rf2051 RF Micro Devices, rf2051 Datasheet - Page 18

• Manufacturer Part Number: rf2051
• Description: High Performance Wideband Rf Synthesizer/vco With Integrated Rf Mixers
• Manufacturer: RF Micro Devices

RF2051
Hardware Control
Three hardware control pins are provided: ENBL, MODE, and RESETB.
ENBL Pin
The ENBL pin has two functions: to enable the analog circuits in the chip and to trigger the VCO band selection as described in
the VCO section on page 11.
As outlined in the VCO section the chip has a built-in automatic VCO band selection to tune the selected VCO to the desired fre-
quency. The band selection is initiated when the ENBL pin is taken high. Every time the frequency of the synthesizer is re-pro-
grammed, the ENBL has to be inserted high to initiate the automatic VCO band selection (VCO coarse tune).
RESETB Pin
The RESETB pin is a hardware reset control that will reset all digital circuits to their start-up state when asserted low. The
device includes a power-on-reset function, so this pin should not normally be required, in which case it should be connected to
the positive supply.
MODE Pin
The MODE pin controls which mixer(s) and PLL programming register bank is active. See the PLL and Mixer description sec-
tions for details.
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Parameter
ENBL Pin
t1
t2
High
High
Low
Low
MODE setup time
MODE hold time
Description
REFSTBY Bit
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0
1
0
1
XO and Bias Block
Time
ENBL
MODE
>5ns
>5ns
Off
On
On
On
t1
t2
Analogue Block
Off
Off
On
On
Digital Block
On
On
On
On
Rev A1 DS090106