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| L4979D L4979MD LOW DROP VOLTAGE REGULATOR 1 FEATURES OPERATING DC SUPPLY VOLTAGE RANGE 5.6V TO 31V LOW QUIESCENT CURRENT (6A Typ. @ 25C with Enable Low) HIGH PRECISION OUTPUT VOLTAGE (2%) LOW DROPOUT VOLTAGE LESS THAN 0.5V RESET CIRCUIT SENSING THE OUTPUT VOLTAGE DOWN TO 1V PROGRAMMABLE RESET PULSE DELAY WITH EXTERNAL CAPACITOR WATCHDOG PROGRAMMABLE WATCHDOG TIMER WITH EXTERNAL CAPACITOR THERMAL SHUTDOWN AND SHORT CIRCUIT PROTECTION AUTOMOTIVE TEMPERATURE RANGE (Tj = -40C TO 150C) ENABLE INPUT FOR ENABLING/DISABLING THE VOLTAGE REGULATOR OUTPUT Figure 1. Packages SO-8 SO-20 Table 1. Order Codes Part Number L4979D L4979MD L4979D13TR L4979MD13TR Package SO-8 SO-20 SO-8 Tape & Reel SO-20 Tape & Reel Figure 2. Block Diagram 5V, 150 mA Vi Vs Vo Co Vcw Ctw watchdog Wi Voltage reference gnd En Res Vcr Ctr reset October 2004 Rev. 5 1/10 L4979MD L4979D Table 2. Pin Function SO8 N 1 SO20 N 1 Pin Name En Function Enable input If high, regulator, watchdog and reset are operating. If low, regulator, watchdog and reset are shut down. Ground reference Ground These pins are to be connected to a heat spreader electrically grounded Reset output. It is pulled down when output voltage drops below Vo_th or frequency at Wi is too low. Reset timing adjust A capacitor between Vcr pin and gnd sets the reset delay time (trd) Watchdog timer adjust A capacitor between Vcw pin and gnd sets the time response of the watchdog monitor. Watchdog input. If the frequency at this input pin is too low, the Reset output is activated. Voltage regulator output Output capacitor >100nF is needed for regulator stability Supply voltage Supply capacitor (e.g. 200nF) is needed for regulator stability. not connected 2 4 5,6,15,16 gnd gnd Res 3 7 4 5 10 11 Vcr Vcw 6 7 8 14 17 20 2, 3, 8, 9, 12, 13, 18, 19 Wi Vo Vs N. C. Figure 3. Pins Connection (Top view) EN GND RES VCR 1 2 3 4 SO8 8 7 VS VO WI VCW SO8 6 5 EN N.C. N.C. GND GND GND RES N.C. N.C. VCR 1 2 3 4 5 6 7 8 9 10 D00AT457 20 19 18 17 16 VS N.C. N.C. VO GND GND WI N.C. N.C. WCW SO20 15 14 13 12 11 2/10 L4979MD L4979D Table 3. Absolute Maximum Ratings Symbol Vvsdc Ivsdc Vvo Ivo Vwi Vod Iod Vcr Vcw Ven Tj VESD DC supply voltage Input current DC output voltage DC output current Watchdog input voltage Open drain output voltage (RES) Open drain output current (RES) Reset delay voltage Watchdog delay voltage Enable input voltage Junction temperature ESD voltage level (HBM-MIL STD 883C) Parameter Value -0.3 to 40 internally limited -0.3 to 6 internally limited -0.3 to Vvo +0.3 -0.3 to Vvo +0.3 internally limited -0.3 to Vvo +0.3 -0.3 to Vvo +0.3 -0.3 to 40 -40 to 150 2 V V V C kV V V V Unit V Note: 1. Maximum ratings are absolute ratings; exceeding any one of these values may cause permanent damage to the integrated circuit. Table 4. Thermal DatA Symbol Rth j-amb Parameter Thermal resistance Junction to Ambient SO8 130 to 180 SO16+2+2 50 to 80 Unit C/W Table 5. Electrical Characteristcs (Vs = 5.6V to 31V, Tj = -40C to +150C unless otherwise specified) Pin GENERAL Vs, Vo Iq Quiescent current Vs = 13.5V, Io=150mA, enable high all I/O currents=0 Vs = 13.5V, Io = 0mA, enable high all I/O currents = 0 Vs = 13.5V, Io = 0mA, enable low all I/O currents = 0 150 10 1.5 3 mA Symbol Parameter Test Condition Min. Typ. Max. Unit Vs, Vo Iq Quiescent current 100 200 A Vs, Vo Iq Quiescent current 6 20 A Tw Tw_hy Thermal protection temperature Thermal protection temperature hysteresis 190 C C 3/10 L4979MD L4979D Table 5: Electrical Characteristics (continued) Pin Symbol Parameter Test Condition Min. Typ. Max. Unit VOLTAGE REGULATOR Vo Vo Vo Vs, Vo Vo Vs, Vo Vs, Vo