- 您现在的位置：买卖IC网 > PDF目录19703 > MAX5953AUTM+T (Maxim Integrated)IC INTERFACE 802.3AF 48TQFN PDF资料下载
参数资料
| 型号： | MAX5953AUTM+T |
| 厂商： | Maxim Integrated |
| 文件页数： | 15/27页 |
| 文件大小： | 371K |
| 描述： | IC INTERFACE 802.3AF 48TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 2,500 |
| 类型： | 以太网供电开关（PoE） |
| 应用： | 远程外设（工业控制，相机，数据访问） |
| 内部开关： | 是 |
| 电源电压： | 11 V ~ 76 V |
| 工作温度： | 0°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 48-WFQFN 裸露焊盘 |
| 供应商设备封装： | 48-TQFN-EP（7x7） |
| 包装： | 带卷 (TR) |
第1页第2页第3页第4页第5页第6页第7页第8页第9页第10页第11页第12页第13页第14页当前第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页
IEEE 802.3af PD Interface and PWM Controllers
with Integrated Power MOSFETs
______________________________________________________________________________________ 15
Detailed Description
PD Interface
The MAX5953A/MAX5953B/MAX5953C/MAX5953D
include complete interface function for a PD to comply
with the IEEE 802.3af standard in a PoE system. They
provide the PD with a detection signature, a classifica-
tion signature, and an integrated isolation switch with
programmable inrush current control. An integrated
MOSFET provides PD isolation during detection and
classification. All devices guarantee a leakage current
offset of less than 10礎 during the detection phase. A
programmable current limit prevents high inrush cur-
rent during power-on. The device features power-mode
UVLO with wide hysteresis and long deglitch time to
compensate for twisted-pair-cable resistive drop and to
assure glitch-free transition between detection, classifi-
cation, and power-on/-off phases. The MAX5953A/
MAX5953C have an adjustable UVLO threshold with
the default value compliant to the 802.3af standard,
while the MAX5953B/MAX5953D have a lower and
fixed UVLO threshold compatible with some legacy
pre-802.3af PSE.
Operating Modes
Depending on the input voltage (V
IN
= V
+
- V
EE
), the PD
front-end section of the MAX5953A/MAX5953B/
MAX5953C/MAX5953D operate in three different modes:
PD detection signature, PD classification, and PD power.
All voltage thresholds are designed to operate with or
without the optional diode bridge while still complying
with the IEEE 802.3af standard (see Figure 2).
Detection Mode (1.4V d V
IN
d 10.1V)
In detection mode, the power source equipment (PSE)
applies two voltages on V
IN
in the range of 1.4V to 10.1V
(1V step minimum), and records the corresponding cur-
rent measurements at those two points. The PSE then
computes V/I to ensure the presence of the 25.5k&
signature resistor. In this mode, most interface circuitry
of the MAX5953A/MAX5953B/MAX5953C/MAX5953D is
off and the offset current is less than 10礎.
Classification Mode (12.6V d V
IN
d 20V)
In the classification mode, the PSE classifies the PD
based on the power consumption required by the PD.
This allows the PSE to efficiently manage power distrib-
ution. The IEEE 802.3af standard defines five different
classes as shown in Table 1. An external resistor
(R
RCLASS
) connected from RCLASS to V
EE
sets the
classification current.
The PSE determines the class of a PD by applying a
voltage at the PD input and measuring the current
sourced out of the PSE. When the PSE applies a volt-
age between 12.6V and 20V, the IC exhibits a current
characteristic with values indicated in Table 2. The PSE
uses the classification current information to classify
the power requirement of the PD. The classification cur-
rent includes the current drawn by the 25.5k& detec-
tion signature resistor and the supply current of the IC
so the total current drawn by the PD is within the IEEE
802.3af standard figures. The classification current is
turned off whenever the device is in power mode.
Table 1. PD Power Classification/
R
RCLASS
Selection
Table 2. Setting Classification Current
*Class 4 reserved for future use.
*V
IN
is measured across the MAX5953A/MAX5953B/MAX5953C/MAX5953D input pins (V+ - V
EE
), which do not include the diode
bridge voltage drop.
LA
USAGE
R
RCLASS
(&)
MAXIMUM POWER
USED BY PD (W)
0
Default
10k
0.44 to 12.95
1
Optional
732
0.44 to 3.84
2
Optional
392
3.84 to 6.49
3
Optional
255
6.49 to 12.95
4
Not
Allowed
178
Reserved*
CLASS CURRENT SEEN AT V
IN
(mA)
IEEE 802.3af PD CLASSIFICATION
CURRENT SPECIFICATION (mA)
CLASS
R
RCLASS
(&)
V
IN
* (V)
MIN
MAX
MIN
MAX
0
10k
12.6 to 20
0
2.00
0
4
1
732
12.6 to 20
9.17
11.83
9
12
2
392
12.6 to 20
17.29
19.71
17
20
3
255
12.6 to 20
26.45
29.55
26
30
4
178
12.6 to 20
36.60
41.40
36
44
相关PDF资料 |
PDF描述 |
|---|---|
| 183-009-213R571 | CONN DB9 FEML .590 R/A MET SHELL |
| BR-2330 | BATTERY LITHIUM COIN 3V 23MM |
| V48A8E400BG | CONVERTER MOD DC/DC 8V 400W |
| FAN6863WLTY | IC PWM CTLR GREEN MODE 6-SSOT |
| HSC30DRAI | CONN EDGECARD 60POS R/A .100 SLD |
相关代理商/技术参数 |
参数描述 |
|---|---|
| MAX5953BUTM+ | 功能描述:电压模式 PWM 控制器 IEEE 802.3af PD Int & PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX5953BUTM+T | 功能描述:电压模式 PWM 控制器 IEEE 802.3af PD Int & PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX5953CUTM+ | 功能描述:电压模式 PWM 控制器 IEEE 802.3af PD Int & PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX5953CUTM+T | 功能描述:电压模式 PWM 控制器 IEEE 802.3af PD Int & PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
| MAX5953DUTM+ | 功能描述:电压模式 PWM 控制器 IEEE 802.3af PD Int & PWM Controller RoHS:否 制造商:Texas Instruments 输出端数量:1 拓扑结构:Buck 输出电压:34 V 输出电流: 开关频率: 工作电源电压:4.5 V to 5.5 V 电源电流:600 uA 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装 / 箱体:WSON-8 封装:Reel |
发布紧急采购，3分钟左右您将得到回复。