SG29125/125A LOW DROPOUT DUAL REGULATOR DESCRIPTION FEATURES The SG29125/125A is a dual 12V/5V positive voltage regulator. One output is a high current (up to 1000 mA) regulator that can be turned on or off by a high impedance low current TTL compatible switch. The second or standby output remains on regardless. The on/off switch not only shuts off the high current output but actually puts the IC in a micropower mode making possible a low quiescent current. This unique characteristic coupled with an extremely low dropout, (.55V for output current of 10mA) makes the SG29125/125A well suited for power systems that require standby memory. The SG29125/125A includes other features which were originally designed for automotive applications. These include protection from reverse battery installations and double battery jumps. The high current regulator has overvoltage shutdown to protect both the internal circuitry and the load during line transients, such as load dump (60V). In addition, the high current regulator design also has built-in protection for short circuit and thermal overload. During these fault conditions of the primary regulator the standby regulator will continue to power its load. • 2% Internally Trimmed Output • Two regulated outputs • Output current in excess of 1000mA • Low quiescent current standby regulator • Input-output differential less than 0.6V at 0.5A • Reverse battery protection • 60V load dump protection • -50V reverse transient protection • Short circuit protection • Internal thermal overload protection • Available in plastic TO-220 • ON/OFF switch for high current output The SG29125 is the 12 volt, ±5% version of a family of dual regulators with a standby output voltage of 5V. Other high current outputs of 5 and 8.2 volts are available. Also available is the SG29125A which offers an improved output voltage tolerance of ±2%. They are available in the plastic TO-220 power package and are designed to function over the automotive ambient temperature range of -40°C to 85°C. * Required if regulator is located far from power supply filter. ** Required for stability. May be increased without bound. Capacitor must be rated to operate at the minimum temperature expected for the regulator system. TYPICAL APPLICATION CIRCUIT INPUT VOLTAGE 1 C1 * 0.1µF SG29125/125A 2 C2** 10µF OVERVOLTAGE THERMAL SHUTDOWN ON/OFF SWITCH (for output voltage only) 4 OUTPUT VOLTAGE (12V, 1000mA) REGULATOR BIAS 1.23V REFERENCE 5 5V STANDBY REGULATOR STANDBY OUTPUT (5V, 50mA) 5.6V 3 C3** 10µF GROUND LINFINITY 12/90 Rev 1.1 2/94 Copyright 1994 1 Microelectronics Inc. 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 SG29125/125A ABSOLUTE MAXIMUM RATINGS Note 1. Exceeding these values may destroy this part. Input Voltage (VIN) Operating .............................................. 26V Input Voltage (VIN) Overvoltage Transient .............. -15V to 60V ON/OFF Switch ....................................................... -0.3V to V IN Storage Temperature Range (TSTG) .................. -65°C to 150°C Operating Junction Temperature (TJ ) .............................. 150°C THERMAL DATA P Package: Thermal Resistance-Junction to Case, θ JT ................ 4.0°C/W* Thermal Resistance-Junction to Ambient, θ JA .............. 55°C/W * Note A. Junction Temperature Calculation: TJ = TA + (PD x θ JA). Note B. The above numbers for θJC are maximums for the limiting thermal resistance of the package in a standard mounting configuration. The θJA numbers are meant to be guidelines for the thermal performance of the device/pcboard system. All of the above assume no ambient airflow. = θ JT (Junction to Tab) RECOMMENDED OPERATING CONDITIONS (Note 2 & 3) Input Voltage (VIN ) .....................................................13V to 26V ON/OFF Threshold Voltage Low Level, VIL (VOUT is OFF) .................................. 0.8V max. High Level, VIH (VOUT is ON) .................................... 2.0V min. Load Current VOUT (with adequate heatsinking) .....5 to 1000mA Maximum Line Transient (Load Dump) VSB ≤ 6V ....... 60V max. Input Capacitor (VIN to GND) ................................... 