L5980TR STMicroelectronics, L5980TR Datasheet
L5980TR
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L5980TR
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L5980TR Summary of contents
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Features ■ 0 output current ■ 2 input voltage ■ Output voltage adjustable from 0.6 V ■ 250 kHz switching frequency, programmable MHz ■ Internal soft-start and inhibit ■ Low dropout ...
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Contents Contents 1 Pin settings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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L5980 8 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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Pin settings 1 Pin settings 1.1 Pin connection Figure 2. Pin connection (top view) 1.2 Pin description Table 1. Pin description Pin n° Type 1 OUT 2 SYNCH 3 INH 4 COMP GND 8 ...
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L5980 2 Maximum ratings 2.1 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol Vcc OUT F , COMP, SYNCH Analog pin SW INH FB P TOT stg 2.2 Thermal data Table 3. Thermal data Symbol R ...
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Electrical characteristics 3 Electrical characteristics ° unless otherwise specified Table 4. Electrical characteristics Symbol Operating input voltage V CC range V Turn on V CCON V V UVLO hysteresis CCHYS CC ...
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L5980 Table 4. Electrical characteristics (continued) Symbol V High level output voltage CH V Low level output voltage CL I Bias source current FB I Source COMP pin O SOURCE I Sink COMP pin O SINK G Open loop voltage ...
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Functional description 4 Functional description The L5980 is based on a “voltage mode”, constant frequency control. The output voltage V is sensed by the feedback pin (FB) compared to an internal reference (0.6 V) providing OUT an error signal that, ...
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L5980 4.1 Oscillator and synchronization Figure 4 shows the block diagram of the oscillator circuit. The internal oscillator provides a constant frequency clock. Its frequency depends on the resistor externally connect to FSW pin. In case the FSW pin is ...
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Functional description Figure 5. Sawtooth: voltage and frequency feed forward; external synchronization Figure 6. Oscillator frequency versus FSW pin resistor 10/42 Doc ID 13003 Rev 6 L5980 ...
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L5980 4.2 Soft-start The soft-start is essential to assure correct and safe start up of the step-down converter. It avoids inrush current surge and makes the output voltage increases monothonically. The soft-start is performed by a staircase ramp on the ...
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Functional description 4.3 Error amplifier and compensation The error amplifier (E/A) provides the error signal to be compared with the sawtooth to perform the pulse width modulation. Its non-inverting input is internally connected to a 0.6 V voltage reference, while ...
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L5980 4.4 Overcurrent protection The L5980 implements the overcurrent protection sensing current flowing through the power MOSFET. Due to the noise created by the switching activity of the power MOSFET, the current sensing is disabled during the initial phase of ...
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Functional description Figure 8. Overcurrent protection strategy 4.5 Inhibit function The inhibit feature allows to put in stand-by mode the device.With INH pin higher than 1.9 V the device is disabled and the power consumption is reduced to less than ...
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L5980 5 Application information 5.1 Input capacitor selection The capacitor connected to the input has to be capable to support the maximum input operating voltage and the maximum RMS input current required by the device. The input capacitor is subject ...
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Application information 5.2 Inductor selection The inductance value fixes the current ripple flowing through the output capacitor. So the minimum inductance value in order to have the expected current ripple has to be selected. The rule to fix the current ...
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L5980 5.3 Output capacitor selection The current in the capacitor has a triangular waveform which generates a voltage ripple across it. This ripple is due to the capacitive component (charge and discharge of the output capacitor) and the resistive component ...
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Application information 5.4 Compensation network The compensation network has to assure stability and good dynamic performance. The loop of the L5980 is based on the voltage mode control. The error amplifier is a voltage operational amplifier with high bandwidth. So ...
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L5980 Equation 13 where: Equation 14 Equation 15 As seen in Chapter 4.3 following paragraph the guidelines to select the type II and type III compensation network are illustrated. 5.4.1 Type III compensation network The methodology to stabilize the loop ...
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Application information Equation 17 Figure 10. Type III compensation network In Figure 11 the Bode diagram of the PWM and LC filter transfer function (G and the open loop gain (G Figure 11. Open loop gain: module Bode diagram The ...
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L5980 Equation 18 where K is the feed forward constant and 1/K is equals Calculate C 4 Equation 19 4. Calculate C 5 Equation 20 5. Set also the first pole at four times the system bandwidth ...
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Application information Figure 12. Open loop gain Bode diagram with ceramic output capacitor 22/42 Doc ID 13003 Rev 6 L5980 ...
