Texas Instruments UC3823N, UC3823J, UC3823DWTR, UC3823DW, UC3823QTR Datasheet
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UC1823
UC2823
UC3823
High Speed PWM Controller
FEATURES
•
Compatible with Voltage or Current-Mode
Topologies
•
Practical Operation @ Switching
Frequencies to 1.0MHz
•
50ns Propagation Delay to Output
•
High Current Totem Pole Output (1.5A peak)
•
Wide Bandwidth Error Amplifier
•
Fully Latched Logic with Double Pulse
Suppression
•
Pulse-by-Pulse Current Limiting
•
Soft Start/Max. Duty Cycle Control
•
Under-Voltage Lockout with Hysteresis
•
Low Start Up Current (1.1mA)
•
Trimmed Bandgap Reference (5.1V ±1%)
DESCRIPTION
The UC1823 famil y of PWM control IC s is optimized for high frequency swi tched mode power suppl y applications. Par ticular care
was given to mini mizing propagation delays through the comparators and logi c circuitry while maximizing bandwidth and slew rate
of the erro r amplifier. This controll er is designed for use in either
current-mode or voltage-mode systems with the capability for i nput
voltage feed-forward.
Protection circuitry includes a current limit comparator, a TTL compatible shu tdown port, and a soft start pin which will double as a
maximum duty cycl e clamp. The logic is fully l atched to provi de jitter free operation and prohibit multiple pulses at the output. An under-voltage lockout section with 800mV of hysteresis assures low
start up current. During under-voltage lockout, the output is high impedance. The current limit reference (pin 11) is a DC input voltage to
the current limit com pa rat or. Con sult sp ecif ication s for deta ils.
These devices feature a totem pole output des igned to source and
sink high peak currents from capacitive loads, such as the gate of
a power MOSFET. The on state is defined as a high level.
BLOCK DIAGRAM
ABSOLUTE MAXIMUM RATINGS
Supply Voltage (Pins 15, 13) . . . . . . . . . . . . . . . . . . . . . . . . 30V
Output Current, Source or Sink (Pin14)
DC. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.5A
Pulse (0.5µs). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.0A
Analog Inputs (Pins 1, 2, 7, 8, 9, 11) . . . . . . . . . . . -0.3V to +6V
Clock Output Current (Pin 4) . . . . . . . . . . . . . . . . . . . . . . . -5mA
Error Amplifier Output Current (Pin 3) . . . . . . . . . . . . . . . . 5mA
Soft Start Sink Current (Pin 8) . . . . . . . . . . . . . . . . . . . . . 20mA
Oscillator Charging Current (Pin 5) . . . . . . . . . . . . . . . . . . -5mA
Power Dissipation at TA = 60 °C . . . . . . . . . . . . . . . . . . . . . 1W
Storage Temperature Range . . . . . . . . . . . . . . -65°C to +150°C
Lead Temperature (Soldering, 10 seconds) . . . . . . . . . . 300°C
Note: All voltages are with respect to ground, Pin 10.
Currents are positive into the specified terminal.
Consult Packaging Section of Databook for thermal
limitations and considerations of packages.
3/97
1
UC1823
UC2823
UC3823
CONNECTION DIAGRAMS
ELECTRICAL CHARACTERISTICS:
PARAMETER TEST CONDITIONS
UC1823
UC2823
UC3823 UNITS
MIN TYP MAX MIN TYP MAX
Reference Section
Output Voltage T
J
= 25°C, lO = 1mA 5.05 5.10 5.15 5.00 5.10 5.20 V
Line Regulation 10 < V
CC
< 30V 2 20 2 20 mV
Load Regulation 1 < I
O
< 10mA 5 20 5 20 mV
Temperature Stability* T
MIN
< TA < T
MAX
0.2 0.4 0.2 0.4 mV/°C
Total Output Variation* Line, Load, Temp. 5.00 5.20 4.95 5.25
Output Noise Voltage* 10Hz < f < 10kHz 50 50 µV
Long Term Stability* T
J
= 125°C, 1000 hrs. 5 25 5 25 mV
Short Circuit Current V
REF
=0V -15 -50 -100 -15 -50 -100 mA
Oscillator Section
Initial Accuracy* T
J
=25°C 360 400 440 360 400 440 kHz
Voltage Stability* 10 < V
CC
< 30V 0.2 2 0.2 2 %
Temperature Stability* T
MIN
<TA < T
MAX
55%
Total Variation* Line, Temp. 340 460 340 460 kHz
Clock Out High 3.9 4.5 3.9 4.5 V
Clock Out Low 2.3 2.9 2.3 2.9 V
Ramp Peak* 2.6 2.8 3.0 2.6 2.8 3.0 V
Ramp Valley* 0.7 1.0 1.25 0.7 1.0 1.25 V
Ramp Valley to Peak* 1.6 1.8 2.0 1.6 1.8 2.0 V
* These parameters are guara nt ee d by des ig n bu t no t 10 0% te st ed in production.
