View RT9185BPL5_4120970.PDF datasheet online --- IC-ON-LINE

Datasheet File OCR Text:

RT9185
Triple, Ultra-Fast CMOS LDO Regulator
General Description
The RT9185 series are efficient, precise triple-channel CMOS LDO regulators specifically designed for motherboard application. The device is intended to powering the standby voltage in which 3.3V_PCI, 2.5V_Clock and 1.8V_ICH2 or 1.5V_ICH4 core voltage of the PC based computer system. Moreover, it is also optimized for CD/ DVD-ROM, CD/RW, XDSL Router or IA equipments applications. The regulator outputs are capable of sourcing 1.5A, 0.8A and 0.3A of output current respectively. The RT9185 also works with low-ESR ceramic capacitors, reducing the amount of board space necessary for power applications. The other features include faster transient response, low dropout voltage, high output accuracy, current limiting and thermal shutdown protections. The RT9185 regulators are available in fused SOP-8, 5-lead TO-252 and 5-lead TO-263 packages.
Features
Fixed Output Voltages : 3.35V at 1.5A, 2.55V at 0.8A and 1.5V or 1.8V at 0.3A Low Quiescent Current (Typically 0.4mA) Operating Voltage Ranges : 3.5V to 5.5V Ultra-Fast Transient Response Tight Load and Line Regulation Current Limiting Protection Thermal Shutdown Protection Only Low-ESR Ceramic Capacitors Required for Stability Custom Voltage Available RoHS Compliant and 100% Lead (Pb)-Free
Applications
Mother-board Power Supply CD/DVD-ROM, CD/RW XDSL Router IA Equipments Cable Modems
Ordering Information
RT9185 Package Type S : SOP-8 L5 : TO-252-5 M5 : TO-263-5 Operating Temperature Range P : Pb Free with Commercial Standard G : Green (Halogen Free with Commercial Standard) VOUT3 A : 1.8V B : 1.5V Other voltage versions please contact RichTek for detail.
Pin Configurations
(TOP VIEW)
VOUT1 VDD VOUT2 VOUT3 2 3 4 8 7 6 5 GND GND GND GND
SOP-8
5 4 3 2 VOUT3 VOUT2 GND (TAB) VDD VOUT1
Note : RichTek Pb-free and Green 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. 100%matte tin (Sn) plating.
5 4 3 2
TO-252-5
VOUT3 VOUT2 GND (TAB) VDD VOUT1
TO-263-5
DS9185-11 March 2007
www.richtek.com 1
RT9185
Typical Application Circuit
VOUT1 (3.35V/1.5A) C2 4.7uF RT9185 VDD (5VSB) C1 2.2uF VDD VOUT2 GND C3 4.7uF VOUT2 (2.55V/0.8A) VOUT1 VOUT3 C4 1uF VOUT3 (1.5V or 1.8V/0.3A)
Function Block Diagram
Current Limiting
VDD + VOUT1
Thermal Sensor +
Error Amplifier
Reference
VDD
Current Limiting
Current Limiting
VDD + -
+ + +
Error Amplifier
Error Amplifier
VOUT3
VOUT2
GND
Functional Pin Description
Pin Name VOUT1 VDD GND VOUT2 VOUT3 Pin Function Channel 1 Output Voltage Supply Input Common Ground Channel 2 Output Voltage Channel 3 Output Voltage
www.richtek.com 2
DS9185-11 March 2007
RT9185
Absolute Maximum Ratings