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L5980 5.4.2 Type II compensation network If the equivalent series resistance (ESR) of the output capacitor introduces a zero with a frequency lower than the desired bandwidth (that is: 2π * ESR * C helps stabilize the loop. Electrolytic capacitors ...
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Application information Figure 14. Open loop gain: module Bode diagram The guidelines for positioning the poles and the zeroes and for calculating the component values can be summarized as follow: 1. Choose a value for R and C5 not comparable ...
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L5980 Equation 25 For example with V ESR = 50 mΩ, the type II compensation network is: In Figure 15 is shown the module and phase of the open loop gain. The bandwidth is about 35 kHz and the phase ...
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Application information Figure 15. Open loop gain Bode diagram with electrolytic/tantalum output capacitor 26/42 Doc ID 13003 Rev 6 L5980 ...
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L5980 5.5 Thermal considerations The thermal design is important to prevent the thermal shutdown of device if junction temperature goes above 150 °C. The three different sources of losses within the device are: a) conduction losses due to the not ...
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Application information of heat. The R thJA paragraph is about 60 °C/W. Figure 16. Switching losses 5.6 Layout considerations The PC board layout of switching DC/DC regulator is very important to minimize the noise injected in high impedance nodes and ...
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L5980 Figure 17. Layout example Doc ID 13003 Rev 6 Application information 29/42 ...
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... A Doc ID 13003 Rev 6 L1 15uH L1 15uH Vout=3.3V Vout=3.3V Vout=3.3V Vout=3. STPS2L25U STPS2L25U STPS2L25U STPS2L25U R1 4.99K R1 4.99K R1 4.99K R1 4.99K R3 180 R3 180 C3 3.3nF C3 3.3nF R2 1.1K R2 1.1K R2 1.1K R2 1.1K Description Manufacturer MURATA MURATA STMicroelectronics Wurth elektronik L5980 22uF 22uF 22uF 22uF ...
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L5980 Figure 19. PCB layout (component side) Figure 20. PCB layout (bottom side) Figure 21. PCB layout (front side) Doc ID 13003 Rev 6 Application information 31/42 ...
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Application information Figure 22. Junction temperature vs output current Figure 24. Junction temperature vs output current Figure 26. Efficiency vs output current VCC= =250KHz SW 76 0.1 0.2 0.3 0.4 ...
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L5980 Figure 28. Load regulation 0.14 F =250KHz SW 0.12 0.1 0.08 0.06 0.04 0.02 0 0.1 0.2 0.3 0.4 Io [A] Figure 30. Short circuit behavior OUT OUT OUT OUT OUT OUT OUT 10V/div 10V/div 10V/div 10V/div 10V/div 10V/div ...
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Application ideas 6 Application ideas 6.1 Positive buck-boost The L5980 can implement the step up/down converter with a positive output voltage. Figure 33 shows the schematic: one power MOSFET and one Schottky diode are added to the standard buck topology ...
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L5980 Equation 32 where I is the average current in the embedded power MOSFET in the ON time chose the right value of the inductor and to manage transient output current, that for short time can exceed the ...
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Application ideas Figure 34. Maximum output current according to max DC switch current (0.7 A): V =12V O Equation 34 where V is the voltage drop across diodes power MOSFET. 6.2 Inverting buck-boost The L5980 can implement the ...
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L5980 As in the positive one, in the inverting buck-boost the current flowing through the power MOSFET is transferred to the load only during the OFF time. So according to the maximum DC switch current (0.7 A), the maximum output ...
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Package mechanical data 7 Package mechanical data In order to meet environmental requirements, ST offers these devices in different grades of ECOPACK® packages, depending on their level of environmental compliance. ECOPACK® specifications, grade definitions and product status are available at: ...
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L5980 Table 10. VFQFPN8 ( 1.08 mm) mechanical data Dim ddd Figure 37. Package dimensions mm Min Typ Max 0.80 0.90 1.00 0.02 0.05 0.70 0.20 ...
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... Order codes 8 Order codes Table 11. Order codes Order codes L5980 L5980TR 40/42 Package VFQFPN8 ( 1.08 mm) Doc ID 13003 Rev 6 L5980 Packaging Tube Tube and reel ...
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L5980 9 Revision history Table 12. Document revision history Date 21-Dec-2006 18-Oct-2007 09-Sep-2008 27-Jan-2009 15-Jun-2009 16-Nov-2009 Revision 1 Initial release 2 Document status promoted from preliminary data to datasheet Updated: Cover page, Figure 9 on page 18, 3 Table 4 ...
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