AD7741BRZ Analog Devices Inc, AD7741BRZ Datasheet - Page 8
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AD7741BRZ
Manufacturer Part Number
AD7741BRZ
Description
IC CONVERTER V TO FREQ 8-SOIC
Manufacturer
Analog Devices Inc
Type
Voltage to Frequencyr
Datasheet
1.AD7741BRZ.pdf
(12 pages)
Specifications of AD7741BRZ
Frequency - Max
3.072MHz
Full Scale
±50ppm/°C
Linearity
±0.012%
Mounting Type
Surface Mount
Package / Case
8-SOIC (0.154", 3.90mm Width)
Frequency
2.75MHz
Full Scale Range
3.072MHz
Linearity %
0.01%
Supply Voltage Range
4.75V To 5.25V
Digital Ic Case Style
SOIC
No. Of Pins
8
Msl
MSL 3 - 168 Hours
Frequency Max
6.144MHz
Converter Function
VFC
Full Scale Frequency
1350
Power Supply Requirement
Single
Single Supply Voltage (typ)
5V
Single Supply Voltage (max)
5.25V
Single Supply Voltage (min)
4.75V
Dual Supply Voltage (typ)
Not RequiredV
Dual Supply Voltage (min)
Not RequiredV
Dual Supply Voltage (max)
Not RequiredV
Operating Temperature (min)
-40C
Operating Temperature (max)
85C
Operating Temperature Classification
Industrial
Package Type
SOIC N
Lead Free Status / RoHS Status
Lead free / RoHS Compliant
For Use With
EVAL-AD7741/42EBZ - BOARD EVAL FOR AD7741/7742
Lead Free Status / Rohs Status
Compliant
Available stocks
Company
Part Number
Manufacturer
Quantity
Price
Part Number:
AD7741BRZ
Manufacturer:
ADI/亚德诺
Quantity:
20 000
Company:
Part Number:
AD7741BRZ-REEL7
Manufacturer:
AD
Quantity:
3 400
AD7741/AD7742
UNI/BIP
N/A
0
0
1
1
As can be seen from Table II, the AD7741 has one input range
configuration whereas the AD7742 has unipolar/bipolar as
well as gain options depending on the status of the GAIN
and UNI/BIP pins.
The transfer function for the AD7741 is shown in Figure 3.
Figure 4 shows the AD7742 transfer function for unipolar input
range configuration while the AD7742 transfer function for
bipolar input range configuration is shown in Figure 5.
Figure 3. AD7741 Transfer Characteristic for Input Range
from 0 to V
Figure 4. AD7742 Transfer Characteristic for Unipolar
Differential Input Range: 0 V to V
common-mode range must be between +0.5 V and
V
DD
FREQUENCY
(0.05 f
(0.45 f
– 1.75 V. UNI/ BIP pin tied to V
FREQUENCY
(0.05 f
OUTPUT
f
f
(0.45 f
OUT
OUT
OUTPUT
f
f
f
OUT
OUT
OUT
f
CLKIN
MIN
OUT
MAX
CLKIN
CLKIN
MIN
MAX
CLKIN
REF
)
)
)
)
0
0
GAIN
N/A
0
1
0
1
+
GAIN
V
REFIN
REF
Gain, G
X1
X1
X2
X1
X2
DD
REF
.
/Gain; the input
Table II. AD7741/AD7742 Input Range Selection
INPUT VOLTAGE
DIFFERENTIAL
VOLTAGE V
INPUT
IN
V
f
0
–V
–V
0
0
OUT
IN
REF
REF
(Min)
= 0.05 f
/2
–8–
VFC Modulator
The analog input signal to the AD7741/AD7742 is continu-
ously sampled by a switched capacitor modulator whose sam-
pling rate is set by a master clock input that may be supplied
externally or by a crystal-controlled on-chip clock oscillator.
However, the input signal is buffered on-chip before being ap-
plied to the sampling capacitor of the modulator. This isolates
the sampling capacitor charging currents from the analog input
pins.
This system is a negative feedback loop that tries to keep the net
charge on the integrator capacitor at zero, by balancing charge
injected by the input voltage with charge injected by the V
The output of the comparator provides the digital input for the
1-bit DAC, so that the system functions as a negative feedback
loop that tries to minimize the difference signal (see Figure 6).
CLKIN
Figure 5. AD7742 Transfer Characteristic for Bipolar
Differential Input Range: –V
common-mode range must be between +0.5 V and
V
DD
INPUT
– 1.75 V. UNI/ BIP pin tied to GND.
Figure 6. AD7741/AD7742 Modulator Loop
–
+
–
GAIN
V
FREQUENCY
REF
(0.45 f
OUTPUT
f
OUT
f
INTEGRATOR
OUT
MAX
CLKIN
V
f
+V
+V
+V
+V
+V
OUT
IN
)
REF
REF
REF
REF
REF
(Max)
+V
–V
(0.05 f
= 0.45 f
REF
REF
f
/2
/2
OUT
COMPARATOR
REF
CLKIN
MIN
+
/Gain to +V
CLKIN
GAIN
)
V
REF
+
–
CLK
INPUT VOLTAGE
DIFFERENTIAL
REF
/Gain; the
STREAM
1-BIT
Part
AD7741
AD7742
AD7742
AD7742
AD7742
REV. 0
REF
.