6, –25°C to + 85°C for the UC2835/6, and –55°C to +125°C for the
UC1835/6, +VIN = 6V, Driver Source= 0V, Driver Sink = 5V, TA = TJ.
PARAMETER
TEST CONDITIONS
MIN. TYP.
Regulating Voltage and Error Amplifier (UC1836 Family Only)
Driver Current = 10mA, TJ = 25°C
2.47
2.5
Regulating Level at VOUT Sense (VREG)
Over Temperature
2.45
6.0
Line Regulation
+VIN = 5.2V to 35V
Load Regulation
Driver Current = 0 to 250mA
3.0
VOUT Sense =2.5V
-1.0
-0.2
Bias Current at VOUT Sense
Error Amp Transconductance
±100µA at Compensation/Shutdown Pin
0.8
1.3
Maximum Compensation Output Current
Sink or Source, Driver Source Open
90
200
Driver
Maximum Current
250
500
Saturation Voltage
Driver Current = 250mA, Driver Sink
2.0
Pull-Up Current at Driver Sink
Compensation/Shutdown=0.45V
140
250
Driver Sink Leakage
In UVLO
In Reverse Voltage (UC1835 Family Only)
Thermal Shutdown
165
Foldback Current Limit
2.2
2.5
Current Limit Levels at Sense Resistor Out
VOUT Sense = (0.99) VREG
VOUT Sense = (0.5) VREG
1.3
1.5
0.25
0.4
VOUT Sense = 0V
12
24
Current Limit Amp Tansconductance
±100µA at Compensation/Shutdown,
VOUT Sense = (0.9) VREG
Limiting Voltage at Current Limit (-)
VOUT Sense = (0.9) VREG
80
100
(Note 2)
Volts Below +VIN, TJ = 25°C
Sense Resistor Value (Note 3)
VOUT Sense = (0.9) VREG,
40
IOUT = IA, TJ = 25°C
Note 2: This voltage has a positive temperature coefficient of approximately 3500ppm/°C.
Note 3: This resistance has a positive temperature coefficient of approximately 3500ppm/°C.
The total resistance from Pin 1 to Pin 8 will include an additional 60 to 100mΩ of package resistance.
MAX. UNITS
2.53
2.55
20
15
2.0
260
2.8
300
10
10
mA
V
µA
µA
µA
°C
2.8
1.7
0.55
42
A
A
A
mS
140
mV
APPLICATION AND OPERATION INFORMATION
UC 1835 − Typical configurations for a 2A,
Low Dropout 5V Regulator
UC1836 − Typical Configuration for a 2A,
Low Dropout Adjustable Regulator
Note 4: Suggested Pass devices are TIP 32B. (Dropout Voltage ≤0.75V) or, D45H, (Dropout Voltage ≤0.5V), or equivalents.
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V
V
mV
mV
µA
mS
µA
mΩ
UC1835 UC1836
UC2835 UC2836
UC3835 UC3836
APPLICATION AND OPERATION INFORMATION (cont.)
UC1835/6 Foldback Current Limiting
UC3835/36 TYPICAL APPLICATIONS
Low Current Application
Typical Output Current vs VIN and VOUT
using the UC3836 internal drive transistor
of the UC3836 internal drive transistor
for PDISS = 0.5W (approx.)
High Current Application
Parallel Pass Transistors
using drive transistor Q2 to increase Q1 base drive
and reduce UC3836 power dissipation
can be added for high current or
high power dissipation applications
EQUATIONS:
R1 = 0.100 V/IOUT (MAX)
R2 = (VOUT - 2.5V/1mA)
R3 = ((VIN - VBE - VSAT)*BETA(min))/IOUT (max)
UNITRODE INTEGRATED CIRCUITS
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX 603-424-3460
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