DIL-16, SOIC-16 (TOP VIEW)
J or N, DW Package
PLCC-20, LCC-20 (TOP VIEW)
Q, L Package
PACKAGE PIN FUNCTION
FUNCTION PIN
N/C 1
Inv. 2
N.I. 3
E/A Out 4
Clock 5
N/C 6
R
T
7
C
T
8
Ramp 9
Soft start 10
N/C 11
I
LIM
/S.D. 12
Ground 13
I
LIM
REF 14
PWR Gnd 15
N/C 16
V
C
17
OUT 18
V
CC
19
V
REF
5.1V 20
Unless otherwise noted, these specifications apply for RT = 3.65k, CT =
1nF, V
CC
= 15V, 0°C < TA < +70°C for the UC3823, -25°C < TA < +85°C for
the UC2823, and -55°C < T
A
< +125°C for the UC1823, TA = T
J.
2
PARAMETER TEST CONDITIONS
UC1823
UC2823
UC3823 UNITS
MIN TYP MAX MIN TYP MAX
Error Amplifier Section
Input Offset Voltage 10 15 mV
Input Bias Current 0.6 3 0.6 3 µA
Input Offset Current 0.1 1 0.1 1 µA
Open Loop Gain 1 < V
O
< 4V 60 95 60 95 dB
CMRR 1.5 < V
CM
< 5.5V 75 95 75 95 dB
PSRR 10 < V
CC
< 30V 85 110 85 110 dB
Output Sink Current V
PIN 3
=1V 1 2.5 1 2.5 mA
Output Source Current V
PIN 3
= 4V -0.5 -1.3 -0.5 -1.3 mA
Output High Voltage I
PIN 3
= −0.5mA 4.0 4.7 5.0 4.0 4.7 5.0 V
Output Low Voltage I
PIN 3
= 1mA 0 0.5 1.0 0 0.5 1.0 V
Unity Gain Bandwi dth* 3 5.5 3 5.5 MHz
Slew Rate* 6 12 6 12 V/µS
PWM Comparator Section
Pin 7 Bias Current V
PIN 7
= 0V -1 -5 -1 -5 µA
Duty Cycle Range 0 80 0 85 %
Pin 3 Zero D.C. Threshold V
PIN 7
= 0V 1.1 1.25 1.1 1.25 V
Delay to Output* 50 80 50 80 ns
Soft-Start Section
Charge Current V
PIN 8
= 0.5V 3 9 20 3 9 20 µA
Discharge Current V
PIN 8
= 1V 1 1 mA
Current Limit/Shutdown Section
Pin 9 Bias Current 0 < V
PIN 9
< 4V ±10 ±10 µA
Current Limit Offset V
PIN 11
= 1.1V 15 15 mV
Current Limit Common Mode
Range (V
PIN 11
)
1.0 1.25 1.0 1.25 V
Shutdown Threshold 1.25 1.40 1.55 1.25 1.40 1.55 V
Delay to Output* 50 80 50 80 ns
Output Section
Output Low Level I
OUT
= 20mA 0.25 0.40 0.25 0.40 V
I
OUT
= 200mA 1.2 2.2 1.2 2.2 V
Output High Level I
OUT
= −20mA 13.0 13.5 13.0 13.5 V
I
OUT
= −200mA 12.0 13.0 12.0 13.0 V
Collector Leakage V
C
= 30V 100 500 100 500 µA
Rise/Fall Time* CL = 1nF 3060 3060ns
Under-Voltage Lockout Section
Start Threshold 8 .8 9.2 9.6 8.8 9.2 9.6 V
UVLO Hysteresis 0.4 0.8 1.2 0.4 0.8 1.2 V
Supply Current
Start Up Current V
CC
= 8V 1.1 2.5 1.1 2.5 mA
I
CC
V
PIN 1
, V
PIN 7, VPIN 9
=0V, V
PIN 2
= 1V 22 33 22 33 mA
* These parameters are guara nt ee d by des ig n bu t no t 10 0% te st ed in production.
UC1823
UC2823
UC3823
ELECTRICAL CHARACTERISTICS:
Unless otherwise noted, these specifications apply for R
T
= 3.65k, CT = 1nF, V
CC
= 15V, 0°C < TA < +70°C for the UC3823, -25°C < TA < +85°C for the
UC2823, and -55°C < T
A
< +125°C for the UC1823, TA = T
J.
3
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