(Note 1) Supply Input Voltage -------------------------------------------------------------------------------------------------- 7V Power Dissipation, PD @ TA = 25C SOP-8 -------------------------------------------------------------------------------------------------------------------- 0.625W TO-252-5 ----------------------------------------------------------------------------------------------------------------- 1.471W TO-263-5 ----------------------------------------------------------------------------------------------------------------- 2.222W Package Thermal Resistance (Note 6) SOP-8, JA -------------------------------------------------------------------------------------------------------------- 160C/W TO-252-5, JA ----------------------------------------------------------------------------------------------------------- 68C/W TO-263-5, JA ----------------------------------------------------------------------------------------------------------- 45C/W Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260C Junction Temperature ------------------------------------------------------------------------------------------------- 150C Storage Temperature Range ---------------------------------------------------------------------------------------- -65C to 150C ESD Susceptibility (Note 2) HBM (Human Body Mode) ------------------------------------------------------------------------------------------ 2kV MM (Machine Mode) -------------------------------------------------------------------------------------------------- 200V
Recommended Operating Conditions
(Note 3)
Supply Input Voltage -------------------------------------------------------------------------------------------------- 3.5V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- -40C to 125C
Electrical Characteristics
(VDD = 5V, CIN = 1F, TA = 25C, for each LDO unless otherwise specified)
Parameter
Symbol VOUT1
Test Conditions IOUT1 = 1mA IOUT2 = 1mA RT9185A RT9185B IOUT3 = 1mA
Min 3.315 2.525 1.782 1.485 1.5 0.8 0.3 --------125
Typ 3.35 2.55 1.8 1.5 1.9 1.3 0.5 0.4 600 700 2 30 30 20 30 165
Max Units 3.415 2.60 1.836 1.530 ---0.8 1085 -10 55 55 45 --PPM C mV mA mV mV mV A V
Output Voltage Accuracy
VOUT2 VOUT3 ILIM1
RLOAD = 1 R LOAD = 1 R LOAD = 1 IOUT = 0mA
Current Limiting
ILIM2 ILIM3
Quiescent Current (triple LDOs) IDD (Note 5) Dropout Voltage Line Regulation (triple LDOs)
VDROP1 IOUT1 = 1.5A VDROP2 IOUT2 = 0.8A VLINE VLOAD1 VLOAD2 VLOAD3 IOUT = 1mA, VDD = 4V to 6V VOUT1, 1mA < IOUT1 <1.5A VOUT2, 1mA < IOUT2 <0.8A VOUT3, 1mA < IOUT3 < 0.3A
Load Regulation
(Note 4)
Temperature Coefficient Thermal Shutdown
DS9185-11 March 2007
TC TSD
www.richtek.com 3
RT9185
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. Devices are ESD sensitive. Handling precaution recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. Regulation is measured at constant junction temperature by using a 20ms current pulse. Devices are tested for load regulation in the load range from 1mA to 1.5A, 0.8A and 0.3A for each LDO respectively. Note 5. Quiescent, or ground current, is the difference between input and output currents. It is defined by IQ = IIN pin current. Note 6. JA is measured in the natural convection at T A = 25C on a low effective thermal conductivity test board of JEDEC 51-3 thermal measurement standard. The pad size is 100mm2 on TO-252 packages, 125mm2 on TO-263 packages.
