NCT3527U-A TR [ETC]
PWR DISTRIBUTION SWITCH;
| 型号： | NCT3527U-A TR |
| 厂家： | 
ETC |
| 描述： | PWR DISTRIBUTION SWITCH |
| 文件： | 总18页 (文件大小：879K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Nuvoton
Adjustable Current-Limited,
Power-Distribution Switch
NCT3527U
NCT3527U-A
NCT3527U/NCT3527U-A
-Table of Content-
1.
GENERAL DESCRIPTION ......................................................................................................... 1
FEATURES ................................................................................................................................. 1
BLOCK DIAGRAM ...................................................................................................................... 2
PIN CONFIGURATION AND TYPICAL APPLICATION CIRCUIT.............................................. 2
PIN DESCRIPTION..................................................................................................................... 3
FUNCTIONAL DESCRIPTION.................................................................................................... 3
ELECTRICAL CHARACTERISTIC ............................................................................................. 6
SWITCHING CHARACTERISTICS ............................................................................................ 9
PACKAGE DIMENSION ........................................................................................................... 13
ORDERING INFORMATION..................................................................................................... 14
TOP MARKING SPECIFICATION ............................................................................................ 14
DATA SHEET REVISION HISTORY ........................................................................................ 15
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
Publication Date: Jul., 2014
-I-
Revision A0
NCT3527U/NCT3527U-A
1. GENERAL DESCRIPTION
The NCT3527U/NCT3527U-A is a high-side adjustable current-limited switch optimized for
general purpose power distribution. The device incorporates a 70-mΩ N-channel MOSFET power
switch.
The NCT3527U/NCT3527U-A also supports output discharge function via external resistor that
provides a controlled discharge of the output voltage stored on the output capacitor. The output
current is limited when the output load reaches the current-limit threshold and a guaranteed
deglitching time of 3-ms ensures that the transient voltage settles down. If after this blanking time
the load current is greater than the current limit, the NCT3527U enters a latch-off state and the
NCT3527U-A enters an auto-retry state. In latch-off state, the switch is turned off and FLAG# is
issued to the host. The switch can be turned on again by cycling the power. In auto-retry state,
the switch would be turned off for 24ms then turn-on again. The NCT3527U/NCT3527U-A
provides up to 2.5A load current.
When continuous heavy overloads or short-circuit causes the junction temperature to rise, an
over-temperature protection mechanism (OTP) will be activated to shut the switch off to prevent
catastrophic failure. Recovery from the OTP is automatic when the junction temperature returns in
a reasonable range. The under-voltage lockout (UVLO) can ensure the switch is in off state
unless there is a valid input voltage. The NCT3527U/NCT3527U-A is in a TSOT23-6 package.
2. FEATURES
70-mΩ High–Side MOSFET Switch
FLAG# Function
Maximum 2.5A Load Current
Built in Soft Start
Adjustable Current Limit Trip
Threshold
Thermal Protection
VIN Under Voltage Lockout
Fast Current Limit Response Time
Reverse Current Flow Blocking (no
body diode)
Provides TSOT23-6 Green Package
(Pb-free ROHS Compliance and
Halogen Free)
Adjustable Output Discharge Function
Reverse Voltage Protection
APPLICATIONS
High-Side Power Protection Switch
Notebook, PC Computers
Hot Plug-in Power Supplies
Publication Date: Jul., 2014
Revision A0
-1-
NCT3527U/NCT3527U-A
3. BLOCK DIAGRAM
Reverse
Voltage
Comparator
Current Sense
VOUT
CS
VIN
Deglitch (0.7-ms)
ILIM
DSG
Current Limit
UVLO
Driver Stage
Deglitch (3-ms)
Shutdown
Logic
Charge
Pump
Thermal
EN/FLAG#
GND
Protection
Fault Logic
4. PIN CONFIGURATION AND TYPICAL APPLICATION CIRCUIT
Power supply
3V ~ 5.5V
VIN VOUT
Load
6
5
1
2
VOUT
GND
VIN
CIN
COUT
RPU
NCT3527U
NCT3527U-A
ILIM
DSG
RDSG
EN /
FLAG#
DSG
ILIM
3
4
EN/FLAG#
Enable Input or
FLAG# Output
(TSOT23-6)
TOP VIEW
GND
RILIM
CIN=1uF~100uF
COUT=1uF~10uF
Figure 1 Typical Application Circuit
Publication Date: Jul., 2014
Revision A0
-2-
NCT3527U/NCT3527U-A
5. PIN DESCRIPTION
PIN
1
NAME
VOUT
GND
I/O
DESCRIPTION
O
Voltage output pin
2
Ground Power ground
This is a bi-directional interface pin. As an input pin, pulling up this pin
to enable chip and pulling down to disable chip. As an output pin, this
pin goes low during fault event(s) occurs.
