SLUSDD5A April   2019  – December 2020 UC1825B-SP

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 Control Methods
      2. 7.3.2 Synchronization
      3. 7.3.3 High Current Outputs
      4. 7.3.4 Open Loop Test Circuit
    4. 7.4 Device Functional Modes
  8. 8 Application and Implementation
    1. 8.1 Application Information
    2. 8.2 Typical Application
      1. 8.2.1 System Design Theory
        1. 8.2.1.1 Switching Frequency
        2. 8.2.1.2 Transformer
        3. 8.2.1.3 RCD and Diode Clamp
        4. 8.2.1.4 Output Diode
        5. 8.2.1.5 Main Switching MOSFETs
        6. 8.2.1.6 Output Filter and Capacitance
        7. 8.2.1.7 Compensation
        8. 8.2.1.8 Sense Resistor
    3. 8.3 Application Curves
  9. 9 Power Supply Recommendations
  10. 10Layout
    1. 10.1 Layout Guidelines
      1. 10.1.1 Feedback Traces
      2. 10.1.2 Input/Output Capacitors
      3. 10.1.3 Compensation Components
      4. 10.1.4 Traces and Ground Planes
      5. 10.1.5 Ground Planes
    2. 10.2 Layout Example
  11. 11Device and Documentation Support
    1. 11.1 Documentation Support
      1. 11.1.1 Related Documentation
    2. 11.2 Receiving Notification of Documentation Updates
    3. 11.3 Support Resources
    4. 11.4 Trademarks
    5. 11.5 Electrostatic Discharge Caution
    6. 11.6 Glossary
  12. 12Mechanical, Packaging, and Orderable Information

Package Options

Mechanical Data (Package|Pins)
Thermal pad, mechanical data (Package|Pins)
Orderable Information

5 Pin Configuration and Functions

GUID-C0979B2F-8EDC-4F25-A684-4D633C9A2BE8-low.png Figure 5-1 HKT Package
16-Pin CFP
Top View
Table 5-1 Pin Functions
NAME NO. I/O DESCRIPTION
CLK 4 O Output of the internal oscillator.
CT 6 I Timing capacitor connection pin for oscillator frequency programming. The timing capacitor should be connected to the device ground using minimal trace length.
EAOUT 3 O Output of the error amplifier for compensation.
GND 10 — Analog ground return pin.
ILIM/SD 9 I Input to the current limit comparator and the shutdown comparator.
INV 1 I Inverting input to the error amplifier.
NI 2 I Non-inverting input to the error amplifier.
OUTA 11 O High-current totem pole output A of the on-chip drive stage.
OUTB 14 O High-current totem pole output B of the on-chip drive stage.
PGND 12 — Ground return pin for the output driver stage.
RAMP 7 I Non-inverting input to the PWM comparator with 1.25-V internal input offset. In voltage mode operation this serves as the input voltage feed-forward function by using the CT ramp. In peak current mode operation, this serves as the slope compensation input.
RT 5 I Timing resistor connection pin for oscillator frequency programming.
SS 8 I Soft-start input pin which also doubles as the maximum duty cycle clamp.
VC 13 — Power supply pin for the output stage. This pin should be bypassed with a 0.1-μF monolithic ceramic low ESL capacitor with minimal trace lengths.
VCC 15 — Power supply pin for the device. This pin should be bypassed with a 0.1-μF monolithic ceramic low ESL capacitor with minimal trace lengths.
VREF 16 O 5.1-V reference. For stability, the reference should be bypassed with a 0.1-μF monolithic ceramic low ESL capacitor and minimal trace length to the ground plane.
Table 5-2 Bare Die Information
DIE THICKNESS BACKSIDE FINISH BACKSIDE POTENTIAL BOND PAD METALLIZATION COMPOSITION BOND PAD THICKNESS
15 mils Backgrind Si - Finish GND AlCu 2000 nm
GUID-20200803-CA0I-J5GZ-HLNS-SPC821VZFC38-low.png Figure 5-2 UC1825B-SP Bare Die Pin Number Locations
Table 5-3 Bond Pad Coordinates in Microns
DESCRIPTION PAD NUMBER X MIN Y MIN X MAX Y MAX

INV

1

962.66

2933.7

1064.26

3035.3

NI

2

754.38

2938.78

855.98

3040.38

EAOUT

3

147.32

2451.1

248.92

2552.7

CLK

4

124.46

2052.32

226.06

2153.92

RT

9

165.1

1244.6

266.7

1346.2

CT

10

134.62

708.66

236.22

810.26

RAMP

11

429.26

167.64

530.86

269.24

SS

12

594.36

167.64

695.96

269.24

ILIM/SD

13

1681.48

307.34

1783.08

408.94

GND

15

2225.04

66.04

2326.64

167.64

OUTA

16

1879.6

751.84

1981.2

853.44

PGND

17

2153.92

1463.04

2255.52

1564.64

VC

18

1564.64

1460.5

1666.24

1562.1

OUTB

19

1889.76

2171.7

1991.36

2273.3

VCC

20

2207.26

2933.7

2308.86

3035.3

RAMP

21

1874.52

3014.98

1976.12

3116.58