LM2611AMFX National Semiconductor, LM2611AMFX Datasheet
LM2611AMFX
Available stocks
Related parts for LM2611AMFX
LM2611AMFX Summary of contents
Page 1
... The LM2611 is available is a small SOT23-5 package. It comes in two grades: Grade A Current Limit 1.2A R 0.5 DS(ON) Typical Application Circuit © 2002 National Semiconductor Corporation Features n 1.4MHz switching frequency n Low R DS(ON) n 1mVp-p output ripple n −5V at 300mA from 5V input n Better regulation than a charge pump n Uses tiny capacitors and inductors n Wide input range: 2 ...
Page 2
... Connection Diagram Ordering Information Order Number Package Type LM2611AMF LM2611AMFX SOT23-5 LM2611BMF LM2611BMFX Pin Description Pin Name GND 3 NFB 4 SHDN Block Diagram www.national.com Top View 20018115 5-lead SOT-23 Package NS Package Number MF05A NSC Package Drawing MF05A Drain of internal switch. Connect at the node of the input inductor and Cuk capacitor. ...
Page 3
... Absolute Maximum Ratings If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications Voltage NFB Voltage SHDN Voltage Maximum Junction Temperature Power Dissipation (Note 2) Lead Temperature Electrical Characteristics Specifications in standard type face are for T ture Range ( T = − ...
Page 4
Typical Performance Characteristics DS(ON) Switch Current Limit vs. V Oscillator Frequency vs V www.national.com IN 20018112 Switch Current Limit vs Ambient Temperature IN 20018111 Oscillator Frequency vs Ambient Temperature IN 20018119 4 R Vs. Ambient Temperature DS(ON) ...
Page 5
Typical Performance Characteristics NFB 25˚ −5V A OUT NFB 25˚ −5V A OUT I vs Ambient Temperature (No Load) q (Continued Ambient ...
Page 6
Typical Performance Characteristics Efficiency vs. Load V = −5V, V OUT IN www.national.com (Continued 20018128 6 Efficiency vs =− 5V 125mA OUT OUT 20018127 ...
Page 7
Operation Cuk Converter FIGURE 1. Operating Cycles of a Cuk Converter The LM2611 is a current mode, fixed frequency PWM switching regulator with a −1.23V reference that makes it ideal for use in a Cuk converter. The Cuk converter inverts ...
Page 8
Operation (Continued) The following equations define values given in Figure 2 and Figure OUT Use these equations to choose correct core sizes for the inductors. The design of the LM2611’s internal compensa- tion assumes ...
Page 9
Operation (Continued) A general rule of thumb is to keep f ESR Cuk designs. Low ESR tantalum capacitors will usually be rated for at least 180mA in a voltage rating of 10V or above. However the ESR in a tantalum ...
Page 10
Operation (Continued) Thermal Shutdown If the junction temperature of the LM2611 exceeds 163˚C, it will enter thermal shutdown. In thermal shutdown, the part deactivates the driver and the switch turns off. The switch Application Circuits FIGURE 10. LM2611 Operating with ...
Page 11
Application Circuits (Continued) Shutdown/Soft Start A soft start circuit is used in switching power supplies to limit the input inrush current upon start-up. Without a soft-start circuit, the inrush current can be several times the steady-state load current, and thus ...
Page 12
Application Circuits High Duty Cycle/Load Current Operation The circuit in Figure 14 is used for high duty cycles (D and high load currents (see Figure 5 ). The duty cycle will begin to increase beyond 50% as the input voltage ...
Page 13
... NATIONAL’S PRODUCTS ARE NOT AUTHORIZED FOR USE AS CRITICAL COMPONENTS IN LIFE SUPPORT DEVICES OR SYSTEMS WITHOUT THE EXPRESS WRITTEN APPROVAL OF THE PRESIDENT AND GENERAL COUNSEL OF NATIONAL SEMICONDUCTOR CORPORATION. As used herein: 1. Life support devices or systems are devices or systems which, (a) are intended for surgical implant ...