3
EN/FLAG#
I/O
4
5
6
DSG
ILIM
VIN
I
External resistor used to set output discharge current.
External resistor used to set current limit threshold. This pin cannot be
left floating.
O
Power
Supply voltage input pin.
6. FUNCTIONAL DESCRIPTION
Power Switch
The internal power switch is a high-side N-channel MOSFET with low on-state resistance. The
device incorporates an internal charge pump and gate driver circuitry to drive the N-channel
MOSFET. The charge pump supplies power to the driver circuit and provides necessary voltage
to pull the gate of the MOSFET above the source. The charge pump operates from input
voltages as low as 3V and requires little supply current. The driver controls the gate voltage to
limit the power switch. The driver incorporates circuitry that controls the rise and fall times of the
output voltage to limit large current and voltage surges and provides built-in soft start
functionality.
EN/FLAG#
This pin serves as both an input and an output. As an output, a logic level fault flag issues to
host. As an input, if kept inactive (low) by the host, shuts down the power switch. An external pull
up resistor is required.
The FLAG# signal indicates when any of the following conditions occur:
Over-current fault persists beyond the 3-ms deglitch timeout.
The chip temperature exceeds the thermal shut down temperature limit of 150°C.
VIN is below UVLO threshold.
The device features deglitch timeout to blank FLAG# assertion when an over-current condition
occurs. Once the deglitching time has elapsed, this output remains asserted (active low) until
cycling the VIN below the UVLO to reset the switch. Blanking allows momentary over-current to
be ignored, for example, current surges caused by hot-plugging into a capacitive load or when
the device is powering up, thus prevent fault alarm from being relayed to the host system. The
internal over-current deglitch eliminates the need for external components to remove unwanted
Publication Date: Jul., 2014
-3-
Revision A0
NCT3527U/NCT3527U-A
pulses. This FLAG# is not deglitched when the switch is turned off due to an over-temperature
shutdown or UVLO condition.
Under-voltage Lockout (UVLO)
An under-voltage lockout prevents the power switch from turning on until input voltage exceeds
approximately 2V. If the input voltage drops below approximately 2V, UVLO turns off the power
switch.
Current Limit and Short Circuit Protection
The current limit circuitry prevents damage to the power switch and the hub downstream port but
can deliver load current through power switch up to the current limit threshold. When a heavy
load or short circuit is applied to an enabled switch, a large transient current any flow until the
current limit circuitry responses. Once this current is exceeded the over current threshold, the
deglitching timer is counting. The timer resets if the over current condition removes before the
deglitching time (3-ms, typically) has elapsed.
In latch-off mode (NCT3527U), the switch is turned off if the over current condition continues up
to the end of the deglitching time. By cycling the VIN below the UVLO could reset the switch.
In auto-retry mode (NCT3527U-A), the switch is turned off for 24-ms if the over current condition
continues up to the end of the deglitching time. Then the switch would be turned on again. The
auto-retry function saves system power in case of an overcurrent or short circuit condition.
