ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B GSC2128 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 GSC2128 series of positive, linear regulators feature low quiescent 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. In applications requiring a low noise, regulated supply, place a 1000pF capacitor between Bypass and Ground. The GSC2128 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 Noise Reduction Bypass Capacitor Power-Saving Shutdown Mode 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 1/6 ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B Absolute Maximum Ratings Parameter Symbol Ratings Unit Input Max Voltage VIN 8 V Output Current IOUT PD/( VIN- VO) A Output Voltage VOUT 1.5~5.0 V Operating Ambient Temperature Topr -40 ~ +85 Tj -40 ~ +125 Tj Max 150 Junction Temperature Maximum Junction Temperature Thermal Resistance Internal Power Dissipation( T=100 ) jc 40 /W PD 810 mW EDS Classification B Electrical Characteristics VIN=VOUT(T)+2V, VEN=VIN, TA=25 Output Voltage Symbol VOUT (E) Output Current Current Limit Load Regulation IO ILIM REGLOAD Parameter (Note1) unless otherwise Condition Min Typ Max Unit VEN=VEHmin, IO=1mA -1.5% VOUT(T) 1.5% V VOUT>1.2V 1.5 - - A VOUT>1.2V 1.5 2.0 - A % IO=1mA to 1.5A 1.5V<VOUT(T) Dropout Voltage VDROPOUT IO=1.5A VO=VOUT(E)-2% 2.0V<VOUT(T) -1 0.2 1 2.0V - - 1300 2.8V - - 800 - - 600 2.8V<VOUT(T) Quiescent Current Ground Pin Current Line Regulation Input Voltage Over Temperature Shutdown Over Temperature Hysterisis Output Voltage Temperature Coefficient Short Circuit Current IQ IGND REGLINE - 45 70 A - 45 - A IO=1mA VOUT(T)<2.0V VIN=VOUT(T)+1 to 2.0V VOUT(T)<4.0V VOUT(T)+2 4.0V VOUT(T) -0.15 - 0.15 -0.1 0.02 0.1 % -0.4 - 0.4 - 7 - 150 - - 30 - TC - 30 - ppm/ - 750 - mA f=1kHz - 50 - f=10kHz - 20 - f=1kHz - 75 - f=10kHz - 55 - Co=4.7 F - 30 - Vrms Co=4.7 F - 30 - Vrms ISC Power Supply Rejection PSRR Output Voltage Noise eN Output Voltage Noise eN Shutdown Supply Current IO=0mA IO=1mA~1.5A Note3 PSRR EN Input Bias Current mV VIN OTS OTH Power Supply Rejection EN Input Threshold (Note2) VEH VEL IEH IEL ISD VOUT<0.4V Io=100mA Co=4.7 F ceramic Io=100mA Co=4.7 F ceramic CBYP=0.01 F f=10Hz~100kHz Io=10mA, CBYP=0 F f=10Hz~100kHz Io=10mA, CBYP=0.01 F V dB dB 2.0 - VIN V 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 2/6 ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B Ordering Information ( contd. ) Part Number GSC2128-15 GSC2128-25 GSC2128-47 Marking 8B152 XXXX 8B252 XXXX 8B472 XXXX Output Voltage Part Number 1.5V GSC2128-18 2.5V GSC2128-33 4.75V GSC2128-50 Marking 8B182 XXXX 8B332 XXXX 8B502 XXXX Output Voltage 1.8V 3.3V 5.0V Characteristics Curve 3/6 ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B 115 85 55 25 -5 -45 4/6 ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B 5/6 ISSUED DATE :2005/06/21 REVISED DATE :2005/10/04B Detailed Description The GSC2128 series of COMS regulators contain 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 GSC2128 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 GSC2128 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. A third capacitor can be connected between the BY-PASS pin and GND. This capacitor can be a low cost Polyester Film variety between the value of 0.001~0.01 F. A large capacitor improves the AC ripple rejection, but also makes the output come up slowly. This “Soft” turn-on is desirable in some applications to limit turn-on surges. 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) 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 6/6