REF191ESZ Analog Devices Inc, REF191ESZ Datasheet - Page 25

• Manufacturer Part Number: REF191ESZ
• Description: IC VOLT REF LDO 2.048V 8SOIC
• Manufacturer: Analog Devices Inc
• Series: REF19r
• Type: Voltage Referencer

Specifications of REF191ESZ

• Temperature Coefficient: 5ppm/°C
• Reference Type: Series
• Voltage - Output: 2.048V
• Tolerance: ±2mV
• Voltage - Input: 3 ~ 15 V
• Number Of Channels: 1
• Current - Quiescent: 45µA
• Current - Output: 30mA
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SOIC (3.9mm Width)
• Topology: Series
• Input Voltage: 3V To 15V
• Reference Voltage: 2.048V
• Reference Voltage Tolerance: 2mV
• Voltage Reference Case Style: SOIC
• No. Of Pins: 8
• Current, Output: 30 mA
• Current, Supply: 45 μA
• Package Type: SOIC-8
• Regulation, Line: 5 ppm/V
• Regulation, Load: 5 ppm/mA
• Regulator Type: Low Dropout
• Resistance, Thermal, Junction To Case: 43 °C/W
• Temperature, Operating, Range: -40 to +85 °C
• Voltage, Dropout: 1.25 V
• Voltage, Noise: 20 μVp-p
• Voltage, Output: 2.048 V
• Voltage, Supply: 3.3 V
• Fixed / Adjust / Prog: Precision
• Output Voltage (max): 2.048V
• Reference Voltage Accuracy (max): 2
• Line Regulation: 4ppm/V
• Load Regulation: 10ppm/mA
• Input Voltage (max): 18V
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 8
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Current - Cathode: -
• Lead Free Status / Rohs Status: RoHS Compliant part Electrostatic Device

For V
low, thus U2 and Q1 are off and U1 is on. For V
than the upper threshold, the situation reverses, with U1 off and
both U2 and Q1 on. In the interest of battery power conserva-
tion, all of the comparison switching circuitry is powered from
V
comes from U1.
For the R1 to R3 values, as shown in Figure 32, lower/upper V
switching thresholds are approximately 5.5 V and 6 V, respec-
tively. These can be changed to suit other V
REF19x devices used for U1 and U2, over a range of 2.5 V to
5 V of output. U3 can operate down to a V
generally compatible with all REF19x family devices.
LOW POWER, STRAIN GAGE CIRCUIT
As shown in Figure 33, the REF19x family of references can be
used in conjunction with low supply voltage operational ampli-
fiers, such as the OP492 or the OP747, in a self-contained strain
gage circuit in which the REF195 is used as the core. Other
references can be easily accommodated by changing circuit
element values. The references play a dual role, first as the
voltage regulator to provide the supply voltage requirements of
the strain gage and the operational amplifiers, and second as a
precision voltage reference for the current source used to
stimulate the bridge. A distinct feature of the circuit is that it
can be remotely controlled on or off by digital means via
the SLEEP pin.
S
and is arranged so that when V
S
levels lower than the lower threshold, the output of U3 is
COMMON
V
S
+V
, V
+V
BAT
BAT
S
S
fails, the default output
R1
1.1MΩ
R2
100kΩ
C4
0.1µF
10MΩ
S
S
R3
of 3.3 V, which is
supplies, as can the
R5
100kΩ
3
2
S
+
–
levels higher
7
4
AD820
U3
6
Figure 32. Fail-Safe 5 V Reference
900kΩ
100Ω
R6
R4
S
Rev. K | Page 25 of 28
Q1
2N3904
0.1µF
C2
10μF
2.21kΩ
C1
0.1µF
+
3
3
0.1μF
(SEE TABLE)
(SEE TABLE)
2
REF195
REF195
REF195
U1
U2
2
4
2
4
13
12
10
4
9
10kΩ
1%
Figure 33. Low Power, Strain Gage Circuit
OP492
OP492
–
+
–
+
1/4
1/4
6
6
10kΩ
10kΩ
6
57kΩ
1%
1%
1%
3
2
+
1μF
+
OP492
–
14
1/4
8
11
4
+
C3
1µF
0.1μF
100Ω
20kΩ
20kΩ
1%
1%
5.000V
V
COMMON
OUT
1
20kΩ
1%
2N2222
0.01μF
6
5
500Ω
0.1%
–
OP492
+
1/4
REF19x Series
10μF
20kΩ
1%
7
OUTPUT