AD8323-EVAL Analog Devices Inc, AD8323-EVAL Datasheet

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AD8323-EVAL

Manufacturer Part Number
AD8323-EVAL
Description
BOARD EVAL FOR AD8323
Manufacturer
Analog Devices Inc
Type
Video Processorr
Datasheet

Specifications of AD8323-EVAL

Rohs Status
RoHS non-compliant
Contents
Evaluation Board
For Use With/related Products
AD8322
a
GENERAL DESCRIPTION
The AD8323 is a low-cost, digitally controlled, variable gain ampli-
fier optimized for coaxial line driving applications such as cable
modems that are designed to the MCNS-DOCSIS upstream
standard. An 8-bit serial word determines the desired output gain
over a 53.5 dB range resulting in gain changes of 0.7526 dB/LSB.
The AD8323 comprises a digitally controlled variable attenuator
of 0 dB to –53.5 dB, which is preceded by a low noise, fixed
gain buffer and is followed by a low distortion high power am-
plifier. The AD8323 accepts a differential or single-ended input
signal. The output is specified for driving a 75 Ω load, such as
coaxial cable.
Distortion performance of –56 dBc is achieved with an output
level up to 60 dBmV at 21 MHz bandwidth. A key performance
and cost advantage of the AD8323 results from the ability to main-
tain a constant 75 Ω output impedance during power-up and
power-down conditions. This eliminates the need for external 75 Ω
termination, resulting in twice the effective output voltage when
compared to a standard operational amplifier. In addition, this
device has a sleep mode function that reduces the quiescent
current to 4 mA.
The AD8323 is packaged in a low-cost 28-lead TSSOP, operates
from a single 5 V supply, and has an operational temperature
range of –40°C to +85°C.
V
V
IN+
IN–
5 V CATV Line Driver Fine Step
Z
Z
IN
IN
(SINGLE) = 800
(DIFF) = 1.6k
–50
–55
–60
–65
–70
–75
DIFF OR
SINGLE
INPUT
AMP
0
R1
R2
FUNCTIONAL BLOCK DIAGRAM
DATEN
V
8
CC
(7 PINS)
Output Power Control
BUFFER
16
DATA CLK
GAIN CONTROL – DEC Code
24
AD8323
32
ATTENUATION
DATA LATCH
GND (11 PINS)
HD3
HD2
REGISTER
DECODE
CORE
SHIFT
F
P
40
O
O
8
8
8
= 42MHz
= 60dBmV @ MAX GAIN
48
BYP
POWER-DOWN
AD8323
PD
POWER
56
AMP
LOGIC
Z
OUT
SLEEP
64
75
DIFF =
72
V
V
OUT+
OUT–

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AD8323-EVAL Summary of contents

Page 1

... Distortion performance of –56 dBc is achieved with an output level dBmV at 21 MHz bandwidth. A key performance and cost advantage of the AD8323 results from the ability to main- tain a constant 75 Ω output impedance during power-up and power-down conditions. This eliminates the need for external 75 Ω ...

Page 2

... AD8323–SPECIFICATIONS Parameter INPUT CHARACTERISTICS Specified AC Voltage Noise Figure Input Resistance Input Capacitance GAIN CONTROL INTERFACE Gain Range Maximum Gain Minimum Gain Gain Scaling Factor OUTPUT CHARACTERISTICS Bandwidth (–3 dB) Bandwidth Roll-Off Bandwidth Peaking Output Noise Spectral Density 1 dB Compression Point Differential Output Impedance ...

Page 3

... VALID DATA WORD G2 MSB .LSB CLOCK CYCLES GAIN TRANSFER (G1) T OFF T GS PEDESTAL VALID DATA BIT MSB MSB AD8323 = 5 V: Full Temperature Range) CC Typ Max Unit 5 –100 nA µA 190 µA –30 µA 190 µA – MHz unless otherwise noted.) CLK ...

Page 4

... AD8323ARU –40°C to +85°C AD8323ARU-REEL –40°C to +85°C AD8323-EVAL Thermal Resistance measured on SEMI standard 4-layer board. CAUTION ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the AD8323 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges ...

Page 5

... FREQUENCY – MHz Typical Performance Characteristics– –30 –34 –38 –42 –46 – –20 –40 –60 –80 –100 1k 0.1 AD8323 P = 60dBmV OUT 1:1 OUT @ MAX GAIN IN– IN 0pF 50pF 20pF 10pF L 10 100 FREQUENCY – MHz f = 10MHz ...

Page 6

... AD8323 –60 – 62dBmV OUT @ MAX GAIN P = 61dBmV OUT –70 @ MAX GAIN P –75 @ MAX GAIN – 58dBmV OUT @ MAX GAIN – FUNDAMENTAL FREQUENCY – MHz – 62dBmV OUT @ MAX GAIN P = 61dBmV –50 OUT @ MAX GAIN – 60dBmV OUT @ MAX GAIN –60 – ...

Page 7

... The serial interface timing for the AD8323 is shown in Figures 2 and 3. The programmable gain range of the AD8323 is – +27.5 dB and scales 0.7526 dB per least significant bit (LSB). Because the AD8323 was characterized with a TOKO transformer, the stated gain values already take into account the losses associ- ated with the transformer ...

Page 8

... Logic enabling forward signal transmission at the desired gain level. Asynchronous Power-Down The asynchronous PD pin is used to place the AD8323 into “Between Burst” mode while maintaining a differential output impedance of 75 Ω. Applying a Logic 0 to the PD pin activates the on-chip reverse amplifier, providing a 74% reduction in consumed power ...

Page 9

... Differential Inputs –53.1 –53.3 The AD8323-EVAL evaluation board is designed to accommodate a Mini-Circuits T1-6T-KK81 1:1 transformer for the purpose of converting a single-ended (ground-referenced) input signal to differential inputs. Figure 8 and the following paragraphs identify two options for providing differential input signals to the AD8323 evaluation board ...

Page 10

... IN– POWER-UP, POWER-DOWN AND SLEEP The “Power-Up” and “Power-Down” buttons select the mode of operation of the AD8323 by controlling the logic level on the asynchronous PD pin. The “Power-Up” button applies a Logic 1 to the PD pin putting the AD8323 in forward transmit mode. The “Power-Down” button applies a Logic 0 to the PD pin selecting reverse mode, where the forward signal transmission is disabled while a back termination of 75 Ω ...

Page 11

... EVALUATION BOARD FEATURES AND OPERATION AD8323 ...

Page 12

... AD8323 ...

Page 13

... AD8323 ...

Page 14

... AD8323 G9 2,4,6,7,8 = OUT 10 G8 PULSEB5008 A– ...

Page 15

... AD8323 Evaluation Board Rev. C SINGLE-ENDED INVERTING INPUT – Revised – June 22, 2000 Qty. Description 10 µ ‘C’ size tantalum chip capacitor 1 0.1 µ 1206 size ceramic chip capacitor 12 0 Ω 1/8 W. 1206 size chip resistor 6 39.2 Ω 1% 1/8 W. 1206 size chip resistor 1 82.5 Ω ...

Page 16

... AD8323 PIN 1 0.006 (0.15) 0.002 (0.05) SEATING PLANE OUTLINE DIMENSIONS Dimensions shown in inches and (mm). 28-Lead TSSOP (RU-28) 0.386 (9.80) 0.378 (9.60 0.177 (4.50) 0.169 (4.30) 0.256 (6.50) 0.246 (6.25 0.0433 (1.10) MAX 8 0.0256 (0.65) 0.0118 (0.30) 0 0.0079 (0.20) BSC 0.0075 (0.19) ...

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