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| AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n General Description The AME8870 family of positive, linear regulators feature low quiescent current (30A typ.) with low dropout voltage, making them ideal for battery applications. The space-saving SOT-23-5 package is attractive for "Pocket" and "Hand Held" applications. 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 1000 pF capacitor between Bypass and Ground. The AME8870 is stable with an output capacitance of 2.2F or greater. n Functional Block Diagram IN Overcurrent Shutdown OUT Thermal Shutdown EN BYP AMP R1 Vref=1.215V R2 GND n Features l l l l l l l l l Very Low Dropout Voltage Guaranteed 300mA Output Accurate to within 1.5% 30A Quiescent Current Over-Temperature Shutdown Current Limiting Short Circuit Current Fold-back Noise Reduction Bypass Capacitor Power-Saving Shutdown Mode n Typical Application INPUT IN OUT OUTPUT AME8870 BYP GND EN l Space-Saving SOT-25 Package l Factory Pre-set Output Voltages l Low Temperature Coefficient C1 5V 1F C2 1000pF C3 2.2F n Applications l l l l l l l Instrumentation Portable Electronics Wireless Devices Cordless Phones PC Peripherals Battery Powered Widgets Electronic Scales 1 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Pin Configuration SOT-25 Top View 5 4 AME8870 AME8870AEEV 1. VIN 2. GND 3. EN 4. BYP 5. OUT 1 2 3 2 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Ordering Information Part Number AME8870AEEV350 AME8870AEEV360 Marking AXJww AXIww Output Voltage 3.5V 3.6V Package SOT-25 SOT-25 Operating Temp. Range - 40oC to + 85oC - 40oC to + 85oC 3 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Absolute Maximum Ratings Parameter Input Voltage Output Current Output Voltage ESD Classification Maximum 8 PD / (VIN - VO) GND - 0.3 to VIN + 0.3 B Unit V mA V Caution: Stress above the listed absolute maximum rating may cause permanent damage to the device n Recommended Operating Conditions Parameter Ambient Temperature Range Junction Temperature Rating - 40 to + 85 - 40 to + 125 Unit o C C o n Thermal Information Parameter Thermal Resistance (ja) Internal Power Dissipation (PD ) (DT = 100oC) Maximum Junction Temperature SOT-25 SOT-25 Maximum 260 380 150 Unit o C/W mW o C 4 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Electrical Specifications TA = 25OC unless otherwise noted Parameter Input Voltage Output Voltage Accuracy Symbol VIN VO IO=300mA VO=VO(NOM) -2.0% IO=1mA 1.2V o o Test Condition Min Note 1 -1.5 Typ Max 7 1.5 1300 Units V % Dropout Voltage VDROPOUT See chart 400 300 mV mA mA 300 50 mA A A IO=1mA to 300mA C C ppm/ oC Output Voltage Noise eN VEH V EL EN Input Threshold VIN =2.7V to 7V VIN =2.7V to 7V VEN =VIN , VIN =2.7V to 7V VEN =0V, VIN =2.7V to 7V V IN =5V, VO=0V, VEN IEH IEL ISD VO,SD Note1: VIN(MIN)=VOUT+VDROPOUT Note2: To prevent the Short Circuit Current protection feature from being prematurely activated, the input voltage must be applied before a current source load is applied. 