High Speed PWM Controller
application
INFO
available
UC1823
UC2823
UC3823
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
•
DESCRIPTION
The UC1823 family of PWM control ICs is optimized for high fre
quency switched mode power supply applications. Particular care
was given to minimizing propagation delays through the compara
tors 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 in
put voltage feed-forward.
Protection circuitry includes a current limit comparator, a TTL
compatible shutdown port, and a soft start pin which will double as
a maximum duty cycle clamp. The logic is fully latched to provide
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 comparator. Consult specifications for det ails.
These devices feature a totem pole output designed to source
• Low Start Up Current (1.1mA)
• Trimmed Bandgap Reference (5.1V±1%)
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.
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 T
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
=60°C......................1W
A
-
-
-
BLOCK DIAGRAM
SLUS219A - MARCH 1997 - REVISED FEBRUARY 2006
CONNECTION DIAGRAMS
UC1823
UC2823
UC3823
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
THERMAL PACKAGING INFORMATION
PACKAGE q
JA
J-16 80 - 120 28 (Note2)
N-16 90 (Note1) 45
DW-16 45 - 90 (Note1) 25
PLCC-20 Q Package 43 - 75 (Note1) 34
LCC-20 LPackage 70 - 80 20 (Note2)
Note 1. Specified qJA(junction to ambient) is for devices mounted to 5-in-2 FR4 PC board with one ounce copper where noted.
When resistance range is given, lower values are for 5-in-2 aluminum PC board. Test PWB was 0.062 in thick and typically used
0.635 mm trace widths for power pkgs and 1.3 mm trace widths for non-power pkgs with a 100 x 100 mil probe land area at the
end of each trace.
Note 2. q
data values stated were derived from MIL-STD-1835B. MIL-STD-1835B states that “The baseline values shown are
JC
worst case (mean + 2s) for a 60 x 60 mil microcircuit device silicon die and applicable for devices with die sizes up to 14400 square
mils. For device die sizes greater than14400 square mils use the following values; dual-in-line, 11°C/W; flat pack, 10°C/W; pin grid
array,10°C/W”
q
JC
2
UC1823
UC2823
UC3823
ELECTRICAL CHARACTERISTICS:
PARAMETER TEST CONDITIONS
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 =TJ.
UC1823
UC3823 UNITS
UC2823
MIN TYP MAX MIN TYP MAX
Reference Section
Output Voltage T
Line Regulation 10 < V
Load Regulation 1 < I
Temperature Stability* T
J = 25°C, lO = 1mA 5.05 5.10 5.15 5.00 5.10 5.20 V
CC < 30V 2 20 2 20 mV
O < 10mA 5 20 5 20 mV
MIN <TA <TMAX 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
Long Term Stability* T
Short Circuit Current V
J = 125°C, 1000 hrs. 5 25 5 25 mV
REF=0V -15 -50 -100 -15 -50 -100 mA
Oscillator Section
Initial Accuracy* T
Voltage Stability* 10 < V
Temperature Stability* T
J=25°C 360 400 440 360 400 440 kHz
CC < 30V 0.2 2 0.2 2 %
MIN <TA <TMAX 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
Error Amplifier Section
Input Offset Voltage 10 15 mV
Input Bias Current 0.6 3 0.6 3
Input Offset Current 0.1 1 0.1 1
Open Loop Gain 1 < V
CMRR 1.5 < V
PSRR 10 < V
Output Sink Current V
Output Source Current V
Output High Voltage I
Output Low Voltage I
O <4V 6095 6095 dB
CM < 5.5V 75 95 75 95 dB
CC < 30V 85 110 85 110 dB
PIN 3 =1V 1 2.5 1 2.5 mA
PIN 3 = 4V -0.5 -1.3 -0.5 -1.3 mA
PIN 3 = −0.5mA 4.0 4.7 5.0 4.0 4.7 5.0 V
PIN 3 = 1mA 0 0.5 1.0 0 0.5 1.0 V
Unity Gain Bandwidth* 3 5.5 3 5.5 MHz
Slew Rate* 6 12 6 12 V/µS
Ramp Valley to Peak* 1.6 1.8 2.0 1.6 1.8 2.0 V
* These parameters are guaranteed by design but not 100% tested in production.
V
µ
A
µ
A
µ
3
UC1823
UC2823
UC3823
ELECTRICAL CHARACTERISTICS: Unless otherwise noted, these specifications apply for RT = 3.65k, CT = 1nF, VCC
= 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 =TJ.
