ISSUED DATE :2006/04/13 REVISED DATE : GSC2138 1 . 5 A C M O S L o w D r o p o u t Vo l t a g e R e g u l a t o r Description The GSC2138 of positive, linear regulator feature low ground current (45 A typ.) with low dropout voltage, making them ideal for battery applications. Output voltages are set at the factory and trimmed to 1.5% accuracy. These rugged devices have both Thermal Shutdown, and Current Fold-back to prevent device failure under the “Worst” of operating conditions. The GSC2138 is stable with an output capacitance of 4.7 F or greater. Features Very Low Dropout Voltage Guaranteed 1.5A output Over-Temperature Shutdown Current Limiting Short Circuit Current Fold-back Highly Accurate± 1.5% Low Temperature Coefficient Power-Saving Shutdown Mode Adjustable Version Functional Block Diagram Applications Battery Powered Widgets Instrumentation Wireless Devices PC Peripherals Portable Electronics Package Dimensions REF. A B C D E F Millimeter Min. Max. 5.80 4.80 3.80 0° 0.40 0.19 6.20 5.00 4.00 8° 0.90 0.25 REF. M H L J K G Millimeter Min. Max. 0.10 0.25 0.35 0.49 1.35 1.75 0.375 REF. 45° 1.27 TYP. Typical Application Circuit GSC2138 Page: 1/7 ISSUED DATE :2006/04/13 REVISED DATE : Absolute Maximum Ratings Parameter Symbol Ratings Unit Input Max Voltage VIN 8 V Output Current IOUT PD/( VIN- VO) A Output Voltage VOUT Gnd-0.3 to VIN+0.3 V Operating Ambient Temperature Topr -40 ~ +85 Junction Temperature Maximum Junction Temperature Internal Power Dissipation( T=100 ) Tj -40 ~ +125 Tj Max 150 PD 810 EDS Classification Electrical Characteristics VIN=VOUT(T)+2V, VEN=VIN, TA=25 Parameter Output Voltage Symbol VOUT (E) Output Current Current Limit Load Regulation IO ILIM REGLOAD Dropout Voltage Ground Pin Current Line Regulation Input Voltage Over Temperature Shutdown Over Temperature Hysterisis (Note1) Typ VOUT(T) VEN=VEHmin, IO=1mA -1.5% VOUT>1.2V 1.5 - (Note2) Max Unit 1.5% V - A 2.0 - A -1 0.2 1 % 1.5V<VOUT(T) 2.0V IO=1.5A 2.0V<VOUT(T) 2.8V VO=VOUT(E)-2% 2.8V<VOUT(T) - - 1300 - - 800 - - 600 IGND IO=1mA~1.5A - 45 - -0.15 - 0.15 REGLINE VOUT(T)<2.0V IO=1mA VIN=VOUT(T)+1 to 2.0V VOUT(T)<4.0V VOUT(T)+2 4.0V VOUT(T) -0.1 0.02 0.1 -0.4 - 0.4 VIN OTS OTH Note3 - 7 - 150 - - 30 - TC - 30 - ppm/ - 750 - mA VDROPOUT PSRR Shutdown Supply Current Min 1.5 Power Supply Rejection EN Input Bias Current Condition VOUT>1.2V ISC IADJ IMin VREF EN Input Threshold unless otherwise IO=1mA to 1.5A Output Voltage Temperature Coefficient Short Circuit Current ADJ Input Bias Current Minimum Load Current ADJ Reference Voltage Output Voltage Noise mW B eN VEH VEL IEH IEL ISD VOUT<0.4V VIN=5V, VADJ=1.242V Io=100mA Co=4.7 F ceramic mV A % V - 1 - A 1 - - mA 1.223 1.242 1.261 V f=1kHz - 50 - f=10kHz - 20 - - 30 - Vrms f=10Hz~100kHz Co=4.7 F Io=10mA, VIN=2.7V to 7V dB 2.0 - VIN V VIN=2.7V to 7V 0 - 0.4 V VIN=7V - - 0.1 A VEN= 0V, VIN=7V - - 0.5 A VIN=5V, VOUT=0V, VEN=0V - 0.5 2 A Note 1: VOUT (E) =Effective Output Voltage (i.e. the output voltage when “VOUT (T) + 2.0V” is provided at the VIN pin while maintaining a certain IOUT value). 