UC1844A-SP PWM controller Datasheet

UC1844A-SP Datasheet, PDF, Equivalent


Part Number

UC1844A-SP

Description

current-mode PWM controller

Manufacture

etcTI

Total Page 29 Pages
Datasheet
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UC1844A-SP
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UC1842A-SP, UC1844A-SP
SLUS872E – JANUARY 2009 – REVISED FEBRUARY 2019
UC184xA-SP QML class V, current-mode PWM controller
1 Features
1 QML Class V (QMLV) Qualified, SMD 5962-86704
• Rad-Tolerant: 30-krad(Si) TID (1) (2)
• Optimized for Offline and DC-to-DC Converters
• Low Start-Up Current (< 0.5 mA)
• Trimmed Oscillator Discharge Current
• Automatic Feed Forward Compensation
• Pulse-by-Pulse Current Limiting
• Enhanced Load Response Characteristics
• Undervoltage Lockout (UVLO) With Hysteresis
• Double-Pulse Suppression
• High-Current Totem-Pole Output
• Internally-Trimmed Bandgap Reference
• 500-kHz Operation
• Low RO Error Amplifier
2 Applications
• DC-DC Converters
• Supports Various Topologies:
– Flyback, Forward, Buck, Boost
– Push-Pull, Half-Bridge, Full-Bridge With
External Interface Circuit
• Available in Military Temperature Range (–55°C to
125°C)
3 Description
The UC184xA-SP family of control ICs is a pin-for-pin
compatible improved version of the UC184x family.
Providing the necessary characteristics to control
current-mode switched-mode power supplies, this
device has improved features. Start-up current is
specified to be less than 0.5 mA and oscillator
discharge is trimmed to 8.3 mA. During UVLO, the
output stage can sink at least 10 mA at less than 1.2
V for VCC over 5 V.
The Device Comparison Table shows the difference
between members of this family. Reference the
individual product data sheets for ordering the
radiation-improved version if available.
(1) The LDR improved die is only available in the UC1843A-SP
(orderable as 5962-8670409VPA). Contact factory to request
an LDR-improved version of the UC1842A-SP or UC1844A-
SP.
(2) Radiation tolerance is a typical value based upon initial device
qualification with dose rate = 10 mrad(Si)/s. Radiation lot
acceptance testing is available - contact factory for details.
Device Information(1)
PART NUMBER
PACKAGE
BODY SIZE (NOM)
UC1842A-SP
UC1844A-SP
CDIP (8)
LCCC (20)
6.67 mm × 9.60 mm
8.89 mm × 8.89 mm
(1) For all available packages, see the orderable addendum at
the end of the data sheet.
Simplified Schematic
VCC 7
Gnd 5
RT/CT 4
VFB 2
Comp 1
C/S 3
34 V
UVLO
S/R
5-V
REF
2.5 V
Osc
Error
Amplifier
VREF
Good
Logic
Internal
Bias
2R S
R 1V
R PWM
Latch
Current
Sense
Comparator
8 VREF
5.0 V
50 mA
7 VC
6 Output
5 Pwr
Ground
1
An IMPORTANT NOTICE at the end of this data sheet addresses availability, warranty, changes, use in safety-critical applications,
intellectual property matters and other important disclaimers. PRODUCTION DATA.

UC1844A-SP
UC1842A-SP, UC1844A-SP
SLUS872E – JANUARY 2009 – REVISED FEBRUARY 2019
www.ti.com
Table of Contents
1 Features .................................................................. 1
2 Applications ........................................................... 1
3 Description ............................................................. 1
4 Revision History..................................................... 2
5 Device Comparison Table..................................... 3
6 Pin Configuration and Functions ......................... 3
7 Specifications......................................................... 4
7.1 Absolute Maximum Ratings ...................................... 4
7.2 ESD Ratings.............................................................. 4
7.3 Recommended Operating Conditions....................... 4
7.4 Thermal Information .................................................. 4
7.5 Electrical Characteristics........................................... 5
7.6 Electrical Characteristics (Radiation-Improved
Devices) ..................................................................... 7
7.7 Typical Characteristics .............................................. 8
8 Detailed Description .............................................. 9
8.1 Overview ................................................................... 9
8.2 Functional Block Diagram ......................................... 9
8.3 Feature Description................................................... 9
8.4 Device Functional Modes........................................ 14
9 Application and Implementation ........................ 15
9.1 Application Information............................................ 15
9.2 Typical Application .................................................. 15
10 Power Supply Recommendations ..................... 23
11 Layout................................................................... 23
11.1 Layout Guidelines ................................................. 23
11.2 Layout Example .................................................... 24
12 Device and Documentation Support ................. 25
12.1 Related Links ........................................................ 25
12.2 Receiving Notification of Documentation Updates 25
12.3 Community Resources.......................................... 25
12.4 Trademarks ........................................................... 25
12.5 Electrostatic Discharge Caution ............................ 25
12.6 Glossary ................................................................ 25
13 Mechanical, Packaging, and Orderable
Information ........................................................... 25
4 Revision History
Changes from Revision D (May 2015) to Revision E
Page
• Removed UC1843A-SP part from this data sheet.................................................................................................................. 1
• Changed the Pin Configuration images.................................................................................................................................. 3
• Changed CT (pF) To: CT (µF) in Equation 1........................................................................................................................ 17
Changes from Revision C (March 2015) to Revision D
Page
• Updated features to remove radiation hardness assurance................................................................................................... 1
• Updated table notes for Electrical Characteristics ................................................................................................................. 5
• Updated table note in Electrical Characteristics (Radiation-Improved Devices) ................................................................... 7
• Corrected minimum discharge current in Electrical Characteristics (Radiation-Improved Devices) ..................................... 7
• Corrected input voltage unit to V and MIN and MAX values ................................................................................................. 7
• Decreased set point variation over temperature from ±10% to ±2% ................................................................................... 13
Changes from Revision B (October 2013) to Revision C
Page
• Added ESD Ratings table, Typical Characteristics, Detailed Description, Application and Implementation, Power
Supply Recommendations, Layout, and Device and Documentation Support sections ........................................................ 1
• Removed UC1845A-SP part from this data sheet.................................................................................................................. 1
2 Submit Documentation Feedback
Copyright © 2009–2019, Texas Instruments Incorporated
Product Folder Links: UC1842A-SP UC1844A-SP


Features Product Folder Order Now Technical Doc uments Tools & Software Support & Com munity UC1842A-SP, UC1844A-SP SLUS872E – JANUARY 2009 – REVISED FEBRUARY 2019 UC184xA-SP QML class V, current-mo de PWM controller 1 Features •1 QML Class V (QMLV) Qualified, SMD 5962-8670 4 • Rad-Tolerant: 30-krad(Si) TID (1) (2) • Optimized for Offline and DC-t o-DC Converters • Low Start-Up Curren t (< 0.5 mA) • Trimmed Oscillator Dis charge Current • Automatic Feed Forwa rd Compensation • Pulse-by-Pulse Curr ent Limiting • Enhanced Load Response Characteristics • Undervoltage Locko ut (UVLO) With Hysteresis • Double-Pu lse Suppression • High-Current Totem- Pole Output • Internally-Trimmed Band gap Reference • 500-kHz Operation • Low RO Error Amplifier 2 Applications • DC-DC Converters • Supports Vari ous Topologies: – Flyback, Forward, B uck, Boost – Push-Pull, Half-Bridge, Full-Bridge With External Interface Cir cuit • Available in Military Temperature Range (–55°C to 125°C) 3 Description The UC184xA-SP family of .
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