L6932 HIGH PERFORMANCE 2A ULDO LINEAR REGULATOR ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ 2V TO 14V INPUT VOLTAGE RANGE 200mΩ Rdson MAX. 200µA QUIESCENT CURRENT AT ANY LOAD EXCELLENT LOAD AND LINE REGULATION 1.8V AND 2.5V FIXED VOLTAGE ADJUSTABLE FROM 1.2V TO 5V (L6932D1.2) 1% VOLTAGE REGULATION ACCURACY SHORT CIRCUIT PROTECTION THERMAL SHUT DOWN SO-8 (4+4) PACKAGE SO-8 (4+4) ORDERING NUMBERS: L6932D1.2 (SO-8) L6932D1.2TR (T&R) L6932D1.8 (SO-8) L6932D1.8TR (T&R) L6932D2.5 (SO-8) L6932D2.5TR (T&R) Mosfet, can be usefull for the DC-DC conversion between 2.5V and 1.8V at 2A in portable applications reducing the power dissipation. APPLICATIONS ■ MOTHERBOARDS ■ MOBILE PC ■ HAND-HELD INSTRUMENTS ■ PCMCIA CARDS ■ PROCESSORS I/O ■ CHIPSET AND RAM SUPPLY L6932 is available in 1.8V, 2.5V and adj version from 1.2V and ensure a voltage regulation accuracy of 1%. The current limit is fixed at 2.5A to control the current in short circuit condition within ±8%. The current is sensed in the power mos in order to limit the power dissipation. The device is also provided of a thermal shut down that limits the internal temperature at 150°C with an histeresys of 20°C. L6932 provides the Enable and the Power good functions. DESCRIPTION The L6932 Ultra Low Drop Output linear regulator operates from 2V to 14V and is able to support 2A. Designed with an internal 50mΩ N-channel TYPICAL OPERATING CIRCUIT IN VIN 2V to 14V OUT 2 VOUT 1.8V or 2.5V 3 L6932D PGOOD 4 C1 5,6,7,8 C2 1 GND EN OUT IN VIN 2V to 14V 4 2 VOUT 1.2V to 5V L6932D1.2 R1 ADJ 3 C1 5,6,7,8 C2 1 GND EN February 2003 R2 1/10 L6932 PIN CONNECTIONS EN 1 8 GND EN 1 8 GND IN 2 7 GND IN 2 7 GND ADJ 3 6 GND OUT 3 6 GND OUT 4 5 GND PGOOD 4 5 GND L6932D1.2 L6932D1.8 L6932D2.5 PIN FUNCTION N° L6232D 1.2 L6232D 1.8/2.5 Description 1 EN Enables the device if connected to Vin and disables the device if forced to gnd. 2 IN Supply voltage. This pin is connected to the drain of the internal N-mos. Connect this pin to a capacitor larger than 10µF. ADJ – Connecting this pin to a voltage divider it is possible to programme the output voltage between 1.2V and 5V. – OUT Regulated output voltage. This pin is connected to the source of the internal N-mos. Connect this pin to a capacitor of 10µF. OUT – Regulated output voltage. This pin is connected to the source of the internal N-mos. Connect this pin to a capacitor of 10µF. – PGOOD Power good output. The pin is open drain and detects the output voltage. It is forced low if the output voltage is lower than 90% of the programmed voltage. 3 4 5, 6, 7, 8 GND Ground pin. ABSOLUTE MAXIMUM RATINGS Symbol Vin Parameter VIN and Pgood EN, OUT and ADJ Value Unit 14.5 V -0.3 to (Vin +0.3) V Value Unit 62 (*) °C/W 150 °C -65 to 150 °C THERMAL DATA Symbol Rth J-amb Parameter Thermal Resistance Junction to Ambient Tmax Maximum Junction Temperature Tstg Storage Temperature Range (*) Measured on Demoboard with about 4 cm2 of dissipating area 2 Oz. 2/10 L6932 BLOCK DIAGRAM (Referred to the Fixed Voltage version) IN CHARGE PUMP VREF REFERENCE VREF=1.25V EN ENABLE CURRENT LIMIT DRIVER + ERROR AMPL. OUT THERMAL SENSOR PG 0.9 VREF + GND D99IN1100 ELECTRICAL CHARACTERISTCS (Tj = 25°C, VIN = 5V unless otherwise specified) (*) Specification referred to Tj from -25°C to 125°C. Symbol Parameter Test Condition Min. Max. Unit 14 V 1.2 1.212 V 1.782 