Current Limit Threshold Setting
The over current threshold is setting via external
Short-circuit Current vs. RILIM Values
resistor. The NCT3527U/ NCT3527U-A uses an
RILIM (Ω) Min. (mA)
Typ. (mA)
Max. (mA)
internal regulation loop to provide a regulated
voltage on the ILIM pin. The current limit threshold
is proportional to the current sourced out of ILIM
pin. Many applications requires that the minimum
current limit is above a certain current level or that
the maximum current is below a certain current
level so it is important to consider the tolerance of
the over current threshold when selecting a value
for RILIM. The traces routing the RILIM resistor to the
7.68k
8.25k
9.53k
10.5k
11.5k
14.3k
17.4k
21k
2430
2250
1980
1800
1620
1350
1080
900
2700
2500
2200
2000
1800
1500
1200
1000
600
2970
2750
2420
2200
1980
1650
1320
1100
700
34.8k
500
NCT3527U/ NCT3527U-A should be as short as possible to reduce parasitic effects on the
current limit accuracy.
Reverse Voltage Protection
The reverse-voltage protection turns off the N-channel MOSFET whenever the output voltage
exceeds the input voltage 55 mV (typical) for 0.7-ms. It prevents damage to devices on the input
side by preventing significant current from sinking into the input capacitance. The N-channel
MOSFET is allowed to turn-on once the output voltage goes below the input voltage for the
Publication Date: Jul., 2014
-4-
Revision A0
NCT3527U/NCT3527U-A
same 0.7-ms deglitch time. The comparator will active to disable N-channel power MOSFET
when OUT minuses VIN is over 55 mV for delay 0.7-ms.
Discharge Function
When the device is disabled, EN is de-asserted or during power up when VIN is below UVLO
threshold, the discharge function is active. By connecting a resistor between DSG pin and VOUT
pin, the discharge function offers a discharge path for the external storage capacitor. This is
suitable only to discharge filter capacitors for limited time and cannot dissipate steady state
current greater than 150mA.
Thermal Shut Down
The device implements a Thermal Sense to monitor the chip temperature. When the chip
temperature exceeds 150C for any reasons, the Thermal Shutdown function turns off the power
switch. A Hysteresis of 50C prevents the switch turning back on until the temperature drops
below 100C.
Input and Output Capacitor
Place a 1~100uF bypass capacitor between VIN to GND, close to the device, is recommended
to reduce power-supply transients that may cause ringing on the input. Furthermore, without the
bypass capacitor, an output short may cause the input ringing (due to the inductance from power
supply to VIN) to destroy the internal control circuitry. Additionally, bypassing the output with a
1~10uF capacitor improves the immunity of the device to short-circuit transients.
Placing a high value capacitor on the output pin is recommended when large currents are
expected on the output.
Layout Consideration
It is important to keep all traces as short as possible to reduce the effect of undesirable parasitic
inductance and the switch response time to output short circuit condition. Place input and output
capacitors as close as possible to the device.
Publication Date: Jul., 2014
-5-
Revision A0
NCT3527U/NCT3527U-A
7. ELECTRICAL CHARACTERISTIC
ABSOLUTE MAXIMUM RATINGS
ITEM
Input voltage, VIN
RATING
-0.3 ~ 6
UNIT
V
Output voltage, VOUT
Continuous output current
Peak Discharge Current, DSG
Junction temperature
-0.3 ~ 6
V
Internally Limited
200
A
mA
C
C
-40 ~ 150
-50 ~ 150
Storage temperature
Soldering temperature
Refer to IPC/JEDEC J-STD-020 Specification
Human Body Mode
Machine Mode
2
kV
V
Electrostatic discharge protection
200
±100
Electrostatic discharge protection, Latch-Up
mA
NOTE： 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 under “recommended operating condition” is not implied. Exposure to absolute-maximum-rated
conditions for extended periods may affect device reliability.
