AMS3120 2A Fast Transient Linear Regulator General Description Features • • The AMS3120 is a high performance linear regulator with very low dropout voltage and excellent transient response. It is designed to operate with wide input voltage range of 1.5 – 7Volts making it ideal for two step conversion while maintaining high efficiency for many power sensitive applications. The device is capable of supplying 2A of output current with a typical dropout voltage of 550mV at 2A. The product is available in either fixed or adjustable output voltage. • • • • • • • • The linear regulator has been optimized for noise sensitive applications. The device includes an Enable pin for electrical on/off of the regulator. Forcing the Enable pin to logic low shuts down the LDO and reduces the supply current to less than 1µA. • • • • The product includes complete short-circuit and thermal protection. The combination of these two internal protection circuits gives the device a comprehensive safety system to safe guard against extreme adverse operating conditions. The AMS3120 is available in a thermally enhanced SOIC-8 EDP package, and it is rated for -40°C to +125°C temperature range. • VIN range: 1.5 – 7V Fixed and Adjustable output voltage as low as 0.6V 2A maximum output current 550mV typical dropout voltage at 2A Low self noise Optional Power Good (PG) output Enable (EN) pin for LDO on/off 125µA typical supply current PSRR >40dB at 10KHz Stable with Electrolytic, Tantalum or Ceramic capacitors Current Limit protection Over-Temperature Shutdown -40 to +125°C temperature range Thermally enhanced SOIC-8 exposed paddle package RoHS & WEEE compliant Applications • • • • • • Set-top Box DVD, Blue-ray DVD writers LCD TVs and LCD monitors Infotainment Wireless & RF: applications Laptops & notebook Typical Application VIN= 3.3V VOUT* VIN VOUT=1.8V AMS3120 CIN=10μF PG* EN COUT = 22μF ADJ* GND * Optional Power Good, Fixed and Adjustable VOUT are available 02/11/2010 www.advanced-monolithic.com 1 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Pin Description (SO-8EP package) Pin # Symbol 1 NC No connection 2 EN Enable pin. It controls the electrical on/off of the device. When connected to logic low, the device shuts off and consumes 1µA of current. A logic high will resume normal operation. 3 VIN Input supply Voltage. It powers the internal control circuitry and the internal power switch. Bypass VIN with at ceramic capacitor from this pin to ground. NC No Connection PG Power Good pin. It is an open collector, active high output that indicates the status of the output voltage. When output voltage (VOUT) exceeds the PG trip threshold, the PG pin goes in to a high impedance state. When the device is out of regulation or shutdown, the PG pin is pulled low. A 10KΩ to 1MΩ resistor should be connected from PG to VOUT. 5 NC No Connection 6 VOUT Output Voltage ADJ Provides feedback to error amplifier from the resistive divider that sets the output voltage. NC No Connection 4 7 8,9 GND Description Ground Pin Configuration SO-8EP (Top View) 02/11/2010 www.advanced-monolithic.com 2 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Absolute Maximum Ratings (1) Recommended Operating Conditions (2) Maximum Input Supply Voltage……………..........….… -0.3V to 15V Enable Voltage (EN)……………....…………...…..…… -0.3V to 15V Power Good (PG).……………..…..………………….… -0.3V to 15V Adjustable Voltage (ADJ).…...……………………....…… -0.3V to 3V Storage Temperature Range……………................. -65⁰C to 150⁰C Lead Temperature…………………..………….……………..… 260⁰C Junction Temperature………...………………..…………..…… 125⁰C Input Voltage………………………………...….………….. 1.5V to 7V Ambient Operating Temperature……………….…… -40⁰C to 125⁰C Thermal Information 8L SOIC EP θJA (3) …………………………....……….….