SLUSC14A May   2015  – February 2019 UC1845A-SP

PRODUCTION DATA.  

  1. 1 Features
  2. 2 Applications
  3. 3 Description
    1.     Device Images
      1.      Simplified Schematic
      2.      VREF Radiation Drift Curve
  4. 4 Revision History
  5. 5 Device Comparison Table
  6. 6 Pin Configuration and Functions
    1.     Pin Functions
  7. 7 Specifications
    1. 7.1 Absolute Maximum Ratings
    2. 7.2 ESD Ratings
    3. 7.3 Recommended Operating Conditions
    4. 7.4 Thermal Information
    5. 7.5 Electrical Characteristics
    6. 7.6 Typical Characteristics
  8. 8 Detailed Description
    1. 8.1 Overview
    2. 8.2 Functional Block Diagram
    3. 8.3 Feature Description
      1. 8.3.1 UVLO
      2. 8.3.2 Reference
      3. 8.3.3 Totem-Pole Output
    4. 8.4 Device Functional Modes
  9. 9 Application and Implementation
    1. 9.1 Application Information
    2. 9.2 Typical Application
      1. 9.2.1 Design Requirements
      2. 9.2.2 Detailed Design Procedure
        1. 9.2.2.1 Oscillator
        2. 9.2.2.2 Current Sensing and Limiting
        3. 9.2.2.3 Error Amplifier
      3. 9.2.3 Application Curves
  10. 10Power Supply Recommendations
  11. 11Layout
    1. 11.1 Layout Guidelines
      1. 11.1.1 Feedback Traces
      2. 11.1.2 Input/Output Capacitors
      3. 11.1.3 Compensation Components
      4. 11.1.4 Traces and Ground Planes
    2. 11.2 Layout Example
  12. 12Device and Documentation Support
    1. 12.1 Receiving Notification of Documentation Updates
    2. 12.2 Community Resources
    3. 12.3 Trademarks
    4. 12.4 Electrostatic Discharge Caution
    5. 12.5 Glossary
  13. 13Mechanical, Packaging, and Orderable Information

Package Options

Refer to the PDF data sheet for device specific package drawings

Mechanical Data (Package|Pins)
  • FK|20
  • HKU|10
  • JG|8
Thermal pad, mechanical data (Package|Pins)
Orderable Information

7.5 Electrical Characteristics

VCC = 15 V(2), RT = 10 kΩ, CT = 3.3 nF, TA = TJ = –55°C to 125°C (unless otherwise noted) (1)
PARAMETER TEST CONDITIONS MIN TYP MAX UNIT
REFERENCE
Output voltage TJ = 25°C, IO = 1 mA,
VCC = 15 V		 5962-8670408VxA 4.95 5 5.06 V
5962P8670411Vxx Pre-radiation 4.94 5 5.06
5962P8670411Vxx Post-radiation 4.85 5.06
Line regulation VIN = 12 to 25 V 6 20 mV
Load regulation IO = 1 to 20 mA 6 25 mV
Temperature stability(3)(4)(9) 0.2 0.4 mV/°C
Total output variation(3) Over line, load, and temperature 4.9 5.1 V
Output noise variation 10 Hz ≤ ƒ ≤ 10 kHz, TJ = 25°C 50 μV
Long-term stability(9) 1000 hours, TA = 125°C(3) 5 25 mV
Short-circuit output current –30 –100 –180 mA
OSCILLATOR
Initial accuracy TJ = 25°C(5) 47 52 57 kHz
Voltage stability VCC = 12 to 25 V 0.2% 1%
Temperature stability TJ = –55°C to 125°C(3) 5%
Amplitude VRT/CT peak to peak(3) 1.7 V
Discharge current V pin 4 = 2 V(6) TJ = 25°C 7.8 8.3 8.8 mA
TJ = Full range 7.5 8.8 mA
ERROR AMPLIFIER
Input voltage VComp = 2.5 V 2.45 2.50 2.55 V
Input bias current –0.3 –1 μA
Open-loop voltage gain VO = 2 to 4 V 65 90 dB
Unity-gain bandwidth TJ = 25°C(3) 0.7 1 MHz
PSRR VCC = 12 to 25 V 60 70 dB
Output sink current VFB = 2.7 V, VComp = 1.1 V 2 6 mA
Output source current VFB = 2.3 V, VComp = 5 V –0.5 –0.8 mA
High-level output voltage VFB = 2.3 V, RL = 15 kΩ to ground 5 6 V
Low-level output voltage VFB = 2.7 V, RL = 15 kΩ to VREF 0.7 1.1 V
CURRENT SENSE
Gain(7)(8) 2.85 3 3.15 V/V
Maximum input signal VComp = 5 V(7) 0.9 1 1.1 V
PSRR VCC = 12 to 25 V(7) 70 dB
Input bias current –2 –10 μA
Delay to output VISENSE = 0 to 2 V(3) 150 300 ns
OUTPUT
Output low-level voltage ISINK = 20 mA 0.1 0.4 V
ISINK = 200 mA 1.5 2.2
Output high-level voltage ISOURCE = –20 mA 13 13.5 V
ISOURCE = –200 mA 12 13.5
Rise time CL = 1 nF, TJ = 25°C(3) 50 150 ns
Fall time CL = 1 nF, TJ = 25°C(3) 50 150 ns
UVLO saturation VCC = 5 V, ISINK = 10 mA 0.7 1.2 V
UNDERVOLTAGE LOCKOUT
Start threshold 7.8 8.4 9 V
Minimum operation voltage after turnon 7 7.6 8.2 V
PWM
Maximum duty cycle 47% 48% 50%
Minimum duty cycle 0%
TOTAL STANDBY CURRENT
Start-up current 0.3 0.5 mA
Operating supply current VFB = VISENSE = 0 V 11 17 mA
VCC Zener voltage ICC = 25 mA 30 34 V
(1) See Mechanical, Packaging, and Orderable Information for radiation improved devices.
(2) Adjust VCC above the start threshold before setting at 15 V.
(3) Parameters ensured by design and/or characterization, if not production tested.
(4) Temperature stability, sometimes referred to as average temperature coefficient, is described by the equation:
Temperature Stability = VREF (max) – VREF (min) / TJ (max) – TJ (min). VREF (max) and VREF (min) are the maximum and minimum reference voltage measured over the appropriate temperature range. Note that the extremes in voltage do not necessarily occur at the extremes in temperature.
(5) Output frequency is one-half oscillator frequency for UC1845A.
(6) This parameter is measured with RT = 10 kΩ to VREF. This contributes approximately 300 μA of current to the measurement. The total current flowing into the RT or CT pin will be approximately 300 μA higher than the measured value.
(7) Parameter measured at trip point of latch with VFB = 0 V.
(8) Gain defined as: G = ΔVComp / ΔVISENSE; VISENSE = 0 to 0.8 V.
(9) Parameter applies only for 5962-8670408VxA.