2: VOUT (T) =Specified Output Voltage 3: VIN (MIN) =V OUT+VDROPOUT GSC2138 Page: 2/7 ISSUED DATE :2006/04/13 REVISED DATE : Ordering Information ( contd. ) Part Number GSC2138-AD Marking 8CAD2 XXXX Output Voltage Part Number Marking Output Voltage Adjustable Detailed Description The GSC2138 of COMS regulator contains a PMOS pass transistor, voltage reference, error amplifier, overcurrent protection, and thermal shutdown. The P-channel pass transistor receives data from the error amplifier, over-current shutdown, and thermal protection circuits. During normal operation, the error amplifier compares the output voltage to a precision reference. Over-current and Thermal shutdown circuits become active when the junction temperature exceeds 140 , or the current exceeds 2.2A. During thermal shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops below 120 . The GSC2138 behaves like a current source when the load reaches 2.2A. However, if the load impedance drops below 0.3 , the current drops back to 600mA to prevent excessive power dissipation. Normal operation is restored when the load resistance exceeds 0.75 . External Capacitors The GSC2138 is stable with an output capacitance to ground of 4.7 F or greater. Ceramic capacitors have the lowest ESR, and will offer the best AC performance. Conversely, Aluminum Electrolytic capacitors exhibit the highest ESR, resulting in the poorest AC response. Unfortunately, large value ceramic capacitors are comparatively expensive. One option is to parallel a 0.1 F ceramic capacitor with a 10 F Aluminum Electrolytic. The benefit is low ESR, high capacitance, and low overall cost. A second capacitor is recommended between the input and ground to stabilize Vin. The input capacitor should be at least 0.1 F to have a beneficial effect. All capacitors should be placed in close proximity to the pins. A “Quiet” ground termination is desirable. This can be achieved with a “Star” connection. Enable When pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered down. In this state, the quiescent current is less than 1 A. This pin behaves much like an electronic switch. 100k resistor is necessary between VEN source and EN pin when VEN is higher than VIN. (Note: there is no internal pull-up for EN PIN) Adjustable Version The adjustable version uses external feedback resistors to generate an output voltage anywhere from 1.5V to 5.0V. Vadj is trimmed to 1.242V and Vout is given by the equation: VOUT=Vadj * (1+R1/R2) Feedback resistors R1 and R2 should be high enough to keep quiescent current low, but increasing R1+R2 will reduce stability. In general, R1 and R2 in the 10’s of k will produce adequate stability, given reasonable layout precautions. To improve stability characteristics, keep parasitic on the ADJ pin to minimum, and lower R1 and R2 values. GSC2138 Page: 3/7 ISSUED DATE :2006/04/13 REVISED DATE : Characteristics Curve GSC2138 Page: 4/7 ISSUED DATE :2006/04/13 REVISED DATE : 115 85 55 25 -5 -45 GSC2138 Page: 5/7 ISSUED DATE :2006/04/13 REVISED DATE : GSC2138 Page: 6/7 ISSUED DATE :2006/04/13 REVISED DATE : External Resistor Divider Table R1(k ) VOUT 1 2 1.30 21.41 1.35 11.50 1.40 1.45 5 10 20 50 R1(k ) VOUT 1 42.83 107.07 214.14 428.28 1070.7 3.20 0.63 1.27 3.17 6.34 12.69 31.72 23.00 57.50 115.00 230.00 575.00 3.25 0.62 1.24 3.09 6.19 12.37 30.93 7.86 15.72 39.30 78.61 157.22 393.04 3.30 0.60 1.21 3.02 6.03 12.07 30.17 5.97 11.94 29.86 59.71 119.42 298.56 3.35 0.59 1.18 2.95 5.89 11.78 29.46 1.50 4.81 9.63 24.07 48.14 96.28 240.70 3.40 0.58 1.15 2.88 5.76 11.51 28.78 