VRE4100 데이터 시트보기 (PDF) - Cirrus Logic
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VRE4100 Datasheet PDF : 8 Pages
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VRE4100
Product Innova tionFrom
For example a designer who needs a 14-bit accurate data acquisition system over the industrial temperature range
(-40ºC to +85ºC), will need a voltage reference with a temperature coefficient (TC) of 1.0ppm/ºC if the reference is
allowed to contribute an error equivalent to 1LSB. The required reference TC vs. ∆T change from 25ºC for resolution
ranging from 8 bits to 20 bits is shown below.
10000
1000
100
8 BIT
10
10 BIT
12 BIT
1
14 BIT
16 BIT
0.1
18 BIT
0.01
1
20 BIT
10
100
Reference TC vs. ∆T change from 25°C for 1 LSB change
4. OPERATIONAL NOTES
Input Capacitor
An input capacitor is recommended for the VRE4112/VRE4125/VRE4141. A supply bypass capacitor on the input
will assure that the reference is working from a low impedance source which will improve stability. It can improve
the transient response when the load current is suddenly increased.
Output Capacitor
This series requires a 1 μF output capacitor for loop stabilization (compensation) as well as transient response.
When the load current changes, the output capacitor must source or sink current during the time it takes the control
loop of the device to respond.
The output capacitor must meet the requirements of minimum capacitance and equivalent series resistance (ESR)
range. See Capacitor Selection below.
Capacitor Selection
A minimum value of 0.2 μF over the operating temperature range is recommended. For a 0.22 μF capacitor the ESR
range for 0°C to +70°C is 0.9 to 6.0; 1.0 μF is 0.8 to 6.0; and 10 μF is 0.4 to 7.0.
Surface mount tantalum capacitors offer small size for the value and ESR in the range required for this series. The
optimum performance for the output capacitor is achieved with a 1.0 μF value.
Aluminum electrolytic capacitors have a relatively large size for the value. They meet the ESR requirements at 1.0
μF as long as the temperature is above 0°C. Below 0°C, the ESR increases and it may exceed the limits indicated
in the figures.
Multilayer ceramic capacitors have a small size for the value, are available in surface mount, and have excellent
RF characteristics. They may not meet the minimum ESR requirements and have a large change in value with
temperature.
VRE4100DS
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