WS4695C
28V, Over-Voltage, Over-Current Protection Load Switch with Adjustable Current-Limit Control

Descriptions
The WS4695C is a small， low RON， single channel load switch with a controlled slew rate. The device can operate over an input voltage range of 2.6 V to 5.5 V and can set  the current limit from 0.1A to 3.5A

The controlled rise time of the device greatly reduces inrush current caused by large bulk load capacitance， thereby reducing or eliminating power supply droop.The WS4695C  has a True Reverse-Current Blocking (TRCB) function that obstructs unwanted reverse current from VOUT to VIN during ON and OFF states. The small size and low RON make the device ideal for being used in space- constrained， battery-powered applications. The wide input voltage range of the switch makes it a versatile solution for  many different voltage rails

The WS4695C is available in the CSP-12L package.
Standard products are Pb-free and Halogen-free

Feature

• Input Voltage Range:2.6V~5.5V
• Absolute Rating at VOUT:28V
• Maximum Output current:4A
• Adjustable Current Limit:0.1A~3.5A 2A ~3.5A with 20% Accuracy
• True Reverse-Current Blocking (TRCB)
• Under-Voltage Lockout&Thermal Shutdown
• CSP-12

Applications

• Smart Phones, Tablet PCs
• Storage, DSLR, and Portable Device

http://www.ovt.com

CSP-12L (Bottom View)

Pin Configuration (Top View)

Marking (Top View)
4695:Device Code
WC: Special Code
Y: Year Code
W: Week Code
Order information

Typical Application

Pin Description

the current limit for the switch.
D1| #OCFLAG| Fault Output: Active LOW，open-drain output that indicates an input over current. An external pull-up resistor to VDD is required

Block Diagram

Absolute Maximum Ratings
These are stress ratings only. Stresses exceeding the range specified under “Absolute Maximum Ratings” may cause substantial damage to the device. Functional operation of  this device under other conditions beyond those listed in the specification is not implied and prolonged exposure to extreme conditions may affect device reliability

Notes:
（1）maximum Junction Temperature = 85°C
Recommend Operating Ratings
The Recommended Operating Conditions table defines the conditions for actual device operation.
Recommended operating conditions are specified to ensure optimal performance of the datasheet specifications.

Notes:
（2）: Surface mounted on FR-4 Board using 2 oz, 1 square inch Cu area, PCB board size 1.5*1.5 square inches.

ELECTRICAL CHARACTERISTICS

(VIN=5VCIN =1μF ,COUT=1μF, at Ta=25° Unless otherwise noted)

Parameter| Symbol| Condition| Min.| Typ.| Max.| Unit
---|---|---|---|---|---|---
Basic Operation
Input Voltage| VIN| | 2.6| | 5.5| V
Quiescent Current| IQ| VIN= VEN， VOUT=Open| | 80| 205| µA
Shutdown Current| IS| VIN=5.5V， VOUT=0V， VEN=GND| | 0.1| 4| µA
Off Supply Current| IQ(OFF)| VEN=GND， VOUT=Open| | 1| 2| µA
On Resistance| RON| VIN=VEN=5.0V， IOUT=1A| | 40| 67| ****

mΩ

VIN=VEN=3.7V， IOUT=1A| | 44| 72
EN Logic High Voltage| VIA| VIN=2.5V to 5.5V，IOUT=0.1A| 1.1| | | V
EN Logic Low Voltage| VIL| VIN=2.5V to 5.5V，IOUT=0.1A| | | 0.4| V

OCFLAG Output Logic Low Voltage| VIL_FLAG| VIN=5 V， ISINK=10mA| | 0.1| 0.2| V

VIN=2.5V，ISINK=10mA| | 0.15| 0.3| V

OCFLAG Output Logic High Leakage Current| IFLAG_LK| VIN=5V， Switch on| | 0.1|

1| µA
EN Input Leakage| ION| VEN=0V to 5V| | | 1| µA
Pull-Down Resistance at EN Pin| REN_PD| VIN=2.5~5.5V，VEN=VIN TA= – 40 to 85 oC| | 14| | MΩ
Over-Voltage Protection

Output OVP Lockout

| ****

VOV_TRIP

| VOUT Rising Threshold| 5.5| 5.8| 6| ****

V

VOUT Falling Threshold| | 5.5|
Output OVP Hysteresis| OTHERS| | | 0.3| | V
OVP Response Time| OVP| IOUT=0.5A，CL=1µF，TA=25oC，VOUT from 5.5 V to 6.0 V| 1| | 4| µs
Over-Current Protection
Current Limit| ILIM| VIN=VEN=5V， RSET=300Ω| 2975| 3500| 4000| ****

mA

VIN=VEN=5V， RSET=500Ω| 1768| 2080| 2390
Under-Voltage Lockout| VOLVO| VIN Increasing| | 2.4| | ****

V

VIN Decreasing| | 2.2|
UVLO Hysteresis| VUVLO_HYS| | | 200| | mV
RCB Protection Trip Point| VT_RCB| VOUT – VIN| | 50| | mV
RCB Protection ReleaseTrip Point| VR_RCB| VIN – VOUT| | 50| | mV
RCB Hysteresis| VRCB_HYS| | | 100| | mV

