EVB9706-02 October 2007 www.richtek.com
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RT9706
Evaluation Board
80mΩΩ
ΩΩ
Ω, 500mA High-Side Power Switch with Flag
General Description
The RT9706 is a cost-effective, low voltage, single
N-Channel MOSFET high-side power switch, optimized
for self-powered and bus-powered Universal Serial Bus
(USB) applications. The RT9706 equipped with a charge
pump circuitry to drive the internal MOSFET switch; the
switch's low RDS(ON), 80mΩ, meets USB voltage drop
requirements; and a flag output is available to indicate
fault conditions to the local USB controller.
Additional features include soft-start to limit inrush current
during plug-in, thermal shutdown to prevent catastrophic
switch failure from high-current loads, under-voltage
lockout (UVLO) to ensure that the device remains off
unless there is a valid input voltage present, lower
quiescent current as 25μA making this device ideal for
portable battery operated equipment.
Features
zz
zz
zCompliant to USB Specifications
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zBuilt-In (Typically 80mΩΩ
ΩΩ
Ω) N-Channel MOSFET
zz
zz
zOutput Can Be Forced Higher than Input (Off-State)
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zGuaranteed 500mA Continuous Load Current
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zWide Input Voltage Ranges : 2V to 5.5V
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zOpen-Drain Fault Flag Output
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zHot Plug-In Application (Soft-Start)
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z1.7V Typical Under-Voltage Lockout (UVLO)
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zCurrent Limiting Protection
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zThermal Shutdown Protection
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zReverse Current Flow Blocking (no body diode)
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zUL Approved−−
−−
−E219878
Applications
zUSB Bus/Self Powered Hubs
zUSB Peripherals
zACPI Power Distribution
zPC Card Hot Swap
zNotebook, Motherboard PCs
zBattery-Powered Equipment
zHot-Plug Power Supplies
zBattery-Charger Circuits
Evaluation Board
Flag Response
Time (10ms/Div)
IOUT
(500mA/Div)
VEN
(5V/Div)
FLAG
(5V/Div)
RL = 0Ω
RT9706 SOT-23-5_V0
IC Part Number RT9706
Board Number RT9706 SOT-23-5_V0
RT9706
EVB9706-02 October 2007www.richtek.com
Evaluation Board
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Specification
Parameter Symbol Min Typ Max Units
Operation Voltage Range VIN 2 5 5.5 V
Under-voltage Lockout VUVLO 1.3 1.7 2.4 V
Under-voltage Hysteresis ΔVUVLO -- 0.1 -- V
Logic-Low Voltage VIL -- -- 0.8 V
EN Threshold Logic-High Voltage VIH 2.0 -- -- V
Current Limit ILIM 0.5 -- 1.25 A
FLAG Delay Time tD 5 12 20 ms
Thermal Shutdown Protection TSD -- 130 -- °C
Thermal Shutdown Hysteresis ΔTSD -- 20 -- °C
Schematic
Figure 1. EVB Circuit
Z13
1
2
3
VIN
R2
/FLG
Cout
12
VIN 1
2
VOUT
1
2
EN
Z14
1
2
3
Z8
1
R1
Z10
1
Z12
1
Z11
1
Z9
1
VOUTVOUT
VIN
Cin
1 2
EN or /FLG
/FLG or EN
Z5
1
GND
GND
VIN
Z15
1
2
Vout
Z7
1
2
R3 R4
Q1
1
23
GATE
1
GATE
R5
C1
C2
RT9711 / RT9706
SOT-23-5
Z6
1
U1
/FLG
1
GND
2
EN
3
VOUT 5
VDD 4
RT9706
3
EVB9706-02 October 2007 www.richtek.com
Evaluation Board
Bill of Materials
Reference Qty Part Number Description Package Manufacture
U2 1 RT9706 High-Side Power Switch SOT-23-5 RichTek
Cin 1 CAP
1μF, Ceramic, ±10%, 16V, X5R 0603 PSA
Cout 1 CAP
10μF, Ceramic, ±10%, 6.3V, X7R 0603 PSA
C1 1 C
33μF, Electrolytic, 50V DIP
R1 1
R 100KΩ, Resistor, 0603
Z13&Z14 1 SIP-3P Jumper Switch DIP
Z7 1 Short by solder
R2 0
0Ω, Short by solder
C2 0 NC
R3 0
NC
R4 0
NC
R5 0
NC
Q1 0 NC
Operating Guideline
1. Connect input power (2V< VIN < 5.5V) and input ground to VIN and GND pins respectively.
2. Connect positive end and negative end of load to VOUT and GND pins respectively.
3. There is a jumper switch EN (at upper site). When the EN is set at LOW (<0.8), RT9706 will be turn on. To turn off the
RT9706, the EN should be set at HIGH (>2V).
PCB Layout
Figure 2. Top Layer Figure 3. Bottom Layer
4EVB9706-02 October 2007www.richtek.com
More Information
For more information, please find the related datasheet or application notes from RichTek website :
http://www.richtek.com
RT9706 Evaluation Board
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: [email protected]
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