UC2833L [ETC]
Positive Adjustable Voltage Regulator ; 正,可调式稳压器\n型号: | UC2833L |
厂家: | ETC |
描述: | Positive Adjustable Voltage Regulator
|
文件: | 总8页 (文件大小:762K) |
中文: | 中文翻译 | 下载: | 下载PDF数据表文档文件 |
UC1832/3
UC2832/3
UC3832/3
Precision Low Dropout Linear Controllers
FEATURES
DESCRIPTION
•
Precision 1% Reference
The UC1832 and UC1833 series of precision linear regulators include all the
control functions required in the design of very low dropout linear regulators.
Additionally, they feature an innovative duty-ratio current limiting technique
which provides peak load capability while limiting the average power dissipa-
tion of the external pass transistor during fault conditions. When the load cur-
rent reaches an accurately programmed threshold, a gated-astable timer is
enabled, which switches the regulator’s pass device off and on at an externally
programmable duty-ratio. During the on-time of the pass element, the output
current is limited to a value slightly higher than the trip threshold of the duty-ra-
tio timer. The constant-current-limit is programmable on the UCx832 to allow
higher peak current during the on-time of the pass device. With duty-ratio con-
trol, high initial load demands and short circuit protection may both be accom-
modated without extra heat sinking or foldback current limiting. Additionally, if
the timer pin is grounded, the duty-ratio timer is disabled, and the IC operates
in constant-voltage/constant-current regulating mode.
•
Over-Current Sense Threshold
Accurate to 5%
•
Programmable Duty-Ratio
Over-Current Protection
•
•
4.5V to 36V Operation
100mA Output Drive, Source or
Sink
•
Under-Voltage Lockout
Additional Features of the UC1832
series:
•
Adjustable Current Limit to
Current Sense Ratio
These IC’s include a 2 Volt (±1%) reference, error amplifier, UVLO, and a high
current driver that has both source and sink outputs, allowing the use of either
NPN or PNP external pass transistors. Safe operation is assured by the inclu-
sion of under-voltage lockout (UVLO) and thermal shutdown.
•
•
Separate +VIN terminal
Programmable Driver Current
Limit
The UC1833 family includes the basic functions of this design in a low-cost, 8-
pin mini-dip package, while the UC1832 series provides added versatility with
the availability of 14 pins. Packaging options include plastic (N suffix), or ce-
ramic (J suffix). Specified operating temperature ranges are: commercial (0°C
to 70°C), order UC3832/3 (N or J); industrial (–25°C to 85°C), order UC2832/3
(N or J); and military (–55°C to 125°C), order UC1832/3J. Surface mount
packaging is also available.
•
•
Access to VREF and E/A(+)
Logic-Level Disable Input
BLOCK DIAGRAMS
UDG-92040
6/94
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UC1832/3
UC2832/3
UC3832/3
ABSOLUTE MAXIMUM RATINGS
Supply Voltage +VIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40V
Driver Output Current (Sink or Source) . . . . . . . . . . . . . 450mA
Driver Sink to Source Voltage . . . . . . . . . . . . . . . . . . . . . . . 40V
TRC Pin Voltage. . . . . . . . . . . . . . . . . . . . . . . . . . –0.3V to 3.2V
Other Input Voltages. . . . . . . . . . . . . . . . . . . . . . . –0.3V to +VIN
Operating Junction Temperature (note 2) . . . –55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . –65°C to +150°C
Lead Temperature (Soldering, 10 Seconds) . . . . . . . . . . 300°C
Note 1: Unless otherwise indicated, voltages are referenced to
ground and currents are positive into, negative out of, the speci-
fied terminals.
Note 2: See Unitrode Integrated Circuits databook for
information regarding thermal specifications and limitations of
packages.
CONNECTION DIAGRAMS
UC1832
UC1833
DIL-14 (Top View)
J Or N Package
DIL-8 (Top View)
J Or N Package
SOIC-16 (Top View)
DW Package
SOIC-16 (Top View)
DW Package
PACKAGE PIN FUNCTION
PACKAGE PIN FUNCTION
LCC-20 & PLCC-20
L & Q Package
(Top View)
LCC-20 & PLCC-20
L & Q Package
(Top View)
FUNCTION
PIN
FUNCTION
PIN
N/C
1
+VIN & C/S(+)
1
+VIN
2
N/C
2
Comp/Shutdown
E/A(+)
3
4
N/C
3
N/C
4
+2V REF
N/C
5
6
Comp/Shutdown
5
Gnd
6
Gnd
7
N/C
7
Logic Disable
Limit
8
9
N/C
8
N/C
9
Source
N/C
E/A(-)
Sink
VADJ
N/C
Timer RC
Current Sense(-)
Current Sense(+)
10
11
12
13
14
15-17
18
19
20
Source
N/C
E/A(-)
N/C
N/C
Sink
Timer RC
Current Sense(+)
N/C
10
11
12
13
14
15
16
17
18-20
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UC1832/3
UC2832/3
UC3832/3
Unless otherwise stated, specifications hold for TA = 0°C to 70°C for the
UC3832/3, –25°C to 85°C for the UC2832/3, and –55°C to 125°C for the
UC1832/3, +VIN = 15V, Driver sink = +VIN, C/S(+) voltage = +VIN. TA=TJ.
