VCC and VIN Power-On-Reset (POR)
The CXSD62154 keeps monitoring the voltage on VIN and VCC pins to prevent
wrong logic operations which may occur when VIN or VCC voltage is not high enough
for internal control circuitry to operate. The VCC POR rising threshold is 2.7V (typical)
with 0.2V hysteresis and VIN POR rising threshold is 2.3V with 0.05V hysteresis.
During startup, the VCC and VIN voltage must exceed the POR threshold. Then the IC starts a starts-up process and ramps up the output voltage to the voltage target.
Output Under-Voltage Protection (UVP)
In the operational process, if a short-circuit occurs, the output voltage will drop quickly. Before the current-limit circuit responds, the output voltage will fall out of the re-
quired regulation range. The under-voltage continually monitors the FB voltage after
soft-start is completed. If a load step is strong enough to pull the output voltage lower
than the under-voltage threshold, the IC shuts down converter’s output.The under-voltage threshold is 50% of the nominal output voltage. The under-voltage comparator has a
built-in 3μs noise filter to prevent the chips from wrong UVP shutdown being caused by noise. The CXSD62154 will be latched after under-voltage protection.
Over-Voltage Protection (OVP)
The over-voltage function monitors the output voltage by FB pin. When the FB voltage increases over 125% of the reference voltage due to the high-side MOSFET failure or
for other reasons, the over-voltage protection comparator will force the low-side MOSFET gate driver high. This action actively pulls down the output voltage and eventually
attempts to blow the internal bonding wires. As soon as the output voltage is within regulation, the OVP comparator is disengaged. The chip will restore its normal operation
Over-Temperature Protection (OTP)
The over-temperature circuit limits the junction temperature of the CXSD62154. When the junction temperature exceeds TJ = 160 oC, a thermal sensor turns off the both power MOSFETs, allowing the devices to cool.The thermal sensor allows the converters to
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1.产品概述 2.产品特点
3.应用范围 4.下载产品资料PDF文档
5.产品封装图 6.电路原理图
7.功能概述 8.相关产品
一,产品概述(General Description)
VCC and VIN Power-On-Reset (POR)
The CXSD62154 keeps monitoring the voltage on VIN and VCC pins to prevent
wrong logic operations which may occur when VIN or VCC voltage is not high enough
for internal control circuitry to operate. The VCC POR rising threshold is 2.7V (typical)
with 0.2V hysteresis and VIN POR rising threshold is 2.3V with 0.05V hysteresis.
During startup, the VCC and VIN voltage must exceed the POR threshold. Then the IC starts a starts-up process and ramps up the output voltage to the voltage target.
Output Under-Voltage Protection (UVP)
In the operational process, if a short-circuit occurs, the output voltage will drop quickly. Before the current-limit circuit responds, the output voltage will fall out of the re-
quired regulation range. The under-voltage continually monitors the FB voltage after
soft-start is completed. If a load step is strong enough to pull the output voltage lower
than the under-voltage threshold, the IC shuts down converter’s output.The under-voltage threshold is 50% of the nominal output voltage. The under-voltage comparator has a
built-in 3μs noise filter to prevent the chips from wrong UVP shutdown being caused by noise. The CXSD62154 will be latched after under-voltage protection.
Over-Voltage Protection (OVP)
The over-voltage function monitors the output voltage by FB pin. When the FB voltage increases over 125% of the reference voltage due to the high-side MOSFET failure or
for other reasons, the over-voltage protection comparator will force the low-side MOSFET gate driver high. This action actively pulls down the output voltage and eventually
attempts to blow the internal bonding wires. As soon as the output voltage is within regulation, the OVP comparator is disengaged. The chip will restore its normal operation
Over-Temperature Protection (OTP)
The over-temperature circuit limits the junction temperature of the CXSD62154. When the junction temperature exceeds TJ = 160 oC, a thermal sensor turns off the both power MOSFETs, allowing the devices to cool.The thermal sensor allows the converters to
start a startup process and to regulate the output voltage again after the junction temperature cools by 50oC. The OTP is designed with a 50 oC hysteresis to lower the average TJduring continuous thermal overload conditions, increasing lifetime of the CXSD62154.
Current-Limit Protection
The CXSD62154 monitors the output current, flows through the high-side and low-side
power MOSFETs, and limits the current peak at current-limit level to prevent the IC
from damaging during overload, short-circuit and overvoltage conditions. Typical high
side power MOSFET current limit is 6A, and low side MOSFET current limit is 1.9A.
Soft-Start
The CXSD62154 has a built-in soft-start to control the rise rate of the output voltage and
limit the input current surge during start-up. During soft-start, an internal voltage ramp
connected to one of the positive inputs of the error amplifier, rises up from 0V to 0.95V to replace the reference voltage (0.8V) until the voltage ramp reaches the reference voltage. During soft-start without output overvoltage, the CXSD62154 converter’s sinking capability is disabled until the output voltage reaches the voltage target.
