SLUS191D February   1997  – July 2017 UC1525A , UC1527A , UC2525A , UC2527A , UC3525A , UC3527A

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
  4. 4 Revision History
  5. 5 Pin Configuration and Functions
  6. 6 Specifications
    1. 6.1 Absolute Maximum Ratings
    2. 6.2 ESD Ratings
    3. 6.3 Recommended Operating Conditions
    4. 6.4 Thermal Information
    5. 6.5 Electrical Characteristics
    6. 6.6 Typical Characteristics
  7. 7 Detailed Description
    1. 7.1 Overview
    2. 7.2 Functional Block Diagram
    3. 7.3 Feature Description
      1. 7.3.1 Adjustable Dead-Time Control
      2. 7.3.2 Soft Start
      3. 7.3.3 Input Undervoltage Lockout With Hysteresis
      4. 7.3.4 Shutdown and Pulse-by-Pulse Current Limiting
    4. 7.4 Device Functional Modes
      1. 7.4.1 Shutdown Options (See )
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 Theory of Operation
      2. 8.2.2 Design Requirements
      3. 8.2.3 Detailed Design Procedure
        1. 8.2.3.1 Timing Resistor and Capacitor Selection
        2. 8.2.3.2 Turns Ratio Selection
        3. 8.2.3.3 Inductor Selection
        4. 8.2.3.4 Rectification Diode Selection
        5. 8.2.3.5 VC Capacitor Selection
        6. 8.2.3.6 Output Capacitor Selection
        7. 8.2.3.7 Input Capacitor Selection
      4. 8.2.4 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Related Links
    3. 11.3 Community Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • J|16
  • FK|20
Thermal pad, mechanical data (Package|Pins)
Orderable Information

6 Specifications

6.1 Absolute Maximum Ratings

over operating free-air temperature range (unless otherwise noted)(1)
MIN MAX UNIT
+VIN Supply voltage 40 V
VC Collector supply voltage 40 V
Logic inputs –0.3 5.5 V
Analog inputs –0.3 +VIN V
Output current, source or sink 500 mA
Reference output current 50 mA
Oscillator charging current 5 mA
Power dissipation at TA = +25°C(2) 1000 mW
Power dissipation at TC = +25°C(2) 2000 mW
Operating junction temperature –55 150 °C
Lead temperature (soldering, 10 seconds) 300 °C
Tstg Storage temperature –65 150 °C
(1) Stresses beyond those listed under Absolute Maximum Ratings may cause permanent damage to the device. These are stress ratings only, which do not imply functional operation of the device at these or any other conditions beyond those indicated under Recommended Operating Conditions. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.

6.2 ESD Ratings

VALUE UNIT
V(ESD) Electrostatic discharge Human-body model (HBM), per ANSI/ESDA/JEDEC JS-001(1) 3000 V
Charged-device model (CDM), per JEDEC specification JESD22-C101(2) 1500
(1) JEDEC document JEP155 states that 500-V HBM allows safe manufacturing with a standard ESD control process.
(2) JEDEC document JEP157 states that 250-V CDM allows safe manufacturing with a standard ESD control process.

6.3 Recommended Operating Conditions

over operating free-air temperature range (unless otherwise noted)
MIN MAX UNIT
+VIN Input voltage 8 35 V
VC Collector supply voltage 4.5 35 V
Sink/source load current (steady state) 0 100 mA
Sink/source load current (peak) 0 400 mA
Reference load current 0 20 mA
Oscillator frequency range 100 400 Hz
Oscillator timing resistor 2 150 kΩ
Oscillator timing capacitor 0.001 0.01 µF
Dead time resistor range 0 500 Ω
Operating ambient temperature UC1525A, UC1527A –55 125 °C
UC2525A, UC2527A –25 85
UC3525A, UC3527A 0 70

6.4 Thermal Information

THERMAL METRIC(1) UCx52xA UNIT
FK
(LCCC)		 J
(CDIP)		 DW
(SOIC)		 N
(PDIP)		 FN
(PLCC)
20 PINS 16 PINS 16 PINS 16 PINS 20 PINS
RθJA Junction-to-ambient thermal resistance N/A N/A 72.6 47.6 55.8 °C/W
RθJC(top) Junction-to-case (top) thermal resistance 32.9 37.4 34 37.3 33.7 °C/W
RθJB Junction-to-board thermal resistance 32.1 54.2 37.3 27.7 21.1 °C/W
ψJT Junction-to-top characterization parameter N/A N/A 8.9 17.3 9.7 °C/W
ψJB Junction-to-board characterization parameter N/A N/A 36.8 27.5 20.8 °C/W
RθJC(bot) Junction-to-case (bottom) thermal resistance 3.5 10.1 N/A N/A N/A °C/W
(1) For more information about traditional and new thermal metrics, see the Semiconductor and IC Package Thermal Metrics application report.