0.1 µF min. Reverse Polarity D.C. Input Voltage (VIN) (VO ≥ -0.6V, 16Ω load) ........................................... -15V max. Reverse Polarity Transient Input Voltage (VIN ) (1% duty cycle, T ≤ 100ms, VO ≥ -9V, 16Ω load) ... -50V max. Output Capacitor with ESR of 1Ω max. (VOUT to GND & VSBto GND) ................................... 10µF min. Operating Ambient Temperature Range (TA) SG29125/125A ............................................... -40°C to 85°C Note 2. Range over which the device is functional. Note 3. During 60V load dump, VSB shall not be less than 4.75V at IOUT = 10mA. ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply for the operating ambient temperature of TA = 25°C, VIN = 14V, IO = 500mA for VOUT and 10mA for VSB and are for DC characteristics only. Low duty cycle pulse testing techniques are used which maintains junction and case temperatures equal to the ambient temperature.) Parameter Voltage Output (VOUT) Section Output Voltage (Note 4) Line Regulation Load Regulation Output Impedance Quiescent Current Output Noise Voltage Long Term Stability Ripple Rejection Dropout Voltage Current Limit Maximum Operational Input Voltage Maximum Line Transient ON/OFF Switch (IIH) ON/OFF Switch (IIL) 13V ≤ VIN ≤ 26V, IO ≤ 1000mA, -40°C ≤ TA ≤ 85°C SG29125 SG29125A 13V ≤ VIN ≤ 16V, IO = 5mA 13V ≤ VIN ≤ 26V, IO = 5mA 5mA ≤ IO ≤ 1000mA 500mADC and 10mARMS , 100Hz - 10kHz IO ≤ 10mA, No Load on Standby IO = 500mA, No Load on Standby IO = 750mA, No Load on Standby IO = 220mA, ISB = 10mA, VIN = VOUT - 200mV 10Hz - 100kHz FO = 120Hz IO = 500mA IO =1000mA Double Battery VO ≤ 13V IO = 10mA, Pin 4 = 2.4V IO = 10mA, Pin 4 = 0.4V 2 Units 11.2 12 12.8 V 11.75 12 12.25 V 4 25 mV 10 50 mV 10 50 mV 200 mΩ 2 mA 40 100 mA 90 mA 15 25 mA 100 µVRMS 20 mV/1000hr 66 dB 0.45 0.6 V .0.7 1.2 V 1.0 1.8 2.5 A 26.5 31 V 60 70 V 10 µA -10 µA LINFINITY 12/90 Rev 1.1 2/94 Copyright 1994 SG29125/125A Min. Typ. Max. Test Conditions Microelectronics Inc. 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 SG29125/125A ELECTRICAL CHARACTERISTICS (continued) Parameter SG29125/125A Min. Typ. Max. Test Conditions Standby Output (VSB ) Section Output Voltage (Note 4) Line Regulation Load Regulation 6V ≤ VIN ≤ 26V, IO ≤ 50mA, -40°C ≤ TA ≤ 85°C 6V ≤ VIN ≤ 26V 1mA ≤ IO ≤ 35mA 1mA ≤ IO ≤ 50mA 1mADC and 1mARMS, 100Hz - 10kHz IO ≤ 10mA, VOUTOFF 10Hz - 100kHz Output Impedance Quiescent Current Output Noise Voltage Long Term Stability Ripple Rejection Dropout Voltage Current Limit Maximum Operational Input Voltage 4.75 FO = 120Hz IO ≤ 50mA 50 60 4.75V ≤ VO ≤ 6V Units 5.0 5.25 V 50 4 mV 10 25 mV 25 50 mV 1 Ω 1.2 3 mA 300 µVRMS 20 mV/1000hr 66 dB 0.55 0.7 V 100 mA 70 V Note 4. The temperature extremes are guaranteed but not 100% production tested. TYPICAL CIRCUIT WAVEFORM 60V 33V INPUT VOLTAGE PIN 1 (V) 26V 14V 14V 4V 0V ON/OFF SWITCH 2V 0.8V 0.8V OUTPUT VOLTAGE PIN 2 (V) 12V 5V 12V 12V 12V 12V 3.5V 0V 0V STANDBY VOLTAGE PIN 5 (V) SYSTEM CONDITION 5.0V 5V 3.7V TURN ON LOAD DUMP LINE NOISE, ETC. LOW VIN VOUT SHORT CIRCUIT THERMAL SHUTDOWN TURN OFF APPLICATION NOTES The advantages of using a low-dropout regulator such as the SG29125/125A are the need for less “headroom” for full regulation, and the inherent reverse polarity protection provided by the PNP output device. A typical NPN regulator design requires an input to output differential of approximately two volts minimum. This is due to the 2Vbe + Vcesat of the NPN Darlington used in the output, coupled with the voltage drop across the current limit resistor. In contrast, the “PNP Regulator” uses a single series pass transistor with its single Vcesat, thus the lower input to output voltage differential or dropout voltage. regulator enters a micropower mode. Here all but the most essential circuitry to power the standby output is deactivated. This allows the lowest possible quiescent current (typical around 1.2mA), a vital factor when used in a battery powered system. In some applications the regulator output voltage is used not only as a power supply but also as a voltage reference for control systems. In such cases not just the temperature stability of the output is important but also the initial accuracy. The SG29125/ 125A fills this need as the internal bandgap reference is trimmed allowing a typical output voltage tolerance of ±1%. In addition to a low dropout voltage, an important advantage of the SG29125/125A series is low quiescent current in the standby mode. When the high current or primary regulator is shut off, the LINFINITY 12/90 Rev 1.1 2/94 Copyright 1994 3 Microelectronics Inc. 