910.24 ELMOS | Alldatasheet

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Technical content

16 | ELMOS Product catalog 10/2004 adjustable, wide input range 910.24/25/26pfm controller DC/DC Converter

features

  • Supply voltage range VS 3.0V to 60V
  • Up to 90% efficiency
  • 40µA standby current
  • 180µA circuit operating current
  • 1.5V to 24V or more adjustable output voltage
  • Up to 300kHz switching frequency
  • Improved current-limited PFM control scheme
  • High current driver for external MOSFET
  • Under-voltage lockout and thermal shutdown
  • -40°C to 125°C operating temperature
  • SO8 package
  • 910.26 basis version
  • 910.24 additive with peak current halving for medium loads and extended max. switch-on-time
  • 910.25 additive with peak current halving for medium loads and extended max. switch-on-time and fault protection

applications

  • Minimum component DC-DC converters
  • 14V , 28V or 42V automotive systems
  • Power conditioning for portable equipment
  • High efficiency on-card switching regulators

description

The family of highly flexible, easy to use PFM controllers is ideal for the use in wide input range switching regulator applications. An advanced PFM control scheme gives these devices the benefits of PWM converters with high efficiency for heavy loads, while using very low operating current for light loads to maintain excellent behaviour with output load variation. The switching circuits are suitable for topologies requiring low side FET, such as boost, flyback, Sepic, etc. Depending on the utilized topology the controllers are capable of producing regulated positive or negative output voltage. Operating from 3V to 60V supply and in temperature ranges from -40°C to 125°C the device is well suited for automotive applications. Requiring a minimum number of external components, these regula- tors are simple to use and cost-saving. Self-protection features include an overload detection circuit, an overtemperature shutdown under fault conditions and an under-volt- age lockout. block diagram VBAT VS PFM Circuit int. Supply & References On/Off Logic Gain Control (1) Overload Protection (2) VSM ON VSM PGND Instr. Ampl. VFB AGND ISEN MDRV VOut DRV

Note: ELMOS Semiconductor AG (below ELMOS) reserves the right to make changes to the product contained in this publication without notice. ELMOS assumes no responsibility for the use of any circuits described herein, conveys no licence under any patent or other right, and makes no representation that the circuits are free of patent infringement. While the information in this publication has been checked, no responsibility, however, is assumed for inaccuracies. ELMOS does not recommend the use of any of its products in life support applications where the failure or malfunction of the product can reasonably be expected to cause failure of a life-support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications. ELMOS Semiconductor AG ELMOS France S.A. ELMOS North America, Inc. Heinrich-Hertz-Str. 1 • 44227 Dortmund • Germany 29, rue des Peupliers • 92752 Nanterre Cedex • France 2747 Albright • Kokomo, Indiana 46902 • USA Phone: +49 (0) 231 75 49 0 • Fax: +49 (0) 231 75 49 149 Phone: +33 (0) 46 52 59 59 • Fax: +33 (0) 42 42 95 54 Phone: +1 317 491 59 19 • Fax: +1 317 774 89 18 Copyright © 2004 ELMOS: Reproduction, in part or whole, without the prior written consent of ELMOS, is prohibited. ELMOS Product catalog 10/2004 | 17 DC/DC Converter package SO 8 pinning Pin Name Description

1 PGND

Driver power ground pin. Connect pin to the current sense resistor, the (-) terminal of the input capacitor and the (-) terminal of the output capacitor. Due to high currents, and high frequency operation of the IC, a low impedance circuit ground plane is highly recommended

2 AGND

Analog ground pin. This pin provides a clean ground for the controller circuitry: The output voltage sensing resistors should be connected to this ground pin. This pin is connected to the IC substrate. Connect to the (-) terminal of the output capacitor 3 ISEN Current sense input pin. Voltage generated across an external sense resistor is fed into this pin. Filters extensive high-frequency noise

4 VFB

Positive feedback pin. Connect to SMPS output via external resistor divider to set output voltage and is referenced to 1.22V . For best stability, keep VFB lead as short as possible and VFB stray capacitance as small as possible 5 ON Switch ON input. Tie this pin to ground to force the IC into idle mode. A voltage of VSM or higher switches the controller in operating mode 6 VS Main supply input. Filters out high-frequency noise with a 100nF ceramic capacitor placed close to the pin to PGND

7 VSM

Internal 5V regulator output. The driver and all control circuits are powered from this voltage. Decouple this pin to PGND with a minimum of 4.7µF tantalum and 100nF ceramic capacitors 8 MDRV Drive output. Drives the gate of the external MOSFET between PGND and VSM. Connect the external MOSFET via a damping resistor to this pin PGND AGND ISEN VFB MDRV VSM VS ON adjustable, wide input range 910.24/25/26pfm controller