A sense resistor (RS), connected between SENSE_ and
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鍨嬭櫉锛� MAX5945CAX+T
寤犲晢锛� Maxim Integrated Products
鏂囦欢闋佹暩(sh霉)锛� 8/44闋�
鏂囦欢澶у皬锛� 0K
鎻忚堪锛� IC NETWORK PWR CTRL 36-SSOP
鐢�(ch菐n)鍝佸煿瑷撴ā濉婏細 Lead (SnPb) Finish for COTS
Obsolescence Mitigation Program
妯欐簴鍖呰锛� 1,000
鎺у埗鍣ㄩ鍨嬶細 缍�(w菐ng)绲￠浕婧愭帶鍒跺櫒
鎺ュ彛锛� I²C
闆绘簮闆诲锛� 3.3V
闆绘祦 - 闆绘簮锛� 4.2mA
宸ヤ綔婧害锛� 0°C ~ 70°C
瀹夎椤炲瀷锛� 琛ㄩ潰璨艰
灏佽/澶栨锛� 36-BSOP锛�0.295"锛�7.50mm 瀵級
渚涙噳鍟嗚ō鍌欏皝瑁濓細 36-SSOP
鍖呰锛� 甯跺嵎 (TR)
MAX5945
Overcurrent Protection
A sense resistor (RS), connected between SENSE_ and
VEE, monitors the load current. Under all circum-
stances, the voltage across RS never exceeds the
threshold VSU_LIM. If SENSE_ exceeds VSU_LIM, an
internal current-limiting circuit regulates the GATE volt-
age, limiting the current to ILIM = VSU_LIM / RS. During
transient conditions, if the SENSE_ voltage exceeds
VSU_LIM, a fast pulldown circuit activates to quickly
recover from the current overshoot. During startup, if
the current-limit condition persists, when the startup
timer, tSTART, times out, the port shuts off and the
STRT_FLT_ bit is set. In normal powered state, the
MAX5945 checks for overcurrent conditions as deter-
mined by VFLT_LIM = ~88% of VSU_LIM. The tFAULT
counter sets the maximum allowed continuous
overcurrent period. The tFAULT counter increases when
VSENSE exceeds VFLT_LIM and decreases at a slower
pace when VSENSE drops below VFLT_LIM. A slower
decrement for the tFAULT counter allows for detecting
repeated short-duration overcurrents. When the counter
reaches the tFAULT limit, the MAX5945 powers off the
port and asserts the IMAX_FLT_ bit. For a continuous
overstress, a fault latches exactly after a period of
tFAULT. VSU_LIM, is programmable using R27h[4-7].
tFAULT is programmable using R16h[2-3] and R28[4-7].
After power-off due to an overcurrent fault, and if the
RSTR_EN bit is set, the tFAULT timer is not immediately
reset but starts decrementing at the same slower pace.
The MAX5945 allows the port to be powered on only
when the tFAULT counter is at zero. This feature sets an
automatic duty-cycle protection to the external MOSFET
to avoid overheating. The duty cycle is programmable
using R16h[6-7].
The MAX5945 continuously flags when the current
exceeds the maximum current allowed for the class as
indicated in the CLASS status register. When class
overcurrent occurs, the MAX5945 sets the IVC bit in
register R09h.
Foldback Current
During startup and normal operation, an internal circuit
senses the voltage at OUT_ and reduces the current-
limit value when (VOUT_ - VEE) > 30V. The foldback
function helps to reduce the power dissipation on the
FET. The current limit eventually reduces to 1/3 of ILIM
when (VOUT_ - VEE ) > 50V (see Figure 4).
Quad Network Power Controller
for Power-Over-LAN
16
______________________________________________________________________________________
Figure 2. Detection, Classification, and Power-Up Port
Sequence
OUT_
-4V
-9V
-18V
-48V
t
tDETI
tDETII
tCLASS
150ms
21.3ms
0V
80ms
Figure 3. PGOOD Timing
PGOOD
POK
tPGOOD
鐩搁棞PDF璩囨枡
PDF鎻忚堪
VE-253-IX-S CONVERTER MOD DC/DC 24V 75W
VE-2TX-IX-S CONVERTER MOD DC/DC 5.2V 75W
VE-2TV-IX-S CONVERTER MOD DC/DC 5.8V 75W
PIC16LF1783-E/ML IC MCU 8BIT 7KB FLASH 28-QFN
PIC16LF1782-E/SP IC MCU 8BIT 3.5KB FLASH 28-SPDIP
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MAX5945EAX+ 鍔熻兘鎻忚堪:鐔辨彃鎷斿姛鐜囧垎甯� IEEE 802.3af Quad Net Pwr Controller RoHS:鍚� 鍒堕€犲晢:Texas Instruments 鐢�(ch菐n)鍝�:Controllers & Switches 闆绘祦闄愬埗: 闆绘簮闆诲-鏈€澶�:7 V 闆绘簮闆诲-鏈€灏�:- 0.3 V 宸ヤ綔婧害鑼冨湇: 鍔熺巼鑰楁暎: 瀹夎棰ㄦ牸:SMD/SMT 灏佽 / 绠遍珨:MSOP-8 灏佽:Tube
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MAX5945EVKIT 鍔熻兘鎻忚堪:闆绘簮绠＄悊IC闁嬬櫦(f膩)宸ュ叿 Evaluation Kit/Evaluation System for the MAX5945 RoHS:鍚� 鍒堕€犲晢:Maxim Integrated 鐢�(ch菐n)鍝�:Evaluation Kits 椤炲瀷:Battery Management 宸ュ叿鐢ㄤ簬瑭曚及:MAX17710GB 杓稿叆闆诲: 杓稿嚭闆诲:1.8 V
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