UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
HIGH SPEED PWM CONTROLLER
FEATURES
•
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DESCRIPTION
Complementary Outputs
Practical Operation Switching Frequencies to
1 MHz
50-ns Propagation Delay to Output
High Current Dual Totem Pole Outputs (1.5 A
Peak)
Wide Bandwidth Error Amplifier
Fully Latched Logic With Double Pulse
Suppression
Pulse-by-Pulse Current Limiting
Soft Start/Maximum Duty Cycle Control
Under-Voltage Lockout with Hysteresis
Low Start Up Current (1.1 mA)
Trimmed Bandgap Reference (5.1 V ± 1%)
The UC1824 family of PWM control devices is
optimized for high frequency switched mode power
supply applications. Particular care was given to
minimizing
propagation
delays
through
the
comparators and logic circuitry while maximizing
bandwidth and slew rate of the error amplifier. This
controller is designed for use in either current mode
or voltage mode systems with the capability for input
voltage feed-forward.
Protection circuitry includes a current limit
comparator with a 1-V threshold, a TTL compatible
shutdown port, and a soft-start pin which doubles as
a maximum duty cycle clamp. The logic is fully
latched to provide jitter free operation and prohibit
multiple pulses at an output. An under-voltage
lockout section with 800 mV of hysteresis assures
low start up current. During under-voltage lockout,
the outputs are high impedance.
BLOCK DIAGRAM
Clock
4
RT
5
CT
6
Ramp
7
E/A Out
3
OSC
PWM Latch (Set Dom.)
R
1.25V
+
S
Wide Bandwidth
(Set Dom.)
NI
2
INV
1
+
Error
Amp
VIN
Inhibit
Soft Start
9mA
VC
11
Out
14
INVOUT
12
Pwr Gnd
10
VREF 5.1V
8
ILIM
CPRTR
1V
ILIM/SD
13
Shutdown
CPRTR
9
1.4V
Output
Inhibit
VCC
15
Gnd
10
Internal
Bias
9V
4V
UVLO
GATE
VCC Good
REF
GEN
VREF Good
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas
Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 1997–2007, Texas Instruments Incorporated
UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
DESCRIPTION (CONTINUED)
These devices feature totem pole outputs designed to source and sink high peak currents from capacitive loads,
such as the gate of a power MOSFET. The on state is designed as a high level.
ABSOLUTE MAXIMUM RATINGS (1) (2)
Supply voltage (pins 13, 15)
VALUE
UNIT
30
V
Output current, source or sink (pins 11, 14)
DC
0.5
Pulse (0.5 ms)
2
A
Analog inputs
(Pins 1, 2, 7)
–0.3 TO 7
(Pin 8, 9)
–0.3 TO 6
Clock output current (pin 4)
–5
Error amplifier output current (pin 3)
5
Soft start sink current (pin 8)
20
Oscillator charging current (pin 5)
–5
Power dissipation
1
Storage temperature range
–65 to 150
Lead temperature (soldering, 10 seconds)
(1)
(2)
300
mA
W
°C
All voltages are with respect to GND (Pin 10); all currents are positive into, negative out of part; pin numbers refer to DIL-16 package.
Consult Unitrode Integrated Circuit Databook for thermal limitations and considerations of package.
SOIC-16
DW PACKAGE
(TOP VIEW)
DIL-16
J OR N PACKAGE
(TOP VIEW)
2
V
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UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
PLCC-20 AND LCC-20
Q AND L PACKAGES
(TOP VIEW)
PACKAGE PIN FUNCTION
FUNCTION
N/C
INV
NI
E/A Out
Clock
N/C
RT
CT
Ramp
Soft Start
N/C
ILIM/SD
Gnd
Out
Pwr Gnd
N/C
VC
INVOUT
VCC
VREF 5.1V
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PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
3
UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
ELECTRICAL CHARACTERISTICS
Unless otherwise stated, these specifications apply for, RT = 3.65k, CT = 1 nF, VCC = 15 V, –55°C < TA < 125°C for the
UC1824, –40°C < TA < 85°C for the UC2824, and 0°C < TA < 70°C for the UC3824, TA = TJ.
