ADR421BR-REEL7 Analog Devices Inc, ADR421BR-REEL7 Datasheet - Page 20

• Manufacturer Part Number: ADR421BR-REEL7
• Description: IC,VOLT REFERENCE,FIXED,2.5V,SOP,8PIN,PLASTIC
• Manufacturer: Analog Devices Inc
• Series: XFET®r

Specifications of ADR421BR-REEL7

• Package / Case: 8-SOIC (3.9mm Width)
• Mounting Type: Surface Mount
• Current - Output: 10mA
• Voltage - Output: 2.5V
• Voltage - Input: 4.5 ~ 18 V
• Operating Temperature: -40°C ~ 125°C
• Temperature Coefficient: 3ppm/°C
• Tolerance: ±0.04%
• Number Of Channels: 1
• Reference Type: Series
• Current - Quiescent: 500µA
• Current - Cathode: -

ADR420/ADR421/ADR423/ADR425
PRECISION VOLTAGE REFERENCE FOR DATA
CONVERTERS
The ADR42x family has a number of features that make it ideal
for use with ADCs and DACs. The exceptionally low noise,
tight temperature coefficient, and high accuracy characteristics
make the ADR42x ideal for low noise applications such as
cellular base station applications.
AD7701
ADR42x. The ADR421 is used as the precision reference for
the converter in Figure 49. The AD7701 is a 16-bit ADC with
on-chip digital filtering intended for measuring wide dynamic
range and low frequency signals, such as those representing
chemical, physical, or biological processes. It contains a charge-
balancing (Σ-Δ) ADC, calibration microcontroller with on-chip
static RAM, clock oscillator, and serial communications port.
ANALOG
SUPPLY
CALIBRATE
ANALOG
GROUND
RANGES
ANALOG
ANALOG
SUPPLY
+5V
SELECT
INPUT
–5V
0.1µF
is an example of an ADC that is well suited for the
0.1µF
Figure 49. Voltage Reference for 16-Bit ADC AD7701
0.1µF
10µF
ADR420/
ADR421/
ADR423/
ADR425
10µF
GND
V
0.1µF
IN
V
OUT
AV
V
BP/UP
CAL
A
AGND
AV
REF
IN
DD
SS
AD7701
CLKOUT
SLEEP
SDATA
MODE
CLKIN
DGND
DRDY
SCLK
DV
DV
SC1
SC2
CS
DD
SS
0.1µF
DATA READY
READ (TRANSMIT)
SERIAL CLOCK
SERIAL CLOCK
0.1µF
Rev. H | Page 20 of 24
PRECISION BOOSTED OUTPUT REGULATOR
A precision voltage output with boosted current capability
can be realized with the circuit shown in Figure 50. In this
circuit, U2 forces V
on of N1. Therefore, the load current is furnished by V
this configuration, a 50 mA load is achievable at V
Moderate heat is generated on the MOSFET, and higher current
can be achieved by replacing the larger device. In addition, for
a heavy capacitive load with step input, a buffer may be added
at the output to enhance the transient response.
V
IN
ADR421
Figure 50. Precision Boosted Output Regulator
GND
2
V
IN
U1
4
V
TRIM
OUT
OUT
6
5
to be equal to V
AD8601
+
–
5V
V+
U2
V–
2N7002
N1
REF
by regulating the turn
R
25Ω
L
IN
V
of 5 V.
OUT
IN
. In