RT9035 3A, Ultra Low Dropout Regulator General Description Features The RT9035 is a high performance positive voltage regulator designed for use in applications requiring very low Input voltage and extremely low dropout voltage at up to 3A. It operates with a VIN as low as 1V and VDD voltage 3V with programmable output voltage as low as 0.8V. The RT9035 features ultra low dropout that is ideal for applications where VOUT is very close to VIN. Additionally, it has an enable pin to further reduce power dissipation while shutdown and provides excellent regulation over variations in line, load and temperature. The RT9035 provides a power good signal to indicate if the voltage level of VOUT reaches z Maximum 3A Low-Dropout Voltage Regulator z High Accuracy Output Voltage 2% Dropout Voltage Typical 270mV at 3A Power Good Output Output Voltage Pull Low Resistance when Disable Thermal and Over Current Protection RoHS Compliant and Halogen Free z z z z Applications z z Note Book PC Applications Motherboard Applications Pin Configurations Ordering Information Lead Plating System G : Green (Halogen Free and Pb Free) Z : ECO (Ecological Element with Halogen Free and Pb free) 1 15 2 14 GND 3 4 13 12 21 5 11 6 7 8 9 NC NC NC NC VDD 10 VIN Package Type QW : WQFN-20L 4x4 (W-Type) 20 19 18 17 16 NC GND NC NC PGOOD NC EN VIN VIN RT9035- VOUT VOUT (TOP VIEW) NC ADJ VOUT 90% of its rating value. The RT9035 is available in the WQFN-20L 4x4 package with 1.05V, 1.2V, 1.5V, 1.8V and 2.5V internally preset outputs that are also adjustable by using external resistors. z WQFN-20L 4x4 Output Voltage 1K : 1.05V/Adj 12 : 1.2V/Adj 15 : 1.5V/Adj 18 : 1.8V/Adj 25 : 2.5V/Adj Marking Information For marking information, contact our sales representative directly or through a Richtek distributor located in your area. Note : Richtek products are : RoHS compliant and compatible with the current requirements of IPC/JEDEC J-STD-020. Suitable for use in SnPb or Pb-free soldering processes. DS9035-02 March 2011 www.richtek.com 1 RT9035 Typical Application Circuit VOUT = 0.8 x R1 + R2 R2 VIN VIN 10F Chip Enable RT9035 VDD 10F Chip Enable PGOOD VDD VIN 10F ADJ EN VIN VOUT VOUT GND 10F R2 PGOOD VDD GND 100k R1 ADJ EN 1F CDummy RT9035 VDD VOUT VOUT 100k 1F VOUT VOUT Figure 1. Fixed Voltage Regulator Figure 2. Adjustable Voltage Regulator Functional Pin Description Pin No. 1, 3, 4, 6, 12, 13, 14, 15, 20 2, 21 (Exposed Pad) Pin Name NC GND Pin Function No Internal Connection. Ground. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. 5 PGOOD Power Good Open Drain Output. 7 EN Chip Enable (Active High). Internal pull low. 8, 9, 10 VIN Supply Input Voltage. 11 VDD Supply Voltage of Control Circuit. VOUT Output Voltage. 16, 17, 18 19 ADJ Set the output voltage by an external feedback resistor divider. If the ADJ pin is grounded, the output voltage will be set by internal feedback resistor divider. Function Block Diagram VOUT VIN SD OTP VDD POR 0.8V - EN + OCP Error Amplifier Mode ADJ PGOOD - 0.72V + GND www.richtek.com 2 DS9035-02 March 2011 RT9035 Absolute Maximum Ratings z z z z z z z z z (Note 1) Supply Input Voltage, VIN -------------------------------------------------------------------------------------------- 6V Control Voltage --------------------------------------------------------------------------------------------------------- 6V Output Voltage --------------------------------------------------------------------------------------------------------- 6V Power Dissipation, PD @ TA = 25C WQFN-20L 4x4 -------------------------------------------------------------------------------------------------------- 1.852W Package Thermal Resistance (Note 2) WQFN-20L 4x4, JA --------------------------------------------------------------------------------------------------- 