ISSUED DATE :2005/06/01 REVISED DATE :2006/06/01B GE1085 3A Low Dropout Positive Adjustable or Fixed-Mode Regulator Description The GE1085 is a low dropout positive adjustable or fixed-mode regulator with minimum of 3A output current capability. The product is specifically designed to provide well-regulated supply for low voltage IC applications such as high-speed bus termination and low current 3.3V logic supply. GE1085 is also well suited for other applications such as VGA cards. GE1085 is guaranteed to have <1.4V dropout at full load current making it ideal to provide well-regulated outputs of 1.25 to 5.0V with 4.7 to 12V input supply by different output voltage. Features 3-Terminal Adjustable or fixed 1.5V,1.8V,2.5V,3.3V,5.0V 1.4V Maximum Dropout at Full Load current Fast Transient response Built-in Thermal Shutdown Output current limiting Package Dimensions REF. A b c D E L4 L5 Millimeter Min. Max. 4.40 4.80 0.76 1.00 0.36 0.50 8.60 9.00 9.80 10.4 14.7 15.3 6.20 6.60 REF. c1 b1 L e L1 Ø A1 Millimeter Min. Max. 1.25 1.45 1.17 1.47 13.25 14.25 2.54 REF. 2.60 2.89 3.71 3.96 2.60 2.80 Typical Circuit 3.3V/3A 2.5V/3A Block Diagram GE1085 Page: 1/4 ISSUED DATE :2005/06/01 REVISED DATE :2006/06/01B Pin Descriptions Name I/O Pin# Adj (GND) Function 1 Adjustable (Ground only for fixed mode) Vout O 2 The output of the regulator. A minimum of 10uF capacitor must be connected from this pin to ground to insure stability. Vin I 3 The input pin of regulator. Typically a large storage capacitor is connected from this pin to ground to insure that the input voltage does not sag below the minimum dropout voltage during the load transient response. This pin must always be 1.4V higher than Vout in order for the device to regulate properly. Absolute Maximum Ratings Symbol Parameter Vin DC Supply Voltage PD Power Dissipation TST Storage Temperature TOP Operating Junction Temperature Range Ratings Unit -0.3 to 12 V Internally Limited -65 ~ + 150 0 ~ + 150 Electrical Characteristics Parameter Reference Voltage Output Voltage Line Regulator Load Regulation Dropout Voltage (Vin-Vout) Conditions MIN TYP MAX UNIT GE1085-ADJ Io=10mA, TJ =25 , (Vin-Vout )=1.5V 1.225 1.250 1.275 V GE1085-1.5 Io=10mA, TJ =25 , 3.0V Vin 12V 1.470 1.500 1.530 V GE1085-1.8 Io=10mA, TJ =25 , 3.3V Vin 12V 1.764 1.800 1.836 V GE1085-2.5 Io=10mA, TJ =25 , 4.0V Vin 12V 2.450 2.500 2.550 V GE1085-3.3 Io=10mA, TJ =25 , 4.8V Vin 12V 3.235 3.300 3.365 V GE1085-5.0 Io=10mA, TJ =25 , 6.5V Vin 12V 4.900 5.000 5.100 V GE1085-XXX Io=10mA, Vout+1.5<Vin<12 - - 0.2 % GE1085ADJ Vin=3.3V, 0mA<Io<3A, TJ=25 (Note 1,2) - - 1 % GE1085-1.5 Vin=3.0V, 0mA<Io<3A, TJ=25 (Note 1,2) GE1085-1.8 Vin=3.3V, 0mA<Io<3A, TJ =25 GE1085-2.5 Vin=4.0V, 0mA<Io<3A, TJ=25 GE1085-3.3 Vin=5.0V, 0mA<Io<3A, TJ=25 GE1085-5.0 Vin=8.0V, 0mA<Io<3A, TJ=25 GE1085-XXX Io=3A( Vout=1% Vout) - 12 15 mV - 15 18 mV (Note 1,2) - 20 25 mV (Note 1,2) - 26 33 mV (Note 1,2) - 40 50 mV - 1.3 1.4 V (Note 1,2) Current Limit GE1085-XXX Vin-Vout=5V 3.1 - - A Minimum Load Current Adjustable model Vin=5V - 5 10 mA Adjust Pin Current Adjustable model Vin=12V, Io=10mA - 55 100 uA Quiescent Current fixed model Vin=12V, Io=0mA - - 12 mA - 0.008 0.04 %/W - 60 70 dB - 0.5 - % - 83 - /W - 0.65/2.7 - /W Thermal Regulation Ripple Rejection Temperature Stability TA=25 , 30ms pulse F=120Hz, COUT=25uF, Tantalum, Io=3A GE1085-XXX Vin=Vout+3V Io=10mA Thermal Resistance Junction-to-Ambient (No heat sink ;No air flow) Thermal Resistance Junction-to-Case Control Circuitry/Power Transistor Note 1: See thermal regulation specifications for changes in output voltage due to heating effects. Line and load regulation are measured at a constant junction Temperature by low duty cycle pulse testing. Load regulation is measured at the output lead =1/18” from the package. Note 2: Line and load regulation are guaranteed up to the maximum power dissipation of 15W. Power dissipation is determined by the difference in input and output and the output current. Guaranteed maximum power dissipation will not be available over the full input/output range. GE1085 Page: 2/4 ISSUED DATE :2005/06/01 REVISED DATE :2006/06/01B Functional Description Introduction The GE1085 adjustable or fixed-mode Low Dropout (LDO) regulator is a 3 terminal device which can easily be programmed by internal mask change to any voltage within the range of 1.25 to Vin-1.4V. The GE1085 only needs 1.4V differential between Vin and Vout to maintain output regulation, in addition, the output voltage tolerances are also extremely tight and they include the transient response as port of the specification. For example, Intel VRE specification calls for a total of ±100mV including initial tolerance, load regulation and 0 to 3A load step. The GE1085 is specifically designed to meet the fast current transient needs as well as providing an accurate initial voltage, reducing the overall system cost with the need for fewer output capacitors. Load Regulation Since the GE1085 is only a 3 terminal device, it is not possible to provide true remote sensing of the output voltage at the load. But it can supply good load regulation by internal feedback bypass the external loss such as adjustable mode. Stability The GE1085 requires the use of an output capacitor as part of the frequency compensation in order to make the regulator stable .For most applications a minimum of 10uF aluminum electrolytic capacitor insures both stability and good transient response. Thermal Design The GE1085 incorporates an internal shutdown that protects the device when the junction temperature exceeds the maximum allowable junction temperatures. Although this device can operate with junction temperatures in the range of 150 , it is recommended that the selected heat sink be chosen such that during maximum continuous load operation the junction temperature is kept below the temperature. Layout Consideration The output capacitors must be located as close to the Vout terminal of the device as possible .It is recommended to use a section of a layer of the PC board as a plane to connect the Vout pin to the output capacitors to prevent any high frequency oscillation that may result due to excessive trace inductance. GE1085 Page: 3/4 ISSUED DATE :2005/06/01 REVISED DATE :2006/06/01B Typical Performance Characteristics 3A 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 GE1085 Page: 4/4