ELECTRICAL CHARACTERISTICS (continued)
(VIN=5V，CIN =1μF ,COUT=1μF, at Ta=25°C， unless otherwise noted)

Parameter| Symbol| Condition| Min.| Typ.| Max.| Unit
---|---|---|---|---|---|---
Default RCB Response Time（3）| CB| VIN=5V， VEN=High/Low| | 2| | µs
RCB Current| IRC| VEN=0V， VOUT=5.5V| | 7| | µA
Over-Current Response Time（3）| tOCP| Moderate Over-Current Condition， IOUT ≥ ILIM， VOUT ≤ VIN| | 10| | µs
Over-Current Flag Response Time| tOC_FLAG| When Over-Current Occurs to Flag Pulling LOW| | 9| | ms
Thermal Shutdown| TSD| Shutdown Threshold| | 150| | oC
Return from Shutdown| | 130|
Hysteresis| | 20|
Turn-On Delay| TENDON| VIN=5V，RL=100Ω，CL=1uF RSET=2kΩ，TA=25oC| | 1.1| | ms
VOUT Rise Time| TR| | 0.6|
Turn-On Time| TON| | 1.7|
Turn-Off Delay| TOFF| | 10| | µs
VOUT Fall Time| TF| | 240|
Turn-Off Time| TOFF| | 250|

Notes:
（3）This parameter is guaranteed by design.

Timing Diagram

Figure 1. Timing Diagram

Typical characteristics
(Ta=25° C,VIN=VEN=5V,CIN=1μF,COUT=1μF，unless otherwise noted)

Figure 1. Startup by EN|
Figure 2. Startup by VIN
---|---

Figure 3. Shut down by EN|
Figure 4. Shut down by EN

Figure 5. Short before Power on|
Figure 6. Short after Power on

Detailed Description

Input Capacitor
To limit the voltage drop on the input supply caused by transient in-rush currents when the switch turns on into a discharged load capacitor or short- circuit, a capacitor needs to be placed between VIN and GND. A 1-µF ceramic capacitor, CIN, placed close to the pins, is usually sufficient. Higher values of CIN can be used to further reduce the voltage drop during high-current applications.

Output capacitor
An output capacitor should be placed between the VOUT and GND pins. This capacitor prevents parasitic board inductance from forcing VOUT below GND when the switch is on. This capacitor also prevents reverse inrush current from creating a voltage spike that could damage the device in the case of a VOUT short.

Fault Reporting
Upon the detection of an over-current, #OC_FLA G signals the fault by activating LOW.
Current Limiting
The current limit ensures that the current through the switch does not exceed the maximum set value, while not limiting the minimum value. The current at which the part’s limit is adjustable through the selection of the external resistor connected to the ISET pin. Information for selecting the resistor is found in the section below. The device acts as a constant-current source when the load draws more than the maximum value set by the device until a thermal shutdown occurs. The device recovers if the die temperature drops below the threshold temperature.

Under-Voltage Lockout (UVLO)
The under-voltage lockout turns the switch off if the input voltage drops below the lockout threshold. With the EN pin active, the input voltage rising above the UVLO  threshold releases the lockout and enables the switch.

True Reverse-Current Blocking
The true reverse-current blocking feature protects the input source against the current flow from output to input regardless of whether the load switch is on or off.
Thermal Shutdown
The thermal shutdown protects the die from internally or externally generated excessive temperature. During an over-temperature condition, the switch is turned off. The switch automatically turns on again if the temperature of the die drops below the threshold temperature.

Setting Current Limit
The current limit is set with an external resistor connected between the ISET and GND pins. It can be calculated as:  A resistor tolerance of 1% or less is recommended.
Layout guide
For best performance, all traces should be as short as possible. To be most effective, the input and output capacitors should be placed close to the device to minimize the effect that parasitic trace inductance may have on normal and short-circuit operation. Using wide traces for VIN, VOUT, and GND helps minimize parasitic electrical effects along with minimizing the case-to ambient thermal impedance.

PACKAGE OUTLINE DIMENSIONS

Symbol

| Dimensions in Millimeters
---|---
Min.| Typ.| Max.
A| 0.45| 0.50| 0.54
A1| 0.18| 0.20| 0.22
A2| 0.27| 0.30| 0.32
A3| 0.025REF
D| 1.80| 1.83| 1.86
E| 1.30| 1.33| 1.36
b| 0.24| 0.26| 0.28
e| 0.40BSC

TAPE AND REEL INFORMATION

Reel Dimensions

Tape Dimensions

Quadrant Assignments For PIN1 Orientation In Tape

4275 Burton Drive Santa Clara, CA 95054 USA

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are trademarks or registered trademarks of OmniVision Technologies, Inc.
All other trademarks are the property of their respective owners.

Tel: + 1 408 567 3000
Fax: + 1 408 567 3001
www.ovt.com

References

• OMNIVISION | Semiconductor Manufacturer of Sensing, Analog and Touch & Display Solutions.

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