AD8322-EVAL Analog Devices Inc, AD8322-EVAL Datasheet

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AD8322-EVAL

Manufacturer Part Number
AD8322-EVAL
Description
BOARD EVAL FOR AD8322
Manufacturer
Analog Devices Inc
Type
Video Processorr
Datasheet

Specifications of AD8322-EVAL

Rohs Status
RoHS non-compliant
Contents
Evaluation Board
For Use With/related Products
AD8322
a
GENERAL DESCRIPTION
The AD8322 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 42.14 dB range, with gain steps of 6.02 dB/major
carry.
The AD8322 comprises a digitally controlled variable attenuator
of 0 dB to –42.14 dB, which is preceded by a low-noise, fixed-gain
buffer and is followed by a low-distortion, high-power ampli-
fier. The AD8322 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 –58 dBc is achieved with an output level
up to 60 dBmV at 21 MHz bandwidth. A key performance and
cost advantage of the AD8322 results from the ability to maintain
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.
The AD8322 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.
Coarse Step Output Power Control
V
V
IN+
IN–
Z
Z
IN
IN
DIFF
OR SINGLE
INPUT
AMP
(SINGLE) = 210
(DIFF) = 235
–55
–60
–65
–70
–75
DATEN
R1
R2
1
V
CC
FUNCTIONAL BLOCK DIAGRAM
(7 PINS)
DATA CLK
2
BUFFER
5 V CATV Line Driver
4
GAIN CODE – Decimal
AD8322
GND (12 PINS)
ATTENUATION
8
DATA LATCH
REGISTER
DECODE
CORE
SHIFT
8
8
8
f
V
@ MAX GAIN
16
O
O
= 42MHz
= 60dBmV
POWER-DOWN
PD
32
POWER
AD8322
AMP
LOGIC
Z
OUT
64
75
HD3
HD2
DIFF =
128
V
V
OUT+
OUT–

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AD8322-EVAL Summary of contents

Page 1

... Distortion performance of –58 dBc is achieved with an output level dBmV at 21 MHz bandwidth. A key performance and cost advantage of the AD8322 results from the ability to maintain a constant 75 Ω output impedance during power-up and power- down conditions. This eliminates the need for external 75 Ω ...

Page 2

... AD8322–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 1 dB Compression Point Differential Output Impedance ...

Page 3

... Decimal Gain Code GAIN TRANSFER (G2) 64 128 0 = low high don’t care PEDESTAL MSB-2 AD8322 = 5 V: Full Temperature Range) CC Typ Max Unit 5 –100 nA µA 190 µA – MHz unless otherwise noted.) CLK Typ Max Unit ns ns ...

Page 4

... AD8322ARU –40°C to +85°C AD8322ARU-REEL –40°C to +85°C AD8322-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 AD8322 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high-energy electrostatic discharges ...

Page 5

... OUT+ AD8322 OUT– V 1:1 IN– TOKO 0.1 F BYP GND 617DB-A0070 0.1 F DEVICE UNDER TEST 60dBmV O @ MAX GAIN 128 f = 10MHz –32 –36 –40 –44 – AD8322 + – 0pF 10pF 20pF 50pF L 10 100 FREQUENCY – MHz 128 GAIN CODE – Decimal ...

Page 6

... AD8322 –10 –20 MAX GAIN –30 –40 –50 MIN GAIN –60 –70 –80 GAIN CODE 0 –90 –100 1 10 FREQUENCY – MHz – 62dBmV O at MAX GAIN – 60dBmV O at MAX GAIN –55 – 58dBmV O at MAX GAIN – FUNDAMENTAL FREQUENCY – MHz – ...

Page 7

... The serial interface timing for the AD8322 is shown in Fig- ures 2 and 3. The programmable gain range of the AD8322 is –12. +29.5 dB and scales 6.02 dB for each major carry. Because the AD8322 was characterized with a TOKO transformer, the stated gain values already take into account the losses asso- ciated with the transformer ...

Page 8

... It should be noted that the AD8322 was characterized with the TOKO 617DB-A0070 transformer. TPC 7 and TPC 8 show the AD8322 second and third harmonic distortion performance versus fundamental frequency for vari- ous output power levels. These figures are useful for determining the in-band harmonic levels from 5 MHz to 65 MHz ...

Page 9

... PULSE. Differential Inputs The AD8322-EVAL evaluation board is designed to accommo- date 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 iden- tify three options for providing differential input signals to the AD8322 evaluation board ...

Page 10

... AD8322 by controlling the logic level on the asynchronous PD pin. The “Power-Up” button applies a Logic 1 to the PD pin putting the AD8322 in forward transmit mode. The “Power-Down” button applies a Logic 0 to the PD pin select- ing reverse mode, where the forward signal transmission is disabled while a back termination of 75 Ω ...

Page 11

... AD8322 ...

Page 12

... AD8322 ...

Page 13

... AD8322 ...

Page 14

... C5 0 VCC2 VCC3 19 R7 OUT– OUT+ 18 118 C12 GND2 GND9 17 0.1 F GND3 GND8 16 GND4 GND7 15 GND5 GND6 R6 0 TP13 AD8322TSSOP YEL TP6 WHT PD TP9 DNI TP12 TP11 DNI DNI C16 C11 DNI 0.1 F TP5 WHT ETCC1-1T CLK 1 T2A C10 DNI ...

Page 15

... AD8322 Evaluation Board Rev. DC 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 1/8 W. 1206 size chip resistor 1 118 1% 1/8 W. 1206 size chip resistor White Test Point (CLK, PD, CP, SDATA, DATEN) ...

Page 16

... AD8322 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 0.0256 (0.65) 0.0118 (0.30) 0.0079 (0.20) BSC 0.0075 (0.19) ...

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