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參數(shù)資料
| 型號(hào)： | LTC4300A-1IMS8 |
| 廠商： | LINEAR TECHNOLOGY CORP |
| 元件分類： | 電源管理 |
| 英文描述： | Hot Swappable 2-Wire Bus Buffers |
| 中文描述： | 2-CHANNEL POWER SUPPLY SUPPORT CKT, PDSO8 |
| 封裝： | PLASTIC, MSOP-8 |
| 文件頁(yè)數(shù)： | 9/16頁(yè) |
| 文件大?。?/td> | 291K |
| 代理商： | LTC4300A-1IMS8 |
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LTC4300A-1/LTC4300A-2
9
sn4300a12 4300a12fs
supply voltage, temperature and the pull-up resistors and
equivalent bus capacitances on both sides of the bus. The
Typical Performance Characteristics section shows t
PHL
as a function of temperature and voltage for 10k pull-up
resistors and 100pF equivalent capacitance on both sides
of the part. By comparison with Figure 2, the V
CC
= 3.3V
curve shows that increasing the capacitance from 50pF to
100pF results in a t
PHL
increase from 55ns to 75ns. Larger
output capacitances translate to longer delays (up to
150ns). Users must quantify the difference in propagation
times for a rising edge versus a falling edge in their
systems and adjust setup and hold times accordingly.
Rise-Time Accelerators
Once connection has been established, rise-time accelera-
tor circuits on all four SDA and SCL pins are activated.
These allow the user to choose weaker DC pull-up currents
on the bus, reducing power consumption while still meet-
ing system rise-time requirements. During positive bus
transitions, the LTC4300A switches in 2mA (typical) of
current to quickly slew the SDA and SCL lines once their
DC voltages exceed 0.6V. Using a general rule of 20pF of
capacitance for every device on the bus (10pF for the
device and 10pF for interconnect), choose a pull-up cur-
rent so that the bus will rise on its own at a rate of at least
1.25V/
μ
s to guarantee activation of the accelerators.
For example, assume an SMBus system with V
CC
= 3V, a
10k pull-up resistor and equivalent bus capacitance of
200pF. The rise-time of an SMBus system is calculated
from (V
IL(MAX)
– 0.15V) to (V
IH(MIN)
+ 0.15V), or 0.65V to
2.25V. It takes an RC circuit 0.92 time constants to
traverse this voltage for a 3V supply; in this case, 0.92
(10k 200pF) = 1.84
μ
s. Thus, the system exceeds the
maximum allowed rise-time of 1
μ
s by 84%. However,
using the rise-time accelerators, which are activated at a
DC threshold of below 0.65V, the worst-case rise-time is:
(2.25V – 0.65V) 200pF/1mA = 320ns, which meets the
1
μ
s rise-time requirement.
READY Digital Output (LTC4300A-1)
This pin provides a digital flag which is low when either
ENABLE is low or the start-up sequence described earlier
in this section has not been completed. READY goes high
when ENABLE is high and start-up is complete. The pin is
driven by an open drain pull-down capable of sinking 3mA
while holding 0.4V on the pin. Connect a resistor of 10k to
V
CC
to provide the pull-up. This feature is available for the
LTC4300A-1 only.
ENABLE Low Current Disable (LTC4300A-1)
Grounding the ENABLE pin disconnects the backplane
side from the card side, disables the rise-time accelera-
tors, drives READY low, disables the bus precharge cir-
cuitry and puts the part in a near-zero current state. When
the pin voltage is driven all the way to V
CC
, the part waits
for data transactions on both the backplane and card sides
to be complete (as described in the Start-Up section)
before reconnecting the two sides. This feature is available
for the LTC4300A-1 only.
ACC Boost Current Enable (LTC4300A-2)
Users having lightly loaded systems may wish to disable
the rise-time accelerators. Driving this pin to ground turns
off the rise-time accelerators on all four SDA and SCL pins.
Driving this pin to the V
CC2
voltage enables normal opera-
tion of the rise-time accelerators, as described in the Rise-
Time Accelerators section above. This feature is available
for the LTC4300A-2 only.
OPERATIOU
Figure 1. Input–Output Connection t
PLH
Figure 2. Input–Output Connection t
PHL
OUTPUT
SIDE
50pF
INPUT
SIDE
150pF
INPUT
SIDE
150pF
OUTPUT
SIDE
50pF
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| LTC4300A-2 | 14/PG/CL/N FLNG |
| LTC4300A-2CMS8 | Hot Swappable 2-Wire Bus Buffers |
| LTC4300A-2IMS8 | Hot Swappable 2-Wire Bus Buffers |
| LTC4300A-3 | Level Shifting Hot Swappable 2-Wire Bus Buffer with Enable |
| LTC4300-1 | Hot Swappable 2-Wire Bus Buffers |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| LTC4300A-1IMS8#PBF | 功能描述:IC BUFFER BUS 2WR HOTSWAP 8-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 產(chǎn)品培訓(xùn)模塊:Lead (SnPb) Finish for COTS Obsolescence Mitigation Program 標(biāo)準(zhǔn)包裝:119 系列:- 類型:熱交換控制器 應(yīng)用:通用型，PCI Express? 內(nèi)部開關(guān):無(wú) 電流限制:- 電源電壓:3.3V，12V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:80-TQFP 供應(yīng)商設(shè)備封裝:80-TQFP（12x12） 包裝:托盤 產(chǎn)品目錄頁(yè)面:1423 (CN2011-ZH PDF) |
| LTC4300A-1IMS8#TR | 功能描述:IC BUFFER BUS 2WR HOTSWAP 8-MSOP RoHS:否 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠(yuǎn)程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無(wú) 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LTC4300A-1IMS8#TRPBF | 功能描述:IC BUFFER BUS 2WR HOTSWAP 8-MSOP RoHS:是 類別:集成電路 (IC) >> PMIC - 熱交換 系列:- 標(biāo)準(zhǔn)包裝:50 系列:- 類型:熱交換控制器 應(yīng)用:-48V 遠(yuǎn)程電力系統(tǒng)，AdvancedTCA ? 系統(tǒng)，高可用性 內(nèi)部開關(guān):無(wú) 電流限制:可調(diào) 電源電壓:11.5 V ~ 14.5 V 工作溫度:-40°C ~ 85°C 安裝類型:表面貼裝 封裝/外殼:10-TFSOP，10-MSOP（0.118"，3.00mm 寬） 供應(yīng)商設(shè)備封裝:10-MSOP 包裝:管件 |
| LTC4300A1MS8TRPBF | 制造商:Linear Technology 功能描述: |
| LTC4300A2CMS8 | 制造商:Linear Technology 功能描述: |
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