PARAMETER TEST CONDITIONS
UC1823
UC2823
UC3823 UNITS
MIN TYP MAX MIN TYP MAX
PWM Comparator Section
Pin 7 Bias Current V
PIN 7 =0V -1-5 -1-5
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
Discharge Current V
= 0.5V 3 9 20 3 9 20
PIN 8
PIN 8 =1V 1 1 mA
Current Limit/Shutdown Section
Pin 9 Bias Current 0 < V
Current Limit Offset V
Current Limit Common Mode
Range (V
PIN 11)
PIN 9 <4V
PIN 11 = 1.1V 15 15 mV
10
±
10
±
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
Output High Level I
Collector Leakage V
Rise/Fall Time* C
OUT = 20mA 0.25 0.40 0.25 0.40 V
I
OUT = 200mA 1.2 2.2 1.2 2.2 V
OUT = −20mA 13.0 13.5 13.0 13.5 V
I
OUT = −200mA 12.0 13.0 12.0 13.0 V
C = 30V 100 500 100 500
L = 1nF 30 60 30 60 ns
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 VPIN 1,VPIN 7, VPIN 9 =0V, VPIN 2 =1V 2233 2233mA
I
CC = 8V 1.1 2.5 1.1 2.5 mA
* These parameters are ensured by design but not 100% tested in production.
A
µ
A
µ
A
µ
A
µ
4
UC1823 PRINTED CIRCUIT BOARD LAYOUT
CONSIDERATIONS
High speed circuits demand careful attention to layout
and component placement. To assure proper perfor
mance of the UC1823, follow these rules. 1) Use a
ground plane. 2) Damp or clamp parasitic inductive kick
energy from the gate of driven MOSFET. Don’t allow the
output pins to ring below ground. A series gate resistor or
a shunt 1 Amp Schottky diode at the output pin will serve
ERROR AMPLIFIER CIRCUIT
Simplified Schematic
UC1823
UC2823
UC3823
this purpose. 3) Bypass VCC,VC, and VREF. Use 0.1µF
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, C
pacitor.
T, like a bypass ca
-
Open Loop Frequency Response
PWM APPLICATIONS
Conventional (Voltage Mode)
Unity Gain Slew Rate
Current-Mode
* A small filter may be required to suppress switch noise
5
OSCILLATOR CIRCUIT
UC1823
UC2823
UC3823
SYNCHRONIZED OPERATION
Two Units in Close Proximity
Generalized Synchronization
6
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, R
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
inverter must be such that the ramp capacitor can be
completely discharged during the minimum deadtime.
T and CR are
OUTPUT SECTION
UC1823
UC2823
UC3823
FEED FORWARD TECHNIQUE FOR OFF-LINE VOLTAGE MODE APPLICATION
7
PACKAGE OPTION ADDENDUM
www.ti.com
PACKAGING INFORMATION
Orderable Device Status
5962-89905012A ACTIVE LCCC FK 20 1 TBD POST-PLATE N / A for Pkg Type
5962-8990501EA ACTIVE CDIP J 16 1 TBD A42 SNPB N / A for Pkg Type
UC1823J ACTIVE CDIP J 16 1 TBD A42 SNPB N / A for Pkg Type
UC1823J883B ACTIVE CDIP J 16 1 TBD A42 SNPB N / A for Pkg Type
UC1823L ACTIVE LCCC FK 20 1 TBD POST-PLATE N / A for Pkg Type
UC1823L883B ACTIVE LCCC FK 20 1 TBD POST-PLATE N / A for Pkg Type
UC2823DW ACTIVE SOIC DW 16 40 Green (RoHS &
UC2823DWG4 ACTIVE SOIC DW 16 40 Green (RoHS &
UC2823DWTR ACTIVE SOIC DW 16 2000 Green (RoHS &
UC2823DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS &
UC2823N ACTIVE PDIP N 16 25 Green (RoHS &
UC2823NG4 ACTIVE PDIP N 16 25 Green (RoHS &
UC2823Q ACTIVE PLCC FN 20 46 Green (RoHS &
UC2823QG3 ACTIVE PLCC FN 20 46 Green (RoHS &
UC2823QTR ACTIVE PLCC FN 20 1000 Green (RoHS &
UC2823QTRG3 ACTIVE PLCC FN 20 1000 Green (RoHS &
UC3823DW ACTIVE SOIC DW 16 40 Green (RoHS &
UC3823DWG4 ACTIVE SOIC DW 16 40 Green (RoHS &
UC3823DWTR ACTIVE SOIC DW 16 2000 Green (RoHS &
UC3823DWTRG4 ACTIVE SOIC DW 16 2000 Green (RoHS &
UC3823N ACTIVE PDIP N 16 25 Green (RoHS &
UC3823NG4 ACTIVE PDIP N 16 25 Green (RoHS &
UC3823Q ACTIVE PLCC FN 20 46 Green (RoHS &
UC3823QG3 ACTIVE PLCC FN 20 46 Green (RoHS &
UC3823QTR ACTIVE PLCC FN 20 1000 Green (RoHS &
UC3823QTRG3 ACTIVE PLCC FN 20 1000 Green (RoHS &
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
(1)
Package
Type
Package
Drawing
Pins Package
Qty
Eco Plan
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
no Sb/Br)
(2)
Lead/Ball Finish MSL Peak Temp
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU N / A for Pkg Type
CU NIPDAU N / A for Pkg Type
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU Level-2-260C-1 YEAR
CU NIPDAU N / A for Pkg Type
CU NIPDAU N / A for Pkg Type
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
CU SN Level-2-260C-1 YEAR
20-Dec-2007
(3)
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
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)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check
http://www.ti.com/productcontent for the latest availability information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements
for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered
at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and
package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS
compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame
retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder
temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is
provided. TI bases its knowledge and belief on information provided by third parties, and makes no representation or warranty as to the
accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and continues to take
reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on
incoming materials and chemicals. TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited
information may not be available for release.
