intersil ISL8843 DATA SHEET

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ISL8843

Data Sheet January 3, 2006

Industry Standard Single-Ended Current Mode PWM Controller

The ISL8843 is an industry standard drop-in replacement for the popular 28C43 and 18C43 PWM controllers suitable for a wide range of power conversion applications including boost, flyback, and isolated output configurations. Its fast signal propagation and output switching characteristics make this an ideal product for existing and new designs.

Features include 30V operation, low operating current, 90µA start-up current, adjustable operating frequency to 2MHz, and high peak current drive capability with 20ns rise and fall times.

PART NUMBER RISING UVLO MAX. DUTY CYCLE

ISL8843 8.4V 100%

Ordering Information

PART

NUMBER

ISL8843ABZ (See Note)

ISL8843AUZ (See Note)

ISL8843MBZ (See Note)

ISL8843MUZ (See Note)

Add -T to part number for Tape and Reel packaging.

PAR T

MARKING

8843 ABZ -40 to 105 8 Ld SOIC

8843Z -40 to 105 8 Ld MSOP

8843 MBZ -55 to 125 8 Ld SOIC

843MZ -55 to 125 8 Ld MSOP

TEMP.

RANGE (°C) PACKAGE

(Pb-free)

PKG.

DWG. #

M8.15

M8.118

M8.15

M8.118

FN9238.1

Features

• 1A MOSFET gate driver

•90µA start-up current, 125µA maximum

• 35ns propagation delay current sense to output

• Fast transient response with peak current mode control

• 30V operation

• Adjustable switching frequency to 2MHz

• 20ns rise and fall times with 1nF output load

• Trimmed timing capacitor discharge current for accurate deadtime/maximum duty cycle control

• 1.5MHz bandwidth error amplifier

• Tight tolerance voltage reference over line, load, and temperature

• ±3% current limit threshold

• Pb-free plus anneal available and ELV, WEEE, RoHS

Compliant

Applications

• Telecom and datacom power

• Wireless base station power

• File server power

• Industrial power systems

• PC power supplies

• Isolated buck and flyback regulators

NOTE: Intersil Pb-free plus anneal products employ special Pb-free material sets; molding compounds/die attach materials and 100% matte tin plate termination finish, which are RoHS compliant and compatible with both SnPb and Pb-free soldering operations. Intersil Pb-free products are MSL classified at Pb-free peak reflow temperatures that meet or exceed the Pb-free requirements of IPC/JEDEC J STD-020.

CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.

1-888-INTERSIL or 1-888-468-3774

• Boost regulators

Pinout

| Intersil (and design) is a registered trademark of Intersil Americas Inc.

All other trademarks mentioned are the property of their respective owners.

ISL8843

(8 LD SOIC, MSOP)

TOP VIEW

COMP

RTCT

VREF

VDD

OUT

GND

Functional Block Diagram

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ENABLE

REF

5.00 V

PWM

COMPARATOR

VREF FAULT

UV COMPARATOR

4.65V ↓ 4.80V ↑

VREF

START/STOP

UV COMPARATOR

VDD OK

GND

2.5V

A=0.5

100mV

VREF

ISL8843

AMPLIFIER

COMP

VREF

100K

150K

RTCT

January 3, 2006

FN9238.1

ERROR

2.9V

1.0V

8.4mA

OSCILLATOR

COMPARATOR

< 10nS

VF Total = 1.15V

CLOCK

100 nS

FALLING EDGE

DELAY

1.1V 3% CLAMP

OUT

SRQ

RESET

DOMINANT

36K

Typical Application - 48V Input Dual Output Flyback

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VIN+

36-75V

CR6

CR2

C17

R21

CR5

CR4

C19

R16

C21

C15 C16

C22

C20

R17

R19

C14

+3.3V

+1.8V

RETURN

R18

VIN-

CR1

VR1

January 3, 2006

FN9238.1

R26

R22

COMP CS

FB RTCT

R27

ISL8843

R10

VREF

OUT GND

R13

C13

C11

R15

R20

ISL8843

C12

ISL8843

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Absolute Maximum Ratings Thermal Information

Supply Voltage, VDD . . . . . . . . . . . . . . . . . . . GND - 0.3V to +30.0V

OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . .GND - 0.3V to V

Signal Pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND - 0.3V to 6.0V

Peak GATE Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1A

ESD Classification

Human Body Model (Per JESD22-A114C.01) . . . . . . . . . . .2000V

Machine Model (Per EIA/JESD22-A115-A) . . . . . . . . . . . . . .200V

Charged Device Model (Per JESD22-C191-A) . . . . . . . . . .1000V

+ 0.3V

Thermal Resistance (Typical, Note 1) θ

SOIC Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100

MSOP Package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130

Maximum Junction Temperature . . . . . . . . . . . . . . . . -55°C to 150°C

Maximum Storage Temperature Range. . . . . . . . . . . -65°C to 150°C

Maximum Lead Temperature (Soldering 10s) . . . . . . . . . . . . . 300°C

(SOIC, MSOP - Lead Tips Only)

Operating Conditions

Temperature Range

ISL8843AxZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .-40°C to 105°C

ISL8843MxZ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -55°C to 125°C

Supply Voltage Range (Typical)

ISL8843 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9V - 30V

CAUTION: Stresses above those listed in “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only rating and operation of the device at these or any other conditions above those indicated in the operational sections of this specification is not implied.

NOTES:

is measured with the component mounted on a high effective thermal conductivity test board in free air. See Tech Brief TB379 for details.

1. θ

2. All voltages are with respect to GND.

Electrical Specifications ISL8843A - Recommended operating conditions unless otherwise noted. Refer to Block Diagram and

Typical Application schematic. V are at T

PARAMETER TEST CONDITIONS MIN TYP MAX UNITS

UNDERVOLTAGE LOCKOUT

START Threshold 8.0 8.4 9.0 V

STOP Threshold 7.3 7.6 8.0 V

Hysteresis -0.8- V

Startup Current, I

Operating Current, I

Operating Supply Current, I

REFERENCE VOLTAGE

Overall Accuracy Over line (V

Long Term Stability T

Current Limit, Sourcing -20 - - mA

Current Limit, Sinking 5--mA

CURRENT SENSE

Input Bias Current V

CS Offset Voltage V

COMP to PWM Comparator Offset Voltage V

Input Signal, Maximum 0.97 1.00 1.03 V

Gain, A

CS to OUT Delay -3555ns

ERROR AMPLIFIER

Open Loop Voltage Gain (Note 5) 60 90 - dB

Unity Gain Bandwidth (Note 5) 1.0 1.5 - MHz

Reference Voltage V

= ∆V

/∆VCS 0 < VCS < 910mV, VFB = 0V 2.5 3.0 3.5 V/V

COMP

= 25°C

VDD < START Threshold - 90 125 µA

(Note 4) - 2.9 4.0 mA

Includes 1nF GATE loading - 4.75 5.5 mA

temperature

= 125°C, 1000 hours (Note 5) - 5 - mV

= 1V -1.0 - 1.0 µA

= 0V (Note 5) 95 100 105 mV

= 0V (Note 5) 0.80 1.15 1.30 V

= V

= 15V, RT = 10kΩ, CT = 3.3nF, TA = -40 to 105°C (Note 3) Typical values

= 12V to 18V), load,

COMP

4.925 5.000 5.050 V

2.475 2.500 2.530 V

(°C/W)

FN9238.1

January 3, 2006

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