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AD8148ACPZ-R7

更新时间： 2024-02-08 08:31:31

品牌	Logo	应用领域
亚德诺 - ADI		驱动器消费电路商用集成电路音频放大器视频放大器
页数	文件大小	规格书
24页	585K
描述
Triple Differential Driver for Wideband Video

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中文翻译

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技术参数
数据手册
替代型号

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AD8148ACPZ-R7 技术参数

是否无铅：	含铅	是否Rohs认证：	符合
生命周期：	Active	包装说明：	,
针数：	24	Reach Compliance Code：	compliant
ECCN代码：	EAR99	HTS代码：	8542.39.00.01
风险等级：	1.35	Is Samacsys：	N
商用集成电路类型：	VIDEO AMPLIFIER	JESD-609代码：	e3
湿度敏感等级：	3	端子面层：	Matte Tin (Sn)
Base Number Matches：	1

AD8148ACPZ-R7 数据手册

AD8146/AD8147/AD8148

Under no circumstances should capacitance be intentionally

added to an output to introduce frequency domain peaking.

Figure 36 and Figure 37 illustrate how adding just 5 pF of

excessive load capacitance influences time and frequency

domain responses.

ADDING PRE-EMPHASIS TO THE AD8148

UTP cables exhibit loss characteristics that are low pass in

nature and are exponential functions of the square root of the

frequency. Over wideband video bandwidths, the losses are

predominantly due to the skin effect, which causes the resistance of

the cable to increase with frequency. Even though the loss

characteristics are nonlinear, suitable linear networks can be

designed to approximately compensate for the losses.

2.0

= ±5V

= 200ꢀ

= 2V p-p

L, dm

1.5

1.0

OUT, dm

= 5pF

Placing the compensation network at the transmitting end of

the cable is referred to as pre-emphasis, because the higher

frequencies are emphasized, or boosted, before they are sent, to

compensate for the low-pass response of the cable. Because the

higher frequencies experience more loss than the lower frequencies

as they pass through the cable, the high and low frequencies

arrive at approximately the same level and at the end of the cable

when a properly designed pre-emphasis network is used at the

transmitter. The ideal cascaded frequency response of the pre-

emphasis network and the cable is therefore nominally flat.

0.5

= 0pF

–0.5

–1.0

–1.5

–2.0

TIME (ns)

Because the AD8148 has an internally set, closed-loop gain of 4

(12 dB), it is possible to reduce the gain at low frequencies using

external frequency selective components, then use these

components to provide increasing gain with increasing

frequency, back to a value close to 12 dB. These components, along

with the AD8148, form the pre-emphasis network. When properly

designed, the combined frequency response of the pre-emphasis

network and cable is approximately flat with a gain of 2 (6 dB).

Figure 36. Large Signal Transient Responses at Various Capacitive Loads

= ±5V

= 200ꢀ

= 2V p-p

L, dm

= 5pF

OUT, dm

Figure 38 illustrates how to construct a pre-emphasis network

using the AD8148 that compensates for 30 meters of UTP cable.

The network in the lower leg is required to match the transfer

function of the two feedback loops.

= 0pF

At dc, the capacitors are open circuits, and the network has a

gain of approximately 6.5 dB. (The additional 0.5 dB is added to

compensate for the cable flat loss that occurs at frequencies

below where the skin effect begins to take effect.) Moving up in

frequency, the 30 pF capacitor begins to take effect and introduces

a zero into the frequency response, causing the gain to increase

with frequency. Continuing to move up in frequency, the 30 pF

capacitor becomes an effective short, and the 487 Ω resistor

goes in parallel with the 442 Ω resistor, forming a pole in the

response. Continuing to move up in frequency, the 15 pF

capacitor takes effect, introducing another zero, and causes

the gain to further increase with frequency until it becomes

an effective short, and the gain starts to flatten out until the

amplifier response begins to roll off. The gain does not reach

12 dB before the amplifier begins to roll off because the 12 dB

value is a high frequency asymptote. The pole and zero locations

cited in the previous discussion are qualitative, but the

discussion describes the basic principles involved with the

operation of the pre-emphasis network.

100

FREQUENCY (MHz)

1000

Figure 37. Large Signal Frequency Responses at Various Capacitive Loads

While high frequency peaking is desirable in some cable

equalization applications, it should be implemented using

methods that do not compromise the stability of the driver and

that do not depend on amplifier parasitic elements. The parasitic

elements are affected by process variations and cannot be

depended upon for circuit designs. The amplifier may break

into oscillation when excess load capacitance is intentionally

added. For more information on this topic, see the Adding Pre-

Emphasis to the AD8148 section for a description on how to

introduce a controlled amount of pre-emphasis for 30 meters of

UTP using the AD8148.

Rev. 0 | Page 20 of 24

1...17 18 192021 22 23 24

中文翻译

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AD8148ACPZ-R7 替代型号

型号	品牌	替代类型	描述	数据表
AD8148ACPZ-RL	ADI	完全替代	Triple Differential Driver for Wideband Video
AD8148ACPZ-R2	ADI	完全替代	Triple Differential Driver for Wideband Video

与AD8148ACPZ-R7相关器件

型号	品牌	获取价格	描述	数据表
AD8148ACPZ-R71	ADI	获取价格	IC 1 CHANNEL, VIDEO AMPLIFIER, QCC24, 4 X 4 MM, ROHS COMPLIANT, MO-220VGGD-2, LFCSP-24, Au
AD8148ACPZ-REEL	ADI	获取价格	IC,DIFFERENTIAL AMPLIFIER,TRIPLE,BIPOLAR,LLCC,24PIN,PLASTIC
AD8148ACPZ-REEL7	ADI	获取价格	IC,DIFFERENTIAL AMPLIFIER,TRIPLE,BIPOLAR,LLCC,24PIN,PLASTIC
AD8148ACPZ-RL	ADI	获取价格	Triple Differential Driver for Wideband Video
AD8148ACPZ-RL1	ADI	获取价格	IC 1 CHANNEL, VIDEO AMPLIFIER, QCC24, 4 X 4 MM, ROHS COMPLIANT, MO-220VGGD-2, LFCSP-24, Au
AD8148ACPZ-RL2	ADI	获取价格	IC,DIFFERENTIAL AMPLIFIER,TRIPLE,BIPOLAR,LLCC,24PIN,PLASTIC
AD815	ADI	获取价格	High Output Current Differential Driver
AD815_05	ADI	获取价格	High Output Current Differential Driver
AD8150	ADI	获取价格	33 x 17, 1.5 Gbps Digital Crosspoint Switch
AD8150AST	ADI	获取价格	33 x 17, 1.5 Gbps Digital Crosspoint Switch

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