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570 SG29125/125A APPLICATION HINTS EXTERNAL CAPACITORS To stabilize the outputs and prevent oscillation (perhaps by many volts) external capacitors are required. The minimum recommended value for the output capacitors is 10µF, although the actual size and type will likely vary according to the particular application, e.g., operating temperature range and load. Another consideration is the effective series resistance (ESR) of the capacitor. Capacitor ESR will vary by manufacturer. Consequently, some evaluation may be required to determine the minimum value of the output capacitors. Generally worst case occurs at the maximum load and minimum ambient temperature. the current through the external resistor should be sufficient to bias internal resistors up to this point. Approximately 60µA will suffice, resulting in a 10k external resistor for most applications (Figure 1). HIGH CURRENT OUTPUT VIN RD 10K STANDBY OUTPUT SG29125/125A The size of the output capacitor can be increased to any value above the minimum. One possible advantage of this would be to maintain the output voltage during brief periods of negative input transients C3 The output capacitors chosen should be rated for the full range of ambient temperature over which the circuit will be exposed and expected to operate. For example, many aluminum type electrolytic capacitors will freeze at -30°C. The effective capacitance is reduced to zero in such a situation. Capacitors rated for -40°C operation must be used in order to maintain regulator stability at that temperature. Tantalum capacitors satisfy this requirement. FIGURE 1. Disabling Standby Output to Eliminate C3 The high current regulated output features fault protection against overvoltage as well as a thermal shutdown feature. If the input voltage rises above 33V (load dump), the high current output shuts down automatically. The internal circuitry is thus protected and the IC is able to survive higher voltage transients than might otherwise be expected. The thermal shutdown of the high current output effectively guards against overheating of the die since this section of the IC is the principle source of power dissipation on the chip. STANDBY OUTPUT The SG29125/125A differs from most fixed voltage regulators in that it is equipped with two regulator outputs instead of one. The additional output is intended for use in systems requiring standby memory circuits. While the high current regulator output can be controlled with the ON/OFF pin described below, the standby remains on under all conditions as long as sufficient input voltage is applied to the IC. Thus, memory and other circuits powered by this output remain unaffected by positive line transients, thermal shutdown, etc. ON/OFF SWITCH The ON/OFF pin is a high impedance low current switch that controls the main output voltage (pin 2). This is directly compatible with all 5 volt logic families. For use with open collector logic outputs, a 100K resistor from this pin to a 5V supply, such as Pin 5, is required. The standby regulator circuit is designed so that the quiescent current to the IC is very low (<1.5mA) when the other regulator output is off. If the standby output is not required it can be disabled. This is accomplished by connecting a resistor from the standby output to the supply voltage, thereby also eliminating the requirement for a more expensive output capacitor to prevent unwanted oscillations. The resistor value depends upon the minimum input voltage expected for a given system. Since the standby output is shunted with an internal 5.6V zener, CONNECTION DIAGRAM & ORDERING INFORMATION Package 5-PIN TO-220 PLASTIC P - PACKAGE Part No. SG29125P SG29125AP (See Note Below) Ambient Temperature Range Connection Diagram -40°C to 85°C -40°C to 85°C GND 5 4 3 2 1 STANBY OUTPUT ON/OFF SWITCH GROUND OUTPUT VOLTAGE (VOUT) INPUT VOLTAGE (VIN) Note: 1. All parts are viewed from the top. LINFINITY 12/90 Rev 1.1 2/94 Copyright 1994 4 Microelectronics Inc. 11861 Western Avenue ∞ Garden Grove, CA 92841 (714) 898-8121 ∞ FAX: (714) 893-2570