THERMAL INFORMATION
PARAMETER
Power dissipation, PD @ TA=25C
RATING
0.5
UNIT
TSOT23-6
W
TSOT23-6, θJA
TSOT23-6, θJC
220
C/W
C/W
Package thermal resistance
90
RECOMMENDED OPERATING CONDITIONS
PARAMETER
VALUE
3.0 ~ 5.5
-0.3 ~ VIN+0.3
1 ~ 10
UNIT
V
Input voltage, VIN
Voltage on EN/FLAG# and DSG
EN/FLAG# pull up resistance
DSG discharge current
V
kΩ
mA
A
0 ~ 150
Continuous output current
0 ~ 2.5
Current limit threshold resistor range for ILIM to GND
VIN capacitance
25 ~ 100
1 ~ 100
1 ~ 10
kΩ
uF
uF
°C
VOUT capacitance
TA, Operating temperature
-40 ~ 85
Publication Date: Jul., 2014
Revision A0
-6-
NCT3527U/NCT3527U-A
DC ELECTRICAL CHARACTERISTICS
VIN=5V, TA=-40C to 85C, Typical Values are at TA=25C. Unless otherwise specified.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNIT
Power Switch
RDS(on)
Static drain-source on-state resistance
Output Discharge Resistance
70
15
110
30
mΩ
Ω
IOUT = 1A, TA=25C
RDIS
IDIS = 1mA, EN=0V, TA=25C
Current Limit
0.5
0.9
0.6
1.0
0.7
1.1
A
A
A
A
A
A
A
A
RILIM = 34.8 kΩ, TA=25C
RILIM = 21 kΩ, TA=25C
RILIM = 10.5 kΩ, TA=25C
RILIM = 7.68 kΩ, TA=25C
21000
IOS
IOS
RILIM
1.82
2.43
2.0
2.22
2.97
0.81
1.27
2.53
3.42
2.7
RILIM = 34.8 kΩ 0.57
0.69
1.15
2.3
VIN=5V, Current
Ramp (0.001 A/us) on
VOUT
RILIM = 21 kΩ
1.04
2.07
2.79
RILIM = 10.5 kΩ
RILIM = 7.68 kΩ
3.1
IOC
Over-current Trip Threshold
RILIM = 34.8 kΩ 0.55
0.65
1.1
0.75
1.21
2.42
3.27
A
A
A
A
RILIM = 21 kΩ
0.99
1.98
2.67
VIN=5V, Continuous
Current on VOUT
RILIM = 10.5 kΩ
RILIM = 7.68 kΩ
2.2
2.97
tIOS
Response time to short circuit
Over current blanking time
Retry time
5
3
us
ms
ms
VIN=5V, TA=25C
VIN=5V, TA=25C
tIOC
2
4
tOCRT
10
24
35
Operating Current
ICC
Supply current
EN=5V, No Load, not including IRLIM
150
45
200
65
1
uA
uA
uA
uA
ISD
Shutdown current
EN=0V
IOUT_LEAK
IREV
VOUT leakage current
Reverse leakage current to VIN
EN=0V
VOUT=5V, VIN=0V
1
EN/FLAG#
VIH
Input logic High level
Input logic Low level
Hysteresis
1.2
V
V
TA=-40C ~ 85C
TA=-40C ~ 85C
VIL
0.8
1
0.2
2
V
IEN_LEAK
ISINK
Leakage current
Sink current
EN=5.5V or GND
EN=0.4V
uA
mA
Under-Voltage Lockout
UVLO Low level input voltage
Hysteresis
Reverse Voltage Protection
VIN Rising
2
2.6
V
200
mV
TA=25C
Publication Date: Jul., 2014
Revision A0
-7-
NCT3527U/NCT3527U-A
VOUT-VIN
Reverse voltage protection threshold
Reverse voltage blanking time
30
55
80
1
mV
ms
0.5
0.7
Timing
tr
Rise time
2
3
ms
ms
ms
ms
CL=10uF , RL= 5Ω, TA=25C
tf
Fall time
0.2
2.5
0.4
1
CL=10uF , RL= 5Ω, RDSG= 33Ω, TA=25C
CL=10uF , RL= 5Ω, TA=25C
ton
toff
Turn on time
Turn off time
3.5
1.2
CL=10uF , RL= 5Ω, RDSG= 33Ω, TA=25C
Thermal shutdown
TSD
Thermal shutdown threshold
Hysteresis
Design guarantee
125
150
50
C
C
PARAMETER MEASURE INFORMATION
VOUT
RL
CL
Test Circuit
TIMING DIAGRAM
50% 50%
VEN
tf
tr
Ton
Toff
90% 90%
10% 10%
VOUT
VOUT
90%
10%
Turn-on Time and Turn-off Time
