SG5842JA Fairchild Semiconductor, SG5842JA Datasheet

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SG5842JA

Manufacturer Part Number
SG5842JA
Description
The highly integrated SG5842A/JA series of PWM controllers provides several features to enhance the performance of flyback converters
Manufacturer
Fairchild Semiconductor
Datasheet
© 2007 Fairchild Semiconductor Corporation
SG5842A/SG5842JA • Rev. 1.4.3
SG5842A/SG5842JA — Highly Integrated Green-Mode
PWM Controller
Features
Applications
General-purpose switch-mode power supplies and
flyback power converters, including:
Green-Mode PWM Controller
Low Startup Current: 14µA
Low Operating Current: 4mA
Programmable PWM Frequency with Hopping
(SG5842JA)
Peak-Current-Mode Control
Cycle-by-Cycle Current Limiting
Synchronized Slope Compensation
Leading-Edge Blanking (LEB)
Constant Output Power Limit
Totem-Pole Output with Soft Driving
V
Programmable Over-Temperature Protection (OTP)
Internal Latch Circuit (OTP, OVP)
Internal Open-Loop Protection
V
GATE Output Maximum Voltage Clamp: 18V
Notebook Power Adapters
Open-Frame SMPS
DD
DD
Over-Voltage Protection (OVP)
Under-Voltage Lockout (UVLO)
Description
The highly integrated SG5842A/JA series of PWM
controllers provides several features to enhance the
performance of flyback converters. To minimize standby
power consumption, a proprietary green-mode function
provides off-time modulation to continuously decrease
the switching frequency at light-load conditions. To
avoid acoustic-noise problems, the minimum PWM
frequency set above 22KHz. This green-mode function
enables the power supply to meet international power
conservation requirements. To further reduce power
consumption, SG5842A/JA is manufactured using the
BiCMOS process. This allows a low startup current,
around 14µA, and an operating current of only 4mA. As
a result, a large startup resistance can be used.
The
compensation
control. SG5842JA integrates a frequency-hopping
function that helps reduce EMI emission of a power
supply with minimum line filters.
SG5842A/JA provides many protection functions. In
addition to cycle-by-cycle current limiting, the internal
open-loop protection circuit ensures safety should an
open-loop or output short-circuit failure occur. PWM
output is disabled until V
limit, then the controller starts again. As long as V
exceeds about 24V, the internal OVP circuit is triggered.
An external NTC thermistor can be applied for over-
temperature protection.
SG5842A/JA is available in an 8-pin DIP or SOP
package.
SG5842A/JA
achieves
built-in
DD
drops below the UVLO lower
stable
synchronized
peak-current-mode
December 2009
www.fairchildsemi.com
slope
DD

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SG5842JA Summary of contents

Page 1

... SG5842A/JA built-in synchronized compensation achieves stable control. SG5842JA integrates a frequency-hopping function that helps reduce EMI emission of a power supply with minimum line filters. SG5842A/JA provides many protection functions. In addition to cycle-by-cycle current limiting, the internal open-loop protection circuit ensures safety should an open-loop or output short-circuit failure occur ...

Page 2

... Ordering Information Operating Part Number Temperature Range SG5842JASZ -40°C to +105°C SG5842JADZ -40°C to +105°C SG5842JASY -40°C to +105°C SG5842ASZ -40°C to +105°C (Preliminary) SG5842ASY -40°C to +105°C (Preliminary) For Fairchild’s definition of Eco Status, please visit: http://www.fairchildsemi.com/company/green/rohs_green.html. Application Diagram © ...

Page 3

... Marking for SG5842JASZ (pb-free) Marking for SG5842JADZ (pb-free) Marking for SG5842ASZ (pb-free) Marking for SG5842ADZ (pb-free) ZXYTT SG5842HA TPM Marking for SG5842JASY (green-compound) Marking for SG5842ASY (green-compound) © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 Figure 2. Function Block Diagram with Frequency Hopping ...

