GSC2138中文资料
G S C 2138
1.5A C M O S L o w D r o p o u t V o 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 Functional Block Diagram
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
Applications
Battery Powered Widgets Instrumentation Wireless Devices PC Peripherals
Portable Electronics
Package Dimensions
Millimeter Millimeter REF . Min. Max.
REF . Min. Max.
A 5.80 6.20 M 0.10 0.25
B 4.80 5.00 H 0.35 0.49
C 3.80 4.00 L 1.35 1.75
D 0° 8° J 0.375 REF.
E 0.40 0.90 K 45° F
0.19
0.25
G
1.27 TYP .
Typical Application Circuit
Absolute Maximum Ratings
Parameter
Symbol
Ratings
Unit
Input Max Voltage V IN 8 V Output Current I OUT P D /( V IN- V O) A Output Voltage
V OUT Gnd-0.3 to V IN +0.3
V Operating Ambient Temperature Topr -40 ~ +85 Junction Temperature
Tj -40 ~ +125
Maximum Junction Temperature Tj Max 150 Internal Power Dissipation( T=100) PD 810 mW EDS Classification
B
Electrical Characteristics V I N =V OUT (T)+2V, V EN =V I N , T A =25 unless otherwise
Parameter
Symbol Condition
Min
Typ
Max
Unit
Output Voltage V OUT (E)
(Note1)
V EN =V EH min, I O =1mA
-1.5% V OUT (T)
(Note2)
1.5% V Output Current I O V OUT >1.2V 1.5 - - A Current Limit I LIM V OUT >1.2V 1.5
2.0 - A Load Regulation REG LOAD I O =1mA to 1.5A
-1 0.2 1 % 1.5V - - 1300 2.0V - - 800 Dropout Voltage V DROPOUT I O =1.5A V O =V OUT (E)-2% 2.8V - - 600 mV Ground Pin Current I GND I O =1mA~1.5A - 45 - A V OUT (T)<2.0V -0.15 - 0.15 2.0V V OUT (T)<4.0V -0.1 0.02 0.1 Line Regulation REG LINE I O =1mA V I N =V OUT (T)+1 to V OUT (T)+2 4.0V V OUT (T) -0.4 - 0.4 % Input Voltage V I N Note3 - 7 V Over Temperature Shutdown OTS - 150 - Over Temperature Hysterisis OTH - 30 - Output Voltage Temperature Coefficient TC - 30 - ppm/ Short Circuit Current I SC V OUT <0.4V - 750 - mA ADJ Input Bias Current I ADJ V I N =5V, V ADJ =1.242V - 1 - A Minimum Load Current I Min 1 - - mA ADJ Reference Voltage V REF 1.223 1.242 1.261 V f=1kHz - 50 - Power Supply Rejection PSRR I o=100mA Co=4.7 F ceramic f=10kHz - 20 - dB Output Voltage Noise eN f=10Hz~100kHz I o=10mA, Co=4.7 F - 30 - Vrms V EH V I N =2.7V to 7V 2.0 - V I N V EN I nput Threshold V EL V I N =2.7V to 7V 0 - 0.4 V I EH V I N =7V - - 0.1 A EN I nput Bias Current I EL V EN = 0V, V I N =7V - - 0.5 A Shutdown Supply Current I SD V I N =5V, V OUT =0V, V EN =0V - 0.5 2 A Note 1: V OUT (E) =Effective Output Voltage (i.e. the output voltage when “V OUT (T) + 2.0V” is provided at the VIN pin while maintaining a certain I OUT value). 2: V OUT (T) =Specified Output Voltage 3: V I N (MIN) =V OUT +V DROPOUT Ordering Information ( contd. ) Part Number Marking Output Voltage Part Number Marking Output Voltage Adjustable GSC2138-AD 8CAD2 XXXX Detailed Description The GSC2138 of COMS regulator contains a PMOS pass transistor, voltage reference, error amplifier, over- current 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 V EN source and EN pin when V EN is higher than V I N. (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: V OUT=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. Characteristics Curve 115 85 55 25 -5 -45 External Resistor Divider Table R1(k ) 1 2 5 10 20 50 R1(k ) 1 2 5 10 20 50 V OUT R2(k )=(1.242*R1(k ))/(V OUT-1.242)V OUT R2(k )=(1.242*R1(k ))/(V OUT-1.242) 1.30 21.41 4 2.83 107.07 214.14 428.28 1070.7 3.20 0.63 1.27 3.17 6.34 12.69 31.72 1.35 11.50 23.00 57.50 115.00 230.00 575.00 3.25 0.62 1.24 3.09 6.19 12.37 30.93 1.40 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 1.45 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 1 7.35 34.69 6 8.39 173.46 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 2 3.81 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 1 5.37 30.74 7 6.86 3.95 0.46 0.92 2.29 4.59 9.17 22.93 2.10 1.45 2.90 7.24 14.48 2 8.95 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 1 4.54 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 1 4.13 3 5.32 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 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 T atung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, T aiwan, R. O. C.