ADN2850BCP250 Analog Devices Inc, ADN2850BCP250 Datasheet

IC DGTL RHEO DL 1024POS 16LFCSP

ADN2850BCP250

Manufacturer Part Number
ADN2850BCP250
Description
IC DGTL RHEO DL 1024POS 16LFCSP
Manufacturer
Analog Devices Inc
Datasheets

Specifications of ADN2850BCP250

Taps
1024
Resistance (ohms)
250K
Number Of Circuits
2
Temperature Coefficient
35 ppm/°C Typical
Memory Type
Non-Volatile
Interface
4-Wire SPI Serial
Voltage - Supply
3 V ~ 5.5 V, ±2.25 V ~ 2.75 V
Operating Temperature
-40°C ~ 85°C
Mounting Type
Surface Mount
Package / Case
16-LFCSP
Resistance In Ohms
250K
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)
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
Contains lead / RoHS non-compliant
For Use With
EVAL-ADN2850-25EBZ - BOARD EVALUATION FOR ADN2850-25
Lead Free Status / RoHS Status
Not Compliant, Contains lead / RoHS non-compliant
FEATURES
Dual-channel, 1024-position resolution
25 kΩ, 250 kΩ nominal resistance
Maximum ±8% nominal resistor tolerance error
Low temperature coefficient: 35 ppm/°C
2.7 V to 5 V single supply or ±2.5 V dual supply
Current monitoring configurable function
SPI-compatible serial interface
Nonvolatile memory stores wiper settings
Power-on refreshed with EEMEM settings
Permanent memory write protection
Resistance tolerance stored in EEMEM
26 bytes extra nonvolatile memory for user-defined
1M programming cycles
100-year typical data retention
APPLICATIONS
SONET, SDH, ATM, Gigabit Ethernet, DWDM laser diode
Mechanical rheostat replacement
Instrumentation gain adjustment
Programmable filters, delays, time constants
Sensor calibration
GENERAL DESCRIPTION
The ADN2850 is a dual-channel, nonvolatile memory
controlled resistors
guaranteed maximum low resistor tolerance error of ±8%. The
device performs the same electronic adjustment function as a
mechanical rheostat with enhanced resolution, solid state
reliability, and superior low temperature coefficient
performance. The versatile programming of the ADN2850 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
for user-defined information 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 resistor and RDAC are used interchangeably.
information
driver, optical supervisory systems
2
with 1024-step resolution, offering
1
, digitally
1
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
1024-Position Digital Resistor
In the scratchpad programming mode, a specific setting can
be programmed directly to the RDAC
resistance between 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 ADN2850 patterned resistance tolerance is stored in the
EEMEM. The actual full scale 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 ADN2850 is available in the 5 mm × 5 mm 16-lead frame
chip scale LFCSP and thin, 16-lead TSSOP package. The part is
guaranteed to operate over the extended industrial temperature
range of −40°C to +85°C.
SDO
GND
CLK
RDY
*R
V
V
SDI
WP
CS
PR
DD
SS
WB
FULL SCALE TOLERANCE.
POWER-ON
CONTROL
INTERFACE
EEMEM
RESET
Nonvolatile Memory, Dual
SERIAL
DECODE
FUNCTIONAL BLOCK DIAGRAM
ADDR
©2004–2011 Analog Devices, Inc. All rights reserved.
RTOL*
USER EEMEM
26 BYTES
REGISTER
REGISTER
Figure 1.
EEMEM1
EEMEM2
RDAC1
RDAC1
2
register, which sets the
ADN2850
ADN2850
CURRENT
MONITOR
RDAC1
RDAC2
www.analog.com
I
I
1
2
W1
B1
W2
B2
V
V
1
2

Related parts for ADN2850BCP250

ADN2850BCP250 Summary of contents

Page 1

FEATURES Dual-channel, 1024-position resolution 25 kΩ, 250 kΩ nominal resistance Maximum ±8% nominal resistor tolerance error Low temperature coefficient: 35 ppm/°C 2 single supply or ±2.5 V dual supply Current monitoring configurable function SPI-compatible serial interface ...

Page 2

ADN2850 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 kΩ, 250 ...

Page 3

SPECIFICATIONS ELECTRICAL CHARACTERISTICS—25 kΩ, 250 kΩ VERSIONS specifications apply to versions with a date code 1045 or later. Table 1. Parameter ...