Output Rise and Fall time
VOU
Decreasing
load resistance
IOS
IOU
IOUT
IOS IOC
tIOS
Response time to shirt circuit waveform
VOUT vs. Current limit threshold
Publication Date: Jul., 2014
Revision A0
-8-
NCT3527U/NCT3527U-A
8. SWITCHING CHARACTERISTICS
Publication Date: Jul., 2014
Revision A0
-9-
NCT3527U/NCT3527U-A
5V
5V
3.3V
3.3V
5V
3.3V
5V
5V
3.3V
3.3V
Publication Date: Jul., 2014
Revision A0
-10-
NCT3527U/NCT3527U-A
5V
5V
3.3V
3.3V
RILIM=10kΩ, RLOAD=5Ω
RILIM=10kΩ, RLOAD=5Ω
Disable with 5Ω Load
Enable with 5Ω Load
RILIM=10kΩ
RLOAD=1Ω
RILIM=10kΩ
VOUT short to ground
Enable with OCP condition
Enable with short circuit condition
Publication Date: Jul., 2014
Revision A0
-11-
NCT3527U/NCT3527U-A
RILIM=10kΩ, RL=1Ω
RILIM=10kΩ, RL=1Ω
Over current protection: Auto-retry Mode
Over current protection: Latch off Mode
RILIM=10kΩ
CIN=560uF, No COUT
Short circuit response
Publication Date: Jul., 2014
Revision A0
-12-
NCT3527U/NCT3527U-A
9. PACKAGE DIMENSION
Taping Specification
Publication Date: Jul., 2014
Revision A0
-13-
NCT3527U/NCT3527U-A
10. ORDERING INFORMATION
PART
NUMBER
CURRENT
LIMIT
OPERATING
TEMPERATURE RANGE
SUPPLIED AS
PACKAGE TYPE
Commercial,
6 PIN TSOT23
NCT3527U
Latch-off
T Shape: 3,000 units/T&R
(Green package)
-40℃ to 85℃
Commercial,
6 PIN TSOT23
NCT3527U-A
Auto-retry
T Shape: 3,000 units/T&R
(Green package)
-40℃ to 85℃
11. TOP MARKING SPECIFICATION
27XYM
1st Line: 27 (NCT3527U/NCT3527U-A)
X: A for NCT3527U, B for NCT3527U-A
YM: The last character of calendar year (Y) + month (M)
(1: Jan., 2: Feb., 3: Mar., 4: Apr., 5: May, 6: Jul., 7:Jul., 8: Aug., 9: Sep., A: Oct., B: Nov., C: Dec.)
Publication Date: Jul., 2014
-14-
Revision A0
NCT3527U/NCT3527U-A
12. DATA SHEET REVISION HISTORY
VERSION
DATE
PAGE
DESCRIPTION
First Release
A0
Jul.,2014
All
Publication Date: Jul., 2014
Revision A0
-15-
NCT3527U/NCT3527U-A
Important Notice
Nuvoton Products are neither intended nor warranted for usage in systems or equipment, any
malfunction or failure of which may cause loss of human life, bodily injury or severe property
damage. Such applications are deemed, “Insecure Usage”.
Insecure usage includes, but is not limited to: equipment for surgical implementation, atomic
energy control instruments, airplane or spaceship instruments, the control or operation of
dynamic, brake or safety systems designed for vehicular use, traffic signal instruments, all
types of safety devices, and other applications intended to support or sustain life.
All Insecure Usage shall be made at customer’s risk, and in the event that third parties lay
claims to Nuvoton as a result of customer’s Insecure Usage, customer shall indemnify the
damages and liabilities thus incurred by Nuvoton.
Publication Date: Jul., 2014
-16-
Revision A0
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