RESET Res Res Res Res Vres_l Ires_h R_p_u Vo_th Reset output low voltage Reset output high leakage current Internal Pull up resistance Reset threshold voltage Rext = 5k to Vo, Vo > 1V Vres = 5V with respect to Vo Vs = 5.6 to 31V Io = 1 to 150mA Vs = 13.5V Vs = 13.5V Vs = 13.5V Vs = 13.5V Vo = Vo_th -100mV Vs = 13.5V, Ctr = 1nF 12 6% below Vo_ref 44% Vo_ref 10% Vo_ref 8 8 100 65 25 8% below Vo_ref 47% Vo_ref 13% Vo_ref 17 17 250 0.4 1 50 10% below Vo_ref 50% Vo_ref 16% Vo_ref 30 30 700 150 A A s ms V A k Vo_ref Ishort Ilim Vline Vload Vdp SVR Output voltage Vs = 5.6 to 31V Io = 1 to 150mA Vs = 13.5V Vs = 13.5V Vs = 5.6 to 31V Io = 1 to 150mA Io = 1 to 150mA Io = 150mA fr = 100 Hz 55 200 4.90 5.00 5.10 V Output short circuit current (1) Output current limitation (1) Line regulation voltage 150 150 280 320 400 500 25 mA mA mV Load regulation voltage Drop voltage Ripple rejection (2) 25 400 mV mV dB Vcr Vcr Vcr Vcr Res Res WATCHDOG Wi Wi Wi Wi Vcw Vcw Vrhth Vrlth Icr Idr trr_2 trd Reset timing high threshold Reset timing low threshold Charge current Discharge current Reset delay time (3) Reset pulse delay Vih Vil Vih Ii Vwhth Vwlth Input high voltage Input low voltage Input hysteresis Pull down current High threshold Low threshold Vs = 13.5V Vs = 13.5V Vs = 13.5V Vs = 13.5V Vs = 13.5V Vs = 13.5V 3.5 1.5 300 10 2.20 0.50 2.35 0.65 20 2.50 0.80 V V mV A V V 4/10 L4979MD L4979D ELECTRICAL CHARACTERISTICS (continued) Pin Vcw Vcw Vcw Res ENABLE En En En En Ven_l Ven_h Ven_hy I_leak Enable input low voltage Enable input high voltage Enable input hysteresis Pull down current En = 5V 3 700 2 1000 10 1100 20 1 V V mV A Symbol Icwc Icwd Twop twol Parameter Charge current Discharge current Watchdog period Watchdog output low time Test Condition Vs = 13.5V, Vcw = 0.1V Vs = 13.5V, Vcw = 2.5V Vs = 13.5V, Ctw = 47nF Vs = 13.5V, Ctw = 47nF Min. 4 1.0 25 6 Typ. 7.5 2.4 50 10 Max. 14 4.5 90 22 Unit A A ms ms Note: 1. see fig4 (behavior of output current versus regulated voltage Vo) 2. guaranteed by design 3. When Vo becomes lower than 4V, the reset reaction time decreases down to 2s assuring a faster reset condition in this particular case. 2 VOLTAGE REGULATOR The voltage regulator uses a p-channel MOS transistor as a regulating element. With this structure a low dropout voltage at current up to 150mA is achieved. The output voltage is regulated up to transient input supply voltage of 40V. No functional interruption due to over-voltage pulses is generated. The high precision of the output voltage is obtained with a pre-trimmed reference voltage. A short circuit protection to GND is provided. Figure 4. Behavior of output current versus regulated voltage Vo (see a.m. Note 1) Vo Vo_ref Ishort Ilim Iout 3 RESET The reset circuit monitors the output voltage Vo. If the output voltage drops below Vo_th then Res becomes low with a delay time trr. Real trr value changes as a non-linear function of delta (Vo-th - Vo). The reset low signal is 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 512 periods of an oscillator (see fig. 5). The oscillator period is given by: 5/10 L4979MD L4979D [ ( V rhth - V rlth ) C tr ] [ ( V rhth - V rlth ) C tr ] T osc = ----------------------------------------------------- + ----------------------------------------------------I cr I dr and reset pulse delay trd is given by: trd = 512 x Tosc Figure 5. Reset Time Diagram. Wi V out_th trr T osc Vrhth Vrlth Vo Vcr < trr trd = 512 T osc R es 4 WATCHDOG The watchdog input Wi monitors a connected microcontroller. If pulses are missing, the reset output Res is set to low. The pulse sequence time can be set within a wide range thorough the external