5 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Detailed Description The AME8870 family of CMOS 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 150oC, or the current exceeds 300mA. During thermal shutdown, the output voltage remains low. Normal operation is restored when the junction temperature drops below 120oC. The AME8870 switches from voltage mode to current mode when the load exceeds the rated output current. This prevents over-stress. The AME8870 also incorporates current foldback to reduce power dissipation when the output is short circuited. This feature becomes active when the output drops below 0.8volts, and reduces the current flow by 65%. Full current is restored when the voltage exceeds 0.8 volts. A third capacitor can be connected between the BYPASS pin and GND. This capacitor can be a low cost Polyester Film variety between the value of 0.001 ~ 0.01F. A larger 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. n Enable The Enable pin normally floats high. When actively, pulled low, the PMOS pass transistor shuts off, and all internal circuits are powered down. In this state, the quiescent current is less than 1A. This pin behaves much like an electronic switch. n Auto-Discharge/No-Discharge VOUT has an internal 100- (typ.) discharge path to ground when the EN pin is low. n External Capacitors The AME8870 is stable with an output capacitor to ground of 2.2F 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 0.1F ceramic capacitor with a 10F 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 0.1F to have a beneficial effect. 6 AME, Inc. AME8870 Ground Current vs. Input Voltage 45 40 y nar limi Pre 300mA CMOS LDO w/ Discharge Load Step (1mA-300mA) CL =2.2F C IN =2.2F Ground Current ( A) 35 30 25 20 15 10 5 0 0 1 2 3 4 85 C 25 C O IL(200mA/DIV) VO (5mV/DIV) O Output I Load 5 6 7 8 0 TIME( 20mS/DIV) Input Voltage (V) Chip Enable Transient Response Enable (2V/DIV) Enable (2V/DIV) Chip Enable Transient Response CL=2F RL=10 CBYP=1000pF CL=2F RL=10 0 0 Output (1V/DIV) 0 Output (1V/DIV) 0 TIME ( 1mS/DIV) TIME ( 1mS/DIV) Drop Out Voltage vs. Output Voltage 300 250 Drop Out Voltage vs. Load Current Top to bottom VOUT=2.5V VOUT=2.8V VOUT=3.0V VOUT=3.3V VOUT=3.5V VOUT=3.8V 250 Drop Out Voltage (mV) 200 I LOAD =300mA I LOAD =200mA Dropout Voltage (mV) 200 150 150 100 100 I LOAD =100mA 50 0 2.5 2.75 3 3.25 3.5 3.75 4 50 0 0 50 100 150 200 250 300 Output Voltage (V) Load Current (mA) 7 AME, Inc. AME8870 Power Supply Rejection Ratio -20 0 y nar limi Pre 300mA CMOS LDO w/ Discharge Power Supply Rejection Ratio -10 -20 100mA -30 CL=2.2F Tantalum CBYP=1000pF PSRR (dB) -40 1mA PSRR (dB) CL=2.2F Tantalum Tantalum C BYP =0 100mA -30 -40 -50 -60 -50 100mA -60 100mA 10mA -70 -80 10 10mA 100A 1K -70 100A -80 100K 10M 10 100 A 1K 100 A 100K 1mA 10M Frequency (Hz) Frequency (Hz) Power Supply Rejection Ratio -10 -20 -10 Power Supply Rejection Ratio CL = 5.6 F Ceramic IL = 100 mA CBYP = 0 CBYP = 100 pF CBYP = 100 pF CL = 10 F Tantalum IL = 100 mA CBYP = 0 -20 -30 -30 PSRR ( dB) PSRR ( dB) -40 -50 -40 -50 -60 -70 -60 CBYP = 1 nF CBYP = 10 nF 10 100 1K 10K 100K 1M CBYP = 1 nF CBYP = 10 nF 100 1K 10K 100K -70 -80 -80 10 Frequency (Hz) Frequency (Hz) Short Circuit Response ILoad(400mA/DIV) Overtemperature