Page 4

... VDD Power supply. The internal protection circuit disables PWM output GATE The totem-pole output driver for the power MOSFET, which is internally clamped below 18V. © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 Figure 4. Pin Configuration Description 4 is over-voltage. DD ...

Page 5

... The Recommended Operating Conditions table defines the conditions for actual device operation. Recommended operating conditions are specified to ensure optimal performance to the datasheet specifications. Fairchild does not recommend exceeding them or designing to Absolute Maximum Ratings. Symbol T Operating Ambient Temperature A © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 Parameter < 50° Human Body Model, JESD22-A114 ...

Page 6

... DD I GATE=OPEN R =26KΩ =5V DD Center R =26KΩ I Frequency R =26KΩ I Hopping Range SG5842JA Only R =26KΩ I SG5842JA Only R =26KΩ =11.5V to 20V DD T =-20 to 85° Pin Open R =26KΩ =26KΩ =26KΩ Min. ...

Page 7

... O V GATE- Gate Output Clamping Voltage CLAMP I Output Current of RT Pin RT Over-Temperature Protection V RTTH Threshold Voltage t Over-Temperature Debounce D-OTP © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 (Continued) Figure 5. V vs. PWM Frequency FB Conditions V –V STHFL STHVA Maximum Duty Cycle R =26KΩ =26KΩ ...

Page 8

... V Voltage (V) DD Figure 8. Operation Current (I Operation 11.5 11.0 10.5 10.0 9.5 -40 -25 - Temperature °C Figure 10. Minimum Operating Voltage (V vs. Temperature © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 5.0 4.5 4.0 3.5 3.0 2 110 125 ) vs. Temperature Figure 7. Operating Supply Current (I IDD-ST 17.5 17.0 16.5 16.0 GATE=OPEN 15 ...

Page 9

... Performance Characteristics -40 -25 - Temperature °C Figure 12. Maximum Duty Cycle (DCY vs. Temperature Figure 14. Output Current of RT Pin (I © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 (Continued) 1.085 1.075 1.065 1.055 1.045 1.035 1.025 1.015 110 125 ) Figure 13 ...

Page 10

... I The range of the PWM oscillation frequency is designed as 47KHz ~ 109KHz. SG5842JA also integrates a frequency hopping function internally. The frequency variation ranges from around 62KHz to 68KHz for a center frequency of 65KHz. The frequency hopping function helps reduce EMI emission of a power supply with minimum line filters. ...

Page 11

... To reset the latch circuit, disconnect the AC line voltage of the power supply. © 2007 Fairchild Semiconductor Corporation SG5842A/SG582JA • Rev. 1.4.3 (Continued) Thermal Protection An external NTC thermistor can be connected from the RT pin to ground ...

Page 12

... C10 CC 222pF/50V C11 CC 470pF/50V D1 D2 Diode BYV95C D3 TVS P6KE16A D4 Diode FR103 F1 FUSE 4A/250V L1 Choke (900µH) L2 Choke (10mH) L3 Inductor (2µH) Q1 Diode 20A/100V © 2007 Fairchild Semiconductor Corporation SG5842A/SG5842JA • Rev. 1.4.3 BD1 GND GATE 2 ...

Page 13

... Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2007 Fairchild Semiconductor Corporation SG5842A/SG5842JA • Rev. 1.4.3 5.00 4.80 A 3.81 ...

Page 14

... Package specifications do not expand the terms of Fairchild’s worldwide terms and conditions, specifically the warranty therein, which covers Fairchild products. Always visit Fairchild Semiconductor’s online packaging area for the most recent package drawings: http://www.fairchildsemi.com/packaging/. © 2007 Fairchild Semiconductor Corporation SG5842A/SG5842JA • Rev. 1.4.3 6.67 6.096 3.683 3.20 3 ...

Page 15

... Fairchild Semiconductor Corporation SG5842A/SG5842JA • Rev. 1.4.3 15 www.fairchildsemi.com ...

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