MAX2065EVKIT Maxim Integrated Products, MAX2065EVKIT Datasheet - Page 21

• Manufacturer Part Number: MAX2065EVKIT
• Description: KIT EVALUATION FOR MAX2065
• Manufacturer: Maxim Integrated Products
• Type: Amplifierr

Specifications of MAX2065EVKIT

• Frequency: 50MHz ~ 1GHz
• For Use With/related Products: MAX2065
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

The analog attenuator is controlled by an external con-
trol voltage applied at ANALOG_VCTRL (pin 39) or by
the on-chip 8-bit DAC, while the digital attenuator is con-
trolled through the SPI-compatible interface or parallel
bus. The DAC enable/disable logic-input pin
(VDAC_EN), digital attenuator SPI or parallel control
selection logic-input pin (SER/PAR), and the DAC refer-
ence voltage selection logic-input pin (VREF_SELECT)
determine how the attenuators are controlled. The on-
chip DAC can also be enabled or disabled. When the
DAC is enabled, either the on-chip voltage reference or
the external voltage reference can be selected. See
Table 1 for the attenuator and DAC operation truth table.
To capitalize on its fast 25ns switching capability, the
MAX2065 offers a supplemental 5-bit parallel control
interface. The digital logic attenuator-control pins
(D0–D4) enable the attenuator stages (Table 3).
Direct access to this 5-bit bus enables the user to avoid
any programming delays associated with the SPI
Table 2. SPI Data Format (continued)
Table 3. Digital Attenuator Settings (Parallel Control)
On-Chip DAC
INPUT
FUNCTION
D0
D1
D2
D3
D4
50MHz to 1000MHz High-Linearity, Serial/
Attenuator and DAC Operation
Using the Parallel Control Bus
______________________________________________________________________________________
Disable 1dB attenuator, or when SPI is default programmer
Disable 2dB attenuator, or when SPI is default programmer
Disable 4dB attenuator, or when SPI is default programmer
Disable 8dB attenuator, or when SPI is default programmer
Disable 16dB attenuator, or when SPI is default programmer
Digital Attenuator Settings
Parallel-Controlled Analog/Digital VGA
D0 (LSB)
BIT
D7
D6
D5
D4
D3
D2
D1
LOGIC = 0 (OR GROUND)
Bit 7 (MSB) of on-chip DAC used to program the analog attenuator
Bit 6 of DAC
Bit 5 of DAC
Bit 4 of DAC
Bit 3 of DAC
Bit 2 of DAC
Bit 1 of DAC
Bit 0 (LSB) of the on-chip DAC
interface. One of the limitations of any SPI bus is the
speed at which commands can be clocked into each
peripheral device. By offering direct access to the 5-bit
parallel interface, the user can quickly shift between
digital attenuator states needed for critical “fast-attack”
automatic gain control (AGC) applications.
The MAX2065 has an added feature that provides
“rapid fire” gain selection between four prepro-
grammed attenuation steps. As with the supplemental
5-bit bus mentioned above, this “rapid fire” gain selec-
tion allows the user to quickly access any one of four
customized digital attenuation states without incurring
the delays associated with reprogramming the device
through the SPI bus.
The switching speed is comparable to that achieved
using the supplemental 5-bit parallel bus. However, by
employing this specific feature, the digital attenuator
I/O is further reduced by a factor of either 5 or 2.5 (5
control bits vs. 1 or 2, respectively) depending on the
number of states desired.
DESCRIPTION
Enable 1dB attenuator
Enable 2dB attenuator
Enable 4dB attenuator
Enable 8dB attenuator
Enable 16dB attenuator
“Rapid-Fire” Preprogrammed
LOGIC = 1
Attenuation States
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