ad7294nbsp Analog Devices, Inc., ad7294nbsp Datasheet

no-image

ad7294nbsp

Manufacturer Part Number
ad7294nbsp
Description
12-bit, Monitor And Control System With Multichannel, Adc, Dacs, Temperature Sensor And Current Sense
Manufacturer
Analog Devices, Inc.
Datasheet
Preliminary Technical Data
FEATURES
12-bit SAR ADC with 3 μs conversion time
Rev. PrD
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 mayresult from its use. Specifications subjectto change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registeredtrademarks arethe property oftheir respective owners.
4 uncommitted analog inputs
2 high-side current sense inputs
2 external diode temperature sensor inputs
1 internal temperature sensor
Built-in monitoring features
4-channel, 12-bit monotonic 15 V DACs
Internal 2.5 V reference
2-wire fast mode I
Temperature range: −40°C to +105°C
Package types: 56-lead LFCSP and 64-lead TQFP
Differential/single ended
Input range: 0 to V
5 V to 59.4 V operating range
>±1% full-scale accuracy
±200 mV input range
−55°C to +150°C measurement range
±2°C accuracy
Series resistance cancellation
±2°C accuracy
Minimum/maximum recorder for each channel
Programmable alert thresholds
Programmable hysteresis
5 V span, 0 V to 10 V offset
10 μs settling time
10 mA sink and source capability
Power-on resets (POR) to 0 V
2
T1
C interface
REF
OVERRANGE
OVERRANGE
Figure 1. Typical Configuration for AD7294 in Cellular Base Station RF LDMOS Power Amplifier Control
T0
, 0 to 2 V
I
I
SENSE
SENSE
D1(+)
D0(+)
D0(–)
D1(–)
VIN0
VIN1
VIN2
VIN3
2
1
VSUPPLY
VPP(1 TO 2)
REF
V
10.41
AD7294
REF
RS1(+)
DVDD
HIGH SIDE
CURRENT
SENSE
12-Bit, Monitor and Control System with Multichannel, ADC,
RS1(–)
(1 TO 2)
DGND
RS2(+)
HIGH SIDE
CURRENT
R
SENSE
SDA SCL A2 A1 A0 CAP ALERT
SENSE
SPI/I
CONTROL LOGIC
PROTOCOL
2
MUX
C INTERFACE
RS2(–)
REFIN ADC
REFOUT/
SENSOR
TEMP
DACs, Temperature Sensor and Current Sense
REGISTERS
12-BIT
ADC
LIMIT
TO LOAD
2.5V
REF
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
REFIN DAC
GENERAL DESCRIPTION
The AD7294 contains all the functions required for general-
purpose monitoring and control of current, voltage, and
temperature integrated into a single-chip solution. The part
includes low voltage (±200 mV) analog input sense amplifiers
for current monitoring across shunt resistors, temperature sense
inputs, and four uncommitted analog input channels multiplexed
into a 200 kSPS SAR analog-to-digital converter (ADC). An
internal low ppm reference is provided to drive both the digital­
to-analog converter (DAC) and ADC. Four 12-bit DACs
provide the outputs for voltage control. The AD7294 also includes
limit registers for alarm functions. The part is designed on a high
voltage DMOS process for high voltage compliance, 59.4 V on
the current sense inputs, and up to 15 V DAC output voltage.
The DACs provide digital control with 1.2 mV resolution to
control the bias currents of the power transistors. Thermal
diode based temperature sensors are incorporated to compensate
for temperature effects. The ADC monitors the high-side current
and temperature. All this functionality is provided in a 56-lead
LFCSP and a 64-lead TQFP operating over a temperature range
of −40°C to +105°C.
REFOUT/
(1 TO 5)
AVDD
12-BIT
12-BIT
12-BIT
12-BIT
DAC
DAC
DAC
DAC
(1 TO 9)
AGND
(1 TO 2)
V+
OFFSET IN A
OFFSET IN B
OFFSET IN C
OFFSET IN D
VOUTA
VOUTB
VOUTC
VOUTD
©2007 Analog Devices, Inc. All rights reserved.
AD7294
www.analog.com

Related parts for ad7294nbsp

ad7294nbsp Summary of contents

Page 1

... One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781.329.4700 Fax: 781.461.3113 AVDD AGND 12-BIT VOUTA DAC OFFSET IN A 12-BIT VOUTB DAC OFFSET IN B 12-BIT VOUTC DAC OFFSET IN C 12-BIT VOUTD DAC OFFSET IN D ©2007 Analog Devices, Inc. All rights reserved. AD7294 www.analog.com ...

