L5983TR STMicroelectronics, L5983TR Datasheet
L5983TR
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L5983TR
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L5983TR Summary of contents
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Features ■ 1 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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L5983 7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...
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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 N. Type 1 OUT 2 SYNCH 3 INH 4 COMP GND 8 V ...
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L5983 2 Maximum ratings 2.1 Absolute maximum ratings Table 2. Absolute maximum ratings Symbol V CC OUT F , COMP, SYNCH SW INH FB P TOT stg 2.2 Thermal data Table 3. Thermal data Symbol R thJA ...
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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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L5983 Table 4. Electrical characteristics 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 gain ...
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Functional description 4 Functional description The L5983 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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L5983 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 connected to the FSW pin. In case the FSW pin ...
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Functional description Figure 5. Sawtooth: voltage and frequency feed forward; external synchronization Figure 6. Oscillator frequency vs. FSW pin resistor 10/43 Doc ID 13005 Rev 7 L5983 ...
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L5983 4.2 Soft-start The soft-start is essential to assure correct and safe startup of the step-down converter. It avoids inrush current surge and makes the output voltage increase monothonically. The soft-start is performed by a staircase ramp on the non-inverting ...
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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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L5983 4.4 Overcurrent protection The L5983 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 the device to be put into standby mode. With the INH pin higher than 1.9 V, the device is disabled and the power consumption is reduced ...
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L5983 5 Application information 5.1 Input capacitor selection The capacitor connected to the input must be able to support the maximum input operating voltage and the maximum RMS input current required by the device. The input capacitor is subject to ...
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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, must be selected. The rule to fix the current ripple ...
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L5983 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 L5983 is based on the voltage mode control. The error amplifier is a voltage operational amplifier with high bandwidth. So, ...
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L5983 Equation 15 As seen in Section following paragraphs the guidelines to select the type II and type III compensation network are illustrated. Figure 9. Error amplifier, PWM modulator and LC output filter V V REF REF FB FB 5.4.1 ...
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Application information 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 guidelines for ...
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L5983 Equation 19 4. Calculate C 5 Equation 20 5. Set the first pole also at four times the system bandwidth and also the second zero at the output filter double pole: Equation 21 The suggested maximum system bandwidth is ...
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Application information Figure 12. Open loop gain Bode diagram with ceramic output capacitor 22/43 Doc ID 13005 Rev 7 L5983 ...
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L5983 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 zeros and for calculating the component values can be summarized as follows: 1. Choose a value for R and C5 not comparable ...
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L5983 Equation 25 For example, with V mΩ, the type II compensation network is: In Figure 15 the module and phase of the open loop gain is shown. The bandwidth is about 30 kHz and the phase margin is 45°. ...
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Application information Figure 15. Open loop gain Bode diagram with electrolytic/tantalum output capacitor 26/43 Doc ID 13005 Rev 7 L5983 ...
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L5983 5.5 Thermal considerations The thermal design is important to prevent the thermal shutdown of the device if junction temperature goes above 150 °C. The three different sources of losses within the device are: a) conduction losses due to the ...
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Application information For this device the path through the exposed pad is the one conducting the largest amount of heat. The Rth JA paragraph, is about 60 °/W. Figure 16. Switching losses 5.6 Layout considerations The PC board layout of ...
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L5983 Figure 17. Layout example Doc ID 13005 Rev 7 Application information 29/43 ...
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... 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 330 R3 330 R3 330 R3 330 C3 2.2nF C3 2.2nF C3 2.2nF C3 2.2nF R2 1.1K R2 1.1K R2 1.1K R2 1.1K Description Manufacturer 10 μ MURATA 22 μ MURATA 2 220 pF nF Coilcraft STMicroelectronics L5983 22uF 22uF 22uF 22uF ...
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L5983 Figure 19. PCB layout (component side) Figure 20. PCB layout (bottom side) Figure 21. PCB layout (front side) Doc ID 13005 Rev 7 Application information 31/43 ...
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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=5V =250kHz 0.2 0.4 0.6 ...
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L5983 Figure 28. Load regulation 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0.2 0.4 0.6 0.8 I [A] O Figure 30. Load transient: from 300 OUT OUT OUT OUT AC ...
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Application ideas 6 Application ideas 6.1 Positive buck-boost The L5983 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 to ...
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L5983 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, which for a short time can exceed ...
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Application ideas Figure 34. Maximum output current according to max DC switch current (1.5 A Equation 34 where V is the voltage drop across the diodes, and V D external power MOSFET. 6.2 Inverting buck-boost ...
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L5983 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 (1.5 A), the maximum output ...
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Application ideas Figure 36. Maximum output current according to max DC switch current (1.5 A 38/43 Doc ID 13005 Rev 7 L5983 ...
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L5983 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: is ...
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Package mechanical data Table 10. VFQFPN8 ( 1.08 mm) mechanical data Dim ddd Figure 37. Package dimensions 40/43 mm Min Typ Max 0.80 0.90 1.00 0.02 ...
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... L5983 8 Order codes Table 11. Order codes Order codes L5983 L5983TR Package VFQFPN8 ( 1.08 mm) Doc ID 13005 Rev 7 Order codes Packaging Tube Tube and reel 41/43 ...
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Revision history 9 Revision history Table 12. Document revision history Date 21-Dec-2006 16-Oct-2007 27-May-2008 16-Sep-2008 28-Jan-2009 15-Jun-2009 29-Nov-2010 42/43 Revision 1 Initial release 2 Document status promoted from preliminary data to datasheet Updated: Cover page, Figure 5 on page 10, ...
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... L5983 Information in this document is provided solely in connection with ST products. STMicroelectronics NV and its subsidiaries (“ST”) reserve the right to make changes, corrections, modifications or improvements, to this document, and the products and services described herein at any time, without notice. All ST products are sold pursuant to ST’s terms and conditions of sale. ...