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RT9715
90m, 2A/1.5A/1.1A/0.7A High-Side Power Switches with Flag
General Description
The RT9715 is a cost-effective, low-voltage, single N-MOSFET high-side Power Switch IC for USB application. Low switch-on resistance (typ. 90m) and low supply current (typ. 50uA) are realized in this IC. The RT9715 integrates an over-current protection circuit, a short fold back circuit, a thermal shutdown circuit and an under-voltage lockout circuit for overall protection. Besides, a flag output is available to indicate fault conditions to the local USB controller. Furthermore, the chip also integrates an embedded delay function to prevent miss-operation from happening due to inrush-current. The RT9715 is an ideal solution for USB power supply and can support flexible applications since it is available in various packages such as SOT-23-5, SOP-8, MSOP-8 and WDFN-8L 3x3.
Features
90m (typ.) N-MOSFET Switch Operating Range : 2.7V to 5.5V Reverse Blocking Current Under Voltage Lockout Deglitched Fault Report (FLG) Thermal Protection with Foldback Over Current Protection Short Circuit Protection UL Approved-E219878 - Nemko Approved-NO49621 - RoHS Compliant and Halogen Free
Applications
USB Peripherals Notebook PCs
Ordering Information
RT9715 Package Type B : SOT-23-5 BG : SOT-23-5 (G-Type) BR : SOT-23-5 (R-Type) S : SOP-8 F : MSOP-8 QW : WDFN-8L 3x3 (W-Type) Operating Temperature Range G : Green (Halogen Free with Commercial Standard) Output Current/EN Function A : 2A/Active High B : 2A/Active Low C : 1.5A/Active High D : 1.5A/Active Low E : 1.1A/Active High F : 1.1A/Active Low G : 0.7A/Active High H : 0.7A/Active Low
Note : Richtek 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.
Pin Configurations
(TOP VIEW)
VIN
5 2
EN/EN
4 3
VIN
5 2
EN/EN
4 3
VOUT GND FLG
VOUT GND NC
SOT-23-5
VOUT
5 2
SOT-23-5 (G-Type)
VIN
4 3
GND VIN VIN EN/EN 2 3 4
8 7 6 5
VOUT VOUT VOUT FLG
FLG GND EN/EN
SOT-23-5 (R-Type)
SOP-8/MSOP-8
GND VIN VIN EN/EN
1 2 3 4 GND
9
8 7 6 5
VOUT VOUT VOUT FLG
WDFN-8L 3x3
Marking Information
For marking information, contact our sales representative directly or through a Richtek distributor located in your area, otherwise visit our website for detail.
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RT9715
Typical Application Circuit
Pull-Up Resistor (10K to 100K) USB Controller Supply Voltage 2.7V to 5.5V CIN 1uF RT9715A/C/E/G Chip Enable VIN RT9715 VOUT COUT 10uF VBUS D+ DGND FLG Over -Current
EN/EN
+ 150uF
GND RT9715B/D/F/H Chip Enable
Ferrite Beads
Data
Note : A low-ESR 150uF aluminum electrolytic or tantalum between VOUT and GND is strongly recommended to meet the 330mV maximum droop requirement in the hub VBUS. (see Application Information Section for further details)
Functional Pin Description
Pin No. SOT-23-5 1 2 3 4 5 --SOT-23-5 SOT-23-5 (G-Type) (R-Type) 1 2 -4 5 3 -5 2 1 3 4 --SOP-8 / MSOP-8 6 , 7,8 1 5 4 2,3 --WDFN-8L Pin Name 3X3 6,7,8 1 5 4 2,3 -9 (Exposed Pad) VOUT GND FLG EN/EN VIN NC Output Voltage. Ground. Fault FLAG Output. Chip Enable (Active High/Low). Power Input Voltage. No Internal Connection. The exposed pad must be soldered to a large PCB and connected to GND for maximum power dissipation. Pin Function
Function Block Diagram
VIN EN/EN Bias UVLO Current Limiting Gate Control Output Voltage Detection Thermal Protection Auto Discharge FLG Delay GND VOUT
Oscillator
Charge Pump
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Absolute Maximum Ratings
