参数资料
| 型号： | DS1874T+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 19/88页 |
| 文件大小： | 0K |
| 描述： | IC CTLR SFP+ ANLG LDD 28-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 60 |
| 类型： | 激光二极管控制器 |
| 通道数： | 1 |
| 电源电压： | 2.85 V ~ 3.9 V |
| 电流 - 电源： | 2.5mA |
| 工作温度： | -40°C ~ 95°C |
| 封装/外壳： | 28-WFQFN 裸露焊盘 |
| 供应商设备封装： | 28-TQFN-EP（5x5） |
| 包装： | 管件 |
| 安装类型： | 表面贴装 |
| 其它名称： | 90-1874T+000 |
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SFP+ Controller with Digital LDD Interface
Low-Voltage Operation
The DS1874 contains two power-on reset (POR) levels.
The lower level is a digital POR (POD) and the higher
level is an analog POR (POA). At startup, before the
supply voltage rises above POA, the outputs are dis-
abled, all SRAM locations are set to their defaults,
shadowed EEPROM (SEE) locations are zero, and all
analog circuitry is disabled. When V CC reaches POA,
the SEE is recalled, and the analog circuitry is enabled.
While V CC remains above POA, the device is in its nor-
mal operating state, and it responds based on its non-
volatile configuration. If during operation V CC falls
below POA, but is still above POD, then the SRAM
retains the SEE settings from the first SEE recall, but the
device analog is shut down and the outputs disabled. If
the supply voltage recovers back above POA, then the
device immediately resumes normal operation. If the
supply voltage falls below POD, then the device SRAM
is placed in its default state and another SEE recall is
required to reload the nonvolatile settings. The EEPROM
recall occurs the next time V CC exceeds POA. Figure 8
shows the sequence of events as the voltage varies.
Any time V CC is above POD, the I 2 C interface can be
used to determine if V CC is below the POA level. This is
accomplished by checking the RDYB bit in the STATUS
(Lower Memory, Register 6Eh) byte. RDYB is set when
V CC is below POA; when V CC rises above POA, RDYB
is timed (within 500μs) to go to 0, at which point the
part is fully functional.
For all device addresses sourced from EEPROM (Table
02h, Register 8Ch), the default device address is A2h
until V CC exceeds POA, allowing the device address to
be recalled from the EEPROM.
Power-On Analog (POA)
POA holds the DS1874 in reset until V CC is at a suitable
level (V CC > POA) for the device to accurately measure
with its ADC and compare analog signals with its quick-
trip monitors. Because V CC cannot be measured by the
ADC when V CC is less than POA, POA also asserts the
VCC LO alarm, which is cleared by a V CC ADC conver-
sion greater than the customer-programmable V CC
alarm low ADC limit. This allows a programmable limit
to ensure that the headroom requirements of the trans-
ceiver are satisfied during a slow power-up. The TXF
output does not latch until there is a conversion above
V CC low limit. The POA alarm is nonmaskable. The TXF
output is asserted when V CC is below POA. See the
Low-Voltage Operation section for more information.
Delta-Sigma Outputs (DAC1 and DAC2)
Two delta-sigma outputs are provided, DAC1 and
DAC2. With the addition of an external RC filter, these
outputs provide two 9-bit resolution analog outputs with
the full-scale range set by the input REFIN. Each output
V POA
V CC
V POD
SEE RECALL
SEE RECALL
SEE
PRECHARGED
TO 0
RECALLED VALUE
PRECHARGED TO 0
RECALLED VALUE
PRECHARGED
TO 0
Figure 8. Low-Voltage Hysteresis Example
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相关代理商/技术参数 |
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| DS1874T+ | 功能描述:ADC / DAC多通道 SFP+ Controller w/ Dgtl LDD Interface RoHS:否 制造商:Texas Instruments 转换速率: 分辨率:8 bit 接口类型:SPI 电压参考: 电源电压-最大:3.6 V 电源电压-最小:2 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-40 |
| DS1874T+T&R | 制造商:Maxim Integrated Products 功能描述:SFP+ CONTROLLER WITH DIGITAL LDD INTERFACE - Tape and Reel 制造商:Maxim Integrated Products 功能描述:MXMDS1874T+T&R SFP+ CTRLR FOR USE W/MAX3 制造商:Maxim Integrated Products 功能描述:IC CTLR SFP+ ANLG LDD 28-TQFN |
| DS1874T+T&R | 功能描述:ADC / DAC多通道 SFP+ Controller w/ Dgtl LDD Interface RoHS:否 制造商:Texas Instruments 转换速率: 分辨率:8 bit 接口类型:SPI 电压参考: 电源电压-最大:3.6 V 电源电压-最小:2 V 最大工作温度:+ 85 C 安装风格:SMD/SMT 封装 / 箱体:VQFN-40 |
| DS1874T+TR | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:SFP+ Controller with Digital LDD Interface |
| DS1875 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:PON Triplexer and SFP Controller |
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