ELECTRICAL CHARACTERISTICS:
PARAMETER
Input Supply
TEST CONDITIONS
MIN
TYP
MAX UNITS
Supply Current
+VIN = 6V
+VIN = 36V
6.5
9.5
3.3
10
15
mA
mA
mA
Logic Disable = 2V (UCx832 only)
Reference Section
Output Voltage (Note 3)
TJ = 25°C, IDRIVER = 10mA
over temperature, IDRIVER = 10mA
IOUT = 0 to 10mA
1.98
1.96
-10
2.00 2.02
V
V
2.00
-5.0
2.04
Load Regulation (UCx832 only)
Line Regulation
mV
mV/V
V
+VIN = 4.5 to 36V, IDRIVER = 10mA
0.033 0.5
Under-Voltage Lockout Threshold
Logic Disable Input (UCx832 only)
Threshold Voltage
3.6
4.5
1.3
1.4
1.5
V
Input Bias Current
Logic Disable = 0V
Over Temperature
-5.0
-1.0
µA
Current Sense Section
Comparator Offset
95
93
100
100
135
135
235
305
100
105
107
170
170
290
360
135
10
mV
mV
mV
mV
mV
mV
µA
Amplifier Offset (UCx833 only)
Amplifier Offset (UCx832 only)
110
110
180
250
65
VADJ = Open
VADJ = 1V
VADJ = 0V
VCM = +VIN
Input Bias Current
Input Offset Current (UCx832 only) VCM = +VIN
-10
µA
Amplifier CMRR (UCx832 only)
Transconductance
VCM = 4.1V to +VIN+0.3V
80
65
-1
dB
±
ICOMP = 100µA
mS
µA
VADJ Input Current (UCx832 only)
VADJ = 0V
-10
Timer
Inactive Leakage Current
Active Pullup Current
Duty Ratio (note 4)
C/S(+) = C/S(-) = +VIN; TRC pin = 2V
0.25
-270
4.8
36
1.0
µA
µA
%
C/S(+) = +VIN, C/S(-) = +VIN - 0.4V; TRC pin = 0V
ontime/period, RT = 200k, CT = 0.27µF
ontime + offtime, RT = 200k, CT = 0.27µF
-345
-175
Period (notes 4,5)
ms
V
Upper Trip Threshold (Vu)
Lower Trip Threshold (Vl)
Trip Threshold Ratio
Error Amplifier
1.8
0.9
2.0
V
Vu/Vl
V/V
Input Offset Voltage (UCx832 only) VCM = VCOMP = 2V
Input Bias Current VCM = VCOMP = 2V
Input Offset Current (UCx832 only) VCM = VCOMP = 2V
-8.0
-4.5
-1.5
50
8.0
1.5
mV
µA
µA
dB
dB
dB
mS
V
-1.1
AVOL
VCOMP = 1V to 13V
70
80
CMRR (UCx832 only)
PSRR (UCx832 only)
Transconductance
VOH
VCM = 0V to +VIN - 3V
VCM = 2V, +VIN = 4.5 to 36V
60
90
±
ICOMP = 10µA
4.3
.95
.45
-500
ICOMP = 0, Volts below +VIN
ICOMP = 0
1.3
0.7
VOL
V
IOH
VCOMP = 2V
-700
-100
µA
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UC1832/3
UC2832/3
UC3832/3
Unless otherwise stated, specifications hold for TA = 0°C to 70°C for the UC3832/3, –25°C to
85°C for the UC2832/3, and –55°C to 125°C for the UC1832/3, +VIN = 15V, Driver sink =
+VIN, C/S(+) voltage = +VIN. TA=TJ.
ELECTRICAL
CHARACTERISTICS (cont.)
PARAMETER
Error Amplifier (cont.)