PARAMETER
UC1824
UC2824
TEST CONDITIONS
UC3824
UNIT
MIN
TYP
MAX
MIN
TYP
MAX
5.05
5
Reference Section
Output voltage
TJ = 25°C, IO = 1 mA
5.10
5.15
5.10
5.20
Line regulation
10 V < VCC < 30 V
2
20
2
20
Load regulation
1 mA < IO < 10 mA
5
20
5
20
Temperature stability (1)
TMIN < TA < TMAX
Total output variation (1)
Line, Load, Temperature
Output noise voltage (1)
10 Hz < f < 10 kHz
long term stability (1)
TJ = 125°C, 1000 hrs.
5
25
5
25
mV
Short circuit current
VREF = 0 V
–15
–50
–100
–15
–50
–100
mA
TJ = 25°C
360
400
440
360
400
440
kHz
0.2%
2%
0.2%
2%
0.2
5
0.4
5.20
0.2
4.95
50
0.4
5.25
V
mV mV
mV/°C
V
μV
50
Oscillator Section
Initial accuracy (1)
Voltage stability
(1)
10 V < VCC < 30 V
Temperature stability (1)
TMIN < TA < TMAX
Total variation (1)
Line, Temperature
5%
340
Clock out high
460
3.9
4.5
Clock out low
Ramp peak (1)
Ramp valley
Ramp valley to peak (1)
340
3.9
2.3
2.9
2.8
3
2.6
0.7
1
1.25
1.6
1.8
2
2.6
(1)
5%
460
kHz
4.5
2.3
2.9
2.8
3
0.7
1
1.25
1.6
1.8
2
V
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 < VO < 4 V
60
95
60
CMRR
1.5 V < VCM < 5.5 V
PSRR
10 V < VCC < 30 V
Output sink current
VPIN
3
Output source current
VPIN
3
Output high voltage
IPIN
3
Output low voltage
IPIN
75
95
75
95
85
110
85
110
=1V
1
2.5
1
2.5
=4V
–0.5
–1.3
–0.5
–1.3
3 = 1 mA
4
4.7
5
4
4.7
5
0
0.5
1
0
0.5
1
3
5.5
3
5.5
MHz
6
12
6
12
V/μs
= –0.5 mA
Unity gain bandwidth (1)
Slew rate
(1)
95
dB
mA
V
PWM Comparator Section
Pin 7 bias current
VPIN
7
=0V
VPIN
7
=0V
–1
Duty cycle range
Pin 3 zero dc threshold
0
1.1
–5
80
1.25
Delay to output (1)
80
9
20
μA
85
%
50
80
ns
9
20
0
1.1
50
–5
–1
1.25
V
Soft-Start Section
Charge current
VPIN
8
Discharge current
VPIN
= 0.5 V
8= 1V
3
1
3
1
μA
mA
Current Limit/Shutdown Section
Pin 9 bias current
(1)
4
0 < VPIN 9 < 4 V
15
This parameter not 100% tested in production but guaranteed by design.
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10
μA
UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
ELECTRICAL CHARACTERISTICS (continued)
Unless otherwise stated, these specifications apply for, RT = 3.65k, CT = 1 nF, VCC = 15 V, –55°C < TA < 125°C for the
UC1824, –40°C < TA < 85°C for the UC2824, and 0°C < TA < 70°C for the UC3824, TA = TJ.
