參數資料
型號: AD548KNZ
廠商: Analog Devices Inc
文件頁數: 11/12頁
文件大小: 0K
描述: IC OPAMP GP 1MHZ LP PREC 8DIP
標準包裝: 50
放大器類型: 通用
電路數: 1
轉換速率: 1.8 V/µs
增益帶寬積: 1MHz
電流 - 輸入偏壓: 30pA
電壓 - 輸入偏移: 300µV
電流 - 電源: 170µA
電流 - 輸出 / 通道: 15mA
電壓 - 電源,單路/雙路(±): ±4.5 V ~ 18 V
工作溫度: 0°C ~ 70°C
安裝類型: 通孔
封裝/外殼: 8-DIP(0.300",7.62mm)
供應商設備封裝: 8-PDIP
包裝: 管件
產品目錄頁面: 773 (CN2011-ZH PDF)
AD548
–8–
REV. D
Figure 2. Board Layout for Guarding Inputs
INPUT PROTECTION
The AD548 is guaranteed to withstand input voltages equal to
the power supply potential. Exceeding the negative supply volt-
age on either input will forward bias the substrate junction of
the chip. The induced current may destroy the amplifier due to
excess heat.
Input protection is required in applications such as a flame
detector in a gas chromatograph, where a very high potential
may be applied to the input terminals during a sensor fault
condition. Figure 3 shows a simple current limiting scheme that
can be used. RPROTECT should be chosen such that the maxi-
mum overload current is 1.0 mA (l00 k
for a 100 V overload,
for example).
Exceeding the negative common-mode range on either input
terminal causes a phase reversal at the output, forcing the
amplifier output to the corresponding high or low state. Exceed-
ing the negative common-mode on both inputs simultaneously
forces the output high. Exceeding the positive common-mode
range on a single input does not cause a phase reversal, but if
both inputs exceed the limit the output will be forced high. In
all cases, normal amplifier operation is resumed when input
voltages are brought back within the common-mode range.
Figure 3. Input Protection of IV Converter
D/A CONVERTER OUTPUT BUFFER
The circuit in Figure 4 shows the AD548 and AD7545 12-bit
CMOS D/A converter in a unipolar binary configuration. VOUT
will be equal to VREF attenuated by a factor depending on the
digital word. VREF sets the full scale. Overall gain is trimmed by
adjusting RIN. The AD548’s low input offset voltage, low drift,
and clean dynamics make it an attractive low power output buffer.
The input offset voltage of the AD548 output amplifier results
in an output error voltage. This error voltage equals the input
offset voltage of the op amp times the noise gain of the amplifier.
Figure 4. AD548 Used as DAC Output Amplifier
That is:
VOS Output
=V
OS Input
1
+
RFB
RO
RFB is the feedback resistor for the op amp, which is internal to
the DAC. RO is the DAC’s R-2R ladder output resistance. The
value of RO is code dependent. This has the effect of changing
the offset error voltage at the amplifier’s output. An output
amplifier with a sub millivolt input offset voltage is needed to
preserve the linearity of the DAC’s transfer function.
The AD548 in this configuration provides a 700 kHz small
signal bandwidth and 1.8 V/
s typical slew rate. The 33 pF
capacitor across the feedback resistor optimizes the circuit’s
response. The oscilloscope charts in Figures 5 and 6 show small
and large signal outputs of the circuit in Figure 4. Upper traces
show the input signal VIN. Lower traces are the resulting output
voltage with the DAC’s digital input set to all 1s. The AD548
settles to
±0.01% for a 20 V input step in 14 s.
0%
10
5V
5S
20V
100
90
Figure 5. Response to
±20 V p-p Reference Square Wave
0%
10
50mV
2S
200mV
100
90
Figure 6. Response to
±100 mV p-p Reference Square Wave
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相關代理商/技術參數
參數描述
AD548KNZ 制造商:Analog Devices 功能描述:Operational Amplifier (Op-Amp) IC 制造商:Analog Devices 功能描述:IC, OP-AMP, 1MHZ, 1.8V/ us, DIP-8
AD548KR 制造商:Rochester Electronics LLC 功能描述:LOW POWER BIFET OP AMP IC - Bulk
AD548KR-REEL 制造商:AD 制造商全稱:Analog Devices 功能描述:Precision, Low Power BiFET Op Amp
AD548S 制造商:AD 制造商全稱:Analog Devices 功能描述:Precision, Low Power BiFET Op Amp
AD548SH 制造商:AD 制造商全稱:Analog Devices 功能描述:Precision, Low Power BiFET Op Amp