Soft-Stop
At the moment of shutdown controlled by EN signal, under-voltage event or overtemperature protection, the CXSD62154 initiates a soft-stop process to discharge the output voltage in the output capacitors. Certainly, the load current also discharges the output voltage. During soft-
stop, the internal voltage ramp (VRAMP) falls down from 0.95V to 0V to replace the eference voltage. Therefore, the output voltage falls down slowly at the light load. After the
soft-stop interval elapses, the soft-stop process ends and the IC turns on the low-side power MOSFET.
Enable and Shutdown
Driving EN to ground places the CXSD62154 in shutdown.In shutdown mode, the internal power MOSFETs turns off, all internal circuitry shuts down and the quiescent supply current reduces to less than 20μA.
Power Good Indicator
POK is actively held low in shutdown and soft-start status.In the soft-start process, the POK is an open-drain. Whenthe soft-start is finished, the POK is released. In normaloperation, the POK window is from 87.5% to 112.5% of the converter reference voltage. When the output voltage has to stay within this window, POK signal will become high after 0.5ms internal delay. When the output voltage outruns 82.55% or 117.5% of the target voltage, POK sig-
nal will be pulled low immediately. In order to prevent false POK drop, capacitors need to parallel at the output to confine the voltage deviation with severe load step transient.
二.产品特点(Features)
High Efficiency up to 94%
- Automatic Skip/PWM Mode Operation
Adjustable Output Voltage from 0.8V to V IN
Operating from 2.9 to 6V Supply
Integrated 85mΩ High Side / 75mΩ Low Side
MOSFETs
Low Dropout Operation: 100% Duty Cycle
Stable with Low ESR Ceramic Capacitors
Current up to 4A
Power-On-Reset Detection on VCC and VIN
Integrate Soft-Start and Soft-Stop
Over-Temperature Protection
Over-Voltage Protection
Under-Voltage Protection
High/ Low Side Current Limit
Power Good Indication
Enable/Shutdown Function
Available in SOP-8P and TDFN3x3-10 Packages
Lead Free and Green Devices Available
(RoHS Compliant)
三,应用范围 (Applications)
Notebook Computer & UMPC
· LCD Monitor/TV
· Set-Top Box
DSL, Switch HUBr
Portable Instrument
四.下载产品资料PDF文档
需要详细的PDF规格书请扫一扫微信联系我们，还可以获得免费样品以及技术支持！
五,产品封装图 (Package)
六.电路原理图
七,功能概述
CXSD62154 is a synchronous buck converters with integrated 85m Ω high side and 75m Ω low side power
MOSFETs. The CXSD62154 with a current-mode control scheme can convert wide input voltage of 2.9V to 6V to
the output voltage adjustable from 0.8V to 6V to provide excellent output voltage regulation.
The CXSD62154 is equipped with an automatic Skip/PWM mode operation. At light load , the IC operates in the Skip
mode to reduce the switching losses. At heavy load, the IC works in PWM mode. The CXSD62154 is also equipped with Power-on-reset, soft start, soft-stop, and whole protections (under-voltage,over-voltage, over-temperature and current-limit) into a single package.This device, available in SOP-8P and TDFN3x3-10
packages, provides a very compact system solution external components and PCB area.
八,相关产品 更多同类产品.......
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Switching Regulator > Buck Converter |
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|
Part_No |
Package |
Architectu |
No.of PWM Outpu |
Drive Lout (A) |
Vin(V) |
Fmax Khz |
Vref (V) |
R-Top (milohm) |
R-Sync (milohm) |
Iq (No load) (uA) |
|
|
min |
max |
||||||||||
|
TQFN5x6-28 |
CM |
1 |
5 |
4.5 |
26 |
380 |
0.8 |
50 |
20 |
1000 |
|
|
SOP-8 |
CM |
1 |
2 |
4.5 |
26 |
380 |
0.8 |
100 |
1000 |
||
|
SOP-8P |
CM |
1 |
4 |
4.5 |
26 |
380 |
0.8 |
80 |
1000 |
||
|
SOT23-5|TSOT23-5 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
SOT23-5 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
SOP-8 |
CM |
1 |
3 |
4.3 |
14 |
500 |
0.8 |
70 |
70 |
500 |
|
|
SOP-8P |
CM |
1 |
3 |
4.3 |
14 |
500 |
0.8 |
55 |
45 |
500 |
|
|
TDFN3x3-10 |
3 |
2.6 |
5.5 |
2000 |
0.8 |
110 |
110 |
460 |
|||
|
TDFN3x3-10 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
500 |
|
|
TDFN3x3-10 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN2x2-6 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
TDFN2x2-6 |
CM |
1 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN3x3-12 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
TDFN3x3-12 |
CM |
2 |
1 |
2.7 |
6 |
1500 |
0.6 |
280 |
250 |
||
|
TDFN 3x3 12 |
CM |
2 |
1 |
3 |
5.5 |
1500 |
0.6 |
280 |
250 |
30 |
|
|
TQFN3x3-20 |
CM |
3 |
2 |
2.9 |
5.5 |
1500 |
0.6 |
- |
- |
300 |
|
|
TDFN2x2-8 |
CM |
1 |
1 |
3.3 |
8 |
1500 |
0.6 |
280 |
250 |
25 |
|
|
SOP-8 |
CM |
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