(Note 1) Supply Input Voltage, VIN -------------------------------------------------------------------------------------------- 6V EN Voltage -------------------------------------------------------------------------------------------------------------- -0.3V to 6V FLAG Voltage ---------------------------------------------------------------------------------------------------------- 6V Power Dissipation, PD @ TA = 25C SOT-23-5 ---------------------------------------------------------------------------------------------------------------- 300mW SOP-8 -------------------------------------------------------------------------------------------------------------------- 469mW MSOP-8 ----------------------------------------------------------------------------------------------------------------- 469mW WDFN-8L 3x3 ---------------------------------------------------------------------------------------------------------- 694mW Package Thermal Resistance (Note 4) SOT-23-5, JA ----------------------------------------------------------------------------------------------------------- 250C/W SOP-8, JA -------------------------------------------------------------------------------------------------------------- 160C/W MSOP-8, JA ------------------------------------------------------------------------------------------------------------ 160C/W WDFN-8L 3x3, JA ----------------------------------------------------------------------------------------------------- 108C/W Junction Temperature ------------------------------------------------------------------------------------------------- 150C Lead Temperature (Soldering, 10 sec.) --------------------------------------------------------------------------- 260C 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, VIN -------------------------------------------------------------------------------------------- 2.7V to 5.5V EN Voltage -------------------------------------------------------------------------------------------------------------- 0V to 5.5V Junction Temperature Range ---------------------------------------------------------------------------------------- -40C to 100C Ambient Temperature Range ---------------------------------------------------------------------------------------- -40C to 85C
Electrical Characteristics
(VIN = 5V, CIN = 1uF, COUT = 10uF, TA = 25C, unless otherwise specified)
Parameter Input Quiescent Current Input Shutdown Current RT9715A/B Switch On Resistance RT9715C/D RT9715E/F RT9715G/H RT9715A/B Current Limit RT9715C/D RT9715E/F RT9715G/H RT9715A/B RT9715C/D RT9715E/F RT9715G/H
Symbol IQ ISHDN
Conditions Switch On, VOUT = Open Switch Off, V OUT = Open VIN = 5V, IOUT = 1.5A VIN = 5V, IOUT =1.3A VIN = 5V, IOUT = 1A VIN = 5V, IOUT = 0.6A
Min ------2 1.5 1.1 0.7 -----
Typ 50 0.1 90 90 90 90 2.5 2 1.5 1 1.7 1.4 1 0.7
Max 70 1 110 110 110 110 3.2 2.8 2.1 1.4 -----
Unit uA
RDS(ON)
m
ILIM
VOUT = 4V
A
Short Current
ISC_FB
VOUT = 0V, Measured Prior to Thermal Shutdown
A
To be continued
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Parameter EN/EN Threshold Logic_High Voltage Logic_Low Voltage Symbol V IH V IL IEN/EN ILEAKAGE TON_RISE R FLG IFLG_OFF TD RDischarge V UVLO VUVLO TSD Conditions VIN = 2.7V to 5.5V VIN = 2.7V to 5.5V VEN = 5V VEN = 0V, RLOAD = 0 10% to 90% of V OUT Rising ISINK = 1mA VFLG = 5V From fault condition to FLG assertion VEN = 0V, VEN = 5V VIN Rising VIN Decreasing VOUT > 1V VOUT = 0V VOUT = 0V Min 2 ------5 -1.3 ----Typ --0.01 0.5 200 20 0.01 12 100 1.7 0.1 120 100 20 Max -0.8 0.1 1 --1 20 150 -----Unit V V uA uA us uA ms V V C C C
EN/EN Input Current Output Leakage Current Output Turn-On Rise Time FLG Output Resistance FLG Off Current FLG Delay Time Shutdown Auto-Discharge Resistance Under-Voltage Lockout Under-Voltage Hysteresis Thermal Shutdown Protection Thermal Shutdown Hysteresis
Note 1. Stresses beyond those listed under "Absolute Maximum Ratings" may cause permanent damage to the device. These are stress ratings only, and 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 affect device reliability. Note 2. Devices are ESD sensitive. Handling precaution is recommended. Note 3. The device is not guaranteed to function outside its operating conditions. Note 4. JA is measured in the natural convection at TA = 25C on a low effective single layer thermal conductivity test board of JEDEC 51-3 thermal measurement standard.
