L4988D STMICROELECTRONICS | Alldatasheet

Document overview

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Technical content

Datasheet sections

  • 1 Block diagram and pin co nfiguration
  • 2 Electrical specifications
  • 2.1 Absolute maximum ratings
  • 2.2 Thermal data
  • 2.3 Electrical characteristics
  • 2.4 Electrical characteristics curves
  • 2.5 Test circuit and waveforms plot
  • 2.5.1 Load regulation
  • 3 Application information
  • 3.1 Voltage regulator
  • 3.2 Reset
  • 3.3 Watchdog
  • 4 Package and PCB thermal data
  • 4.1 SO-8 thermal data
  • 4.2 SO-20 thermal data
  • 5 Package and packing information
  • 5.1 ECOPACK ® packages
  • 5.2 SO-8 package information
  • 5.3 SO-20 package information
  • 5.4 SO-8 packing information
  • 5.5 SO-20 packing information
  • 6 Revision history

Features

■ Operating DC supply voltage range 5.6V to 31V ■ Reset circuit sensing the output voltage down to 1V ■ Programmable reset pulse delay with external capacitor ■ Watchdog ■ Programmable watchdog timer with external capacitor ■ Enable input for enabling/disabling the watchdog functionality ■ Thermal shutdown and short circuit protection ■ Wide temperature range (Tj = -40°C to 150°C)

Description

The L4988 is a monolithic integrated 5V voltage regulator with a low drop voltage at currents up to 200mA. The output voltage regulating element consists in a p-channel MOS and the regulation is performed regardless of input voltage transients up to 40V. The high precision of the output voltage is obtained with a pre-trimmed reference voltage. The L4988 is protected against short circuit and an over-temperature protection switches off the device in case of extremely high power dissipa- tion. The L4988 is active when the Enable is high. State of the art features like reset and watchdog make this device particularly suitable to supply microprocessor systems in automotive applications. Max DC supply voltage V S 40V Max output voltage tolerance V0 +/-2% Max dropout voltage V dp 500 mV Output current I 0 200 mA Quiescent current I qn 75 µA(1) 1. Typical value wi th watchdog disabled. SO-8 SO-20 Table 1. Device summary

1 Block diagram and pin configuration

Figure 1. Block diagram

Figure 2. Pins configuration Table 2. Pins description or frequency at Wi is too low. response of the watchdog monitor.

2 Electrical specifications

2.1 Absolute maximum ratings

2.2 Thermal data

Table 3. Absolute maximum ratings

  1. Using the typical application sche matic with Cout= 10 µF and Iout=0 A, when the regulator is switched-on,

an overshoot exceeding 6 V could occur.This behavior does not impact the reliability of the regulator. Table 4. Thermal data

  1. With copper area 2 cm 2 ; for details see Figure 29.
  2. With copper area 6 cm 2 ; for details see Figure 33.

2.3 Electrical characteristics

Vs =5.6V to 31V, Tj= -40°C to +150°C unless otherwise specified. Table 5. General

  1. Measured output current when the output voltage has dropped 100mV from its nominal value obtained at
  2. Vs-Vo measured when the output voltage has dr opped 100mV from its nominal value obtained at

Table 6. Reset

  1. When Vo becomes lower than 4V, t he reset reaction time decreases down to 2µs assuring a faster reset

condition in this particular case. Table 7. Watchdog

Table 8. Watchdog Enable

2.4 Electrical characteristics curves

Figure 3. Output voltage vs. Tj Figure 4. Output voltage vs. Vs Figure 5. Drop Voltage vs. Output Current Figure 6. Current consumption vs. Output Figure 7. Current consumption vs. Input Figure 8. Current limitation vs. Tj

2.5 Test circuit and waveforms plot

2.5.1 Load regulation

Figure 22. Load regulation test circuit Figure 21. PSRR

Figure 23. Maximum load variation response

3 Application information

Figure 24. L4988 application schematic an additional electrolytic capacitor C02 > 10µF at the output pin.

3.1 Voltage regulator

precision of the output voltage is obtained with a pre-trimmed reference voltage.

Figure 25. Behavior of output current versus regulated voltage Vo

3.2 Reset

guaranteed for an output voltage Vo greater than 1V. When the output voltage becomes higher than Vo_th then Res goes high with a delay trd. This delay is obtained by an internal oscillator. Ctr: is an external capacitance. Reset is active when En is high.

Figure 26. Reset timing diagram

3.3 Watchdog

saw-tooth voltage at the watchdog timer capacitor Ctw. Figure 27. Watchdog timing diagram

4 Package and PCB thermal data

4.1 SO-8 thermal data

Figure 28. SO-8 PC board Figure 29. SO-8 R thj-amb Vs. PCB copper area in open box free air condition

Table 9. SO-8 thermal parameter

4.2 SO-20 thermal data

Figure 32. SO-20 PC board thickness = 2mm, Cu thickness=35m , Copper areas: from minimum pad lay-out to 8cm2). Figure 33. SO-20 R thj-amb Vs. PCB copper area in open box free air condition

Table 10. SO-20 thermal parameter

5 Package and packing information

5.1 ECOPACK ® packages

conditions are also marked on the inner box label. ECOPACK is an ST trademark. ECOPACK specifications are available at: www.st.com.

5.2 SO-8 package information

Figure 36. SO-8 package dimensions

Table 11. SO-8 mechanical data

  1. Dimensions D does not include mold flash, protrusions or gate burrs. Mold flash, potrusions or gate burrs

shall not exceed 0.15mm in total (both side).

  1. Dimension “E1” does not include interlead flash or pr otrusions. Interlead flash or protrusions shall not

5.3 SO-20 package information

Figure 37. SO-20 package dimensions Table 12. SO-20 mechanical data

5.4 SO-8 packing information

Figure 38. SO-8 tube shipment (no suffix)

  1. “D” dimension does not include mold flash, protusions or gate burrs. Mold flash, protusions or gate burrs

shall not exceed 0.15mm per side. Table 12. SO-20 mechanical data (continued)

Figure 39. SO-8 tape and reel shipment (suffix “TR”)

5.5 SO-20 packing information

Figure 40. SO-20 tube shipment (no suffix) Figure 41. SO-20 tape and reel shipment (suffix “TR”)

6 Revision history

Table 13. Document revision history Added list of tables and figures. Updated Section 2.3: Electrical characteristics. Added Section 4: Package and PCB thermal data. Added SO-8 packing information and SO-20 packing information. 13-Feb-2008 3 Update Section 2.3: Electrical characteristics. Changed Figure 1: Block diagram. – changed Iq_1_wd typical value from 80 to 75 µA. – changed Vwhth values in Vo_ref percentages. Added Figure 24: L4988 application schematic. Added Section 2.4: Electrical characteristics curves. Added Section 2.5: Test circuit and waveforms plot. 05-Apr-2012 5 Update Table 3: Absolute maximum ratings. 20-Sep-2013 6 Updated disclaimer.