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LM1949 Dataheets PDF



Part Number LM1949
Manufacturers Texas Instruments
Logo Texas Instruments
Description Injector Drive Controller
Datasheet LM1949 DatasheetLM1949 Datasheet (PDF)

LM1949 www.ti.com SNLS349C – FEB 1995 – REVISED MARCH 2013 LM1949 Injector Drive Controller Check for Samples: LM1949 FEATURES 1 •2 Low Voltage Supply (3V–5.5V) • 22 mA Output Drive Current • No RFI Radiation • Adaptable to All Injector Current Levels • Highly Accurate Operation • TTL/CMOS Compatible Input Logic Levels • Short Circuit Protection • High Impedance Input • Externally Set Holding Current, IH • Internally Set Peak Current (4 × IH) • Externally Set Time-Out • Can be Modified for F.

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LM1949 www.ti.com SNLS349C – FEB 1995 – REVISED MARCH 2013 LM1949 Injector Drive Controller Check for Samples: LM1949 FEATURES 1 •2 Low Voltage Supply (3V–5.5V) • 22 mA Output Drive Current • No RFI Radiation • Adaptable to All Injector Current Levels • Highly Accurate Operation • TTL/CMOS Compatible Input Logic Levels • Short Circuit Protection • High Impedance Input • Externally Set Holding Current, IH • Internally Set Peak Current (4 × IH) • Externally Set Time-Out • Can be Modified for Full Switching Operation • Available in Plastic 8-Pin PDIP APPLICATIONS • Fuel Injection • Throttle Body Injection • Solenoid Controls • Air and Fluid Valves • DC Motor Drives DESCRIPTION The LM1949 linear integrated circuit serves as an excellent control of fuel injector drive circuitry in modern automotive systems. The IC is designed to control an external power NPN Darlington transistor that drives the high current injector solenoid. The current required to open a solenoid is several times greater than the current necessary to merely hold it open; therefore, the LM1949, by directly sensing the actual solenoid current, initially saturates the driver until the “peak” injector current is four times that of the idle or “holding” current (Figure 19–Figure 22). This guarantees opening of the injector. The current is then automatically reduced to the sufficient holding level for the duration of the input pulse. In this way, the total power consumed by the system is dramatically reduced. Also, a higher degree of correlation of fuel to the input voltage pulse (or duty cycle) is achieved, since opening and closing delays of the solenoid will be reduced. Normally powered from a 5V ± 10% supply, the IC is typically operable over the entire temperature range (−55°C to +125°C ambient) with supplies as low as 3 volts. This is particularly useful under “cold crank” conditions when the battery voltage may drop low enough to deregulate the 5-volt power supply. The LM1949 is available in the plastic PDIP, (contact factory for other package options). Typical Application Figure 1. Typical Application and Test Circuit 1 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. All trademarks are the property of their respective owners. 2 PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of the Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. Copyright © 1995–2013, Texas Instruments Incorporated LM1949 SNLS349C – FEB 1995 – REVISED MARCH 2013 www.ti.com IN 1 OUT 2 COMP 3 SENSE INPUT 4 LM1949N 8 TIMER 7 SUPPLY 6 SUPPLY GND 5 SENSE GND Figure 2. Package Number P0008E These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates. Absolute Maximum Ratings (1)(2) Supply Voltage Power Dissipation (3) Input Voltage Range Operating Temperature Range Storage Temperature Range Junction Temperature Lead Temp. (Soldering 10 sec.) 8V 1235 mW −0.3V to VCC −40°C to +125°C −65°C to +150°C 150°C 260°C (1) Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. (2) If Military/Aerospace specified devices are required, please contact the Texas Instruments Sales Office/ Distributors for availability and specifications. (3) For operation in ambient temperatures above 25°C, the device must be derated based on a 150°C maximum junction temperature and a thermal resistance of 100°C/W junction to ambient. Electrical Characteristics (VCC = 5.5V, VIN = 2.4V, TJ = 25°C, Figure 1, unless otherwise specified.) Symbol Parameter Conditions ICC Supply Current Off VIN = 0V Peak Pin 8 = 0V Hold Pin 8 Open VOH Input On Level VCC = 5.5V VCC = 3.0V VOL Input Off Level VCC = 5.5V VCC = 3.0V IB Input Current IOP Output Current Peak Pin 8 = 0V Hold Pin 8 Open VS Output Saturation Voltage 10 mA, VIN = 0V VP Sense Input Peak Threshold VCC = 4.75V VH Hold Reference t Time-out, t t ÷ RTCT Min Typ Max Units 11 23 mA 28 54 mA 16 26 mA 1.4 2.4 V 1.2 1.6 V 1.0 1.35 V 0.7 1.15 V −25 3 +25 µA −10 −22 −1.5 −5 0.2 mA mA 0.4 V 350 386 415 mV 88 94 102 mV 90 100 110 % 2 Submit Documentation Feedback Product Folder Links: LM1949 Copyright © 1995–2013, Texas Instruments Incorporated www.ti.com LM1949 SNLS349C – FEB 1995 – REVISED MARCH 2013 Typical Performance Characteristics Output Current vs Supply Voltage Supply Current vs Supply Voltage Figure 3. Quiescent Current vs Supply Voltage Figure 4. Input Voltage .


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