1.8 1.818 V 2.475 2.5 2.525 V Vin = 2.5V ±10%; Io = 10mA 5 mV Vin = 3.3V ±10%; Io = 10mA 5 mV Vin = 5V ±10%; Io = 10mA 5 mV L6932D1.8 Line Regulation Vin = 2.5V ±10%; Io = 10mA 5 mV Vin = 3.3V ±10%; Io = 10mA 5 mV Vin = 5V ±10%; Io = 10mA 5 mV L6932D2.5 Line Regulation Vin = 3.3V ±10%; Io = 10mA 5 mV Vin = 5V ±10%; 5 mV L6932D1.2 Load Regulation Vin = 3.3V; 0.1A < Io < 2A 15 mV L6932D1.8 Load Regulation Vin = 3.3V; 0.1A < Io < 2A 15 mV L6932D2.5 Load Regulation Vin = 3.3V; 0.1A < Io < 2A 15 mV Vin Operating Supply Voltage Vo Output voltage L6932D1.2 Io = 0.1A; Vin = 3.3V 1.188 Output voltage L6932D1.8 Io = 0.1A; Vin = 3.3V Output voltage L6932D2.5 Io = 0.1A; Vin = 3.3V L6932D1.2 Line Regulation Rdson Iocc Io = 10mA Drain Source ON resistance Current limiting 2.3 Iq Quiescent current Ish Shutdown current 2V < Vin < 14V Ripple Rejection f = 120Hz, Io = 1A Vin = 5V, ∆Vin = 2Vpp Ven Typ. 2 EN Input Threshold 200 mΩ 2.5 2.7 A 0.2 0.4 mA 25 µA * 60 75 0.5 0.65 dB 0.8 V 3/10 L6932 ELECTRICAL CHARACTERISTCS (continued) Symbol Parameter Test Condition Pgood threshold Min. Typ. Vo rise 90 Ipgood =1mA 0.2 Pgood Hysteresis Max. Unit %Vo 10 Pgood saturation Figure 1. Output Voltage vs. Junction Temperature (L6932D1.2) %Vo 0.4 V Figure 4. Quiescent Current vs. Junction Temperature 1.213 310 1.212 300 1.212 Vin=5V 290 1.211 V Iq 280 1.211 (uA) 1.210 270 1.210 260 1.209 -60 -40 -20 0 20 40 60 80 Temp [°C] 250 100 120 140 160 Figure 2. Output Voltage vs. Junction Temperature (L6932D1.8) -40 -20 0 20 40 60 Temp [°C ] 80 100 120 140 Figure 5. Shutdown Current vs. Junction Temperature 1.808 7.5 7 1.804 6.5 1.800 Vin=5V Ishdn V 6 (uA) 1.796 5.5 5 1.792 4.5 1.788 -60 -40 -20 0 20 40 60 80 Temp [°C] 100 120 140 160 4 -40 -20 0 20 40 Temp [°C ] Figure 3. Output Voltage vs. Junction Temperature (L6932D2.5) 2.520 2.515 2.510 V 2.505 2.500 2.495 -60 -40 -20 0 20 40 60 Temp [°C] 4/10 80 100 120 140 160 60 80 100 120 140 L6932 APPLICATION INFORMATIONS APPLICATION CIRCUIT In figure 6 the schematic circuit of the demoboards are shown. Figure 6. Demoboards Schematic Circuit VIN OUT IN EN 1 5 C1 VOUT=2.5V/1.8V 3 2 L6932D2.5 L6932D1.8 6 4 8 7 PGOOD C2 GND VIN 2 4 R1 L6932D1.2 EN C1 VOUT=1.2V TO 5V OUT IN ADJ 1 6 5 7 3 8 GND C2 R2 1.2 V OUT = -------- ⋅ ( R1 + R 2 ) R2 COMPONENT LIST Fixed version Reference Part Number Description Manufacturer C1 C34Y5U1E106Z 10uF, 25V TOKIN C2 C34Y5U1E106Z 10uF, 25V TOKIN Figure 7. Demoboard Layout (Fixed Version) 5/10 L6932 Adjustable version Reference Part Number Description Manufacturer C1 C34Y5U1E106Z 10uF, 25V TOKIN C2 C34Y5U1E106Z 10uF, 25V TOKIN R1 5.6K, 1%, 0.25W Neohm R2 3.3K, 1%, 0.25W Neohm Figure 8. Demoboard Layout (Adjustable Version) COMPONENTS SELECTION Input Capacitor The input capacitor value depends on a lot of factors such as load transient requirements, input source (battery or DC/DC converter) and its distance from the input cap. Usually a 47µF is enough for any application but a much lower value can be sufficient in many cases. Output Capacitor The output capacitor choice depends basically on the load transient requirements. Tantalum, Speciality Polimer, POSCAP and aluminum capacitors are good and offer very low ESR values. Multilayer ceramic caps have the lowest ESR and can be required for particular applications. Nevertheless in several applications they are ok, the