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Typical Operating Characteristics
On Resistance vs. Input Voltage
108 106
On Resistance vs. Temperature
125 120
IOUT = 2A SOP-8
VIN = 5V, IOUT = 2A
On Resistance (m)
On Resistance (m)
104 102 100 98 96 94 92 90 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
115 110 105 100 95 90 85 80 75 70 -40 -25 -10 5 20 35 50 65 80
SOP-8 SOT-23-5
SOT-23-5
Input Voltage (V)
Temperature (C)
Quiescent Current vs. Input Voltage
60 58
Quiescent Current vs. Temperature
60 59
No Load
VIN = 5V,No Load
Quiescent Current (uA)
Quiescent Current (uA)
56 54 52 50 48 46 44 42 40 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
58 57 56 55 54 53 52 51 50 -40 -25 -10 5 20 35 50 65 80 95 110
Input Voltage (V)
Temperature (C)
Shutdown Current vs. Input Voltage
1.0 0.9
Shutdown Current vs. Temperature
1.0 0.9
No Load
VIN = 5V
Shutdown Current (uA)
0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
Shutdown Current (uA)
0.8
0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 -40 -25 -10 5 20 35 50 65 80 95 110
Input Voltage (V)
Temperature (C)
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Output Voltage vs. Output Current
6.0 5.5 5.0 4.5 4.0 3.5 3.0 2.5 2.0 1.5 1.0 0.5 0.0 0 0.25 0.5 0.75 1 1.25 1.5 1.75 2 2.25 2.5
UVLO Threshold vs. Temperature
2.2
VIN = 5V
2.0
UVLO Threshold (V)
Output Voltage (V)
1.8 1.6
VIN = 3.3V
Rising Falling
1.4 1.2 1.0 -40 -25 -10 5 20 35 50 65 80 95 110
Output Current (A)
Temperature (C)
Current Limit vs. Input Voltage
2.4 2.3 2.2
Current Limit vs. Temperature
2.40 2.35 2.30
VIN = 5V
Current Limit (A)
2.1 2.0 1.9 1.8 1.7 1.6 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
Current Limit (A)
2.25 2.20 2.15 2.10 2.05 2.00 -40 -25 -10 5 20 35 50 65 80 95 110
Input Voltage (V)
Temperature (C)
Short Current vs. Input Voltage
2.0 1.9 1.8
2.00 1.90 1.80
Short Current vs. Temperature
VIN = 5V
Short Current (A)
Short Current (A)
1.7 1.6 1.5 1.4 1.3 1.2 1.1 1.0 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
1.70 1.60 1.50 1.40 1.30 1.20 1.10 1.00 -40 -25 -10 5 20 35 50 65 80 95 110
Input Voltage (V)
Temperature (C)
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FLG Delay Time vs. Input Voltage
12 11
12.0 11.5
FLG Delay Time vs. Temperature
VIN = 5V
FLG Delay Time (ms)
FLG Delay Time (ms)
10 9 8 7 6 5 4 2.7 3.1 3.5 3.9 4.3 4.7 5.1 5.5
11.0 10.5 10.0 9.5 9.0 8.5 8.0 -40 -25 -10 5 20 35 50 65 80 95 110
Input Voltage (V)
Temperature (C)
Power On from VIN
EN = 0V, No Load
Power Off from VIN
EN = 0V, No Load
VIN (2V/Div)
VIN (2V/Div)
VOUT (2V/Div) Time (25ms/Div)
VOUT (2V/Div) Time (25ms/Div)
Power On from EN
VIN = 5V, RLOAD = 2.7
FLG Response
VOUT (2V/Div) I IN (1A/Div) EN (5V/Div) FLG (5V/Div)
VOUT (2V/Div) EN (5V/Div)
I IN (1A/Div) Time (100us/Div)
VIN = 5V, RLOAD = 0.5
Time (2.5ms/Div)
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RT9715
Applications Information
The RT9715 is a single N-MOSFET high-side power switches with enable input, optimized for self-powered and bus-powered Universal Serial Bus (USB) applications. The RT9715 is equipped with a charge pump circuitry to drive the internal N-MOSFET switch; the switch's low RDS(ON), 90m, meets USB voltage drop requirements; and a flag output is available to indicate fault conditions to the local USB controller. Input and Output VIN (input) is the power source connection to the internal circuitry and the drain of the MOSFET. VOUT (output) is the source of the MOSFET. In a typical application, current flows through the switch from VIN to VOUT toward the load. If VOUT is greater than VIN, current will flow from VOUT to VIN since the MOSFET is bidirectional when on. Unlike a normal MOSFET, there is no parasitic body diode between drain and source of the MOSFET, the RT9715 prevents reverse current flow if VOUT is externally forced to a higher voltage than VIN when the chip is disabled (VEN < 0.8V or VEN > 2V).
