L4925
14Pages

Catalog excerpts

L4925 Very low drop voltage regulator Features ■ Operating DC supply voltage range 6 V to 28 V Transient supply voltage up to 40 V Extremely low quiescent current High precision output voltage Output current capability up to 500 mA Very low dropout voltage less than 0.6 V Reset circuit sensing the output voltage Programmable reset pulse delay with external capacitor Thermal shutdown and short circuit protections Description The L4925 is a monolithic integrated 5 V voltage regulator with a very low dropout output and additional functions such as power-on reset and programmable reset delay time. It is designed for supplying microcomputer controlled systems especially in automotive applications. Table 1. Device summary Order codes Package Tube PowerSO-20

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Block and pin connections diagrams . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 1.1 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Voltage regulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Reset circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Supply voltage transients . . . . . . . . . . . . . . . . . . . . . . . ....

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List of tables Table 2. Table 3. Table 4. Table 5. Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

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List of figures Figure 1. Figure 2. Figure 3. Figure 4. Figure 5. Figure 6. Figure 7. Figure 8. Figure 9. Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 PowerSO-20 pin connections (top view). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 Foldback characteristics of VO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Output voltage vs input voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ....

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Block and pin connections diagrams Block and pin connections diagrams Figure 1. PowerSO-20 pin connections (top view) Connected to pin 1-10-11-20 Thermal data Table 2. Symbol Rth(j-amb) Rth(j-c) Thermal data Parameter Thermal resistance junction to ambient Thermal resistance junction to case (max)

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Electrical specifications Electrical specifications Absolute maximum ratings Table 3. Absolute maximum ratings DC operating supply voltage Transient supply voltage (t < 1s) Output current internally limited Output voltage Output voltage Output current Storage temperature Operating junction temperature Thermal shutdown-junction temperature The circuit is ESD protected according to MIL-STD-883C. According to ISO/DIS 7637 the transients must be clamped with external circuitry (see Application Circuit). Electrical characteristics VS =14 V; Tj = –40 to 125 °C unless otherwise specified....

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Electrical specifications Electrical characteristics (continued) Parameter Test condition Reset threshold voltage Reset threshold Reset pulse delay Reset reaction time Reset output low voltage Reset output high leakage current Delay comparator threshold Delay comparator threshold hysteresis

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Functional description Functional description The L4925 is a monolithic integrated voltage regulator, based on the STM modular voltage regulator approach. Several outstanding features and auxiliary functions are implemented to meet the requirements of supplying microprocessor systems in automotive applications. Nevertheless, it is suitable also in other applications where the present functions are required. The modular approach of this device allows to get easily also other features and functions when required. Voltage regulator The voltage regulator uses an Isolated Collector Vertical PNP...

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Functional description Figure 4. Output voltage vs input voltage Quiescent current vs supply voltage Reset circuit The block circuit diagram of the reset circuit is shown in Figure 6. The reset circuit supervises the output voltage. The reset threshold of 4.5 V is defined with the internal reference voltage and standby output divider. The reset pulse delay time tRD, is defined with the charge time of an external capacitor CT: C T  2V t RD = ------------------2A The reaction time of the reset circuit originates from the discharge time limitation of the reset capacitor CT and it is...

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Functional description Block circuit diagram Reset output waveforms

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Application information Application information Supply voltage transients High supply voltage transients can cause a reset output signal disturbance. For supply voltage greater than 8 V the circuit shows a high immunity of the reset output against supply transients of more than 100 V/ms. For supply voltage lower than 8 V, supply transients of more than 0.4 V/ms. can cause a reset signal disturbance. Application circuit Application circuit diagram Vo For stability: CS  1 µF; CO  10 µF; ESR  2.5  at 10 KHz Recommended for application: CS = CO = 10 µF to 100 µF

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Package Informations Package Informations PowerSO-20 mechanical data and package dimensions DIM. OUTLINE AND MECHANICAL DATA (1) “D and E1” do not include mold flash or protusions. - Mold flash or protusions shall not exceed 0.15mm (0.006”) - Critical dimensions: “E”, “G” and “a3”. (2) For subcontractors, the limit is the one quoted in jedec MO-166 SEATING PLANE BOTTOM VIEW

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