AD5235BRU250-RL7 Analog Devices Inc, AD5235BRU250-RL7 Datasheet

AD5235BRU250-RL7

Manufacturer Part Number
AD5235BRU250-RL7
Description
Manufacturer
Analog Devices Inc
Datasheet

Specifications of AD5235BRU250-RL7

Number Of Elements
2
# Of Taps
1024
Resistance (max)
250KOhm
Power Supply Requirement
Single/Dual
Interface Type
Serial (4-Wire/SPI)
Single Supply Voltage (typ)
3.3/5V
Dual Supply Voltage (typ)
±2.5V
Single Supply Voltage (min)
3V
Single Supply Voltage (max)
5.5V
Dual Supply Voltage (min)
±2.25V
Dual Supply Voltage (max)
±2.75V
Operating Temp Range
-40C to 85C
Operating Temperature Classification
Industrial
Mounting
Surface Mount
Pin Count
16
Lead Free Status / RoHS Status
Not Compliant
FEATURES
Dual-channel, 1024-position resolution
25 kΩ, 250 kΩ nominal resistance
Low temperature coefficient: 35 ppm/°C
Nonvolatile memory stores wiper settings
Permanent memory write protection
Wiper setting readback
Resistance tolerance stored in EEMEM
Predefined linear increment/decrement instructions
Predefined ±6 dB/step log taper increment/decrement
SPI-compatible serial interface
3 V to 5 V single supply or ±2.5 V dual supply
26 bytes extra nonvolatile memory for user-defined
100-year typical data retention, T
Power-on refreshed with EEMEM settings
APPLICATIONS
DWDM laser diode driver, optical supervisory systems
Mechanical potentiometer replacement
Instrumentation: gain, offset adjustment
Programmable voltage-to-current conversion
Programmable filters, delays, time constants
Programmable power supply
Low resolution DAC replacement
Sensor calibration
GENERAL DESCRIPTION
The AD5235 is a dual-channel, nonvolatile memory,
controlled potentiometer
performs the same electronic adjustment function as a mechanical
potentiometer with enhanced resolution, solid state reliability,
and superior low temperature coefficient performance. The
versatile programming of the AD5235 via an SPI®-compatible
serial interface allows 16 modes of operation and adjustment
including scratchpad programming, memory storing and restoring,
increment/decrement, ±6 dB/step log taper adjustment, wiper
setting readback, and extra EEMEM
such as memory data for other components, look-up table, or
system identification information.
1
2
Rev. C
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
The terms nonvolatile memory and EEMEM are used interchangeably.
The terms digital potentiometer and RDAC are used interchangeably.
instructions
information
2
with 1024-step resolution. The device
1
A
for user-defined information
= 55°C
1
digitally
1024-Position Digital Potentiometer
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
In the scratchpad programming mode, a specific setting can
be programmed directly to the RDAC
resistance between Terminal W and Terminal A and Terminal W
and Terminal B. This setting can be stored into the EEMEM
and is restored automatically to the RDAC register during
system power-on.
The EEMEM content can be restored dynamically or through
external PR strobing, and a WP function protects EEMEM
contents. To simplify the programming, the independent or
simultaneous linear-step increment or decrement commands
can be used to move the RDAC wiper up or down, one step at a
time. For logarithmic ±6 dB changes in the wiper setting, the
left or right bit shift command can be used to double or halve the
RDAC wiper setting.
The AD5235 patterned resistance tolerance is stored in the
EEMEM. The actual end-to-end resistance can, therefore, be
known by the host processor in readback mode. The host can
execute the appropriate resistance step through a software
routine that simplifies open-loop applications as well as
precision calibration and tolerance matching applications.
The AD5235 is available in a thin, 16-lead TSSOP package. The
part is guaranteed to operate over the extended industrial
temperature range of −40°C to +85°C.
CLK
SDO
*RAB TOLERANCE
RDY
SDI
WP
CS
PR
POWER-ON
CONTROL
Nonvolatile Memory, Dual
EEMEM
INTERFACE
RESET
SERIAL
FUNCTIONAL BLOCK DIAGRAM
DECODE
ADDR
©2004–2009 Analog Devices, Inc. All rights reserved.
RTOL*
USER EEMEM
Figure 1.
26 BYTES
REGISTER
REGISTER
EEMEM1
EEMEM2
RDAC1
RDAC2
2
register, which sets the
AD5235
RDAC2
RDAC1
AD5235
www.analog.com
A2
W2
B2
GND
V
A1
W1
B1
V
DD
SS