D S
Fault Flag The RT9715 series provides a FLG signal pin which is an N-Channel open drain MOSFET output. This open drain output goes low when current limit or the die temperature exceeds 120C approximately. The FLG output is capable of sinking a 10mA load to typically 200mV above ground. The FLG pin requires a pull-up resistor, this resistor should be large in value to reduce energy drain. A 100k pull-up resistor works well for most applications. In the case of an over-current condition, FLG will be asserted only after the flag response delay time, tD, has elapsed. This ensures that FLG is asserted only upon valid over-current conditions and that erroneous error reporting is eliminated. For example, false over-current conditions may occur during hot-plug events when extremely large capacitive loads are connected and causes a high transient inrush current that exceeds the current limit threshold. The FLG response delay time tD is typically 12ms. Under-Voltage Lockout Under-voltage lockout (UVLO) prevents the MOSFET switch from turning on until input the voltage exceeds approximately 1.7V. If input voltage drops below approximately 1.3V, UVLO turns off the MOSFET switch. Under-voltage detection functions only when the switch is enabled. Current Limiting and Short-Circuit Protection The current limit circuitry prevents damage to the MOSFET switch and the hub downstream port but can deliver load current up to the current limit threshold of typically 2A through the switch of the RT9715A/B, 1.5A for RT9715C/D, 1.1A for RT9715E/F and 0.7A for RT9715G/H respectively. When a heavy load or short circuit is applied to an enabled switch, a large transient current may flow until the current limit circuitry responds. Once this current limit threshold is exceeded, the device enters constant current mode until the thermal shutdown occurs or the fault is removed. Thermal Shutdown Thermal protection limits the power dissipation in RT9715. When the operation junction temperature exceeds 120C, the OTP circuit starts the thermal shutdown function and
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D
S
G
G
Normal MOSFET
RT9715
Chip Enable Input The switch will be disabled when the EN/EN pin is in a logic low/high condition. During this condition, the internal circuitry and MOSFET will be turned off, reducing the supply current to 0.1uA typical. Floating the EN/EN may cause unpredictable operation. EN should not be allowed to go negative with respect to GND. The EN/EN pin may be directly tied to VIN (GND) to keep the part on. Soft Start for Hot Plug-In Applications In order to eliminate the upstream voltage droop caused by the large inrush current during hot-plug events, the "softstart" feature effectively isolates the power source from extremely large capacitive loads, satisfying the USB voltage droop requirements.
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turns the pass element off. The pass element turn on again after the junction temperature cools to 80C. The RT9715 lowers its OTP trip level from 120C to 100C when output short circuit occurs (VOUT < 1V) as shown in Figure 1.
V OUT Short to GND
The junction to ambient thermal resistance (JA) for SOT-23-5/TSOT-23-5, SOP-8/MSOP-8 and WDFM-8L 3x3 packages at recommended minimum footprint are 250C/ W, 160C/W and 108C/W respectively (JA is layout dependent). Universal Serial Bus (USB) & Power Distribution The goal of USB is to enable device from different vendors to interoperate in an open architecture. USB features include ease of use for the end user, a wide range of workloads and applications, robustness, synergy with the PC industry, and low-cost implementation. Benefits include self-identifying peripherals, dynamically attachable and reconfigurable peripherals, multiple connections (support for concurrent operation of many devices), support for as many as 127 physical devices, and compatibility with PC Plug-and-Play architecture. The Universal Serial Bus connects USB devices with a USB host: each USB system has one USB host. USB devices are classified either as hubs, which provide additional attachment points to the USB, or as functions, which provide capabilities to the system (for example, a digital joystick). Hub devices are then classified as either Bus-Power Hubs or Self-Powered Hubs. A Bus-Powered Hub draws all of the power to any internal functions and downstream ports from the USB connector power pins. The hub may draw up to 500mA from the upstream device. External ports in a Bus-Powered Hub can supply up to 100mA per port, with a maximum of four external ports. Self-Powered Hub power for the internal functions and downstream ports does not come from the USB, although the USB interface may draw up to 100mA from its upstream connect, to allow the interface to function when the remainder of the hub is powered down. The hub must be able to supply up to 500mA on all of its external downstream ports. Please refer to Universal Serial Specification Revision 2.0 for more details on designing compliant USB hub and host systems. Over-Current protection devices such as fuses and PTC resistors (also called polyfuse or polyswitch) have slow trip times, high on-resistance, and lack the necessary circuitry for USB-required fault reporting.