capacitor Ctw. The watchdog circuit discharges the capacitor Ctw with the constant current Icwd. If the lower threshold Vwlth is reached, a watchdog reset is generated. To prevent this reset, the microcontroller must generate a positive edge during the discharge of the capacitor before the voltage has reached the threshold Vwlth. In order to calculate the minimum time Tdis during which the microcontroller must generate the positive edge, the following equation can be used: (Vwhth - Vwlth) x Ctw = Icwd x Tdis Each Wi positive edge switches the current source from discharging to charging; the same happens when the lower Vwlth threshold is reached. When the voltage reaches the upper threshold Vwhth the current switches from charging to discharging. The result is a saw tooth voltage at the watchdog timer capacitor Ctw. Figure 6. Watchdog time diagram Wi Twop Vwhth Vcw Tdis twol Vwlth Res 6/10 L4979MD L4979D Figure 7. SO-8 Mechanical Data & Package Dimensions mm DIM. MIN. A A1 A2 B C D (1) E e H h L k ddd 5.80 0.25 0.40 1.35 0.10 1.10 0.33 0.19 4.80 3.80 1.27 6.20 0.50 1.27 0.228 0.010 0.016 TYP. MAX. 1.75 0.25 1.65 0.51 0.25 5.00 4.00 MIN. 0.053 0.004 0.043 0.013 0.007 0.189 0.15 0.050 0.244 0.020 0.050 TYP. MAX. 0.069 0.010 0.065 0.020 0.010 0.197 0.157 inch OUTLINE AND MECHANICAL DATA 0 (min.), 8 (max.) 0.10 0.004 Note: (1) Dimensions D does not include mold flash, protrusions or gate burrs. Mold flash, potrusions or gate burrs shall not exceed 0.15mm (.006inch) in total (both side). SO-8 0016023 C 7/10 L4979MD L4979D Figure 8. SO-20 Mechanical Data & Package Dimensions mm DIM. MIN. A A1 B C D (1) E e H h L k ddd 10.0 0.25 0.40 2.35 0.10 0.33 0.23 12.60 7.40 1.27 10.65 0.75 1.27 0.394 0.010 0.016 TYP. MAX. 2.65 0.30 0.51 0.32 13.00 7.60 MIN. 0.093 0.004 0.013 0.009 0.496 0.291 0.050 0.419 0.030 0.050 TYP. MAX. 0.104 0.012 0.200 0.013 0.512 0.299 inch OUTLINE AND MECHANICAL DATA 0 (min.), 8 (max.) 0.10 0.004 (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. SO20 0016022 D 8/10 L4979MD L4979D Table 6. Revision History Date June 2004 July 2004 Revision 3 4 Description of Changes Changed the values of the parameter "Reset timing high/low threshold. Pin Connection SO-20 changed. Changed some textes in the Features and table 2. Changed some values in the tables 3, 4 and 5. Changed some textes in the sections 2, 3 and 4. Changed from Product Preview to final datasheet. October 2004 5 9/10 L4979MD - L4979D Information furnished is believed to be accurate and reliable. However, STMicroelectronics assumes no responsibility for the consequences of use of such information nor for any infringement of patents or other rights of third parties which may result from its use. No license is granted by implication or otherwise under any patent or patent rights of STMicroelectronics. Specifications mentioned in this publication are subject to change without notice. This publication supersedes and replaces all information previously supplied. STMicroelectronics products are not authorized for use as critical components in life support devices or systems without express written approval of STMicroelectronics. The ST logo is a registered trademark of STMicroelectronics. All other names are the property of their respective owners (c) 2004 STMicroelectronics - All rights reserved STMicroelectronics GROUP OF COMPANIES Australia - Belgium - Brazil - Canada - China - Czech Republic - Finland - France - Germany - Hong Kong - India - Israel - Italy - Japan Malaysia - Malta - Morocco - Singapore - Spain - Sweden - Switzerland - United Kingdom - United States www.st.com 10/10 |
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