L4901A

L4901A STMICROELECTRONICS | Alldatasheet

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Technical content

DUAL 5V REGULA TOR WITH RESET June 2000 PIN CONNECTION HEPTAWATT (Vertical) (Plastic Package) ORDERING NUMBER : L4901A .OUTPUT CURRENTS : I 01 = 400mA I02 = 400mA .FIXED PRECISION OUTPUT VOLT AGE 5V ± 2% .RESET FUNCTION CONTROLLED BY INPUT VOLT AGE AND OUTPUT 1 VOLT AGE .RESET FUNCTION EXTERNALLY PRO- GRAMMABLE TIMING .RESET OUTPUT LEVEL RELATED TO OUT- PUT 2 .OUTPUT 2 INTERNALL Y SWITCHED WITH ACTIVE DISCHARGING .LOW LEAKAGE CURRENT , LESS THAN 1 µA AT OUTPUT 1 .LOW QUIESCENT CURRENT (Input 1) .INPUT OVERVOLT AGE PROTECTION UP TO 60V .RESET OUTPUT HIGH .OUTPUT TRANSISTORS SO A PROTECTION .SHORT CIRCUIT AND THERMAL OVER- LOAD PROTECTION

DESCRIPTION

The L4901A is a monolithic low drop dual 5V regulatordesignedmainly for supplying microproc- essor systems. Reset and data save functions during switch on/off can be realized.

N ° Name Function 1 Input 1 Low Quiescent Current 400mA Regulator Input. 2 Input 2 400mA regulator input.

3 Timing

If Reg. 2 is switched-ON the delay capacitor is charged with a 10µA constant current. When Reg. 2 is switched-OFF the delay capacitor is decharged. 4 GND Common Ground.

5 Reset

When pin 3 reaches 5V the reset output is switched high. Therefore tRD =C t ( 5V 10µA ); tRD (ms) = Ct (nF) 6 Output 2 5V – 400mA Regulator Output. Enabled if Vo 1>V RT and VIN 2>V IT. If Reg. 2 is switched-OFF the C02 capacitor is discharged. 7 Output 1 5V – 400mA regulator output with Low leakage (in switch-OFF condition). L4901A

Symbol Parameter Value Unit V IN DC Input Voltage Transient Input Overvoltage (t = 40ms) V V Io Output Current Internally Limited Tj Storage and Junction Temperature – 40 to 150 °C THERMAL DAT A Symbol Parameter Value Unit R th (j-c) Thermal Resistance Junction-case Max. 4 °C/W ELECTRICAL CHARACTERISTICS (VIN = 14, 4V, Tamb =2 5°C unless otherwise specified) Symbol Parameter Test Conditions Min. Typ. Max. Unit Vi DC Operating Input Voltage 20 V V01 Output Voltage 1 R Load 1kΩ 4.95 5.05 5.15 V V02 H Output Voltage 2 HIGH R Load 1kΩ V01 –0.1 5 V 01 V V02 L Output Voltage 2 LOW I 02 = – 5mA 0.1 V I01 Output Current 1 Δ V01 = – 100mV 400 mA IL01 Leakage Output 1 Current VIN =0 ,V01 ≤ 3V 1 µA I02 Output Current 2 Δ V02 = – 100mV 400 mA VI01 Output 1 Dropout Voltage (*) I01 = 10mA I01 = 100mA I01 = 300mA 0.7 0.8 1.1 0.8 1.4 V V V VIT Input Threshold Voltage V 01 + 1.2 6.4 V 01 + 1.7 V VITH Input Threshold Voltage Hyst. 250 mV ΔV01 Line Regulation 1 7V < V IN < 18V, I01 = 5mA 5 50 mV ΔV02 Line Regulation 2 7V < V IN < 18V, I02 = 5mA 5 50 mV ΔV01 Load Regulation 1 5mA < I 01 < 400mA 50 100 mV ΔV02 Load Regulation 2 5mA < I 01 < 400mA 50 100 mV IQ Quiescent Current I02 =I01 ≤ 5mA 0<V IN < 13V 7V < VIN < 13V 4.5 1.6 6.5 3.5 mA IQ1 Quiescent Current 1 I01 ≤ 5mA, I02 =0 ,VIN2 =0 6.3V < VIN < 13V 0.6 0.9 mA VRT Reset Threshold Voltage V 02 – 0.15 4.9 V 02 –0.05 V VRTH Reset Threshold Hysteresis 30 50 80 mV VRH Reset Output Voltage HIGH IR = 500µA V02 – 1 4.12 V 02 V VRL Reset Output Voltage LOW I R = –<0>5mA 0.25 0.4 V tRD Reset Pulse Delay C t = 10nF 3 5 11 ms td Timing Capacitor Discharge Time Ct = 10nF 20 µs ΔV01 ΔT Thermal Drift –2 0°C ≤ Tamb ≤ 125°C 0.3 – 0.8 mV/°C ΔV02 ΔT Thermal Drift –2 0°C ≤ Tamb ≤ 125°C 0.3 – 0.8 mV/°C SVR1 Supply Voltage Rejection f = 100Hz, V R = 0.5V Io = 100mA 50 84 dB SVR2 Supply Voltage Rejection 50 80 dB * The dropout voltage is defined as the difference between the input and the output voltage when the output voltage is lowered of 25 mV under constant output current condition. L4901A

In power supplies forµP systems it is necessaryto provide power continuously to avoid loss of infor- mation in memories and in time of day clocks, or to savedatawhen the primary supplyis removed.The L4901A makes it very easy to supply such equip- ments ; it providestwo voltage regulators (both 5 V high precision) with separate inputs plus a reset output for the data save function. CIRCUIT OPERATION (see Figure 1) After switch on Reg. 1 saturates until V 01 rises to the nominal value. When the input 2 reaches VIT and the output 1 is higher than VRT the output 2 (V02) switches on and the reset output (VR ) also goes high after a pro- grammable time TRD (timing capacitor). V02 and VR are switched togetherat low level when one of the following conditions occurs : - an input overvoltage - an overload on the output 1 (V01 <V RT ); - a switch off (VIN <V IT-VITH); and they start again as before when the condition is removed. An overload on output 2 does not switch Reg. 2, and does not influence Reg. 1. The V01 output features : - 5 V internal reference without voltage divider between the output and the error comparator ; - very low drop series regulator element utilizing current mirrors ; permit high output impedance and then very low leakage current error even in power down condi- Figure 1 L4901A

DIM. mm inch A 4.8 0.189 C 1.37 0.054 D 2.4 2.8 0.094 0.110 D1 1.2 1.35 0.047 0.053 E 0.35 0.55 0.014 0.022 E1 0.7 0.97 0.028 0.038 F 0.6 0.8 0.024 0.031 F1 0.9 0.035 H2 10.4 0.409 H3 10.05 10.4 0.396 0.409 L1 14.92 0.587 L4 1.29 0.051 L9 0.2 0.008 V4 40 ° (typ.) Dia 3.65 3.85 0.144 0.152 A L C D E M Dia. F1H2 F GG 1 G 2 F E VV HEPTAMEC OUTLINE AND MECHANICAL DATA L4901A

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