- 您现在的位置：买卖IC网 > PDF目录378049 > PGA309EVM (Texas Instruments, Inc.) PGA309 Evaluation Module(PGA309评估模块) PDF资料下载
参数资料
| 型号： | PGA309EVM |
| 厂商： | Texas Instruments, Inc. |
| 英文描述： | PGA309 Evaluation Module(PGA309评估模块) |
| 中文描述： | PGA309评估模块（PGA309评估模块） |
| 文件页数： | 8/53页 |
| 文件大小： | 4221K |
| 代理商： | PGA309EVM |
第1页第2页第3页第4页第5页第6页第7页当前第8页第9页第10页第11页第12页第13页第14页第15页第16页第17页第18页第19页第20页第21页第22页第23页第24页第25页第26页第27页第28页第29页第30页第31页第32页第33页第34页第35页第36页第37页第38页第39页第40页第41页第42页第43页第44页第45页第46页第47页第48页第49页第50页第51页第52页第53页
4.4 Two-Wire Digital Interface
Two-Wire digital interface is provided through the conversion of RS-232 signals from U9 into open drain
outputs with pull-ups (SDA
OUT
through U6 and SCL
OUT
through U8). SDA
IN
is tied direct to U9 which is looking
for <0.8V for a logic low and >2.0V (3V supply) or >2.4V (5V supply) for a logic high. U10 and U11 provide a
mechanism, through software or hardware (JE), to separate the Two-Wire bus interface from the PGA309 if it
is physically connected. If the PGA309 is in stand-alone mode it will be routinely accessing its external
EEPROM via the Two-Wire interface as a master. By disconnecting from the PGA309 Two-Wire connections
dedicated, local Two-Wire transactions on the PGA309 PC Interface Board such as reading the ADS1100, U3,
can be conducted reliably and without interruption.
Note: It is recommended to keep One-Wire interface on the PGA309 PC Interface Board connected to
the PGA309 Sensor Interface Board even when using Two-Wire communication mode to the PGA309
and EEPROM from the PGA309EVM Board Software. See Section 7.8 for details.
4.5 ADS1100 (On-Board A/D Converter)
The ADS1100 is a 16-Bit A/D available to measure Vout from the PGA309. The ADS1100 is configurable
through the Board Control Software. U4 provides a means of measuring the ADS1100 initial offset for
improved accuracy in its readings.
4.6 Test Points and Miscellaneous Breadboard Area
There are several Test Points, including a 3-position one for GND, provided for ease of measuring analog
signals. Also provided are reserved areas with plated-through, standard-spacing, 0.1” holes for miscellaneous
proof-of-concept breadboarding as desired for a given application.
5.0
PGA309 PC Interface Board Overview – Part 2
(Refer to PGA309EVM PC Interface Board Schematic, Sheet 2 of 2)
5.1 One-Wire Active Pull-Up
The One-Wire Active Pull-Up circuitry is intended to provide a fast rising edge pull-up when the One-Wire
interface is connected to heavy capacitive loads such as when PRG is tied to Vout on the PGA309 and there
is a 10nF capacitor on Vout to GND. In this configuration there is an extremely long rise time due to a 4.7k
pull-up on the One-Wire interface. One-Shot U14 is rising edge triggered only, non-retriggerable. Comparator
U12 looks for a rising edge to transition above 0.7V. The One-Shot, U14, then triggers and produces a 5
μ
S
wide pulse which controls switch U13. When switch U13 is turned on a 200
pull-up to V
S
is provided on the
One-Wire Interface. At the end of the 5
μ
S pulse the 200
pull-up to V
S
is removed. The 5
μ
S was chosen to
provide a near-symmetrical rise and fall time into a 10nF load on the One-Wire interface. RT is a provisional
potentiometer which can be added to change the time the active pull-up is applied to the One-Wire Interface.
D5, D6 and R22 proved a clamp to keep the input of U12 inside its allowed input voltage range for reliable
operation. Figure 2 illustrates the One-Wire Pull-Up into a non-capacitive load. The table shows typical
values for a supply voltage of 3.0V.
Page 8 of 53
相关PDF资料 |
PDF描述 |
|---|---|
| PGE60801 | Erbium-Doped Fiber Amplifier for Digital Applications |
| PGE60802 | Erbium-Doped Fiber Amplifier for Digital Applications |
| PGE60803 | Erbium-Doped Fiber Amplifier for Digital Applications |
| PGE60816 | EDFA Gain Block for DWDM Applications |
| PGE60817 | EDFA Gain Block for DWDM Applications |
相关代理商/技术参数 |
参数描述 |
|---|---|
| PGA309EVM-EU | 功能描述:光学传感器开发工具 PGA309 Eval Mod- Wldwide RoHS:否 制造商:ams 工具用于评估: 接口类型: 最大工作温度: |
| PGA309EVM-US | 功能描述:光学传感器开发工具 PGA309 Eval Mod- US & Canada RoHS:否 制造商:ams 工具用于评估: 接口类型: 最大工作温度: |
| PGA309EVM-USB | 功能描述:放大器 IC 开发工具 PGA309 Eval Mod RoHS:否 制造商:International Rectifier 产品:Demonstration Boards 类型:Power Amplifiers 工具用于评估:IR4302 工作电源电压:13 V to 23 V |
| PGA309EVM-USB | 制造商:Texas Instruments 功能描述:ANALOG SIGNAL CONDITIONING EVAL. MODULE |
| PGA309-HT | 制造商:TI 制造商全称:Texas Instruments 功能描述:VOLTAGE OUTPUT PROGRAMMABLE SENSOR CONDITIONER |
发布紧急采购，3分钟左右您将得到回复。