Page 2

AD7294 TABLE OF CONTENTS Features .............................................................................................. 1 Applications.................................. Error! Bookmark not defined. General Description ......................................................................... 1 Revision History ............................................................................... 2 Functional Block Diagram ......... Error! Bookmark not defined. Specifications..................................................................................... 3 DAC Specifications....................................................................... 3 ADC Specifications ...................................................................... 4 General Specifications ................................................................. ...

Page 3

Preliminary Technical Data SPECIFICATIONS DAC SPECIFICATIONS 4 5.5 V, AGND = DGND = 0 V, internal 2.5 V reference version: −40°C to +105°C. All specifications T from ...

Page 4

AD7294 ADC SPECIFICATIONS 4 5.5 V, AGND = DGND = 0 V, internal 2.5 V reference version: −40°C to +105°C. All specifications T characterization, not subject to production test. Parameter ...

Page 5

Preliminary Technical Data Parameter Medium Level Output Current Source High Level Output Current Source Maximum Series Resistance for External Diode CURRENT SENSE Supply Range Gain RS(+) and RS(−) Input Bias Current CMRR/PSRR Accuracy Offset Error Offset Drift Amplifier Peak-To-Peak Noise ...

Page 6

AD7294 GENERAL SPECIFICATIONS 4 5.5 V, AGND = DGND internal 2.5 V reference version: −40°C to +105°C. All specifications T characterization, not subject to production test. Parameter LOGIC ...

Page 7

Preliminary Technical Data TIMING CHARACTERISTICS Serial Interface 4 5.5 V, AGND = DGND = noted. Specifications guaranteed by design and characterization, not subject to production test. ...

Page 8

AD7294 ABSOLUTE MAXIMUM RATINGS 25°C, unless otherwise noted. A Table 3. Parameter Rating V to AGND −0 + AGND −0 V(+) to AGND −0 ...

Page 9

Preliminary Technical Data PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS REFOUT / REFIN DAC CONNECT NC RS2(-) RS2(+) NC AVDD1 AGND1 AGND2 AVDD2 D2(-) D2(+) D1(+) D1(-) AGND3 AVDD3 REFOUT / REFIN DAC NC RS2 (-) 1 RS2(+) ...

Page 10

AD7294 Table 4. Pin Function Descriptions LFCSP Pin No. TQFP Pin No. Mnemonic RS2(−), RS1(− RS2(+), RS1(+) 16, 17, 32, NC 33, 59 13, 22, ...

Page 11

Preliminary Technical Data LFCSP Pin No. TQFP Pin No. Mnemonic N/A 48 DAC High 49, 50, 51, 52 VIN3 to VIN0 47 53 REFOUT/REFIN ADC 48 54 DCAP 55, 56 62, 63 VPP1, VPP2 Description High Impedance ...

Page 12

AD7294 TERMINOLOGY DAC TERMINOLOGY Relative Accuracy For the DAC, relative accuracy or integral nonlinearity (INL measure of the maximum deviation, in LSBs, from a straight line passing through the endpoints of the DAC transfer func­ tion. Differential Nonlinearity ...

Page 13

Preliminary Technical Data Differential Nonlinearity The difference between the measured and the ideal 1 LSB change between any two adjacent codes in the ADC. Offset Error The deviation of the first code transition (00…000) to (00…001) from the ideal—that is, ...

