ADA4692-2ARZ(RevA) Просмотр технического описания (PDF) - Analog Devices
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производитель
ADA4692-2ARZ
(Rev.:RevA)
(Rev.:RevA)
Analog Devices
ADA4692-2ARZ Datasheet PDF : 16 Pages
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SHUTDOWN OPERATION
INPUT PIN CHARACTERISTICS
The ADA4691-2 has a classic CMOS logic inverter input for
each shutdown pin, as shown in Figure 50.
VDD
INPUT
P-CHANNEL
OUTPUT
N-CHANNEL
Figure 50. CMOS Inverter
With slowly changing inputs, the top transistor and bottom
transistor may be slightly on at the same time, increasing the
supply current. This can be avoided by driving the input with a
digital logic output having fast rise and fall times. Figure 51
through Figure 53 show the supply current for both sections
switching simultaneously with rise times of 1 μs, 10 μs, and
1 ms. Clearly, the rise and fall times should be faster than 10 us.
Using an RC time constant to enable/disable shutdown is not
recommended.
ISY = 196mV/1k = 196µA
SDA, B
DUT OUTPUT
TIME (400µs/DIV)
Figure 51. Shutdown Pin Rise Time = 1 μs
ISY = 192mV/1k = 196µA
SDA, B
DUT OUTPUT
TIME (400µs/DIV)
Figure 52. Shutdown Pin Rise Time = 10 μs
ADA4691-2/ADA4692-2
SDA, B
ISY = 724mV/1k = 724µA
DUT OUTPUT
TIME (400µs/DIV)
Figure 53. Shutdown Pin Rise Time = 1 ms
INPUT THRESHOLD
The input threshold is approximately 1.2 V above the V− pin
when operating on ground and +5 V, and 0.9 V when operating
on 2.7 V (see Figure 54 and Figure 55). The threshold is rela-
tively stable over temperature. For operation on split supplies,
the logic swing may have to be level shifted.
500
ADA4691-2
450 TA = 25°C
VSY = 5V
400
350
300
TA = +125°C
TA = +85°C
250
200
150
100
TA = –40°C
TA = +25°C
50
0
0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0
SD VOLTAGE (V)
Figure 54. Supply Current vs. Temperature, VSY = 5 V
300
ADA4691-2
VSY = 2.7V
250
200
TA = +125°C
TA = +85°C
150
100
TA = –40°C
TA = +25°C
50
0
0 0.3 0.6 0.9 1.2 1.5 1.8 2.1 2.4 2.7
SD VOLTAGE (V)
Figure 55. Supply Current vs. Temperature, VSY = 2.7 V
Rev. A | Page 15 of 16
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