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参数资料
| 型号： | DS1873T+T&R |
| 厂商： | Maxim Integrated |
| 文件页数： | 14/86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： | 2,500 |
| 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： | 带卷 (TR) |
| 安装类型： | 表面贴装 |
| 其它名称： | 90-1873T+TRL |
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SFP+ Controller with Analog LDD Interface
enabled. If IBIASMAX is exceeded during the binary
search, the next smaller step is activated. ISTEP or
binary increments that would cause the BIAS DAC to
exceed IBIASMAX are not taken. Masking the alarms
until the completion of the binary search prevents false
positive alarms during startup.
ISTEP is programmed by the customer using Table
02h, Register BBh. ISTEP should be programmed to
the maximum safe increase that is allowable during
startup. If this value is programmed too low, the
DS1873 still operates, but it could take significantly
longer for the algorithm to converge and hence to con-
trol the average power.
If a fault is detected, and TXD is toggled to reenable
the outputs, the DS1873 powers up following a similar
sequence to an initial power-up. The only difference is
that the DS1873 already has determined the present
temperature, so the t INIT time is not required for the
DS1873 to recall the APC and MOD set points from
EEPROM.
BIAS and MOD DACs as a Function of
Transmit Disable (TXD)
If TXD is asserted (logic 1) during normal operation, the
outputs are disabled within t OFF . When TXD is
deasserted (logic 0), the DS1873 sets the MOD DAC
register with the value associated with the present tem-
perature, and initializes the BIAS DAC using the same
search algorithm as done at startup. When asserted,
soft TXD (TXDC) (Lower Memory, Register 6Eh) would
allow a software control identical to the TXD pin (see
Figure 2).
TXD
APC and Quick-Trip Timing
As shown in Figure 3, the DS1873’s input comparator is
shared between the APC control loop and the quick-trip
alarms (TXP HI, TXP LO, LOS LO, and BIAS HI). The
comparator polls the alarms in a multiplexed sequence.
Five of every eight comparator readings are used for
APC loop bias-current control. The other three updates
are used to check the HTXP/LTXP (monitor diode volt-
age), the HBATH (MON1), and LOS (MON3) signals
against the internal APC, BIAS, and MON3 reference,
respectively. If the last APC comparison was higher
than the APC set point, it makes an HTXP comparison,
and if it is lower, it makes an LTXP comparison.
Depending on the results of the comparison, the corre-
sponding alarms and warnings (TXP HI, TXP LO) are
asserted or deasserted.
The DS1873 has a programmable comparator sample
time based on an internally generated clock to facilitate
a wide variety of external filtering options and time
delays. The UPDATE RATE register (Table 02h,
Register 88h) determines the sampling time. Samples
occur at a regular interval, t REP , which is set at 1.6μs.
Table 2 shows the sample rate options available. Any
quick-trip alarm that is detected by default remains
active until a subsequent comparator sample shows
the condition no longer exists. A second bias current
monitor (BIAS MAX) compares the BIAS DAC’s code to
a digital value stored in the IBIASMAX register. This
comparison is made at every bias current update to
ensure that a high-bias current is quickly detected.
The quick-trip comparator uses a 1.6 μ s window to sam-
ple each input. After an APC comparison that requires
Figure 2. TXD Timing
BIAS DAC
MOD DAC SETTING
t OFF
t OFF
t ON
t ON
APC QUICK-TRIP SAMPLE TIMES
HBIAS
SAMPLE
APC
SAMPLE
APC
SAMPLE
APC
SAMPLE
APC
SAMPLE
APC
SAMPLE
HTXP/LTXP
SAMPLE
LOS
SAMPLE
HBIAS
SAMPLE
APC
SAMPLE
t REP
Figure 3. APC Loop and Quick-Trip Sample Timing
14
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1874 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:SFP+ Controller with Digital LDD Interface |
| 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 |
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