1.55 4.03 8.06 20.16 40.32 80.65 201.62 3.45 0.56 1.13 2.81 5.63 11.25 28.13 1.60 3.47 6.94 17.35 34.69 68.39 173.46 3.50 0.55 1.10 2.75 5.50 11.00 27.50 1.65 3.04 6.09 15.22 30.44 60.88 152.21 3.55 0.54 1.08 2.69 5.38 10.76 26.91 1.70 2.71 5.42 13.56 27.12 54.24 135.59 3.60 0.53 1.05 2.63 5.27 10.53 26.34 1.75 2.44 4.89 12.22 24.45 48.90 122.24 3.65 0.52 1.03 2.58 5.16 10.32 25.79 1.80 2.23 4.45 11.13 22.26 44.52 111.29 3.70 0.51 1.01 2.53 5.05 10.11 25.26 1.85 2.04 4.09 10.21 20.43 40.86 102.14 3.75 0.50 0.99 2.48 4.95 9.90 24.76 1.90 1.89 3.78 9.44 18.88 37.75 94.38 3.80 0.49 0.97 2.43 4.86 9.71 24.28 1.95 1.75 3.51 8.77 17.54 35.08 87.71 3.85 0.48 0.95 2.38 4.76 9.52 23.81 2.00 1.64 3.28 8.19 16.39 32.77 81.93 3.90 0.47 0.93 2.34 4.67 9.35 23.36 2.05 1.54 3.07 7.69 15.37 30.74 76.86 3.95 0.46 0.92 2.29 4.59 9.17 22.93 2.10 1.45 2.90 7.24 14.48 28.95 72.38 4.00 0.45 0.90 2.25 4.50 9.01 22.52 2.15 1.37 2.74 6.84 13.68 27.36 68.39 4.05 0.44 0.88 2.21 4.42 8.85 22.12 2.20 1.30 2.59 6.48 12.96 25.93 64.82 4.10 0.43 0.87 2.17 4.35 8.69 21.73 2.25 1.23 2.46 6.16 12.32 24.65 61.61 4.15 0.43 0.85 2.14 4.27 8.54 21.35 2.30 1.17 2.35 5.87 11.74 23.48 58.70 4.20 0.42 0.84 2.10 4.20 8.40 20.99 2.35 1.12 2.24 5.60 11.21 22.42 56.05 4.25 0.41 0.83 2.06 4.13 8.26 20.64 2.40 1.07 2.15 5.36 10.73 21.45 53.63 4.30 0.41 0.81 2.03 4.06 8.12 20.31 2.45 1.03 2.06 5.14 10.28 20.56 51.41 4.35 0.40 0.80 2.00 4.00 7.99 19.98 2.50 0.99 1.97 4.94 9.87 19.75 49.36 4.40 0.39 0.79 1.97 3.93 7.87 19.66 2.55 0.95 1.90 4.75 9.50 18.99 47.48 4.45 0.39 0.77 1.94 3.87 7.74 19.36 2.60 0.91 1.83 4.57 9.15 18.29 45.73 4.50 0.38 0.76 1.91 3.81 7.62 19.06 2.65 0.88 1.76 4.41 8.82 17.64 44.11 4.55 0.38 0.75 1.88 3.75 7.51 18.77 2.70 0.85 1.70 4.26 8.52 17.04 42.59 4.60 0.37 0.74 1.85 3.70 7.40 18.49 2.75 0.82 1.65 4.12 8.24 16.47 41.18 4.65 0.36 0.73 1.82 3.64 7.29 18.22 2.80 0.80 1.59 3.99 7.97 15.94 39.86 4.70 0.36 0.72 1.80 3.59 7.18 17.96 2.85 0.77 1.54 3.86 7.72 15.45 38.62 4.75 0.35 0.71 1.77 3.54 7.08 17.70 2.90 0.75 1.50 3.75 7.49 14.98 37.45 4.80 0.35 0.70 1.75 3.49 6.98 17.45 2.95 0.73 1.45 3.64 7.27 14.54 36.36 4.85 0.34 0.69 1.72 3.44 6.88 17.21 3.00 0.71 1.41 3.53 7.06 14.13 35.32 4.90 0.34 0.68 1.70 3.40 6.79 16.98 3.05 0.69 1.37 3.43 6.87 13.74 34.35 4.95 0.33 0.67 1.67 3.35 6.70 16.75 3.10 0.67 1.34 3.34 6.68 13.37 33.42 5.00 0.33 0.66 1.65 3.30 6.61 16.52 3.15 0.65 1.30 3.25 6.51 13.02 32.55 R2(k )=(1.242*R1(k ))/(VOUT-1.242) 2 5 10 20 50 R2(k )=(1.242*R1(k ))/(VOUT-1.242) Note: Small load (greater than 2mA) is necessary as R1 or R2 is larger than 50k . Otherwise, output voltage probably can not be pulled down to 0V on disable mode. Important Notice: All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of GTM. GTM reserves the right to make changes to its products without notice. GTM semiconductor products are not warranted to be suitable for use in life-support Applications, or systems. GTM assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. Head Office And Factory: Taiwan: No. 17-1 Tatung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, Taiwan, R. O. C. TEL : 886-3-597-7061 FAX : 886-3-597-9220, 597-0785 China: (201203) No.255, Jang-Jiang Tsai-Lueng RD. , Pu-Dung-Hsin District, Shang-Hai City, China TEL : 86-21-5895-7671 ~ 4 FAX : 86-21-38950165 GSC2138 Page: 7/7