54C/W WQFN-20L 4x4, JC -------------------------------------------------------------------------------------------------- 7C/W Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260C Junction Temperature ------------------------------------------------------------------------------------------------- 150C Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C ESD Susceptibility (Note 3) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V Recommended Operating Conditions z z z z (Note 4) Supply Input Voltage, VIN -------------------------------------------------------------------------------------------- 1.5V to 5V Control Voltage, VDD -------------------------------------------------------------------------------------------------- 4.5V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- -40C to 125C Ambient Temperature Range ---------------------------------------------------------------------------------------- -40C to 85C Electrical Characteristics (VIN = VOUT + 500mV, VEN = VDD = 5V, CIN = COUT = 10F, TA = 25C, unless otherwise specified) Parameter Symbol Test Conditions Min Typ Max Unit -- 0.6 1.2 mA 4.5 -- 5.5 V POR Threshold 2.4 2.7 3 V POR Falling Hysteresis 0.15 0.2 -- V VDD = 5V -2 0 2 % VDD = 5V, IOUT = 3A, VIN = VOUT + 1V -- 0.2 1 % VDD Quiescent Current (GND Current) (Note 5) IQ VDD = 5V VDD Operation Range VDD VDD Input Range Power On Reset VOUT Fixed Output Voltage VOUT Load Regulation (Note 6) VLOAD VOUT Line Regulation (VIN) VLINE_IN VDD = 5V, VIN = VOUT + 1V to 5V IOUT = 1mA -- 0.2 0.6 % Dropout Voltage VDROP VDD = 5V, IOUT = 3A -- 270 400 mV ILIM VDD = 5V, VIN = 3.6V -- 4.5 -- A VDD = 5V , VOUT < 0.2V -- 2.5 -- A (Note 7) Current Limit Short Circuit Current To be Continued DS9035-02 March 2011 www.richtek.com 3 RT9035 Parameter Symbol Test Conditions Min Typ Max Unit In-rush Current VDD = 5V, COUT = 10F, Enable Start-up, ILOAD = 1A -- 0.5 -- A VOUT Pull Low Resistance VEN = 0V -- 150 -- 0.788 0.8 0.812 V -- 0.2 -- V ADJ Reference Voltage (Adj) VDD = 5V, VOUT = 2.5V ADJ Pin Threshold Power Good Power Good Rising Threshold VDD = 5V -- 90 -- % Power Good Hysteresis VDD = 5V -- 10 -- % Power Good Sink Capability VDD = 5V, IOUT = 10mA -- 0.2 0.4 V Logic-Low VEN_L VDD = 5V -- -- 0.6 Logic-High VEN_H VDD = 5V 1.2 -- -- Chip Enable EN Threshold Voltage V EN Pin Bias Current IEN VEN = 5V -- 12 -- A VDD Shutdown Current ISHDN VDD = 5V, VEN = 0V -- -- 1 A -- 160 -- C -- 110 -- C Over Temperature Protection Thermal Shutdown Temperature T SD Thermal Shutdown Returned Temperature Note 1. Stresses listed as the above "Absolute Maximum Ratings" may cause permanent damage to the device. These are for stress ratings. Functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may remain possibility to affect device reliability. Note 2. JA is measured in the natural convection at TA = 25C on a high effective thermal conductivity test board (4 Layers, 2S2P) of JEDEC 51-7 thermal measurement standard. The case point of JC is on the expose pad for WQFN package. Note 3. Devices are ESD sensitive. Handling precaution is recommended. Note 4. The device is not guaranteed to function outside its operating conditions. Note 5. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN - IOUT under no load condition (IOUT = 0mA). Note 6. Regulation is measured at constant junction temperature by using a 2ms current pulse. Devices are tested for load regulation in the load range from 1mA to 3A. Note 7. The dropout voltage is defined as VIN -VOUT, which is measured when VOUT is VOUT(NORMAL) - 100mV. www.richtek.com 4 DS9035-02 March 2011 RT9035 Typical Operating Characteristics Load Transient Response Load Transient Response VDD = 5V, VIN = 1.8V, VOUT = 1.2V VDD = 5V, VIN = 1.8V, VOUT = 1.2V VOUT (20mV/Div) VOUT (20mV/Div) IOUT (1A/Div) IOUT (1A/Div) Time (250s/Div) Time (250s/Div) VDD Line Transient Response VDD Line Transient Response VIN = 1.8V, VOUT = 1.2V, IOUT = 10mA VIN = 1.8V, VOUT = 1.2V, IOUT = 2A 5 5 VDD VDD 4 4 VOUT (10mV/Div) VOUT (10mV/Div) Time (250s/Div) Time (250s/Div) VIN Line Transient Response VIN Line Transient Response VDD = 5V, VOUT = 1.2V, IOUT = 10mA VDD = 5V, VOUT = 1.2V, IOUT = 2A 3 3 VIN VIN 2 2 VOUT (10mV/Div) VOUT (10mV/Div) Time (250s/Div) DS9035-02 March 2011 Time (250s/Div) www.richtek.com 5 RT9035 Dropout Voltage vs. Load Current Start Up from Enable 400 IOUT = 3A Dropout Voltage (mV) 350 125C 300 250 EN (1V/Div) 25C VOUT (1V/Div) 200 150 PGOOD (1V/Div) -40C 100 I IN (2A/Div) 50 0 0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7 3 Time (500s/Div) Load Current (A) Start Up from VDD Start Up from VIN IOUT = 3A IOUT = 3A VIN (1V/Div) VDD (5V/Div) VOUT (1V/Div) VOUT (1V/Div) PGOOD (1V/Div) PGOOD (1V/Div) I IN (2A/Div) I IN (2A/Div) Time (500s/Div) Time (1ms/Div) Short Circuit Protection Short Current vs. Temperature 3.0 2.8 Current Limit (A) 2.6 2.4 2.2 2.0 1.8 1.6 1.4 IOUT (1A/Div) VDD = 5V, VIN = 1.8V, VOUT = 1.2V 1.2 VDD = 5V, VIN = 1.8V, VOUT = 1.2V 1.0 Time (1ms/Div) -40 -20 0 20 40 60 80 100 Temperature (C) www.richtek.com 6 DS9035-02 March 2011 RT9035 Quiescent Current vs. Temperature Current Limit vs. Temperature 1000 5.0 900 Quiescent Current Iq (uA) 5.5 Current Limit (A) 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 800 700 600 500 400 300 200 100 VDD = 5V, VIN = 2.5V, VOUT = 1.2V 0.0 VDD = 5V, VIN = 1.8V, VOUT = 1.2V 0 -40 -20 0 20 40 60 80 100 -40 -25 -10 5 Temperature (C) 20 35 50 65 80 95 110 125 Temperature (C) Reference Voltage vs. Temperature Output Voltage vs. Temperature 0.84 1.25 0.83 1.24 1.23 0.82 Output Voltage (V) Reference Voltage (V) VIN = 1.8V, VADJ = 0V, IOUT = 0A 0.81 0.80 0.79 0.78 1.22 1.21 1.20 1.19 1.18 1.17 0.77 1.16 0.76 1.15 -40 -25 -10 5 20 35 50 65 80 95 110 125 -40 -25 -10 5 Temperature (C) VDD POR Threshold Voltage vs. Temperature 2.95 POR Voltage (V) 2.90 Rising 2.80 2.75 2.70 2.65 Falling 2.60 35 50 65 80 95 110 125 ADJ Threshold Voltage vs. Temperature ADJ Threshold Voltage Range (V) 3.00 2.85 20 Temperature (C) 2.55 2.50 2.45 2.40 0.30 0.28 0.26 0.24 0.22 0.20 0.18 0.16 0.14 0.12 0.10 -40 -25 -10 5 20 35 50 65 Temperature (C) DS9035-02 March 2011 80 95 110 125 -40 -25 -10 5 20 35 50 65 80 95 110 125 Temperature (C) www.richtek.com 7 RT9035 Application Information Adjustable Mode Operation The output voltage of RT9035 is adjustable from 0.8V to VIN by external voltage divider resisters as shown in Typical Application Circuit (Figure 2). The value of resisters R1 and R2 should be more than 10k to reduce the power loss. The PGOOD pin will output high immediately after the output voltage arrives 90% of normal output voltage. The PGOOD pin will output high with typical 1.5ms delay time. Thermal-Shutdown Protection The RT9035 goes into shutdown mode when the EN pin is in the logic low condition. During this condition, the pass transistor, error amplifier, and band gap are turned off. The RT9035 goes into operation mode when the EN pin is in the logic high condition. The RT9035 has an internal pull low resistor at EN pin so that the regulator will be turn off when EN pin is floating. Thermal protection limits power dissipation to prevent IC over temperature in RT9035. When the operation junction temperature exceeds 160C, the over-temperature protection circuit starts the thermal shutdown function and turns the pass transistor off. The pass transistor turn on again after the junction temperature cools by 30C. RT9035 lowers its OTP trip level from 160C to 110C when output short circuit occurs (VOUT < 0.2V). It limits IC case temperature under 100C and provides maximum safety to