Page 14

AD7294 THEORY OF OPERATION ADC OVERVIEW The AD7294 consists of a successive approximation ADC based around a capacitive DAC. The analog input range for the part can be selected input × ...

Page 15

Preliminary Technical Data +2.5V R +1.25V –1.25V R 1 ADDITIONAL PINS OMITTED FOR CLARITY. Figure 8. Single-Ended Mode Connection Diagram Differential Mode The AD7294 can have two differential analog input pairs. Differential signals have ...

Page 16

AD7294 An op amp pair can be used to directly couple a differential signal to one of the analog input pairs of the AD7294. The circuit con­ figurations illustrated in Figure 12 and Figure 13 show how a dual op ...

Page 17

Preliminary Technical Data V REF p-p DC INPUT VOLTAGE 1 ADDITIONAL PINS OMITTED FOR CLARITY. Figure 16. Pseudo Differential Mode Connection Diagram CURRENT SENSOR Two bidirectional high-side current sense amplifiers are provided, which can accurately amplify small differential current shunt ...

Page 18

AD7294 SENSE RESISTOR CURRENT FLOW FROM SUPPLY KELVIN SENSE TRACES RSX(+) RSX(–) AD7294 Figure 19. Kelvin Sense Connections ANALOG COMPARATOR LOOP The AD7294 consists of two setpoint comparators that are used for independent analog control. The advantage of using analog ...

Page 19

Preliminary Technical Data AD7294 2N3904 D+ NPN 10pF D– Figure 21. Measuring Temperature Using an NPN Transistor AD7294 D+ 10pF 2N3906 D– PNP Figure 22. Measuring Temperature Using a PNP Transistor Series Resistance Cancellation Parasitic resistance to the D+ and ...

Page 20

AD7294 OUTPUT R AMPLIFIER R R Figure 24. Resistor String Structure Output Amplifier Referring to Figure 23, the purpose buffer the DAC output range from The second amplifier, ...

Page 21

Preliminary Technical Data REGISTER SETTING The AD7294 contains internal registers (see Figure 25) that are used to store conversion results, high and low conversion limits, and information to configure and control the device. COMMAND REGISTER RESULT REGISTER DAC REGISTERS T ...

Page 22

AD7294 COMMAND REGISTER (0x00) Writing in the command register puts the part into command mode. When in command mode, the part cycles through the selected channels on each subsequent read. If the external T channels are selected in the command ...

Page 23

Preliminary Technical Data ADC Channel Allocation These nine channel address bits select which analog input channel is to convert using the multiplexer, see Table 11. Choosing Channel 1 to Channel 4 selects the standard analog voltage inputs. Channel 5 and ...

Page 24

AD7294 DAC4 REGISTER (0x04) Writing to this register address sets the DAC4 output code. Bits[D11:D0] in the result register are the data bits sent to DAC4. Bits[D14:D12] are ignored and the MSB, D15, is reserved as an Alert_Flag bit. Table ...

Page 25

Preliminary Technical Data Table 25. Configuration Register Bit Function Description D15 to D8 Channel Bit D15 D14 Function Reserved Enable noise- delayed sampling. Use to delay critical sample intervals from occurring when there is when there is activity on 2 ...

Page 26

AD7294 Channel 7 to Channel and T SENSE SENSE to 3FF and 400 for the DATA and DATA HIGH are in twos complement 10-bit format. Differential mode is not available for Channel 7 to Channel ...

Page 27

Preliminary Technical Data INTERFACE 2 GENERAL I C TIMING Figure 26 shows the timing diagram for general read and write 2 operations using an I C-compliant interface. 2 The I C bus uses open-drain drivers, therefore, when ...

Page 28

AD7294 SERIAL BUS ADDRESS BYTE The first byte the user writes to the device is the slave address 2 Similar to all I C-compatible devices, the AD7294 has a byte. 7-bit serial address. The 5 LSBs are user programmable by ...

Page 29

Preliminary Technical Data Table 36, H means tie the pin to VDRIVE, L means tie the pin to GND, and NC refers to a pin left floating. Note that in this final case, the stray capacitance on the pin must ...