…...45⁰C/W Electrical Characteristics Unless otherwise noted: VIN=3.3V; VOUT=1.8V; CIN=10 µF; COUT=22µF; -40⁰C≤TA=TJ≤85⁰C; TJ(Max)= 125°C; Typical values are TA= 25°C Parameter Output Voltage Accuracy Adjustable Voltage Adjustable Pin bias current Maximum Output Current Load Regulation Line Regulation Supply Current Shutdown Current Current Limit Dropout Voltage Symbol VOUT VADJ IADJ_Bias IOUT_Max ISUP ISHDN ILIM VDO ΔVOUT/ΔVIN PSRR Conditions Adjustable VOUT only Adjustable VOUT only Min. -3 0.588 Typ. Max. Units 0.6 10 3 0.612 100 % V nA A % % mA µA A 2 IOUT= 0 – 2A VIN=3.0 – 7.0V; IOUT=100mA VIN=3.3V, Io=0A VIN=3.3V, VEN=0V 0.1 0.2 0.2 <1 2.5 IOUT=0.1A; VOUT=90% of VOUT(NOM) 85 IOUT=0.5A; VOUT=90% of VOUT(NOM) 180 IOUT=1A; VOUT=90% of VOUT(NOM) 275 IOUT=2A; VOUT=90% of VOUT(NOM) 550 F=10KHz Io=20mA 40 dB BW = 100Hz –100 KHz COUT = 10µF IOUT = 500mA 125 µV(rms) 0.5 3 mV Output Noise Voltage en Enable Threshold Low VEN(L) 1.2 V Enable Threshold High VEN(H) 1.3 V Input Enable Low Current IEN(L) VEN = 0V Input Enable High Current IEN(H) VEN = 1.5V Power Good Low Threshold Power Good High Threshold VPG VPG % of VOUT PG ON % of VOUT PG OFF Power Good Output Low Voltage VPGL IPG_SINK = 500μA, Fault Condition 200 Power Good Leakage Current Thermal Shutdown Thermal Shutdown Hysteresis IPG TSD PG off, VPG = 12V 0.01 145 15 Notes: 1. 2. 3. TSD_HYS 0 10 nA 150 300 nA 97 % % 300 mV 89 μA °C °C Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Measured on approximately 1” square of 1 oz. copper. The total power dissipation for SO-8 EDP package is recommended to 2.5W rated at 25⁰C ambient temperature. The thermal resistance Junction to Case is 45⁰C/W. Total power dissipation for the switching regulator and the LDO should be taken in consideration when calculating the output current capability of each regulator 02/11/2010 www.advanced-monolithic.com 3 Phone (925) 443-0722 Fax (925) 443-0723 A AMS3 3120 2A Fas st Transien nt Linear Regulator 1.808 1.806 1.804 1.802 1.800 1.798 1.796 1.794 1.792 Ou utput Voltage e Temperaturre Variation (Fixed Voltage Option) VO = 1.8V 0.603 0.601 0.599 0.597 0.595 25 0 25 5 50 75 100 125 -2 Ambient Te emperature (ºC) ( Dro opout Voltag ge vs. Tempe erature 1.0 0.8 0.1 0.0 -0.1 -0.2 2A 0.6 0.4 0.2 1 A 0.0 3 4 5 6 Input Voltage (V) 7 -50 Load Regulation 0.3 -25 0 25 5 50 75 100 125 Ambient Te emperature (°C) ( Dropout Voltage e vs. Output Current 0.6 0.5 0.2 Voltage (V) Output p Voltage g Change g (%) ( ) Ad djust (ADJ) Voltage V Temp perature Variation (Adjus stable Voltage Option) -50 Line Regullation VOUT = 2.5V 0.2 0.605 -25 0 25 50 75 5 100 125 5 Ambient Temperature T e (ºC) Voltage (V) Output p Voltage g Error (%) ( ) -50 Adjustable Voltage (V) Output p Voltage g (V) ( ) Ty ypical Perfo ormance Characteris C stics (TA = 25°C 2 unless otherwise o sp pecified) 0.1 0.0 -0.1 0.4 0.3 0.2 -0.2 0.1 -0.3 0.0 0.0 02/11/2010 0 0.1 1.0 Output Current (A) 10.0 0 VOUT = 2.5V O 0 www.ad dvanced-mono olithic.com 4 0.5 1 1.5 Output Current (A) 2 Phone (925)) 443-0722 Fax (925)) 443-0723 AMS3120 2A Fast Transient Linear Regulator Typical Performance Characteristics (TA = 25°C unless otherwise specified) IGND vs. Output Current VO=1.8V, VIN=2.5V 1.5 70 Ground Current (mA) Shutdown Current (µA) Shutdown Current vs. Input Voltage 125°C 1.0 0.5 ‐50°C & 25°C 0.0 0 1 2 3 4 5 6 7 60 50 40 30 20 10 0 0.0 0.8 1.2 1.6 2.0 Output Current (A) Input Voltage (V) Load Transient 100mA to 1.5A, VOUT=1.8V,VIN=3.3V, CIN=COUT=22µF Enable Start-Up 550mA, VOUT=1.8V,VIN=3.3V, CIN=COUT=22µF V OUT 50mVac /div V OUT 1V /div ISW OUT 500mA /div Enable 1V/div 100 µsec/div 10 µsec/div 02/11/2010 0.4 www.advanced-monolithic.com 5 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Functional Block Diagram Figure 1: Block Diagram of AMS 3120 with Power Good and Adjustable Voltage option Figure 2: Block Diagram of AMS 3120 with Power Good and Fixed Voltage option Figure 3: Block Diagram of AMS 3120 with Fixed Voltage option only 02/11/2010 www.advanced-monolithic.com 6 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Table 1: Adjustable Feedback Resistor values R1 (kΩ) VOUT (V) (R2=10kΩ) 1.8 20.0 2.5 31.6 3.3 45.3 5.0 73.2 Device Summary The AMS3120 is a high voltage low drop out linear regulator with a current capability of up to 2A. The LDO has an input voltage range of 1.5V to 7V with an output voltage as low as 0.6V and is stable with a wide range of ceramic, tantalum, and electrolytic output capacitors. Shutdown/Enable The Enable (on/off) input threshold voltage is 1.2V. When disabled the LDO quiescent current decreases to a typical value of <1µA. Fault Protection Short circuit and over-temperature shutdown disable the converter and LDO in the event of an overload condition. Overtemp shutdown disables the device when the junction temperature exceeds 145 ºC. The output current is internally limited to 2.5A. PCB Layout The following guidelines should be followed to insure proper layout. 