Related parts for AD5235BRU250-RL7

AD5235BRU250-RL7 Summary of contents

Page 1

FEATURES Dual-channel, 1024-position resolution 25 kΩ, 250 kΩ nominal resistance Low temperature coefficient: 35 ppm/°C Nonvolatile memory stores wiper settings Permanent memory write protection Wiper setting readback Resistance tolerance stored in EEMEM Predefined linear increment/decrement instructions Predefined ±6 dB/step log ...

Page 2

AD5235 TABLE OF CONTENTS Features .............................................................................................. 1 Applications ....................................................................................... 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications ..................................................................................... 3 Electrical Characteristics—25 kΩ, 250 kΩ Versions ............... 3 Interface Timing and EEMEM Reliability Characteristics—25 ...

Page 3

SPECIFICATIONS ELECTRICAL CHARACTERISTICS—25 kΩ, 250 kΩ VERSIONS 5 2 operated at 2.7 V single supply, except from 0°C to −40°C, where a minimum ...

Page 4

AD5235 Parameter 7 EEMEM Restore Mode Current Power Dissipation 8 5 Power Supply Sensitivity DYNAMIC CHARACTERISTICS 5, 9 Bandwidth Total Harmonic Distortion V Settling Time W Resistor Noise Density Crosstalk ( Analog Crosstalk 1 Typicals represent ...

Page 5

INTERFACE TIMING AND EEMEM RELIABILITY CHARACTERISTICS—25 kΩ, 250 kΩ VERSIONS Guaranteed by design and not subject to production test. See the Timing Diagrams section for the location of measured values. All input control voltages are specified with ...

Page 6

AD5235 Timing Diagrams CLK CPOL = 1 HIGH OR LOW SDI t 8 B24* SDO t 14 RDY *THE EXTRA BIT THAT IS NOT DEFINED IS NORMALLY THE LSB OF THE CHARACTER PREVIOUSLY TRANSMITTED. THE CPOL = ...

Page 7

ABSOLUTE MAXIMUM RATINGS T = 25°C, unless otherwise noted. A Table 3. Parameter V to GND GND GND ...

Page 8

AD5235 PIN CONFIGURATION AND FUNCTION DESCRIPTIONS Table 4. Pin Function Descriptions Pin No. Mnemonic Description 1 CLK Serial Input Register Clock. Shifts in one bit at a time on positive clock edges. 2 SDI Serial Data Input. Shifts in one ...

Page 9

TYPICAL PERFORMANCE CHARACTERISTICS 1.0 0.8 0.6 0.4 0.2 0 –0.2 –0.4 –0.6 –0.8 –1.0 0 200 400 600 DIGITAL CODE Figure 5. INL vs. Code −40°C, +25°C, +85°C Overlay 1.0 0.8 0.6 0.4 0.2 0 –0.2 ...

Page 10

AD5235 25° 200 400 600 CODE (Decimal) Figure 11. Wiper On Resistance vs. Code ...

Page 11

CODE 0x200 –10 0x100 0x080 –20 0x040 0x020 –30 0x010 –40 0x008 0x004 –50 0x002 0x001 –60 1k 10k 100k FREQUENCY (Hz) Figure 17. Gain vs. Frequency vs. Code 250 kΩ (See Figure 31 ...

Page 12

AD5235 5V/DIV 5V/DIV 5V/DIV 4ms/DIV *SUPPLY CURRENT RETURNS TO MINIMUM POWER CONSUMPTION, IF INSTRUCTION 0 (NOP) IS EXECUTED IMMEDIATELY AFTER INSTRUCTION 1 (READ EEMEM). Figure 23. I vs. Time when Restoring Data from EEMEM DD TEST CIRCUITS Figure 25 to ...