6.5 Electrical Characteristics

over operating free-air temperature range (unless otherwise noted)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
REFERENCE
Output voltage TJ = 25°C UC152xA, UC252xA 5.05 5.1 5.15 V
UC352xA 5 5.1 5.2
Line regulation VIN = 8 V to 35 V 10 20 mV
Load regulation IL = 0 mA to 20 mA 20 50 mV
Temperature stability(1) Over operating 20 50 mV
Total output variation(1) Line, load, and temperature UC152xA, UC252xA 5 5.2 V
UC352xA 4.95 5.25
Shorter circuit current VREF = 0, TJ = 25°C 80 100 mA
Output noise Voltage(1) 10 Hz ≤ 10 kHz, TJ = 25°C 40 200 µVrms
Long-term stability(1) TJ = 125°C 20 50 mV
OSCILLATOR SECTION(2)
Initial accuracy(1)(2) TJ = 25°C 2% 6%
Voltage stability(1)(2) VIN = 8 V to 35 V UC152xA, UC252xA 0.3% 1%
UC352xA 1% 2%
Temperature stability(1) Over operating 3% 6%
Minimum frequency RT = 200 kΩ, CT = 0.1 mF 120 Hz
Maximum frequency RT = 2 kΩ, CT = 470 pF 400 kHz
Current mirror IRT = 2 mA 1.7 2 2.2 mA
Clock amplitude(1)(2) 3 3.5 V
Clock width(1)(2) TJ = 25°C 0.3 0.5 1 µs
Syncronization threshold(1)(2) 1.2 2 2.8 V
Sync input current Sync voltage = 3.5 V 1 2.5 mA
ERROR AMPLIFIER SECTION (VCM = 5.1 V)
Input offset voltage UC152xA, UC252xA 0.5 5 mV
UC352xA 2 10
Input bias current 1 10 µA
Input offset current 1
DC open loop gain RL ≥ 10 MΩ 60 75 dB
Gain-bandwidth product(1) AV = 0 dB, TJ = 25°C 1 2 MHz
DC transconductance(1)(3) TJ = 25°C, 30 kΩ ≤ RL ≤ 1 MΩ 1.1 1.5 mS
Low-level output voltage 0.2 0.5 V
High-level output voltage 3.8 5.6
Common mode rejection VCM = 1.5 V to 5.2 V 60 75 dB
Supply voltage rejection VIN = 8 V to 35 V 50 60
PWM COMPARATOR
Minimum duty-cycle 0%
Maximum duty-cycle 45% 49%
Input threshold(4) Zero duty-cycle 0.7 0.9 V
Maximum duty-cycle 3.3 3.6
Input bias current(4) 0.05 1 µA
SHUTDOWN
Soft-start current VSD = 0 V, VSS = 0 V 25 50 80 µA
Soft-start low level VSD = 2.5 V 0.4 0.7 V
Shutdown threshold To outputs, VSS = 5.1 V, TJ = 25°C 0.6 0.8 1
Shutdown input current VSD = 2.5 V 0.4 1 mA
Shutdown Delay(5) VSD = 2.5 V, TJ = 25°C 0.2 0.5 µS
OUTPUT DRIVERS (EACH OUTPUT) (VC = 20 V)
Low-level output voltage ISINK = 20 mA 0.2 0.4 V
ISINK = 100 mA 1 2
High-level output voltage ISOURCE = 20 mA 18 19 V
ISOURCE = 100 mA 17 18
Undervoltage lockout VCOMP and VSS = High 6 7 8 V
VC OFF current(6) VC = 35 V 200 µA
Rise time(5) CL = 1 nF, TJ = 25°C 100 600 ns
Fall time(5) CL = 1 nF, TJ = 25°C 50 300
TOTAL STANDBY CURRENT
Supply current VIN = 35 V 14 20 mA
(1) These parameters, although ensured over the recommended operating conditions, are not 100% tested in production.
(2) Tested at fOSC = 40 kHz (RT = 3.6 kΩ, CT = 0.01 mF, RD = 0. Approximate oscillator frequency is defined by UC1525A UC1527A UC2525A UC2527A UC3525A UC3527A Equation1.gif .
(3) DC transconductance (gM) relates to DC open-loop voltage gain (AV) according to the following equation: AV = gMRL where RL is the resistance from pin 9 to ground. The minimum gM specification is used to calculate minimum AV when the error amplifier output is loaded.
(4) Tested at fOSC = 40 kHz (RT = 3.6 kΩ, CT = 0.01 mF, RD = 0 Ω.
(5) These parameters, although ensured over the recommended operating conditions, are not 100% tested in production.
(6) Collector off-state quiescent current measured at pin 13 with outputs low for UC1525A and high for UC1527A.

6.6 Typical Characteristics

UC1525A UC1527A UC2525A UC2527A UC3525A UC3527A D002_SLUS191.gif
Figure 1. Oscillator Charge Time vs RT and CT
UC1525A UC1527A UC2525A UC2527A UC3525A UC3527A D004_SLUS191.gif
Figure 3. Maximum Value RD vs Minimum Value RT
UC1525A UC1527A UC2525A UC2527A UC3525A UC3527A D003_SLUS191.gif
Figure 2. Oscillator Discharge Time vs RT CT
UC1525A UC1527A UC2525A UC2527A UC3525A UC3527A D005_SLUS191.gif
Figure 4. Error Amplifier Voltage Gain and Phase vs Frequency