欢迎访问ic37.com |
会员登录 免费注册
发布采购

UC2845N 参数 Datasheet PDF下载

UC2845N图片预览
型号: UC2845N
PDF下载: 下载PDF文件 查看货源
内容描述: 高性能电流模式控制器 [HIGH PERFORMANCE CURRENT MODE CONTROLLERS]
分类和应用: 稳压器开关式稳压器或控制器电源电路开关式控制器光电二极管
文件页数/大小: 14 页 / 380 K
品牌: FREESCALE [ FREESCALE SEMICONDUCTOR, INC ]
 浏览型号UC2845N的Datasheet PDF文件第2页浏览型号UC2845N的Datasheet PDF文件第3页浏览型号UC2845N的Datasheet PDF文件第4页浏览型号UC2845N的Datasheet PDF文件第5页浏览型号UC2845N的Datasheet PDF文件第6页浏览型号UC2845N的Datasheet PDF文件第7页浏览型号UC2845N的Datasheet PDF文件第8页浏览型号UC2845N的Datasheet PDF文件第9页  
Order this document by UC3844/D
UC3844, 45
UC2844, 45
High Performance
Current Mode Controllers
The UC3844, UC3845 series are high performance fixed frequency
current mode controllers. They are specifically designed for Off–Line and
dc–to–dc converter applications offering the designer a cost effective
solution with minimal external components. These integrated circuits feature
an oscillator, a temperature compensated reference, high gain error
amplifier, current sensing comparator, and a high current totem pole output
ideally suited for driving a power MOSFET.
Also included are protective features consisting of input and reference
undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting,
a latch for single pulse metering, and a flip–flop which blanks the output off
every other oscillator cycle, allowing output deadtimes to be programmed for
50% to 70%.
These devices are available in an 8–pin dual–in–line plastic package as
well as the 14–pin plastic surface mount (SO–14). The SO–14 package has
separate power and ground pins for the totem pole output stage.
The UCX844 has UVLO thresholds of 16 V (on) and 10 V (off), ideally
suited for off–line converters. The UCX845 is tailored for lower voltage
applications having UVLO thresholds of 8.5 V (on) and 7.6 V (off).
Current Mode Operation to 500 kHz Output Switching Frequency
HIGH PERFORMANCE
CURRENT MODE
CONTROLLERS
N SUFFIX
PLASTIC PACKAGE
CASE 626
8
1
D SUFFIX
PLASTIC PACKAGE
CASE 751A
(SO–14)
14
1
PIN CONNECTIONS
Compensation 1
Voltage Feedback 2
Current Sense 3
RT/CT 4
(Top View)
8
7
6
5
Vref
VCC
Output
Gnd
Output Deadtime Adjustable from 50% to 70%
Automatic Feed Forward Compensation
Latching PWM for Cycle–By–Cycle Current Limiting
Internally Trimmed Reference with Undervoltage Lockout
High Current Totem Pole Output
Input Undervoltage Lockout with Hysteresis
Low Startup and Operating Current
Direct Interface with Motorola SENSEFET Products
Compensation
NC
Voltage Feedback
NC
Current Sense
1
2
3
4
5
6
7
(Top View)
14 Vref
13 NC
12 VCC
11 VC
10 Output
9
8
Gnd
Power Ground
Simplified Block Diagram
VCC
Vref
8(14)
R
R
RTCT
4(7)
Voltage
Feedback
2(3)
1(1)
Output
Comp.
Vref
Undervoltage
Lockout
Oscillator
Flip
Flop
&
Latching
PWM
5.0V
Reference
7(12)
NC
RT/CT
VCC
Undervoltage
Lockout
VC
7(11)
Output
6(10)
PWR GND
5(8)
Current
Sense
3(5)
ORDERING INFORMATION
Device
UC3844D
UC3845D
UC3844N
UC3845N
UC2844D
UC2845D
TA = – 25° to +85°C
TA = 0° to +70°C
Operating
Temperature Range
Package
SO–14
SO–14
Plastic
Plastic
SO–14
SO–14
Plastic
Plastic
Rev 1
+
Error
Amplifier
Gnd
5(9)
UC2844N
UC2845N
Pin numbers in parenthesis are for the D suffix SO–14 package.
©
Motorola, Inc. 1996
MOTOROLA ANALOG IC DEVICE DATA
1