Page 13

DUT OP42 B OFFSET GND 2.5V –15V Figure 31. Gain vs. Frequency 0. DUT I SW CODE = 0x00 0. – ...

Page 14

AD5235 THEORY OF OPERATION The AD5235 digital potentiometer is designed to operate as a true variable resistor. The resistor wiper position is determined by the RDAC register contents. The RDAC register acts as a scratchpad register, allowing unlimited changes of ...

Page 15

EEMEM PROTECTION The write protect ( WP ) pin disables any changes to the scratchpad register contents, except for the EEMEM setting, which can still be restored using Instruction 1, Instruction 8, and the PR pulse. Therefore, WP can be ...

Page 16

AD5235 When two AD5235s are daisy-chained, 48 bits of data are required. The first 24 bits (formatted 4-bit command, 4-bit address, and 16-bit data U2, and the second 24 bits with the same format go to U1. Keep ...

Page 17

In Table 6, command bits are C0 to C3, address bits are A0 to A3, Data Bit D0 to Data Bit D9 are applicable to RDAC, and D0 to D15 are applicable to EEMEM. Table 6. 24-Bit Serial Data-Word MSB ...

Page 18

AD5235 ADVANCED CONTROL MODES The AD5235 digital potentiometer includes a set of user programming features to address the wide number of applications for these universal adjustment devices. Key programming features include the following: • Scratchpad programming to any desirable values ...

Page 19

Using CS to Re-Execute a Previous Command Another subtle feature of the AD5235 is that a subsequent CS strobe, without clock and data, repeats a previous command. Using Additional Internal Nonvolatile EEMEM The AD5235 contains additional user EEMEM registers for ...

Page 20

AD5235 PROGRAMMING THE VARIABLE RESISTOR Rheostat Operation The nominal resistance of the RDAC between Terminal A and Terminal available with 25 kΩ and 250 kΩ with AB 1024 positions (10-bit resolution). The final digits of the ...

Page 21

Because the AD5235 can also be supplied by dual supplies, the general equation defining the output voltage ground for any given input voltages applied to Terminal A and Terminal × ...

Page 22

AD5235 APPLICATIONS INFORMATION BIPOLAR OPERATION FROM DUAL SUPPLIES The AD5235 can be operated from ±2.5 V dual supplies, which enable control of ground referenced ac signals or bipolar operation. AC signals as high as V and V can be applied ...

Page 23

BIPOLAR PROGRAMMABLE GAIN AMPLIFIER For applications requiring bipolar gain, Figure 49 shows one implementation. Digital Potentiometer U1 sets the adjustment range; the wiper voltage (V ) can, therefore, be programmed W2 between V and − given U2 setting. ...

Page 24

AD5235 PROGRAMMABLE CURRENT SOURCE A programmable current source can be implemented with the circuit shown in Figure 52. + (2.048V + SLEEP OUTPUT B REF191 C1 1µF GND ...

Page 25

First, users should select convenient values for the capacitors. To achieve maximally flat bandwidth, where Q = 0.707, let C1 be twice the size of C2 and let R1 equal R2 result, the user can adjust R1 and ...

Page 26

AD5235 RESISTANCE SCALING The AD5235 offers 25 kΩ or 250 kΩ nominal resistance. When users need lower resistance but must maintain the number of adjustment steps, they can parallel multiple devices. For example, Figure 57 shows a simple scheme of ...

Page 27

RDAC CIRCUIT SIMULATION MODEL The internal parasitic capacitances and the external capacitive loads dominate the ac characteristics of the RDACs. Configured as a potentiometer divider, the −3 dB bandwidth of the AD5235 (25 kΩ resistor) measures 125 kHz at half ...

Page 28

... R (kΩ) WB_FS AD5235BRU25 25 AD5235BRU25-RL7 25 2 AD5235BRUZ25 25 2 AD5235BRUZ25-RL7 25 AD5235BRU250 250 2 AD5235BRUZ250 250 2 AD5235BRUZ250-R7 250 EVAL-AD5235EBZ Line 1 contains the ADI logo followed by the date code, YYWW. Line 2 contains the model number followed by the end-to-end resistance value (note 250 kΩ). —OR— ...

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