- IOUT under
no load condition (IOUT = 0mA). The total current drawn from the supply is the sum of the load current plus the ground
www.richtek.com 4
DS9185-11 March 2007
RT9185
Typical Operating Characteristics
Temperature Stability
4.2 3.8
600
Quiescient Current
VOUT1 = 3.35V
Output Voltage (V)
3.4 3
500
VDD = 5V
VDD = 6V VDD = 4V
VOUT2 = 2.55V
2.6 2.2
Iq (uA)
400
VOUT3 = 1.8V/1.5V
1.8 1.4 -35 -40 -15 5 25 45 65 85 105 125
300
200 -40 -35
-15
5
25
45
65
85
105
125
Temperature (C)
Temperature (C)
Current Limit vs. Temperature
2.5
-10
PSRR
-20 -30
VDD = 5V V OUT1
2
Current Limit (A)
V OUT2
1.5
VDD = 5V C1 = 2.2uF, C2 = 4.7uF C3 = 4.7uF, C4 = 1uF IO1, IO2, IO3 = 10mA
TA = 25C
PSRR (dB)
-40 -50 -60 -70
1
V OUT3
0.5
V OUT2
VOUT3
VOUT1 1K 1000 10K 10000 100K 100000 1M 1000000
0
-80
-40 -35
-15
5
25
45
65
85
105
125
10
100
Temperature (C)
Frequency (Hz)
Dropout Valtage vs. Temperature
1
Short Thermal Shutdown
VDD = 5V C1 = 2.2uF TA = 25C
VDD = 5V
Dropout Valtage (V)
0.8
VOUT2 = 2.55V
0.6
VOUT1 = 3.35V
0.4
0.2
-40 -35
-15
5
25
45
65
85
105
125
ILoad1 (A)
Temperature (C)
DS9185-11 March 2007
Time (25ms/Div)
www.richtek.com 5
RT9185
Load Transient Response
Output Voltage Deviation (mV)
100 50 0 -50 VDD = 5V, VOUT1 = 3.35V C1 = 2.2uF, C2 = 4.7uF TA = 25C
Load Transient Response
Output Voltage Deviation (mV)
100 50 0 -50 VDD = 5V, VOUT2 = 2.55V C1 = 2.2uF, C3 = 4.7uF TA = 25C
Load Current (A)
Load Current (A)
1 0
1 0
Time (500s/Div)
Time (500s/Div)
Load Transient Response
Output Voltage Deviation (mV) Output Voltage Deviation (mV)
VDD = 5V, VOUT3 = 1.5V 100 C1 = 2.2uF, C4 = 1uF 50 0 -50 TA = 25C 10 5 0 -5
Line Transient Response
VDD = 4.5V to 5.5V VOUT1 = 3.35V C1 = 2.2uF, C2 = 4.7uF TA = 25C IOUT1 = 500mA
Load Current (mA)
400 200 0
Input Voltage Deviation (V)

5.5 4.5
Time (500s/Div)
Time (100s/Div)
Line Transient Response
Output Voltage Deviation (mV)
TA = 25C IOUT1 = 400mA
Line Transient Response
Output Voltage Deviation (mV)
20 10 0 -10 VDD = 4.5V to 5.5V VOUT1 = 1.5V C1 = 2.2uF, C2 = 4.7uF TA = 25C IOUT1 = 150mA
VDD = 4.5V to 5.5V 20 VOUT2 = 2.55V C1 = 2.2uF, C3 = 4.7uF 10 0 -10
Input Voltage Deviation (V)
5.5 4.5
Input Voltage Deviation (V)

5.5 4.5
Time (100s/Div)
Time (100s/Div)
www.richtek.com 6
DS9185-11 March 2007
RT9185
Power Dissipation vs. Copper Area
500
500
Power Dissipation vs. Copper Area
TJ = 125C
400
TJ = 125C
400
Copper Area (mm 2 )
300
Copper Area (mm 2 )
2
2
300
200
200
100
100
TA = 65C
0 1 1.5
TA = 50C
TA = 25C SOP-8
0
TA = 65C
TA = 50C
TA = 25C TO-252
2
2.5
3
2
2.5
3
3.5
4
4.5
5
Power Dissipation (W)
Power Dissipation (W)
Power Dissipation vs. Copper Area
300
TJ = 125C
Copper Area (mm 2 )
250
2
TA = 65C
TA = 50C
TA = 25C
200
150
TO-263-5
100 2.5 3.5 4.5 5.5 6.5 7.5 8.5
Power Dissipation (W)
DS9185-11 March 2007
www.richtek.com 7
RT9185
Application Information
Like any low-dropout regulator, the RT9185 requires input and output decoupling capacitors. The device is specifically designed for portable applications requiring minimum board space and smallest components. These capacitors must be correctly selected for good performance (see Capacitor Characteristics Section). Please note that linear regulators with a low dropout voltage have high internal loop gains which require care in guarding against oscillation caused by insufficient decoupling capacitance. Input Capacitor An input capacitance of 2.2F is required between the device input pin and ground directly (the amount of the capacitance may be increased without limit). The input capacitor MUST be located less than 1 cm from the device to assure input stability (see PCB Layout Section). A lower ESR capacitor allows the use of less capacitance, while higher ESR type (like aluminum electrolytic) require more capacitance. Capacitor types (aluminum, ceramic and tantalum) can be mixed in parallel, but the total equivalent input capacitance/ ESR must be defined as above to stable operation. There are no requirements for the ESR on the input capacitor, but tolerance and temperature coefficient must be considered when selecting the capacitor to ensure the capacitance will be 2.2F over the entire operating temperature range. Output Capacitor The RT9185 is designed specifically to work with very small ceramic output capacitors. The recommended minimum capacitance (temperature characteristics X7R, X5R, Z5U, or Y5V) are 2.2F to 4.7F range with 10m to 50m range ceramic capacitors