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| 型号： | DS1875T+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 18/92页 |
| 文件大小： | 0K |
| 描述： | IC SFP CTRLR/TRIPLEXER 38-TQFN |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 90 |
| 应用： | 光纤 |
| 接口： | I²C |
| 电源电压： | 2.85 V ~ 3.9 V |
| 封装/外壳： | 38-WFQFN 裸露焊盘 |
| 供应商设备封装： | 38-TQFN（5x7） |
| 包装： | 管件 |
| 安装类型： | 表面贴装 |
| 产品目录页面： | 1431 (CN2011-ZH PDF) |
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DS1875
two thresholds. The actual threshold values are a func-
tion of the number of right-shifts being used. Table 7
shows the threshold values for each possible number
of right-shifts.
The RSSI_FF and RSSI_FC (Table 02h, Register 89h)
bits are used to force fine-mode or coarse-mode con-
versions, or to disable the dual-range functionality.
Dual-range functionality is enabled by default (both
RSSI_FC and RSSI_FF are factory programmed to 0 in
EEPROM). It can be disabled by setting RSSI_FC to 0
and RSSI_FF to 1. These bits are also useful when cali-
brating MON3. For additional information, see the
Memory Map section.
PWM Controller
The DS1875 has a PWM controller that, when used with
external components, generates a low-noise, high-volt-
age output to bias APDs in optical receivers. The
achievable boost voltage is determined by the external
component selection. Figure 12 shows a typical
schematic. Selection of switching frequency, external
inductor, capacitors, resistor network, switching FET,
and switch diode determine the performance of the
DC-DC converter. The PWM controller can be config-
ured in boost or buck mode. Both modes require an
external nMOS or npn transistor.
The DS1875 PWM controller consists of several sec-
tions used to create a PWM signal to drive a DC-DC
converter. Figure 11 is a block diagram of the DS1875
PWM controller. Following is a description of each
block in the PWM controller and some guidelines for
selecting components for the DC-DC converter.
The PWM DAC is used to set the desired output voltage
of the DC-DC converter section. The feedback from the
DC-DC converter is compared to the output from the
PWM DAC by an error amplifier. If the FB level is less
Table 7. MON3 Hysteresis Threshold Values
*
This is the minimum reported coarse-mode conversion.
NO. OF RIGHT-
SHIFTS
FINE MODE
(MAX)
COARSE MODE
(MIN*)
0
FFF8h
F000h
1
7FFCh
7800h
2
3FFEh
3C00h
3
1FFFh
1E00h
4
0FFFh
0F00h
5
07FFh
0780h
6
03FFh
03C0h
7
01FFh
01E0h
MUX
PWM DAC
8-BIT
0 TO 1.25V
10
μA
MANUAL I2C CONTROL
PWM_FR[1:0]
RAMP
90% DUTY
CYCLE OSC
SW
COMP
M3QT
1.9V
1.0V
FB
PWM EN
PWM CONTROLLER
GATE DRIVER
90% MAX
DUTY CYCLE
PWM DAC
TABLE 02h
REGISTER FEh
PWM DAC TEMPERATURE-
REFERENCED LUT
TABLE 07h
VOLTAGE CLAMP
HIGH = 2.1V
LOW = 0.8V
ERROR
AMPLIFIER
10
μA
DS1875
Figure 11. PWM Controller Diagram
PON Triplexer and SFP Controller
______________________________________________________________________________________
25
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1875T+ | 功能描述:ADC / DAC多通道 PON Triplexer & SFP Controller 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 |
| DS1875T+T&R | 制造商:Maxim Integrated Products 功能描述:PON TRIPLEXER 38TQFN EP - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC SFP CTRLR/TRIPLEXER 38-TQFN 制造商:Maxim Integrated Products 功能描述:ADC / DAC Multichannel PON Triplexer & SFP Controller |
| DS1875T+T&R | 功能描述:ADC / DAC多通道 PON Triplexer & SFP Controller 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 |
| DS1875T+TR | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:PON Triplexer and SFP Controller |
| DS1876 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:SFP Controller with Dual LDD Interface |
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