Electronic Components Datasheet Search
  English  ▼

Delete All
ON OFF
ALLDATASHEET.COM

X  

Preview PDF Download HTML

AD5171 Datasheet(PDF) 13 Page - Analog Devices

Part No. AD5171
Description  64-Position OTP Digital Potentiometer
Download  20 Pages
Scroll/Zoom Zoom In 100% Zoom Out
Maker  AD [Analog Devices]
Homepage  http://www.analog.com
Logo AD - Analog Devices

AD5171 Datasheet(HTML) 13 Page - Analog Devices

Back Button AD5171 Datasheet HTML 9Page - Analog Devices AD5171 Datasheet HTML 10Page - Analog Devices AD5171 Datasheet HTML 11Page - Analog Devices AD5171 Datasheet HTML 12Page - Analog Devices AD5171 Datasheet HTML 13Page - Analog Devices AD5171 Datasheet HTML 14Page - Analog Devices AD5171 Datasheet HTML 15Page - Analog Devices AD5171 Datasheet HTML 16Page - Analog Devices AD5171 Datasheet HTML 17Page - Analog Devices Next Button
Zoom Inzoom in Zoom Outzoom out
 13 / 20 page
background image
AD5171
TERMINAL VOLTAGE OPERATING RANGE
There are also ESD protection diodes between VDD and the
RDAC terminals. The VDD of AD5171 therefore defines their
voltage boundary conditions, see Figure 29. Supply signals
present on terminals A, B, and W that exceed VDD will be
clamped by the internal forward-biased diodes and should be
avoided.
GND
A
W
B
VDD
Figure 29. Maximum Terminal Voltages Set by VDD
POWER-UP/POWER-DOWN SEQUENCES
Similarly, because of the ESD protection diodes, it is important
to power VDD first before applying any voltages to terminals A,
B, and W. Otherwise, the diode will be forward-biased such that
VDD will be powered unintentionally and may affect the rest of
the users’ circuits. The ideal power-up sequence is in the
following order: GND, VDD, digital inputs, and VA/VB/VW. The
order of powering VA, VB, VW, and digital inputs is not
important as long as they are powered after VDD. Similarly, VDD
should be powered down last.
POWER SUPPLY CONSIDERATIONS
To minimize the package pin count, both the one-time
programming and normal operating voltages are applied to the
same VDD terminal of the AD5171. The AD5171 employs fuse
link technology that requires 6 V to blow the internal fuses to
achieve a given setting. On the other hand, it operates at 2.7 V to
5.5 V once the programming is complete. Such dual voltage
requires isolation between supplies. The fuse programming
supply (either an on-board regulator or rack-mount power
supply) must be rated at 6 V and be able to handle 400 ms and
100 mA of transient current for one-time programming. Once
programming is complete, the 6 V supply must be removed to
allow normal operation of 2.7 V to 5.5 V. Figure 30 shows the
simplest implementation using a jumper. This approach saves
one voltage supply, but draws additional current and requires
manual configuration.
AD5171
VDD
C2
0.1
µF
5V
CONNECT J1
HERE FOR OTP
C1
1
µF
J1
R1
50k
R2
250k
6V
CONNECT J1
HERE AFTER OTP
Figure 30. Power Supply Requirement
An alternate approach in 3.5 V to 5.5 V systems adds a signal
diode between the system supply and the OPT supply for
isolation, as shown in Figure 31.
AD5171
VDD
C2
0.1
µF
APPLY FOR OTP ONLY
C1
10
µF
D1
3.5V–5.5V
6V
Figure 31. Isolating the 6 V OPT Supply from the 3.5V to 5.5 V Normal
Operating Supply. The 6 V supply must be removed once OPT is complete.
AD5171
VDD
C2
0.1
µF
APPLY FOR OTP ONLY
C1
10
µF
10k
2.7V
6V
P1
P2
R1
P1 = P2 = FDV302P, NDS0610
Figure 32. Isolating the 6 V OPT Supply from the 2.7 V Normal Operating
Supply. The 6 V supply must be removed once OPT is complete.
For users who operate their systems at 2.7 V, it is recommended
to use the bi-directional low-threshold P-Ch MOSFETs for the
supplies isolation. As shown in Figure 32 assumes the 2.7 V
system voltage is applied first but not the 6 V. The gates of P1
are P2 are pulled to ground, which turns on P1 and subse-
quently P2. As a result, VDD of AD5171 becomes 2.7 V minus a
few tenths of mV drop across P1 and P2. When the AD5171
setting is found, the factory tester applies the 6 V to VDD and
also to the gates of P1 and P2 to turn them off. While the OTP
command is executing at this time to program AD5171, the
2.7 V source is therefore protected. Once the OTP is complete,
the tester withdraws the 6 V, and AD5171 setting is permanently
fixed.
Rev. PrC | Page 13 of 20
Preliminary Technical Data


Html Pages

1  2  3  4  5  6  7  8  9  10  11  12  13  14  15  16  17  18  19  20 


Datasheet Download

Go To PDF Page


Link URL




Privacy Policy
ALLDATASHEET.COM
Does ALLDATASHEET help your business so far?  [ DONATE ]  

About Alldatasheet   |   Advertisement   |   Datasheet Upload   |   Contact us   |   Privacy Policy   |   Alldatasheet API   |   Link Exchange   |   Manufacturer List
All Rights Reserved© Alldatasheet.com


Mirror Sites
English : Alldatasheet.com  |   English : Alldatasheet.net  |   Chinese : Alldatasheetcn.com  |   German : Alldatasheetde.com  |   Japanese : Alldatasheet.jp
Russian : Alldatasheetru.com  |   Korean : Alldatasheet.co.kr  |   Spanish : Alldatasheet.es  |   French : Alldatasheet.fr  |   Italian : Alldatasheetit.com
Portuguese : Alldatasheetpt.com  |   Polish : Alldatasheet.pl  |   Vietnamese : Alldatasheet.vn