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参数资料
| 型号： | DS1864T+ |
| 厂商： | Maxim Integrated |
| 文件页数： | 19/72页 |
| 文件大小： | 0K |
| 描述： | IC LASER CTRLR 1CHAN 5.5V 28TQFN |
| 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（光纤） |
| 通道数： | 1 |
| 电源电压： | 2.97 V ~ 5.5 V |
| 电流 - 电源： | 3mA |
| 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 |
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SFP Laser Controller and
Diagnostic IC
Table 4. Voltage Monitor Factory Default
Calibration
input that would produce a digital result of all zeros is
the null value (normally this input is GND). The input
that would produce a digital result of all ones (FFF8h) is
SIGNAL
V CC
MON1
MON2
MON3
+FS
(V)
6.5528V
2.4997V
2.4997V
2.4997V
+FS
(hex)
FFF8
FFF8
FFF8
FFF8
-FS
(V)
0V
0V
0V
0V
-FS
(hex)
0000
0000
0000
0000
the full-scale (FS) value. The expected FS value is also
found by multiplying FFF8h by the LSB weight.
The right-shifting operation on the A/D converter output
is carried out based on the contents of Registers Right
Shift1 and Right Shift2 in EEPROM. Each of the three
analog channels (MON1 (Bias Current (IBI)), MON2
(Transmitted Power (TXP)), and MON3 (Received Power
(RIN)) is allocated 3 bits to set the number of right shifts.
To calculate the voltage measured from the register
value, first calculate the LSB weight of the 16-bit register.
The LSB weight is equal to the full-scale voltage span
divided 65528. Next, convert the hexadecimal register
value to decimal and multiply it times the LSB weight.
Example: Using the factory default V CC trim, what volt-
age is measured if the V CC register value is C340h?
The LSB for V CC is equal to (6.5528V - 0V) / 65528 =
100.00μV. C340h is equal to 49984 decimal, which
yields a supply voltage equal to 49984 x 100.00μV =
4.9984V. Table 5 shows more conversion examples
based on the factory trimmed A/D settings.
The factory-programmed LSB for V CC is 100μV. The
factory-programmed LSB weight for the MON channels
is 38.147μV.
Table 5. Voltage Monitor Conversion
Examples
Up to 7 right-shift operations are allowed and will be
executed as a part of every conversion before the result
is loaded in the corresponding measurement registers
62h to 69h. This is true during the setup of internal cali-
bration as well as during subsequent data conversions.
Example: Since the FS digital reading is 65528 (FFF8h)
LSBs, if the LSB’s weight is 50μV, then the FS value is
65528 x 50μV = 3.2764V.
A binary search is used to calibrate the gain of the con-
verter. This requires forcing two known voltages on the
input pin. It is preferred that one of the forced voltages is
the null input and the other is 90% of FS. Since the LSB
of the least significant bit in the digital reading register is
known, the expected digital results can be calculated
for both the null input and the 90% of full-scale value.
An explanation of the binary search used to scale the gain
is best served with the following example pseudo-code:
/* Assume that the null input is 0.5V */
SIGNAL
V CC
V CC
MON1
MON2
MON3
LSB
WEIGHT μV)
100.00
100.00
38.147
38.147
38.147
REGISTER
VALUE (HEX)
8080
C0F0
AA00
1880
9CF0
INPUT
VOLTAGE
(V)
3.2896
4.9392
1.6601
0.2392
1.5326
/* Assume that the requirement for the LSB is 50 μ V */
FS = 65528 * 50e-6; /*3.2764V */
CNT1 = 0.5 / 50e-6; /* 1000 */
CNT2 = 0.9 X FS / 50e-6; /* 58968 */
/* So the null input is 0.5V and 90% of FS is 2.94876V */
Set the input's offset register to zero
gain_result = 0h; /* Working register for gain calculation */
CLAMP = FFF0h; /* This is the max A/D value*/
For n = 15 down to 0
begin
gain_result = gain_result + 2^n;
Voltage Monitor Calibration
(Gain, Offset, and Right Shifting)
The DS1864 has the ability to scale each analog volt-
Write gain_result to the input's gain register;
Force the 90% FS input (2.94876V);
Meas2 = A/D result from DS1864;
If Meas2 >= CLAMP
age’s gain and offset to produce the desired digital
result. Each of the inputs (V CC , MON1, MON2, MON3)
Then
Else
gain_result = gain_result - 2^n;
has specific registers for the gain, offset, and right shift-
ing (in memory Table 04h (Table 01h in DS1859 config-
uration)) allowing them to be individually calibrated.
To scale the gain and offset of the converter for a spe-
cific input, one must first know the relationship between
the analog input and the expected digital result. The
Force the null input (0.5V)
Meas1 = A/D result from DS1864
If [(Meas2-Meas1)>(CNT2-CNT1)]
Then
gain_result = gain_result - 2^n;
end;
Write gain_result to the input's gain register;
____________________________________________________________________
19
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS1864T+ | 功能描述:激光驱动器 SFP Laser Controller & Diagnostic IC RoHS:否 制造商:Micrel 数据速率:4.25 Gbps 工作电源电压:3 V to 3.6 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:QFN-16 封装:Tube |
| DS1864T+T&R | 制造商:Maxim Integrated Products 功能描述:DUAL TMP CTRL DAC+MON QFN T&R LF - Tape and Reel 制造商:Maxim Integrated Products 功能描述:IC LASER CTRLR 1CHAN 5.5V 28TQFN |
| DS1864T+T&R | 功能描述:激光驱动器 SFP Laser Controller & Diagnostic IC RoHS:否 制造商:Micrel 数据速率:4.25 Gbps 工作电源电压:3 V to 3.6 V 电源电流:80 mA 最大工作温度:+ 85 C 封装 / 箱体:QFN-16 封装:Tube |
| DS1865 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:PON Triplexer Control and Monitoring Circuit |
| DS1865_09 | 制造商:MAXIM 制造商全称:Maxim Integrated Products 功能描述:PON Triplexer Control and Monitoring Circuit |
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