- 您现在的位置：买卖IC网 > Sheet目录1222 > ISL21400USB-EVALZ (Intersil)EVAL BOARD FOR ISL21400
ISL21400
IDENTIFICATION
SIGNALS
FROM THE
MASTER
S
T
A IDENTIFICATION
R BYTE WITH R/W = 0
T
ADDRESS
BYTE
S
T
A
R
T BYTE WITH R/W = 1
A
C
K
A
C
K
S
T
O
P
SIGNAL AT SDA
0 1 0 1 A A A 0
A
0 0 0 0 0
A
0 1 0 1 A A A 1
A
SIGNALS FROM
THE SLAVE
C
K
C
K
C
K
FIRST READ
DATA BYTE
LAST READ
DATA BYTE
FIGURE 18. RANDOM ADDRESS READ SEQUENCE
Applications Information
Power-Up Considerations
DC OUTPUT CONTROL DISCUSSION
The reference term yields Equation 4 for Reference Output:
The ISL21400 has on-chip EEPROM memory storage for
the DAC and gain settings of the device. These settings
V OUT (DC) = A V ? V REF ? A REF
(EQ. 4)
must be recalled correctly on power-up for proper operation.
Normally there are no issues with recall, although it is always
best to provide a smooth, glitch-free power-up waveform on
V CC . Adding a small 0.1μF capacitor at the device V CC will
help with power-up as well as V OUT load changes.
Noise Performance
The output noise voltage in a 0.1Hz to 10Hz bandwidth is
typically 90μV P-P . The noise measurement is made with a
bandpass filter made of a 1-pole high-pass filter with a
corner frequency at 0.1Hz and a 2-pole low-pass filter with a
corner frequency at 12.6Hz to create a filter with a 9.9Hz
bandwidth. Load capacitance up to 5000pF can be added
Note that the DC term is dependent on the 1.20V reference
voltage, which is constant, the overall gain, A V , and the
Reference gain, A REF . Since the product A V *A REF ranges
from 0 to 4, the total reference DC output can range from
0.0V to 4.8V. In order to get the 4.8V output, V CC must be
greater than 4.8V by the output dropout plus any overhead
for output loading (the specification for V OUT = 5.0V is listed
with V CC = 5.5V). The Resolution of V OUT (DC) control
changes with A V , so that with a 4.80V full scale output
(A V = 4), the resolution is 4.80/255 or 18.8mV/bit. With
A V = 1, the resolution is 4.7mV/bit.
TEMP SENSE CONTROL DISCUSSION
but will result in only marginal improvements in output noise
and transient response. The output stage of the ISL21400 is
not designed to drive heavily capacitive loads. For high
impedance loads, an R-C network can be added to filter high
frequency noise and preserve DC control.
Equation 4 yields this expression, Equation 5, for
Temperature Slope:
V OUT ( TS ) = A V ? V TS ? A TS
(EQ. 5)
? ? ---------------------------------- ? ?
V OUT = ? A V ? V REF ? ---------- ? + ? A V ? V
? ?
? ?
A REF = ---------- (ranges from 0 to 1)
A TS = ? ---------------------------------- ?
( 2 ? m ) – 255
?
?
255
Output Voltage Programming Considerations
Setting and controlling the output voltage of the ISL21400
can be done easily by breaking down the components into
temperature variant and invariant, and setting them
separately. Let’s use Equation 1 to derive separate
Reference Output and Output Temperature Slope equations:
? n ? ? ( 2 ? m ) – 255 ?
255 TS ? 255 ?
= { A V ? V REF ? A REF } + { A V ? V TS ? A TS } ""
Reference Term + Temp Slope Term
The first term controls the output DC value, and the second
term controls the Temperature slope, where
n
255
(ranges from -1 to +1)
14
Since V TS = K(T - T 0 ), the slope term is dependent on the
base temp slope of the device, K (-2.1mV/°C), and the gain
terms A V and A TS . This gives a formula (Equation 6) for the
portion of V OUT at a specific temperature:
V OUT ( TS ) = A V ? K ? A TS ? ( T – T 0 ) (EQ. 6)
The product A V *A TS ranges from -4 to 4, so the Temperature
Slope can range from -8.4 to +8.4mV/°C, which is
independent of the output DC voltage. The resolution of
Slope control is determined by this range (±8.4mV/°C) and
the gain terms, and will vary from 65.8μV/°C/bit (A V = 4)
down to 16.2μV/°C/bit (A V = 1).
At T = T 0 = +25°C, V OUT (TS) = 0, no changes in A TS will
cause a change in V OUT , and V OUT will only vary with the
V OUT (DC) control. As temperature increases or decreases,
from T = +25°C, V OUT will then change according to the
programmed Temp Slope.
FN8091.3
March 31, 2011
发布紧急采购，3分钟左右您将得到回复。
相关PDF资料
ISL28210SOICEVAL1Z
EVAL BOARD FOR ISL28210 8SOIC
ISL28217SOICEVAL2Z
EVAL BAORD FOR ISL28217 8SOIC
ISL28218SOICEVAL1Z
EVAL BOARD FOR ISL28218 8SOIC
ISL28236SOICEVAL1Z
EVAL BOARD 1 FOR ISL28236 SOIC
ISL28248MSOPEVAL1Z
EVAL BOARD FOR ISL28248 MSOP
ISL28433TSSOPEVAL1Z
EVAL BOARD FOR ISL28433 14TSSOP
ISL54222IRUEVAL1Z
EVAL BOARD 1 FOR ISL54222IRU
ISL54406EVAL1Z
EVALUATION BOARD FOR ISL54406
相关代理商/技术参数
ISL21440
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Micropower Voltage Reference with Comparator
ISL21440_11
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Micropower Voltage Reference with Comparator
ISL21440IRTZ
功能描述:基准电压& 基准电流 ISL21440IRTZ MICRO PWR FGAFERENCE RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel
ISL21440IRTZ-T13
功能描述:基准电压& 基准电流 ISL21440IRTZ MICRO PWR FGAFERENCE RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel
ISL21440IUZ
功能描述:基准电压& 基准电流 ISL21440IUZ MICRO PWR FGAFERENCE RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel
ISL21440IUZ-T13
功能描述:基准电压& 基准电流 ISL21440IUZ MICRO PWR FGAFERENCE RoHS:否 制造商:STMicroelectronics 产品:Voltage References 拓扑结构:Shunt References 参考类型:Programmable 输出电压:1.24 V to 18 V 初始准确度:0.25 % 平均温度系数（典型值）:100 PPM / C 串联 VREF - 输入电压（最大值）: 串联 VREF - 输入电压（最小值）: 分流电流（最大值）:60 mA 最大工作温度:+ 125 C 封装 / 箱体:SOT-23-3L 封装:Reel
ISL22102
制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:32 Tap, Push-button, Dual Audio Logarithmic Potentiometer with Buffer Amplifiers and Audio Detection
ISL22102IR20Z
功能描述:数字电位计 IC 32 TAP PUSH-BUTTON DL AUD LOG W/BUFR RoHS:否 制造商:Maxim Integrated 电阻:200 Ohms 温度系数:35 PPM / C 容差:25 % POT 数量:Dual 每 POT 分接头:256 弧刷存储器:Volatile 缓冲刷: 数字接口:Serial (3-Wire, SPI) 描述/功能:Dual Volatile Low Voltage Linear Taper Digital Potentiometer 工作电源电压:1.7 V to 5.5 V 电源电流:27 uA 最大工作温度:+ 125 C 安装风格:SMD/SMT 封装 / 箱体:TQFN-16 封装:Reel