JM3851012801BGA Datasheet, PDF (8/12 Pages) Analog Devices – Pin Programmable, Precision Voltage Reference

AD584
NOISE FILTERING
The bandwidth of the output amplifier in the AD584 can be
reduced to filter output noise. A capacitor ranging between 0.01 µF
and 0.1 µF connected between the CAP and VBG terminals further
reduces the wideband and feedthrough noise in the output of
the AD584, as shown in Figure 9 and Figure 10. However, this
tends to increase the turn-on settling time of the device; therefore,
allow for ample warm-up time.
SUPPLY
0.01µF*
TO
0.1µF
CAP
7
V_{BG 6}
V+
8
1
AD584
10.0V
4
COMMON
*INCREASES TURN-ON TIME
Figure 9. Additional Noise Filtering with an External Capacitor
1000
NOISE SPECTRAL DENSITY (nV/ Hz)
1000pF
100
0.01µF
100pF
NO CAP
NO CAP
10
TOTAL NOISE (µV rms) UP TO
SPECIFIED FREQUENCY
1
10
100
1k
10k
100k
1M
FREQUENCY (Hz)
Figure 10. Spectral Noise Density and Total RMS Noise vs. Frequency
Data Sheet
USING THE STROBE TERMINAL
The AD584 has a strobe input that can be used to zero the output.
This unique feature permits a variety of new applications in
signal and power conditioning circuits.
Figure 11 illustrates the strobe connection. A simple NPN switch
can be used to translate a TTL logic signal into a strobe of the
output. The AD584 operates normally when there is no current
drawn from Pin 5. Bringing this terminal low, to less than 200 mV,
allows the output voltage to go to zero. In this mode, the AD584
is not required to source or sink current (unless a 0.7 V residual
output is permissible). If the AD584 is required to sink a transient
current while strobe is off, limit the strobe terminal input current
by a 100 Ω resistor, as shown in Figure 11.
LOGIC ^{HI = OFF}
INPUT _{LO = ON}
100Ω
20kΩ
10kΩ
STROBE
5
V+
8
10.0V
1
AD584 ²
3
2N2222
4
COMMON
Figure 11. Use of the Strobe Terminal
The strobe terminal tolerates up to 5 µA leakage, and its driver
should be capable of sinking 500 µA continuous. A low leakage,
open collector gate can be used to drive the strobe terminal directly,
provided the gate can withstand the AD584 output voltage plus 1 V.
PERCISION HIGH CURRENT SUPPLY
The AD584 can be easily connected to a power PNP or power
PNP Darlington device to provide much greater output current
capability. The circuit shown in Figure 12 delivers a precision
10 V output with up to 4 A supplied to the load. If the load has a
significant capacitive component, the 0.1 µF capacitor is required.
If the load is purely resistive, improved high frequency, supply
rejection results from removing the capacitor.
V_IN ≥ 15V
470Ω
2N6040
V+ ^0.1µF
8
10.0V
AD584 1
4
V_OUT
10V @ 4A
COMMON
Figure 12. High Current Precision Supply
Rev. C | Page 8 of 12