PARAMETER
UC1824
UC2824
TEST CONDITIONS
MIN
Current limit threshold
TYP
UC3824
MAX
MIN
TYP
UNIT
MAX
0.9
1
1.1
0.9
1
1.1
1.25
1.40
1.55
1.25
1.40
1.55
50
80
50
80
IOUT = 20 mA
0.25
0.40
0.25
0.40
IOUT = 200 mA
1.2
2.2
1.2
2.2
Shutdown threshold
Delay to output
V
ns
Output Section
Output low level
Output high level
Collector leakage
Rise/fall time
(2)
IOUT = –20 mA
13
IOUT = –200 mA
12
13.5
13
13
13.5
12
13
V
VC = 30 V
100
500
10
500
μA
CL = 1 nF
30
60
30
60
ns
Under-Voltage Lockout Section
Start threshold
8.8
9.2
9.6
8.8
9.2
9.6
UVLO hysteresis
0.4
0.8
1.2
0.4
0.8
1.2
V
Supply Current Section
(2)
Start up current
VCC = 8 V
1.1
2.5
1.1
2.5
ICC
VPIN 1, VPIN 7, VPIN 9 = 0 V; VPIN 2 = 1 V
22
33
22
33
mA
This parameter not 100% tested in production but guaranteed by design.
UC1824 Printed Circuit Board Layout Considerations
High speed circuits demand careful attention to layout and component placement. To assure proper
performance of the UC1824 follow these rules:
1. Use a ground plane.
2. Damp or clamp parasitic inductive kick energy from the gate of driven MOSFETs. Do not allow the output
pins to ring below ground. A series gate resistor or a shunt 1-A Schottky diode at the output pin serves
this purpose.
3. Bypass VCC, VC, and VREF. Use 0.1-μF monolithic ceramic capacitors with low equivalent series
inductance. Allow less than 1 cm of total lead length for each capacitor between the bypassed pin and the
ground plane.
4. Treat the timing capacitor, CT, like a bypass capacitor.
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UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
Error Amplifier Circuit
Simplified Schematic
Open Loop Frequency Response
Unity Gain Slew Rate
Synchronized Operation
Two Units in Close Proximity
6
Generalized Synchronization
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UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
Oscillator Circuit
m
Primary Output Deadtime vs CT (3k £ RT £ 100k)
Primary Output Deadtime vs Frequency
Timing Resistance vs Frequency
160
1.0 nF
TD (ns)
140
120
100
470 pF
80
10k
100k
1M
FREQ (Hz)
Typical Non-Overlap Time (T NO) Over Temperature
80
70
60
50
40
TNO (ns) 30
20
10
0
-75
-50
-25
0
25
50
75
100
125
T (°C)
Non-Overlap Time (TNO)
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UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
Forward Technique for Off-Line Voltage Mode Application
Constant Volt-Second Clamp Circuit
The circuit shown here will achieve a constant volt-second product clamp over varying input voltages. The
ramp generator components, RT and CR are chosen so
that the ramp at Pin 9 crosses the 1V threshold at the
same time the desired maximum volt-second product
is reached. The delay through the functional nor block
must be such that the ramp capacitor can be completely discharged during the minimum deadtime.
Output Section
Simplified Schematic
Rise/Fall Time (CL=10 nF)
8
Rise/Fall Time (C L=1 nF)
Saturation Curves
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UC1824
UC2824
UC3824
www.ti.com
SLUS326A – MARCH 1997 – REVISED JULY 2007
Open-Loop Laboratory Test Fixture
UDG-92036-2
This test fixture is useful for exercising many of the As with any wideband circuit, careful grounding and byUC1824’s functions and measuring their specifications.
pass procedures should be followed. The use of a
ground plane is highly recommended.
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9
PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
UC2824DW
ACTIVE
SOIC
DW
16
40
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
-40 to 85
UC2824DW
UC2824N
ACTIVE
PDIP
N
16
25
RoHS & Green
NIPDAU
N / A for Pkg Type
-40 to 85
UC2824N
UC3824DW
ACTIVE
SOIC
DW
16
40
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
0 to 70
UC3824DW
UC3824DWTR
ACTIVE
SOIC
DW
16
2000
RoHS & Green
NIPDAU
Level-2-260C-1 YEAR
0 to 70
UC3824DW
UC3824N
ACTIVE
PDIP
N
16
25
RoHS & Green
NIPDAU
N / A for Pkg Type
0 to 70
UC3824N
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of