1V V OUT
IOUT
Thermal Shutdown 120 C 100 C OTP Trip Point
100 C 80 C
IC Temperature
Figure 1. Short Circuit Thermal Folded Back Protection when Output Short Circuit Occurs (Patent) Power Dissipation The junction temperature of the RT9715 series depend on several factors such as the load, PCB layout, ambient temperature and package type. The output pin of the RT9715 can deliver the current of up to 2A (RT9715A/B), 1.5A (RT9715C/D), 1.1A (RT9715E/F) and 0.7A (RT9715G/ H) 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 100C. With all possible conditions, the junction temperature must be within the range specified under operating conditions. Power dissipation can be calculated based on the output current and the RDS(ON) of the switch as below. PD = RDS(ON) x IOUT2 Although the devices are rated for 2A, 1.5A, 1.1A and 0.7A of output current, but 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 (100C) and TA is the maximum ambient temperature.
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The faster trip time of the RT9715 power distribution allows designers to design hubs that can operate through faults. The RT9715 provides low on-resistance and internal faultreporting circuitry to meet voltage regulation and fault notification requirements. Because the devices are also power switches, the designer of self-powered hubs has the flexibility to turn off power to output ports. Unlike a normal MOSFET, the devices have controlled rise and fall times to provide the needed inrush current limiting required for the bus-powered hub power switch. Supply Filter/Bypass Capacitor A 1uF low-ESR ceramic capacitor from VIN to GND, located at the device is strongly recommended to prevent the input voltage drooping during hot-plug events. However, higher capacitor values will further reduce the voltage droop on the input. Furthermore, without the bypass capacitor, an output short may cause sufficient ringing on the input (from source lead inductance) to destroy the internal control circuitry. The input transient must not exceed 6V of the absolute maximum supply voltage even for a short duration. Output Filter Capacitor A low-ESR 150uF aluminum electrolytic or tantalum between VOUT and GND is strongly recommended to meet the 330mV maximum droop requirement in the hub VBUS (Per USB 2.0, output ports must have a minimum 120uF of low-ESR bulk capacitance per hub). Standard bypass methods should be used to minimize inductance and resistance between the bypass capacitor and the downstream connector to reduce EMI and decouple voltage droop caused when downstream cables are hot-insertion transients. Ferrite beads in series with VBUS, the ground line and the 0.1uF bypass capacitors at the power connector pins are recommended for EMI and ESD protection. The bypass capacitor itself should have a low dissipation factor to allow decoupling at higher frequencies. Voltage Drop The USB specification states a minimum port-output voltage in two locations on the bus, 4.75V out of a Self-Powered Hub port and 4.40V out of a Bus-Powered Hub port. As with the Self-Powered Hub, all resistive voltage drops for the Bus-Powered Hub must be accounted for to guarantee voltage regulation (see Figure 7-47 of Universal Serial Specification Revision 2.0 ). The following calculation determines VOUT (MIN) for multiple ports (NPORTS) ganged together through one switch (if using one switch per port, NPORTS is equal to 1) : VOUT (MIN) = 4.75V - [ II x ( 4 x RCONN + 2 x RCABLE ) ] - (0.1A x NPORTS x RSWITCH ) - VPCB Where RCONN = Resistance of connector contacts (two contacts per connector) RCABLE = Resistance of upstream cable wires (one 5V and one GND) RSWITCH = Resistance of power switch (90m typical for RT9715) VPCB = PCB voltage drop The USB specification defines the maximum resistance per contact (RCONN) of the USB connector to be 30m and the drop across the PCB and switch to be 100mV. This basically leaves two variables in the equation: the resistance of the switch and the resistance of the cable. If the hub consumes the maximum current (II) of 500mA, the maximum resistance of the cable is 90m. The resistance of the switch is defined as follows : RSWITCH = { 4.75V - 4.4V - [ 0.5A x ( 4 x 30m + 2 x 90m) ] - VPCB } / ( 0.1A x NPORTS ) = (200mV - VPCB ) / ( 0.1A x NPORTS ) If the voltage drop across the PCB is limited to 100mV, the maximum resistance for the switch is 250m for four ports ganged together. The RT9715, with its maximum 100m on-resistance over temperature, can fit the demand of this requirement. Thermal Considerations For continuous operation, do not exceed absolute maximum operation junction temperature. The maximum power dissipation depends on the thermal resistance of IC package, PCB layout, the rate of surroundings airflow and temperature difference between junction to ambient. The
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maximum power dissipation can be calculated by following formula : PD(MAX) = (TJ(MAX) - TA) / JA Where T J(MAX) is the maximum operation junction temperature 100C, TA is the ambient temperature and the JA is the junction to ambient thermal resistance. For recommended operating conditions specification of RT9715, where T J(MAX) is the maximum junction temperature of the die (100C) and TA is the maximum ambient temperature. The junction to ambient thermal resistance JA is layout dependent. For SOT-23-5 packages, the thermal resistance JA is 250C/W on the standard JEDEC 51-3 single-layer thermal test board. And for SOP-8 and MSOP-8 packages, the thermal resistance JA is 160C/W. The maximum power dissipation at TA = 25C can be calculated by following formula : P D(MAX) = (100C - 25C) / (250C/W) = 0.3W for SOT-23-5 packages PD(MAX) = (100C - 25C) / (160C/W) = 0.469W for SOP-8/MSOP-8 packages PD(MAX) = (100C - 25C) / (108C/W) = 0.694W for WDFN-8L 3x3 packages The maximum power dissipation depends on operating ambient temperature for fixed TJ(MAX) and thermal resistance JA. For RT9715 packages, the Figure 2 of derating curves allows the designer to see the effect of rising ambient temperature on the maximum power allowed.