between each LDO output and GND for transient stability, but it may be increased without limit. Higher capacitance values help to improve transient. The output capacitor's ESR is critical because it forms a zero to provide phase lead which is required for loop stability. No Load Stability The device will remain stable and in regulation with no external load. This is specially important in CMOS RAM keep-alive applications. Input-Output (Dropout) Voltage A regulator's minimum input-to-output voltage differential (dropout voltage) determines the lowest usable supply voltage. In battery-powered systems, this determines the useful end-of-life battery voltage. Because the device uses a PMOS, its dropout voltage is a function of drain-to-source on-resistance, RDS(ON), multiplied by the load current: VDROPOUT = VDD - VOUT = RDS(ON) x IOUT Current Limit The RT9185 monitors and controls the PMOS' gate voltage, limiting the output current to 1.9A, 1.3A and 0.5A (typ.) respectively. The outputs can be shorted to ground for an indefinite period of time without damaging the part. Short-Circuit Protection The device is short circuit protected and in the event of a peak over-current condition, the short-circuit control loop will rapidly drive the output PMOS pass element off. Once the power pass element shuts down, the control loop will rapidly cycle the output on and off until the average power dissipation causes the thermal shutdown circuit to respond to servo the on/off cycling to a lower frequency. Please refer to the section on thermal information for power dissipation calculations. Capacitor Characteristics It is important to note that capacitance tolerance and variation with temperature must be taken into consideration when selecting a capacitor so that the minimum required amount of capacitance is provided over the full operating temperature range. In general, a good tantalum capacitor will show very little capacitance variation with temperature, but a ceramic may not be as good (depending on dielectric type). Aluminum electrolytics also typically have large temperature variation of capacitance value.
www.richtek.com 8
DS9185-11 March 2007
RT9185
Equally important to consider is a capacitor's ESR change with temperature: this is not an issue with ceramics, as their ESR is extremely low. However, it is very important in tantalum and aluminum electrolytic capacitors. Both show increasing ESR at colder temperatures, but the increase in aluminum electrolytic capacitors is so severe they may not be feasible for some applications. Ceramic : For values of capacitance in the 10F to 100F range, ceramics are usually larger and more costly than tantalums but give superior AC performance for by-passing high frequency noise because of very low ESR (typically less than 10m). However, some dielectric types do not have good capacitance characteristics as a function of voltage and temperature. Z5U and Y5V dielectric ceramics have capacitance that drops severely with applied voltage. A typical Z5U or Y5V capacitor can lose 60% of its rated capacitance with half of the rated voltage applied to it. The Z5U and Y5V also exhibit a severe temperature effect, losing more than 50% of nominal capacitance at high and low limits of the temperature range. X7R and X5R dielectric ceramic capacitors are strongly recommended if ceramics are used, as they typically maintain a capacitance range within 20% of nominal over full operating ratings of temperature and voltage. Of course, they are typically larger and more costly than Z5U/Y5U types for a given voltage and capacitance. Tantalum : Solid tantalum capacitors are recommended for use on the output because their typical ESR is very close to the ideal value required for loop compensation. They also work well as input capacitors if selected to meet the ESR requirements previously listed. Tantalums also have good temperature stability: a good quality tantalum will typically show a capacitance value that varies less than 10~15% across the full temperature range of 125C to -40C. ESR will vary only about 2X going from the high to low temperature limits. The increasing ESR at lower temperatures can cause oscillations when marginal quality capacitors are used (if the ESR of the capacitor is near the upper limit of the stability range at room temperature). Aluminum : This capacitor type offers the most capacitance for the money. The