loop stability issue has to be considered (see loop stability section). Below a list of some suggested capacitor manufacturers. Manufacturer Type Cap Value (µF) Rated Voltage (V) PANASONIC CERAMIC 1 to 47 4 to 16 TAYO YUDEN CERAMIC 1 to 47 4 to 16 TDK CERAMIC 1 to 47 4 to 16 TOKIN CERAMIC 1 to 47 4 to 16 SANYO POSCAP 1 to 47 4 to 16 PANASONIC SP 1 to 47 4 to 16 KEMET TANTALUM 1 to 47 4 to 16 6/10 L6932 Loop Stability The stability of the loop is affected by the zero introduced by the output capacitor. The time constant of the zero is given by: T = ESR ⋅ C OUT 1 F ZERO = -------------------------------------------2π ⋅ ESR ⋅ C OUT This zero helps to increase the phase margin of the loop until the time constant is higher than some hundreds of nsec, depending also on the output voltage and current. So, using very low ESR ceramic capacitors could produce oscillations at the output, in particular when regulating high output voltages (adjustable version). To solve this issue is sufficient to add a small capacitor (e.g. 1nF to 10nF) in parallel to the high side resistor of the external divider, as shown in figure 9. Figure 9. Compensation Network VIN=2V TO 14V OUT IN 2 R1 L6932D1.2 EN C1 VOUT=1.2V TO 5V UP to 2A 4 C3 ADJ 1 6 5 GND 7 3 8 C2 R2 Thermal Considerations Since the device is housed in a small SO(4+2+2) package the thermal issue can be the bottleneck of many applications. The power dissipated by the device is given by: PDISS = (VIN - VOUT) · IOUT The thermal resistance junction to ambient of the demoboard is approximately 62°C/W. This mean that, considering an ambient temperature of 60°C and a maximum junction temperature of 150°C, the maximum power that the device can handle is 1.5W. This means that the device is able to deliver a DC output current of 2A only with a very low dropout. In many applications, high output current pulses are required. If their duration is shorter than the thermal constant time of the board, the thermal impedance (not the thermal resistance) has to be considered. In figure 10 the thermal impedance versus the duration of the current pulse for the SO(4+2+2) mounted on board is shown. 7/10 L6932 Figure 10. Thermal Impedance Considering a pulse duration of 1sec, the thermal impedance is close to 20°C/W, allowing much bigger power dissipated. Example: Vin = 3.3V Vout = 1.8V Iout = 2A Pulse Duration = 1sec The power dissipated by the device is: PDISS = (VIN - VOUT) · IOUT = 1.5 · 2 3W Considering a thermal impedance of 20°C/W, the maximum junction temperature will be: TJ = TA + ZTHJA · PDISS = 60 + 60 = 120°C Obviously, with pulse durations longer than approximately 10sec the thermal impedance is very close to the thermal resistance (60°C/W to 70°C/W). 8/10 L6932 mm DIM. MIN. TYP. A a1 inch MAX. MIN. TYP. 1.75 0.1 0.25 a2 MAX. 0.069 0.004 0.010 1.65 0.065 a3 0.65 0.85 0.026 0.033 b 0.35 0.48 0.014 0.019 b1 0.19 0.25 0.007 0.010 C 0.25 0.5 0.010 0.020 c1 45° (typ.) D (1) 4.8 5.0 0.189 0.197 E 5.8 6.2 0.228 0.244 e 1.27 0.050 e3 3.81 0.150 F (1) 3.8 4.0 0.15 0.157 L 0.4 1.27 0.016 0.050 M S OUTLINE AND MECHANICAL DATA 0.6 0.024 SO8 8 ° (max.) (1) D and F do not include mold flash or protrusions. Mold flash or potrusions shall not exceed 0.15mm (.006inch). 9/10 L6932 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. 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