Datasheet > UC3870N-1

UC3870N-1

更新时间： 2024-02-24 04:28:52

品牌	Logo	应用领域
其他 - ETC		开关光电二极管控制器
页数	文件大小	规格书
10页	354K
描述
Current-Mode SMPS Controller

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中文翻译

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技术参数
数据手册

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UC3870N-1 技术参数

是否无铅：	含铅	是否Rohs认证：	不符合
生命周期：	Obsolete	零件包装代码：	DIP
包装说明：	DIP, DIP18,.3	针数：	18
Reach Compliance Code：	not_compliant	ECCN代码：	EAR99
HTS代码：	8542.39.00.01	风险等级：	5.79
Is Samacsys：	N	模拟集成电路 - 其他类型：	SWITCHING CONTROLLER
控制模式：	CURRENT-MODE	控制技术：	PULSE WIDTH MODULATION
最大输入电压：	24 V	最小输入电压：	12 V
标称输入电压：	12 V	JESD-30 代码：	R-PDIP-T18
功能数量：	1	端子数量：	18
最高工作温度：	70 °C	最低工作温度：
最大输出电流：	1 A	封装主体材料：	PLASTIC/EPOXY
封装代码：	DIP	封装等效代码：	DIP18,.3
封装形状：	RECTANGULAR	封装形式：	IN-LINE
峰值回流温度（摄氏度）：	NOT SPECIFIED	认证状态：	Not Qualified
子类别：	Switching Regulator or Controllers	表面贴装：	NO
切换器配置：	PUSH-PULL	最大切换频率：	300 kHz
技术：	BIPOLAR	温度等级：	COMMERCIAL
端子形式：	THROUGH-HOLE	端子节距：	2.54 mm
端子位置：	DUAL	处于峰值回流温度下的最长时间：	NOT SPECIFIED
Base Number Matches：	1

UC3870N-1 数据手册

UC1870 -1/ -2

UC2870 -1/ -2

UC3870 -1/ -2

APPLICATION INFORMATION (continued)

UDG-96159

Figure 1. Typical Application: UC3870-1, -2 Pentium Pro Power Converter

gle external capacitor connected between CT and GND, chronous regulator must be capable of LDO or 100%

and is capable of switching frequencies up to 300kHz. duty cycle operation. The UC3870 includes circuitry to

The UC3870 can be synchronized to an external clock insure that this mode of operation is possible even

by capacitively coupling the signal to the junction of the though it uses a bootstrapped drive technique for the

capacitor at CT and a low value resistor tied to GND. Re- high side MOSFET. During commanded 100% duty cycle

fer to Application Note U-111.

operation, the UC3870 monitors the V_GSdrive signal ap-

plied to the high side MOSFET, and automatically pro-

vides complementary pulses to refresh the bootstrap

capacitor when this voltage falls below a set threshold. In

this way, near 100% duty cycle operation is possible,

with effective duty cycle dependent only upon the value

The PWM drive signal is applied to the complementary

output driver stages. Since the high side switch is an

N–channel MOSFET, a means for driving its gate above

VCC is required. This is accomplished via the internal

11V (UC3870-2)/7.5V (UC3870-1) regulator and an ex-

ternal capacitor (C_BST). C_BSTis charged through an ex-

of C_BST

ternal diode to VCC or CAP when the low side MOSFET High efficiency is obtained primarily by the low side

is on. The charging level on C_BSTis internally regulated MOSFET which replaces the Schottky diode in the stan-

to 11V or 7.5V minus an external diode drop by the dard buck configuration. Its low R_DS(ON)produces a

UC3870 as long as VCC is above 11V. When the low much lower voltage drop than a low VF Schottky diode.

side MOSFET turns off, C_BSTis applied across the gate As output voltages get lower, these improvements be-

to the source of the upper MOSFET allowing it to begin come more evident.

turn-on. As the upper MOSFET turns on, it lifts or boot-

Another efficiency consideration is the the possibility of

straps the low end of C_BST, along with its source. Shortly

reverse current in the output inductor. For a non-

thereafter, the source voltage level is reduced by

synchronous regulator this isn’t a problem since the di-

RDS(on) · I_LOADbelow VCC. When VCC < 10V, V_GSfor

ode will block reverse current, allowing discontinuous in-

the high side MOSFET is approximately equal to VCC. If

ductor current operation at light loads. Since the

VCC < 8V, logic level MOSFETs are recommended. In

synchronous regulator replaces the diode with a switch,

these applications, CAP should be shorted to VCC and

reverse current can and will flow if the low side switch is

an external Schottky diode is connected between

on when the inductor is depleted. The UC3870 includes

CAP/VCC and BOOT. For low battery applications, a syn-

circuitry to prevent reverse current from flowing in the in-

1...4 5 678 9 10

中文翻译

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与UC3870N-1相关器件

型号	品牌	获取价格	描述	数据表
UC3870N-2	ETC	获取价格	Current-Mode SMPS Controller
UC3870Q-1	TI	获取价格	1A SWITCHING CONTROLLER, 300kHz SWITCHING FREQ-MAX, PQCC20
UC3870Q-2	TI	获取价格	1A SWITCHING CONTROLLER, 300kHz SWITCHING FREQ-MAX, PQCC20, PLASTIC, LCC-20
UC3870QTR-2	TI	获取价格	1A SWITCHING CONTROLLER, 300kHz SWITCHING FREQ-MAX, PQCC20, PLASTIC, LCC-20
UC3871	TI	获取价格	Resonant Fluorescent Lamp Driver
UC3871DW	TI	获取价格	Resonant Fluorescent Lamp Driver
UC3871DWG4	TI	获取价格	Resonant Fluorescent Lamp Driver
UC3871DWTR	TI	获取价格	Resonant Fluorescent Lamp Driver
UC3871DWTRG4	TI	获取价格	Resonant Fluorescent Lamp Driver
UC3871J	ETC	获取价格	Industrial Control IC

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