参数资料
| 型号： | LTC2281IUP#PBF |
| 厂商： | Linear Technology |
| 文件页数： | 7/24页 |
| 文件大小： | 0K |
| 描述： | IC ADC 10BIT DUAL 64-QFN |
| 标准包装： | 40 |
| 位数： | 10 |
| 采样率（每秒）： | 125M |
| 数据接口： | 并联 |
| 转换器数目： | 2 |
| 功率耗散（最大）： | 915mW |
| 电压电源： | 单电源 |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 表面贴装 |
| 封装/外壳： | 64-WFQFN 裸露焊盘 |
| 供应商设备封装： | 64-QFN（9x9） |
| 包装： | 管件 |
| 输入数目和类型： | 2 个单端，双极; 2 个差分, 双极 |
LTC2281
15
2281fb
APPLICATIONS INFORMATION
Reference Operation
Figure 9 shows the LTC2281 reference circuitry consisting
of a 1.5V bandgap reference, a difference amplier and
switching and control circuit. The internal voltage reference
can be congured for two pin selectable input ranges of
2V (±1V differential) or 1V (±0.5V differential). Tying the
SENSE pin to VDD selects the 2V range; tying the SENSE
pin to VCM selects the 1V range.
The 1.5V bandgap reference serves two functions: its
output provides a DC bias point for setting the common
mode voltage of any external input circuitry; additionally,
the reference is used with a difference amplier to gener-
ate the differential reference levels needed by the internal
ADC circuitry. An external bypass capacitor is required
for the 1.5V reference output, VCM. This provides a high
frequency low impedance path to ground for internal and
external circuitry.
Figure 9. Equivalent Reference Circuit
VCM
REFH
SENSE
TIE TO VDD FOR 2V RANGE;
TIE TO VCM FOR 1V RANGE;
RANGE = 2 VSENSE FOR
0.5V < VSENSE < 1V
1.5V
REFL
2.2μF
INTERNAL ADC
HIGH REFERENCE
BUFFER
0.1μF
2281 F09
4W
DIFF AMP
1μF
INTERNAL ADC
LOW REFERENCE
1.5V BANDGAP
REFERENCE
1V
0.5V
RANGE
DETECT
AND
CONTROL
LTC2281
The difference amplier generates the high and low
reference for the ADC. High speed switching circuits are
connected to these outputs and they must be externally
bypassed. Each output has two pins. The multiple output
pins are needed to reduce package inductance. Bypass
capacitors must be connected as shown in Figure 9. Each
ADC channel has an independent reference with its own
bypass capacitors. The two channels can be used with the
same or different input ranges.
Other voltage ranges between the pin selectable ranges
can be programmed with two external resistors as shown
in Figure 10. An external reference can be used by ap-
plying its output directly or through a resistor divider to
SENSE. It is not recommended to drive the SENSE pin
with a logic device. The SENSE pin should be tied to the
appropriate level as close to the converter as possible. If
the SENSE pin is driven externally, it should be bypassed
to ground as close to the device as possible with a 1μF
ceramic capacitor. For the best channel matching, connect
an external reference to SENSEA and SENSEB.
Figure 10. 1.5V Range ADC
VCM
SENSE
1.5V
0.75V
2.2μF
12k
1μF
12k
2281 F10
LTC2281
Input Range
The input range can be set based on the application.
The 2V input range will provide the best signal-to-noise
performance while maintaining excellent SFDR. The 1V
input range will have better SFDR performance, but the
SNR will degrade by 0.9dB. See the Typical Performance
Characteristics section.
Driving the Clock Input
The CLK inputs can be driven directly with a CMOS or
TTL level signal. A sinusoidal clock can also be used
along with a low jitter squaring circuit before the CLK pin
(Figure 11).
相关PDF资料 |
PDF描述 |
|---|---|
| LTC2282CUP#PBF | IC ADC DUAL 12BIT 105MSPS 64-QFN |
| LTC2284CUP#PBF | IC ADC DUAL 14BIT 105MSPS 64-QFN |
| LTC2285CUP#PBF | IC ADC DUAL 14BIT 125MSPS 64QFN |
| LTC2289IUP#PBF | IC ADC DUAL 10BIT 80MSPS 64QFN |
| LTC2290IUP#TRPBF | IC ADC DUAL 12BIT 10MSPS 64QFN |
相关代理商/技术参数 |
参数描述 |
|---|---|
| LTC2281IUP-TR | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 10-Bit, 125Msps Low Power 3V ADC |
| LTC2281IUP-TRPBF | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 10-Bit, 125Msps Low Power 3V ADC |
| LTC2281UP | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 10-Bit, 125Msps Low Power 3V ADC |
| LTC2282 | 制造商:LINER 制造商全称:Linear Technology 功能描述:Dual 12-Bit, 105Msps Low Power 3V ADC |
| LTC2282CUP | 制造商:Linear Technology 功能描述:ADC Dual Pipelined 105Msps 12-bit Parallel 64-Pin QFN EP |
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