参数资料
| 型号： | LTC4266IGW#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 7/30页 |
| 文件大小： | 0K |
| 描述： | IC CTRLR IEEE 802.3AT 36-SSOP |
| 产品培训模块： | Power over Ethernet |
| 标准包装： | 32 |
| 控制器类型： | 以太网控制器（IEEE 802.3） |
| 接口： | I²C，2 线串口 |
| 电源电压： | 3.3V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 36-BSOP（0.295"，7.50mm 宽） |
| 供应商设备封装： | 36-SSOP |
| 包装： | 管件 |
| 产品目录页面： | 1338 (CN2011-ZH PDF) |
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LTC4266
15
4266fd
OPERATION
more power that the PSE has available. The classification
step is optional; if a PSE chooses not to classify a PD, it
must assume that the PD is a 13W (full 802.3af power)
device.
New in 802.3at
The newer 802.3at standard supersedes 802.3af and brings
several new features:
A PD may draw as much as 25.5W. Such PDs (and the
PSEs that support them) are known as Type 2. Older
13W 802.3af equipment is classified as Type 1. Type 1
PDs will work with all PSEs; Type 2 PDs may require
Type 2 PSEs to work properly. The LTC4266 is designed
to work in both Type 1 and Type 2 PSE designs, and
also supports non-standard configurations at higher
power levels.
The Classification protocol is expanded to allow Type 2
PSEs to detect Type 2 PDs, and to allow Type 2 PDs to
determine if they are connected to a Type 2 PSE. Two
versions of the new Classification protocol are avail-
able: an expanded version of the 802.3af Class Pulse
protocol, and an alternate method integrated with the
existing LLDP protocol (using the Ethernet data path).
The LTC4266 fully supports the new Class Pulse protocol
and is also compatible with the LLDP protocol (which
is implemented in the data communications layer, not
in the PoE circuitry).
Fault protection current levels and timing are adjusted
to reduce peak power in the MOSFET during a fault;
this allows the new 25.5W power levels to be reached
using the same MOSFETs as older 13W designs.
BACKWARDS COMPATIBILITY
The LTC4266 is designed to be backward compatible with
earlier PSE chips in both software and pin functions. Exist-
ing systems using either the LTC4258 or LTC4259A (or
compatible) devices can be substituted with the LTC4266
without software or PCB layout changes; only minor BOM
changes are required to implement a fully compliant
802.3at design.
Because of the backwards compatibility features, some of
the internal registers are redundant or unused when the
LTC4266 is operated as recommended. For more details
on usage in compatibility mode, refer to the LTC4258/
LTC4259A device datasheets.
Special Compatibility Mode Notes
The LTC4266 can use either 0.5Ω or 0.25Ω sense
resistors, while the LTC425x chips always used 0.5Ω.
To maintain compatibility, if the AUTO pin is low when
the LTC4266 powers up it assumes the sense resistor
is 0.5Ω; if it is high at power up, the LTC4266 assumes
0.25Ω. The resistor value setting can be reconfigured
at any time after power up. In particular, systems that
use 0.25Ω sense resistors and have AUTO tied low
must reconfigure the resistor settings after power up.
The LTC4259A included both AC and DC disconnect
sensing circuitry, but the LTC4266 has only DC discon-
nect sensing. For the sake of compatibility, register
bits used to enable AC disconnect in the LTC4259A are
implemented in the LTC4266, but they simply mirror
the bits used for DC disconnect.
The LTC4258 and LTC4259A required 10k resistors
between the OUTn pins and the drains of the external
MOSFETs. These resistors must be shorted or replaced
with zero ohm jumpers when using the LTC4266.
The LTC4258 and LTC4259A included a BYP pin, de-
coupled to AGND with 0.1μF. This pin changes to the MID
pin on the LTC4266. The capacitor should be removed
for Endspan applications, or replaced with a zero ohm
jumper for Midspan applications.
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相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC4266IUHF#PBF | 制造商:Linear Technology 功能描述:POE Controller 25.5W 38-Pin QFN EP 制造商:Linear Technology 功能描述:IC POE 802.3AT QUAD PSE 38-QFN 制造商:Linear Technology 功能描述:POE CNTRL QUAD 25.5W 1MHZ 制造商:Linear Technology 功能描述:IC, POE CONTROLLER, 3.3V, QFN-38; Input Voltage:3.3V; Supply Current:-2.4mA; UVLO:25V; Digital IC Case Style:QFN; No. of Pins:38; Frequency:1MHz; Operating Temperature Min:-40C; Operating Temperature Max:85C; MSL:MSL 1 - Unlimited ;RoHS Compliant: Yes |
| LTC4266IUHF#TRPBF | 制造商:Linear Technology 功能描述:POE Controller 25.5W 38-Pin QFN EP |
| LTC4267 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Quad IEEE 802.3at Power over Ethernet Controller |
| LTC4267-1 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator |
| LTC4267-3 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Power over Ethernet IEEE 802.3af PD Interface with Integrated Switching Regulator |
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