IOL
TEST CONDITIONS
MIN
TYP
MAX UNITS
VCOMP = 2V, C/S(-) = +VIN
100
2
500
6
700
µA
VCOMP = 2V, C/S(-) = +VIN - 0.4V
mA
Driver
Maximum Current
Driver Limit & Source pins common; TJ = 25°C
Over Temperature
200
100
300
300
400
450
mA
mA
Limiting Voltage (UCx832 only)
Driver Limit to Source voltage at current limit,
ISOURCE = -10mA; TJ = 25°C (Note 6)
TJ = 25°C (Note 6)
.72
2.4
V
Ω
Internal Current Sense Resistance
Pull-Up Current at Driver Sink
Compensation/Shutdown = 0.4V; Driver Sink = +VIN - 1V -800
Compensation/Shutdown = 0.4V, +VIN = 36V; Driver
-300
-100
µA
Sink = 35V
Pull-Down Current at Driver Source Compensation/Shutdown = 0.4V; Driver Source = 1V
-1000 -300
-75
µA
µA
V
150
300
1.5
700
Saturation Voltage Sink to Source
Maximum Source Voltage
Driver Source = 0V; Driver Current = 100mA
Driver Sink = +VIN, Driver Current = 100mA
Volts below +VIN
3.0
25
V
UVLO Sink Leakage
+VIN = C/S(+) = C/S(-) = 2.5V, Driver Sink = 15V, Driver
Source = 0V, TA = 25°C
µA
Maximum Reverse Source Voltage Compensation/Shutdown = 0V; ISOURCE = 100µA,
+VIN = 3V
1.6
V
Thermal Shutdown
160
°C
Note 3: On the UCx833 this voltage is defined as the regulating level at the error amplifier inverting input, with the error amplifier
driving VSOURCE to 2V.
Note 4: These parameters are first-order supply-independent, however both may vary with supply for +VIN less than about 4V. This
supply variation will cause a slight change in the timer period and duty cycle, although a high off-time/on-time ratio will be main-
tained.
±
Note 5: With recommended RT value of 200k, TOFF ≈ RT CT * ln(Vu/Vl) 10%.
Note 6: The internal current limiting voltage has a temperature dependence of approximately -2.0mV/°C, or -2800ppm/°C. The inter-
nal 2.4 Ω sense resistor has a temperature dependance of approximately +1500ppm/°C.
APPLICATION AND OPERATION INFORMATION
NPN Pass (Local 100mA Regulator) (UCx833)
UDG-92041-1
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UC1832/3
UC2832/3
UC3832/3
APPLICATION AND OPERATION INFORMATION (cont.)
PNP Pass (Low Drop-Out Regulator) (UCx833)
UDG-92042-1
NPN Pass (Medium Power, Low Drop-Out Regulator) (UCx832)
UDG-92043-1
Estimating Maximum Load Capacitance
For any power supply, the rate at which the total output
capacitance can be charged depends on the maximum
output current available and on the nature of the load. For
a constant-current current-limited power supply, the out-
put will come up if the load asks for less than the maxi-
mum available short-circuit limit current.
Current Sense Amplifier OffsetVoltage
and
K =
100mA
≈1.35 for UCx833, and is variable from 1.35 to 3.05
with VADJ for the UCx832.
For a worst-case constant-current load of value just less
than ITH, CMAX can be estimated from:
To guarantee recovery of a duty-ratio current-limited
power supply from a short-circuited load condition, there
is a maximum total output capacitance which can be
charged for a given unit ON time. The design value of ON
time can be adjusted by changing the timing capacitor.
Nominally, TON = 0.693 x 10k x CT.
TON
VOUT
CMAX = ((K−1)ITH) (
),
where VOUT is the nominal regulator output voltage.
For a resistive load of value RL, the value of CMAX can be
estimated from:
TON
RL
1
VOUT
K • ITH • RL
CMAX =
•
.
Typically, the IC regulates output current to a maximum of
IMAX = K x ITH, where ITH is the timer trip-point current,
−1
In [(1−
)
]
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UC1832/3
UC2832/3
UC3832/3
APPLICATION AND OPERATION INFORMATION (cont.)
Current Sense Amplifier Offset Voltage vs VADJ
UCx832/33 Timer Function
UCx832/33 Current Sense Input Configuration
Load current, timing capacitor voltage, and output voltage of
the regulator under fault conditions.
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UC1832/3
UC2832/3
UC3832/3
APPLICATION AND OPERATION INFORMATION (cont.)
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
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pertaining to warranty, patent infringement, and limitation of liability.
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accordance with TI’s standard warranty. Testing and other quality control techniques are utilized to the extent
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