Shutdown I OUT (200mA/DIV) R LOAD =100 R SHORT =0.1 0 R LOAD=6.6 0 0 TIME (2mS/DIV) TIME (0.5Sec/DIV) VOUT (1V/DIV) Vout (1V/DIV) 0 8 AME, Inc. AME8870 Current Limit Response IOUT(200mA/DIV) y nar limi Pre 300mA CMOS LDO w/ Discharge Noise Measurement RLoad=3.3 0 Vo (1mV DIV) CL=2.2F No Filter VOUT(1V/DIV) 0 TIME (2mS/DIV) TIME (20ms/DIV) Line Transient Response VIN(1V/DIV) Safe Operating Area VINDC=5.0V CL=2.2F Output Current (mA) 300 VO(1mV/DIV) 100 SOT-23-5 10 0.1 1.0 8.0 TIME (2mS/DIV) Input-Output Voltage Differential (V) Stability vs. ESR vs. ILoad 10000 10000 Stability vs. ESR vs. ILoad Unstable Region 1000 Unstable Region 1000 100 CL=1F ESR ( ) 100 CL=2F Stable Region ESR ( ) 10 Stable Region 10 1 1 0.1 0.1 Untested Region Untested Region 0.01 0 50 100 150 200 0.01 0 50 100 150 200 ILOAD (mA) ILOAD (mA) 9 AME, Inc. AME8870 Stability vs. ESR vs. ILoad 10000 10000 y nar limi Pre 300mA CMOS LDO w/ Discharge Stability vs. ESR vs. ILoad Unstable Region Unstable Region 1000 1000 100 CL=3F ESR ( ) CL=10F 100 10 1 0.1 ESR ( ) Stable Region 10 Stable Region 1 0.1 Untested Region 0.01 0.001 0 50 100 150 200 0 50 Untested Region 0.01 100 150 200 ILOAD (mA) ILOAD (mA) Quiescent Current vs. Temp. 35 0.58 0.56 Load Regulation vs. Temp. Quiescent Current @ 5V (uA) 34 33 32 31 30 29 28 27 -45 Load Regulation (%) -5 25 55 85 0.54 0.52 0.50 0.48 0.46 0.44 0.42 0.40 -45 -5 25 55 85 Temperature (oC) Temperature (oC) Shut Down Current vs. Temp. 1.0 -0.20 0.9 EN pin LO bias Current vs. Temp. EN pin LO bias current (uA) Shut Down Current (uA) 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -45 -0.25 -0.30 -0.35 -0.40 -0.45 -5 Temperature (oC) 25 55 85 -0.50 -45 -5 25 55 85 Temperature (oC) 10 AME, Inc. AME8870 Dropout Voltage vs. Temp. 220 y nar limi Pre 300mA CMOS LDO w/ Discharge Dropout Voltage @ 300mA (mV) 210 200 190 180 170 160 150 -45 -5 25 55 85 Temperature (oC) 11 AME, Inc. AME8870 y nar limi Pre 300mA CMOS LDO w/ Discharge n Package Dimension SOT-25 Top View D L Side View SYMBOLS A A1 b D E e H L e1 A MILLIMETERS MIN 0.00 0.30 2.70 1.40 INCHES MIN 0.0000 0.0118 0.1063 0.0551 MAX 0.15 0.55 3.10 1.80 MAX 0.0059 0.0217 0.1220 0.0709 1.20REF 0.0472REF H E S1 e 1 c 1.90 BSC 2.60 3.00 0.07480 BSC 0.10236 0.11811 0.0146BSC 0o 10o 0.37BSC 0o 10o Front View S1 0.95BSC 0.0374BSC b 12 A1 www.ame.com.tw E-Mail: sales@ame.com.tw Life Support Policy: These products of AME, Inc. are not authorized for use as critical components in life-support devices or systems, without the express written approval of the president of AME, Inc. AME, Inc. reserves the right to make changes in the circuitry and specifications of its devices and advises its customers to obtain the latest version of relevant information. (c) AME, Inc. , November 2003 Document: 2057-DS8870-A Corporate Headquarter AME, Inc. 2F, 189 Kang-Chien Road, Nei-Hu District Taipei 114, Taiwan, R.O.C. Tel : 886 2 2627-8687 Fax: 886 2 2659-2989 U.S.A. (Subsidiary) Analog Microelectronic, Inc. 3100 De La Cruz Blvd., Suite 201 Santa Clara, CA. 95054-2046 Tel : (408)988-2388 Fax : (408)988-2489 |
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