ISL8845A

Manufacturer Part NumberISL8845A
Description(ISL8840A - ISL8845A) High Performance Industry Standard Single-Ended Current Mode PWM Controller
ManufacturerIntersil Corporation
ISL8845A datasheet
 
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Data Sheet
High Performance Industry Standard
Single-Ended Current Mode PWM
Controller
The ISL884xA is a high performance drop-in replacement for
the popular 28C4x and 18C4x 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
ISL8840A
7.0
ISL8841A
7.0
ISL8842A
14.4V
ISL8843A
8.4V
ISL8844A
14.4V
ISL8845A
8.4V
Pinout
ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A
(8 LD SOIC, MSOP)
TOP VIEW
COMP
1
8
FB
2
7
3
CS
6
RTCT
4
5
1
ISL8840A, ISL8841A, ISL8842A,
ISL8843A, ISL8844A, ISL8845A
April 18, 2007
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
MAX. DUTY CYCLE
• Tight tolerance voltage reference over line, load and
temperature
100%
50%
• ±3% current limit threshold
100%
• Pb-free plus anneal available and ELV, WEEE, RoHS
Compliant
100%
50%
Applications
50%
• Telecom and datacom power
• Wireless base station power
• File server power
• Industrial power systems
• PC power supplies
• Isolated buck and flyback regulators
VREF
VDD
• Boost regulators
OUT
GND
CAUTION: These devices are sensitive to electrostatic discharge; follow proper IC Handling Procedures.
1-888-INTERSIL or 1-888-468-3774
All other trademarks mentioned are the property of their respective owners.
FN6320.3
|
Intersil (and design) is a registered trademark of Intersil Americas Inc.
Copyright © Intersil Americas Inc. 2005, 2006, 2007. All Rights Reserved.

ISL8845A Summary of contents

  • Page 1

    ... PART NUMBER RISING UVLO ISL8840A 7.0 ISL8841A 7.0 ISL8842A 14.4V ISL8843A 8.4V ISL8844A 14.4V ISL8845A 8.4V Pinout ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A (8 LD SOIC, MSOP) TOP VIEW COMP RTCT ISL8840A, ISL8841A, ISL8842A, ...

  • Page 2

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Ordering Information PART PART TEMP. NUMBER* MARKING RANGE (°C) ISL8840AABZ 8840 AABZ -40 to +105 8 Ld SOIC (See Note) ISL8840AAUZ 40AAZ -40 to +105 8 Ld MSOP M8.118 (See Note) ISL8840AMBZ 8840 AMBZ -55 to +125 8 Ld SOIC (See Note) ...

  • Page 3

    ... VF TOTAL = 1.15V ERROR AMPLIFIER COMP VREF 100k 2.9V 1.0V 150k OSCILLATOR COMPARATOR <10ns - RTCT + CLOCK 8.4mA ON V REF 5.00V ENABLE OK VREF FAULT UV COMPARATOR PWM COMPARATOR + - 100mV ONLY ISL8841A/ 2R 1.1V ISL8844A/ CLAMP ISL8845A RESET DOMINANT ON VREF - + VREF 4.65V 4.80V OUT 36k ...

  • Page 4

    Typical Application - 48V Input Dual Output Flyback 36V TO 75V VR1 CR2 C5 CR6 R22 R27 U4 R26 COMP CS FB RTCT ISL884xA ...

  • Page 5

    Typical Application - Boost Converter L1 VIN+ C1 VIN- R8 C10 CR1 VREF COMP VDD FB CS OUT C4 RTCT GND R3 C7 +VOUT + C2 C3 RETURN VIN+ C5 ...

  • Page 6

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Absolute Maximum Ratings Supply Voltage GND -0.3V to +30V DD OUT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . GND -0. 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- .200V Charged Device Model (Per JESD22-C191- .1000V ...

  • Page 7

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Electrical Specifications ISL884xAA - Typical Application schematic onpage 3 and page 4. V (Note 3). Typical values are at T PARAMETER Input Signal, Maximum = ΔV Gain, A /ΔV CS COMP OUT Delay ERROR AMPLIFIER Open Loop Voltage Gain Unity Gain Bandwidth ...

  • Page 8

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Electrical Specifications ISL884xAM Typical Application schematic. V are at T PARAMETER UNDERVOLTAGE LOCKOUT START Threshold (ISL8840A, ISL8841A) START Threshold (ISL8843A, ISL8845A) START Threshold (ISL8842A, ISL8844A) STOP Threshold (ISL8840A, ISL8841A) STOP Threshold (ISL8843A, ISL8845A) STOP Threshold (ISL8842A, ISL8844A) ...

  • Page 9

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Electrical Specifications ISL884xAM Typical Application schematic. V are at T PARAMETER Amplitude, Peak to Peak RTCT Discharge Voltage (Valley Voltage) Discharge Current OUTPUT Gate VOH Gate VOL Peak Output Current Rise Time Fall Time GATE VOL UVLO Clamp Voltage ...

  • Page 10

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Typical Performance Curves 1.001 1.000 0.998 0.997 0.996 -60 -40 - TEMPERATURE (°C) FIGURE 3. EA REFERENCE vs TEMPERATURE Pin Descriptions RTCT - This is the oscillator timing control pin. The operational frequency and maximum duty cycle are set by connecting a resistor, RT, between VREF and this pin and a timing capacitor, CT, from this pin to GND ...

  • Page 11

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Soft-Start Operation Soft-start must be implemented externally. One method, illustrated below, clamps the voltage on COMP. VREF D1 R1 COMP Q1 GND C1 FIGURE 5. SOFT-START The COMP pin is clamped to the voltage on capacitor C1 plus a base-emitter junction by transistor Q1 charged from VREF through resistor R1 and the base current of Q1. ...

  • Page 12

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A The current sense signal at the end of the ON time for CCM operation is ⋅ ⋅ ⋅ ⎛ – ⎞ ⎜ ⎟ ------------------------ I + ------------------------------------------- - ⎝ 2L ⎠ where V is the voltage across the current sense resistor, ...

  • Page 13

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Example 12V 48V 800μH s Ns/ 8.0μ 200mA O Switching Frequency 200kHz sw Duty Cycle 28. 499Ω 6 Solve for the current sense resistor 295mΩ CS Determine the amount of voltage, Ve, that must be added to the current feedback signal using Equation 12. ...

  • Page 14

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Small Outline Plastic Packages (SOIC) N INDEX 0.25(0.010) H AREA E - SEATING PLANE - -C- α 0.10(0.004) 0.25(0.010 NOTES: 1. Symbols are defined in the “MO Series Symbol List” in Section 2.2 of Publication Number 95. ...

  • Page 15

    ... ISL8840A, ISL8841A, ISL8842A, ISL8843A, ISL8844A, ISL8845A Mini Small Outline Plastic Packages (MSOP -B- INDEX 0.20 (0.008 AREA TOP VIEW 0.25 (0.010) GAUGE PLANE SEATING PLANE - 0.10 (0.004) b -H- - 0.20 (0.008) SIDE VIEW 0.20 (0.008) NOTES: 1. These package dimensions are within allowable dimensions of JEDEC MO-187BA ...