Page 30

AD7294 INTERFACE PROTOCOL 2 The AD7294 uses the following I C protocols. Writing a Single Byte of Data to an 8-Bit Register The alert registers (0x05, 0x06, 0x07), power down register (0x0A), channel sequence register (0x08), temperature offset registers (0x26, ...

Page 31

Preliminary Technical Data Writing Two Bytes of Data to a 16-Bit Register The limit and hysteresis registers (0x0B to 0x25), the result registers (0x01 ~ 0x04), and the configuration register (0x09) are 16-bit registers; therefore, two bytes of data are ...

Page 32

AD7294 Writing to Multiple Registers Writing to multiple address registers consists of the following: 1. The master device asserts a start condition on SDA. 2. The master sends the 7-bit slave address followed by the write bit (low). 3. The ...

Page 33

Preliminary Technical Data Reading Data from an 8-Bit Register Reading the contents from any of the 8-bit registers is a single- byte read operation, as shown in Figure 30. In this protocol, the first part of the transaction writes to ...

Page 34

AD7294 Reading Two Bytes of Data from a 16-Bit Register In this example, the master device reads three lots of two-byte data from a slave device. This protocol assumes that the particular register address has been set ...

Page 35

Preliminary Technical Data MODES OF OPERATION There are two different methods of initiating a conversion on the AD7294. COMMAND MODE In command mode, the AD7294 ADC converts on demand on either a single channel or a sequence of channels. To ...

Page 36

AD7294 AUTOCYCLE MODE The AD7294 can be configured to convert continuously on a programmable sequence of channels. These conversions take place in the background approximately every 45 µs, and are transparent to the master. Reads and writes can still be ...

Page 37

Preliminary Technical Data ALERTS AND LIMITS THEORY ALERT_FLAG BIT The Alert_Flag bit indicates whether the conversion result being read or any other channel result has violated the limit registers associated with it alert occurs and the Alert_Flag bit ...

Page 38

AD7294 contain a value of 8 LSB for nontemperature result registers and 8° LSB, for the T registers different hysteresis SENSE value is required, that value must be written to the hysteresis register for the channel ...

Page 39

... RF IN signal is switched off by the comparator. By measuring the transmitted power (Tx) and the received power (Rx), the device can dynamically change the drivers and PA signal to optimize performance. This application requires a logarithmic detector/controller, such as Analog Devices, Inc. AD8317. R SENSE R SENSE RS2(– ...

Page 40

AD7294 GAIN CONTROL OF POWER AMPLIFIER In gain control mode, a setpoint voltage, proportional the desired output power, is applied to a power detector such as the AD8362. A sample of the output power from the power ...

Page 41

Preliminary Technical Data LAYOUT AND CONFIGURATION POWER SUPPLY BYPASSING AND GROUNDING When accuracy is important in a circuit, carefully consider the power supply and ground return layout on the board. The printed circuit board containing the AD7294 should have separate ...

Page 42

AD7294 EVALUATION BOARD FOR THE AD7294 The AD7294 evaluation board consists of the AD7294 LFCSP package along with two R resistors and a number of SMB SENSE sockets and jumpers to allow access to the various on-chip functionalities of the ...

Page 43

Preliminary Technical Data Figure 38. Evaluation Board Schematic Rev. PrD | Page AD7294 ...

Page 44

AD7294 Figure 39. Component Side Artwork Figure 40. Component Side SilkScreen Rev. PrD | Page Preliminary Technical Data ...

Page 45

Preliminary Technical Data Figure 41. Solder Side Artwork Rev. PrD | Page AD7294 ...

Page 46

... Temperature Range AD7294BCPZ 1 −40°C to +105°C 1 AD7294BSUZ −40°C to +105°C 1 EVAL-AD7294EBZ RoHS Compliant Part. ©2007 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. PR05747-0-10/07(PrD) 8.00 BSC SQ 0.60 MAX 43 42 TOP 7.75 VIEW BSC SQ 0 ...

Related keywords