20-Dec-2007
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI
to Customer on an annual basis.
Addendum-Page 2
PACKAGE MATERIALS INFORMATION
www.ti.com
TAPE AND REEL INFORMATION
11-Mar-2008
*All dimensions are nominal
Device Package
UC2823DWTR SOIC DW 16 2000 330.0 16.4 10.85 10.8 2.7 12.0 16.0 Q1
UC3823DWTR SOIC DW 16 2000 330.0 16.4 10.85 10.8 2.7 12.0 16.0 Q1
Type
Package
Drawing
Pins SPQ Reel
Diameter
(mm)
Reel
Width
W1 (mm)
A0 (mm) B0 (mm) K0 (mm) P1
(mm)W(mm)
Pin1
Quadrant
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
11-Mar-2008
*All dimensions are nominal
Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm)
UC2823DWTR SOIC DW 16 2000 346.0 346.0 33.0
UC3823DWTR SOIC DW 16 2000 346.0 346.0 33.0
Pack Materials-Page 2
IMPORTANT NOTICE
Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements,
and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should
obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are
sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment.
TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard
warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where
mandated by government requirements, testing of all parameters of each product is not necessarily performed.
TI assumes no liability for applications assistance or customer product design. Customers are responsible for their products and
applications using TI components. To minimize the risks associated with customer products and applications, customers should provide
adequate design and operating safeguards.
TI does not warrant or represent that any license, either express or implied, is granted under any TI patent right, copyright, mask work right,
or other TI intellectual property right relating to any combination, machine, or process in which TI products or services are used. Information
published by TI regarding third-party products or services does not constitute a license from TI to use such products or services or a
warranty or endorsement thereof. Use of such information may require a license from a third party under the patents or other intellectual
property of the third party, or a license from TI under the patents or other intellectual property of TI.
Reproduction of TI information in TI data books or data sheets is permissible only if reproduction is without alteration and is accompanied
by all associated warranties, conditions, limitations, and notices. Reproduction of this information with alteration is an unfair and deceptive
business practice. TI is not responsible or liable for such altered documentation. Information of third parties may be subject to additional
restrictions.
Resale of TI products or services with statements different from or beyond the parameters stated by TI for that product or service voids all
express and any implied warranties for the associated TI product or service and is an unfair and deceptive business practice. TI is not
responsible or liable for any such statements.
TI products are not authorized for use in safety-critical applications (such as life support) where a failure of the TI product would reasonably
be expected to cause severe personal injury or death, unless officers of the parties have executed an agreement specifically governing
such use. Buyers represent that they have all necessary expertise in the safety and regulatory ramifications of their applications, and
acknowledge and agree that they are solely responsible for all legal, regulatory and safety-related requirements concerning their products
and any use of TI products in such safety-critical applications, notwithstanding any applications-related information or support that may be
provided by TI. Further, Buyers must fully indemnify TI and its representatives against any damages arising out of the use of TI products in
such safety-critical applications.
TI products are neither designed nor intended for use in military/aerospace applications or environments unless the TI products are
specifically designated by TI as military-grade or "enhanced plastic." Only products designated by TI as military-grade meet military
specifications. Buyers acknowledge and agree that any such use of TI products which TI has not designated as military-grade is solely at
the Buyer's risk, and that they are solely responsible for compliance with all legal and regulatory requirements in connection with such use.
TI products are neither designed nor intended for use in automotive applications or environments unless the specific TI products are
designated by TI as compliant with ISO/TS 16949 requirements. Buyers acknowledge and agree that, if they use any non-designated
products in automotive applications, TI will not be responsible for any failure to meet such requirements.
Following are URLs where you can obtain information on other Texas Instruments products and application solutions:
Products Applications
Amplifiers amplifier.ti.com Audio www.ti.com/audio
Data Converters dataconverter.ti.com Automotive www.ti.com/automotive
DSP dsp.ti.com Broadband www.ti.com/broadband
Clocks and Timers www.ti.com/clocks Digital Control www.ti.com/digitalcontrol
Interface interface.ti.com Medical www.ti.com/medical
Logic logic.ti.com Military www.ti.com/military
Power Mgmt power.ti.com Optical Networking www.ti.com/opticalnetwork
Microcontrollers microcontroller.ti.com Security www.ti.com/security
RFID www.ti-rfid.com Telephony www.ti.com/telephony
RF/IF and ZigBee® Solutions www.ti.com/lprf Video & Imaging www.ti.com/video
Mailing Address: Texas Instruments, Post Office Box 655303, Dallas, Texas 75265
Copyright © 2008, Texas Instruments Incorporated
Wireless www.ti.com/wireless
Loading...