Page 4

ADN2850 Parameter CURRENT MONITOR TERMINALS Current Sink Current Sink DYNAMIC CHARACTERISTICS Resistor Noise Density Analog Crosstalk 1 Typicals represent average readings at 25°C and V 2 Resistor position nonlinearity error (R-INL) is ...

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

ADN2850 Timing Diagrams CLK CPOL = 1 HIGH OR LOW SDI t 8 SDO B24 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 Pulsed ...

Page 8

ADN2850 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

Table 5. Pin Function Descriptions Pin No. Mnemonic Description 1 SDO Serial Data Output. Serves readback and daisy-chain functions. Command 9 and Command 10 activate the SDO output for the readback function, delayed clock pulses, depending ...

Page 10

ADN2850 TYPICAL PERFORMANCE CHARACTERISTICS 0.20 +85°C +25°C 0.15 –40°C 0.10 0.05 0 –0.05 –0.10 –0.15 –0.20 0 200 400 600 DIGITAL CODE Figure 6. R-INL vs. Code −40°C, +25°C, +85°C Overlay 0.20 +85°C +25°C –40°C 0.15 ...

Page 11

VDIO (V) Figure 12 Digital Input Voltage ± 10 0V, I (25k) = 200µ –10 I (250k) = ...

Page 12

ADN2850 CS (5V/DIV) CLK (5V/DIV) SDI (5V/DIV) Figure 18. I vs. Time when Storing Data to EEMEM DD TEST CIRCUITS Figure 20 to Figure 24 define the test conditions used in the Specifications section. DUT ...

Page 13

THEORY OF OPERATION The ADN2850 digital programmable resistor 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 14

ADN2850 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 ...

Page 15

SDO-to-SDI interface may require additional time delay between subsequent devices. When two ADN2850s are daisy-chained, 48 bits of data are required. The first 24 bits (formatted 4-bit command, 4-bit address, and 16-bit data) ...

Page 16

ADN2850 In Table 7, 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 7. 24-Bit Serial Data-Word ...

Page 17

ADVANCED CONTROL MODES The ADN2850 digital resistor 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 18

ADN2850 Using CS to Re-Execute a Previous Command Another subtle feature of the ADN2850 is that a subsequent CS strobe, without clock and data, repeats a previous command. Using Additional Internal Nonvolatile EEMEM The ADN2850 contains additional user EEMEM registers ...

Page 19

PROGRAMMING THE VARIABLE RESISTOR The nominal resistance of the RDAC between Terminal W and Terminal available with 25 kΩ and 250 kΩ with WB 1024 positions (10-bit resolution). The final digits of the part number determine ...

Page 20

ADN2850 Table 17. Using Left-Shift by One to Increment 6 dB Steps SDI SDO Action 0xC0XXXX 0xXXXXXX Moves Wiper 1 to double the present data contained in the RDAC1 register. 0xC1XXXX 0xC0XXXX Moves Wiper 2 to double the present data ...

Page 21

APPLICATIONS INFORMATION GAIN CONTROL COMPENSATION A digital resistor is commonly used in gain control such as the noninverting gain amplifier shown in Figure 34. C2 2.2pF R2 250kΩ 47kΩ 11pF V I Figure 34. Typical ...

Page 22

ADN2850 At the resonant frequency the overall phase shift is zero, and O the positive feedback causes the circuit to oscillate. With and R2 = R2A /(R2B + R ), the ...

Page 23

I and I are saturation current are V , base-emitted voltages of the diode connector transistors the thermal voltage, which is equal to k × T ...

Page 24

ADN2850 RESISTANCE TOLERANCE, DRIFT, AND TEMPERATURE COEFFICIENT MISMATCH CONSIDERATIONS In operation, such as gain control, the tolerance mismatch between the digital resistor and the discrete resistor can cause repeatability issues among various systems (see Figure 42). Because of the inherent ...

Page 25

OUTLINE DIMENSIONS BSC SQ PIN 1 INDICATOR 12° MAX 1.00 0.85 0.80 SEATING PLANE 4.50 4.40 4.30 PIN 1 0.15 0.05 ORDERING GUIDE 1 Model R (kΩ) WB ADN2850BRUZ25 25 ADN2850BRUZ25-RL7 25 ADN2850BCPZ25 25 ADN2850BCPZ25-RL7 25 ADN2850BCPZ250 250 ADN2850BCPZ250-RL7 250 ...

Page 26

ADN2850 NOTES Rev Page ...

Page 27

NOTES Rev Page ADN2850 ...

Page 28

ADN2850 NOTES ©2004–2011 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D02660-0-4/11(C) Rev Page ...

Related keywords