disadvantages are that they are larger in physical size, not widely available in surface mount, and have poor AC performance (especially at higher frequencies) due to higher ESR and ESL. Compared by size, the ESR of an aluminum electrolytic is higher than either Tantalum or ceramic, and it also varies greatly with temperature. A typical aluminum electrolytic can exhibit an ESR increase of as much as 50X when going from 25C down to -40C. It should also be noted that many aluminum electrolytics only specify impedance at a frequency of 120Hz, which indicates they have poor high frequency performance. Only aluminum electrolytics that have an impedance specified at a higher frequency (between 20kHz and 100kHz) should be used for the device. Derating must be applied to the manufacturer's ESR specification, since it is typically only valid at room temperature. Any applications using aluminum electrolytics should be thoroughly tested at the lowest ambient operating temperature where ESR is maximum. Thermal Considerations The RT9185 is a triple channel CMOS regulator designed to provide two output voltage from one package. Each output pin the RT9185 can deliver a current of up to 1.5A, 0.8A and 0.3A respectively over the full operating junction temperature range. However, the maximum output current must be derated at higher ambient temperature to ensure the junction temperature does not exceed 125C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Each regulator contributes power dissipation to the overall power dissipation of the package. Power dissipation can be calculated based on the output current and the voltage drop across each regulator.
DS9185-11 March 2007
www.richtek.com 9
RT9185
PD = (VDD - VOUT1) IOUT1 + (VDD - VOUT2) IOUT2 + (VDD VOUT3) IOUT3 + VIN IGND Although the device is rated for 1.5A, 0.8A and 0.3A of output current, the application may limit the amount of output current based on the total power dissipation and the ambient temperature. The final operating junction temperature for any set of conditions can be estimated by the following thermal equation: PD (MAX) = ( TJ (MAX) - TA ) / JA Where TJ (MAX) is the maximum junction temperature of the die (125 C) and T A is the maximum ambient temperature. JA is the thermal resistance from the junction to the surrounding environment which is combined with JC + CA. Where JC is junction to case thermal resistance which for fused SOP-8 is 20C/W, TO-252-5 is 10C/W and TO-263-5 is 5.5C/W, CA is case to ambient thermal resistance which depend on PCB board area and air flow. PCB Layout The RT9185 is a fixed output voltage regulator which the voltage are sensed at the output pin. A long PCB trace to load will cause a voltage drop between load and RT9185. Be careful with PCB layout which minimum the output trace length and maximum the trace width.
TRACE RESISTANCE
Good board layout practices must be used or instability can be induced because of ground loops and voltage drops. The input and output capacitors MUST be directly connected to the input, output, and ground pins of the device using traces which have no other currents flowing through them. The best way to do this is to layout CIN and COUT near the device with short traces to the VDD, VOUT, and ground pins. The regulator ground pin should be connected to the external circuit ground so that the regulator and its capacitors have a "single point ground". It should be noted that stability problems have been seen in applications where "vias" to an internal ground plane were used at the ground points of the device and the input and output capacitors. This was caused by varying ground potentials at these nodes resulting from current flowing through the ground plane. Using a single point ground technique for the regulator and it's capacitors fixed the problem. Since high current flows through the traces going into VIN and coming from VOUT, Kelvin connect the capacitor leads to these pins so there is no voltage drop in series with the input and output capacitors. Optimum performance can only be achieved when the device is mounted on a PC board according to the diagram below:
RT9185 VDD
+
RP IO
+
VOUT1 VOUT3 VOUT2 DROP = IO * RP GND
LOAD
GND PLANE
The GND pin of the RT9185 performs the dual function of providing an electrical connection to ground and channeling heat away. Connect the GND pin to ground using a large pad or ground plane.