customer while output short circuit occurring. Output Capacitor Power Dissipation The RT9035 is specifically designed to employ ceramic output capacitors as low as 10F. The ceramic capacitors offer significant cost and space savings, along with high frequency noise filtering. For continuous operation, do not exceed absolute maximum operation junction temperature 125C. The power dissipation definition in device is: Input Capacitor The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junctions to ambient. The maximum power dissipation can be calculated by following formula: Enable Good bypassing is recommended from input to ground to help improve AC performance. A 10F input capacitor or greater located as close as possible to the IC is recommended. Current Limit The RT9035 contains an independent current limit and the short circuit current protection to prevent unexpected applications. The current limit monitors and controls the pass transistor' s gate voltage, limiting the output current to higher than 4.5A typical. When the output voltage is less than 0.2V, the short circuit current protection starts the current fold back function and maintains the loading current 2.5A. The output can be shorted to ground indefinitely without damaging the part. Power Good The power good function is an open-drain output. Connects 100k pull up resistor to VOUT to obtain an output voltage. www.richtek.com 8 PD = (VIN - VOUT) x IOUT + VIN x IQ PD(MAX) = ( TJ(MAX) - TA ) / JA Where T J(MAX) is the maximum operation junction temperature 125C, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9035, where T J (MAX) is the maximum junction temperature of the die (125C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance for WQFN-20L 4x4 package is 54C/W on the standard JEDEC 51-7 (4 layers, 2S2P) thermal test board. The copper thickness is 2oz. The maximum power dissipation at TA = 25C can be calculated by following formula: PD (MAX) = (125C - 25C) / (54C/W) = 1.852W DS9035-02 March 2011 RT9035 The maximum power dissipation depends on operating ambient temperature for fixed T J(MAX) and thermal resistance JA . For RT9035 packages, the Figure 3 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed. Power Dissipation (W) 2.4 4-Layers PCB 2 1.6 1.2 0.8 0.4 0 0 20 40 60 80 100 120 140 Ambient Temperature (C) Figure 3. De-rating Curve DS9035-02 March 2011 www.richtek.com 9 RT9035 Outline Dimension 1 1 2 2 DETAIL A Pin #1 ID and Tie Bar Mark Options Note : The configuration of the Pin #1 identifier is optional, but must be located within the zone indicated. Symbol Dimensions In Millimeters Dimensions In Inches Min Max Min Max A 0.700 0.800 0.028 0.031 A1 0.000 0.050 0.000 0.002 A3 0.175 0.250 0.007 0.010 b 0.150 0.300 0.006 0.012 D 3.950 4.050 0.156 0.159 D2 2.650 2.750 0.104 0.108 E 3.950 4.050 0.156 0.159 E2 2.650 2.750 0.104 0.108 e L 0.500 0.350 0.020 0.450 0.014 0.018 W-Type 20L QFN 4x4 Package Richtek Technology Corporation Richtek Technology Corporation Headquarter Taipei Office (Marketing) 5F, No. 20, Taiyuen Street, Chupei City 5F, No. 95, Minchiuan Road, Hsintien City Hsinchu, Taiwan, R.O.C. Taipei County, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611 Tel: (8862)86672399 Fax: (8862)86672377 Email: marketing@richtek.com Information that is provided by Richtek Technology Corporation is believed to be accurate and reliable. Richtek reserves the right to make any change in circuit design, specification or other related things if necessary without notice at any time. No third party intellectual property infringement of the applications should be guaranteed by users when integrating Richtek products into any application. No legal responsibility for any said applications is assumed by Richtek. www.richtek.com 10 DS9035-02 March 2011