0.8
PCB Layout Guide In order to meet the voltage drop, droop, and EMI requirements, careful PCB layout is necessary. The following guidelines must be followed : Locate the ceramic bypass capacitors as close as possible to the VIN pins of the RT9715. Place a ground plane under all circuitry to lower both resistance and inductance and improve DC and transient performance (Use a separate ground and power plans if possible). Keep all VBUS traces as short as possible and use at least 50-mil, 2 ounce copper for all VBUS traces. Avoid vias as much as possible. If vias are necessary, make them as large as feasible. Place cuts in the ground plane between ports to help reduce the coupling of transients between ports. Locate the output capacitor and ferrite beads as close to the USB connectors as possible to lower impedance (mainly inductance) between the port and the capacitor and improve transient load performance. Locate the RT9715 as close as possible to the output port to limit switching noise.
The input capacitor should be placed as close as possible to the IC. V OUT V IN
V BUS
Maximum Power Dissipation (W)
0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 0
WDFN-8L 3x3
Single Layer PCB
GND
SOP-8/MSOP-8
GND_BUS FLG V IN EN
SOT-23-5
Figure 3
10
20
30
40
50
60
70
80
90
100
Ambient Temperature (C)
Figure 2. Derating Curves for RT9715 Package
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Outline Dimension
H D L C B
b A A1 e
Symbol A A1 B b C D e H L
Dimensions In Millimeters Min 0.889 0.000 1.397 0.356 2.591 2.692 0.838 0.080 0.300 Max 1.295 0.152 1.803 0.559 2.997 3.099 1.041 0.254 0.610
Dimensions In Inches Min 0.035 0.000 0.055 0.014 0.102 0.106 0.033 0.003 0.012 Max 0.051 0.006 0.071 0.022 0.118 0.122 0.041 0.010 0.024
SOT-23-5 Surface Mount Package
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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
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D L
E
E1
e A A1 b A2
Symbol A A1 A2 b D e E E1 L
Dimensions In Millimeters Min 0.810 0.000 0.750 0.220 2.900 0.650 4.800 2.900 0.400 5.000 3.100 0.800 Max 1.100 0.150 0.950 0.380 3.100
Dimensions In Inches Min 0.032 0.000 0.030 0.009 0.114 0.026 0.189 0.114 0.016 0.197 0.122 0.031 Max 0.043 0.006 0.037 0.015 0.122
8-Lead MSOP Plastic Package
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D2
D
L
E
E2 SEE DETAIL A
1
e A A1 A3
b
2
1
2
1
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 A A1 A3 b D D2 E E2 e L
Dimensions In Millimeters Min 0.700 0.000 0.175 0.200 2.950 2.100 2.950 1.350 0.650 0.425 0.525 Max 0.800 0.050 0.250 0.300 3.050 2.350 3.050 1.600
Dimensions In Inches Min 0.028 0.000 0.007 0.008 0.116 0.083 0.116 0.053 0.026 0.017 0.021 Max 0.031 0.002 0.010 0.012 0.120 0.093 0.120 0.063
W-Type 8L DFN 3x3 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
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.
DS9715-02 April 2009
www.richtek.com 15

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