The JTMA7068,JTMA7065,JTMA7065C integrates synchronous buck

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)
  The JTMA7068 integrates synchronous buck PWM, linear controller, and 0.8V Reference
Out Voltage, as well as the monitoring and protection functions into a single package. The
fixed 300kHz switching frequency synchro-nous PWM controller drives dual N-channel
MOSFETs,which provides one controlled power output with over-voltage and over-current
protections. Linear controller drives an external N-channel MOSFET with under-volt-
age protection.
The JTMA7068 provides excellent regulation for output load variation. An internal 0.8V
temperature-compensated ref-erence voltage is designed to meet the requirement of
low output voltage applications.
The JTMA7068 with excellent protection functions: POR,OCP, OVP and UVP. The
Power-On-Reset (POR) circuit can monitor VCC12 supply voltage exceeds its threshold
voltage while the controller is running, and a built-in digi-tal soft-start provides both outputs
with controlled rising voltage. The Over-Current Protection (OCP) monitors the output current
by using the voltage drop across the lower MOSFET’s RDS(ON), comparing with the voltage
of OCSET pin, VOCSET. The maximum VOCSET voltage is limited to the internal default value
0.25V. In addition, when OCSET pin is floating (no ROCSET resistor), the over current threshold
will also be internal default value, 0.25V. When the output current reaches the trip point, the
controller will shutdown the IC directly, and latch the converter’s output. The Un-der-Voltage Protection (UVP) monitors the voltage of FBL pin for short-circuit protection. When the VFBL is less than
50% of VREF, the controller will shutdown the IC directly.The Over-Voltage Protection (OVP)
monitors the voltage of FB. When the VFB is over 135% of VREF, the controller will
make Low-side gate signal fully turn on until the fault events are removed.

二.产品特点(Features)
1.)Two Regulated Voltages and REF_OUT   Synchronous Buck Converter
Linear Regulator
REF_OUT = 0.8V±1% with 3mA Source Current
2.)Single 12V Power Supply Required
3.)Excellent Both Output Voltage Regulation
0.8V Internal Reference
±1% Over Line Voltage and Temperature
4.)Integrated Soft-Start for PWM and Linear Outputs
5.)300KHz Fixed Switching Frequency
6.)Voltage Mode PWM Control Design and Up to 89%(Typ.) Duty Cycle
7.)Under-Voltage Protection Monitoring Linear Out-put
8.)Over-Voltage Protection Monitoring PWM Output
9.)Over-Current Protection for PWM Output
Sense Low-side MOSFET’s RDS(ON)
(责任编辑：oumao18)