1. 2. Input Capacitor An input bypass capacitor ranging from 1µF to 10µF is required. The capacitor should be placed as close as possible to the device and not be placed more than 1 inch from the LDO. Output Capacitor The output capacitor requirements range from the minimum value required to guarantee stability to larger values required to meet the extreme transient response requirements. Values range from 10 to 22µF X5R ceramic capacitors. Due to the extreme voltage coefficient of X5R ceramic capacitors, the voltage rating should be at least double the maximum applied voltage. Adjustable Version: Feedback Resistor Selection Choosing AMS 3120 with adjustable output voltage option allows the user to select an output voltage by using an external resistor divider. AMS 3120 uses a 0.6V reference voltage at the positive terminal of the error amplifier. To set the output voltage a programming resistor from the adjust pin (ADJ) to ground must be selected (See Pg.1). A 10kΩ resistor is a good selection for a programming resistor R2. A higher value may result in an excessively sensitive feedback node while a lower value will draw more current and degrade the light load efficiency. The equation for selecting the voltage specific resistor is: R4= Vout Vref -1 ·R3 = 5V 0.6V -1 ·10kΩ=73.2kΩ 3. 4. VIN Capacitor. A low ESR ceramic bypass capacitor must be placed as close to the IC as possible. Adjustable (ADJ) Feedback Resistors. The adjustable feedback resistors should be placed as close as possible the IC. Minimize the length of the trace from the feedback pin to the resistors. This is a high impedance node susceptible to interference from external RF noise sources. Ground. For good thermal performance vias are required to couple the exposed tab of the SO-8 package to the PCB ground plane. The via diameter should be 0.3mm to 0.33mm positioned on a 1.2mm grid. Power Good During operation, fault conditions can occur unexpectedly. Such conditions include input voltage dropout (low VIN), overheating, or overloading (excessive output current). If any of these conditions occurs, the PG pin will set an “error flag”. The PG pin, which is an opencollector output, will go LOW when VOUT is less than 95% or the specified output voltage. When the voltage at VOUT is greater than 95% of the specified output voltage, the PG pin is HIGH. A logic pull-up resistor of 10KΩ is recommended at this output. The pin can be left disconnected if unused. Output Power and Thermal Limits The AMS3120 junction temperature and current capability depends on the internal dissipation and the junction to case thermal resistance of the SO8 exposed paddle package. Additionally, the paddle and PCB temperature will be elevated due to the total losses of the LDO and of other circuits mounted to the PCB. Tjmax=Pd·θjc+Tpcb+Tamb The internal losses contribute to the junction temperature rise above the paddle and PCB temperature. 02/11/2010 www.advanced-monolithic.com 7 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Figure 4: AMS3120 SOIC-8 Adjustable Option Evaluation Board - Top Side Figure 5: AMS3120 SOIC-8 Adjustable Option Evaluation Board - Bottom Side R2 10.0k Enable 1 2 1 2 Vin 3 C1 10uF gnd 4 U1 NC EN GND ADJ VIN VOUT NC NC 8 R1 20.0k 7 C3 5.6nF Vout 6 5 C2 22uF gnd AMS3120-8 Figure 4. AMS3120 Evaluation Board Schematic Component C1,C2 C3 R2 R1 U1 02/11/2010 Value Table 2. Evaluation Board Bill of Materials Manufacturer Manufacturer Part Number 22µF, 10V, X5R, 0805, Ceramic 5.6nF 0603 20% 10kΩ, 0.1W, 0603 1% See table 2 Low Drop Out Linear Regulator Taiyo Yuden LMK212BJ226MG-T Various Various AMS CRCW060310K0FKEA CRCW0603xxKxFKEA AMS3120 www.advanced-monolithic.com 8 Phone (925) 443-0722 Fax (925) 443-0723 AMS3120 2A Fast Transient Linear Regulator Ordering Information Device AMS3120S(1)(2) Package SOIC-8 EDP AMS3120S-PG(1)(2) (1)(2) SOIC-8 EDP AMS3120S-XXPG SOIC-8 EDP (1)(2) SOIC-8 EDP AMS3120S-XX Notes: 1. Available in tape and reel only. A reel contains 2,500 devices. 2. Available in lead-free package only. Device is fully WEEE and RoHS compliant 3. Need to specify output voltage option ( ) 4. Outline Drawing and Landing Pattern Package dimensions are inches (millimeters) unless otherwise noted. 02/11/2010 www.advanced-monolithic.com 9 Phone (925) 443-0722 Fax (925) 443-0723