www.richtek.com 10
DS9185-11 March 2007
RT9185
GND
+ VOUT1
+ VOUT3
+
+
GND
VDD
VOUT2
GND
SOP-8 Board Layout
GND
+ VOUT1
+ VOUT3
+
+
GND
VDD
VOUT2
GND
TO-252-5/TO-263-5 Board Layout
DS9185-11 March 2007
www.richtek.com 11
RT9185
Outline Dimension
A
H M
J
B
F
C I D
Dimensions In Millimeters Symbol Min A B C D F H I J M 4.801 3.810 1.346 0.330 1.194 0.170 0.050 5.791 0.400 Max 5.004 3.988 1.753 0.508 1.346 0.254 0.254 6.200 1.270
Dimensions In Inches Min 0.189 0.150 0.053 0.013 0.047 0.007 0.002 0.228 0.016 Max 0.197 0.157 0.069 0.020 0.053 0.010 0.010 0.244 0.050
8-Lead SOP Plastic Package
www.richtek.com 12
DS9185-11 March 2007
RT9185
E b3 L3 T V D H S C2 R
L b P L2
A
Symbol A b b3 C2 D E H L L2 L3 P V R S T
Dimensions In Millimeters Min 2.184 0.381 4.953 0.457 5.334 6.350 9.000 0.508 Max 2.388 0.889 5.461 0.889 6.223 6.731 10.414 1.780
Dimensions In Inches Min 0.086 0.015 0.195 0.018 0.210 0.250 0.354 0.020 Max 0.094 0.035 0.215 0.035 0.245 0.265 0.410 0.070
0.508 Ref. 0.889 2.032
0.020 Ref. 0.035 0.080
1.270 Ref. 5.200 Ref. 0.200 2.500 0.500 1.500 3.400 0.850
0.050 Ref. 0.205 Ref. 0.008 0.098 0.020 0.059 0.134 0.033
5-Lead TO-252 Surface Mount Package
DS9185-11 March 2007
www.richtek.com 13
RT9185
D B
C
U
V E L1
L2 e b b2
A
Symbol A B b b2 C D E e L1 L2 U V
Dimensions In Millimeters Min 4.064 1.143 0.660 0.305 1.143 9.652 8.128 1.524 14.605 2.286 Max 4.826 1.676 0.914 0.584 1.397 10.668 9.652 1.829 15.875 2.794
Dimensions In Inches Min 0.160 0.045 0.026 0.012 0.045 0.380 0.320 0.060 0.575 0.090 Max 0.190 0.066 0.036 0.023 0.055 0.420 0.380 0.072 0.625 0.110
6.223 Ref. 7.620 Ref.
0.245 Ref. 0.300 Ref.
5-Lead TO-263 Surface Mount Package
Richtek Technology Corporation
Headquarter 5F, No. 20, Taiyuen Street, Chupei City Hsinchu, Taiwan, R.O.C. Tel: (8863)5526789 Fax: (8863)5526611
Richtek Technology Corporation
Taipei Office (Marketing) 8F, No. 137, Lane 235, Paochiao Road, Hsintien City Taipei County, Taiwan, R.O.C. Tel: (8862)89191466 Fax: (8862)89191465 Email: marketing@richtek.com
www.richtek.com 14
DS9185-11 March 2007

▲Up To Search▲

Price & Availability of RT9185BPL5

	To Download RT9185BPL5 Datasheet File
If you can't view the Datasheet, Please click here to try to view without PDF Reader .