ISLA224P
Typical Performance Curves
All Typical Performance Characteristics apply under the following conditions unless otherwise noted: AVDD = OVDD = 1.8V, T A = +25°C,
A IN = -dBFS, f IN = 105MHz, f SAMPLE = 250MSPS. (Continued)
0
IMD2
0
IMD2
-20
IMD3
2ND HARMONICS
-20
IMD3
2ND HARMONICS
-40
-60
3RD HARMONICS
-40
-60
3RD HARMONICS
-80
-100
IMD3 = 87dBFS
-80
-100
IMD3 = 96dBFS
-120
0
20
40
60
80
100
120
-120
0
20
40
60
80
100
120
FREQUENCY (MHz)
FIGURE 19. TWO-TONE SPECTRUM
(F1 = 70MHz, F2 = 71MHz AT -7dBFS)
Theory of Operation
Functional Description
The ISLA224P25 is based upon a 14-bit, 250MSPS A/D converter
core that utilizes a pipelined successive approximation
architecture (see Figure 21). The input voltage is captured by a
Sample-Hold Amplifier (SHA) and converted to a unit of charge.
Proprietary charge-domain techniques are used to successively
compare the input to a series of reference charges. Decisions
made during the successive approximation operations determine
the digital code for each input value. Digital error correction is also
applied, resulting in a total latency of 10 clock cycles. This is
evident to the user as a latency between the start of a conversion
and the data being available on the digital outputs.
Power-On Calibration
As mentioned previously, the cores perform a self-calibration at
start-up. An internal power-on-reset (POR) circuit detects the
supply voltage ramps and initiates the calibration when the
analog and digital supply voltages are above a threshold. The
following conditions must be adhered to for the power-on
calibration to execute successfully:
? A frequency-stable conversion clock must be applied to the
CLKP/CLKN pins
? DNC pins must not be connected
? SDO has an internal pull-up and should not be driven externally
? RESETN is pulled low by the ADC internally during POR.
External driving of RESETN is optional.
? SPI communications must not be attempted
16
FREQUENCY (MHz)
FIGURE 20. TWO-TONE SPECTRUM
(F1 = 170MHz, F2 = 171MHz AT -7dBFS)
A user-initiated reset can subsequently be invoked in the event
that the above conditions cannot be met at power-up.
After the power supply has stabilized the internal POR releases
RESETN and an internal pull-up pulls it high, which starts the
calibration sequence. If a subsequent user-initiated reset is
desired, the RESETN pin should be connected to an open-drain
driver with an off-state/high impedance state leakage of less
than 0.5mA to assure exit from the reset state so calibration can
start.
The calibration sequence is initiated on the rising edge of
RESETN, as shown in Figure 22. Calibration status can be
determined by reading the cal_status bit (LSB) at 0xB6. This bit is
‘0’ during calibration and goes to a logic ‘1’ when calibration is
complete. The data outputs produce 0xCCCC during calibration;
this can also be used to determine calibration status.
If the selectable clock divider is set to 1 (default), the output
clock (CLKOUTP/CLKOUTN) will not be affected by the assertion
of RESETN. If the selectable clock divider is set to 2 or 4, the
output clock is set low while RESETN is asserted (low). Normal
operation of the output clock resumes at the next input clock
edge (CLKP/CLKN) after RESETN is de-asserted. At 250MSPS the
nominal calibration time is 200ms, while the maximum
calibration time is 550ms.
FN7570.1
November 30, 2012
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相关代理商/技术参数
ISLA224P 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual 14-Bit, 250MSPS/200MSPS/130MSPS ADC
ISLA224P12 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:High Performance Dual 14-Bit, 125MSPS ADC
ISLA224P12IRZ 制造商:Intersil Corporation 功能描述:DUAL 14-BIT 125MSPS UNBUFFERED INPUT, 72-PIN - Trays 制造商:Intersil Corporation 功能描述:IC ADC 14BIT SPI/SRL 125M 48QFN 制造商:Intersil 功能描述:Dual 14-Bit 125MSPS Unbuffered Input, 72
ISLA224P13 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual 14-Bit, 250MSPS/200MSPS/130MSPS ADC
ISLA224P13IRZ 制造商:Intersil Corporation 功能描述:DUAL 14-BIT 130MSPS UNBUFFERED INPUT, 72-PIN - Trays 制造商:Intersil Corporation 功能描述:IC ADC 14BIT SRL/SPI 72QFN 制造商:Intersil 功能描述:DL 14-BIT 130MSPS UNBUFRED INPUT 72PIN
ISLA224P20 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual 14-Bit, 250MSPS/200MSPS/130MSPS ADC
ISLA224P20IRZ 制造商:Intersil Corporation 功能描述:DUAL 14-BIT 200MSPS UNBUFFERED INPUT, 72-PIN - Trays 制造商:Intersil Corporation 功能描述:IC ADC 14BIT SRL/SPI 72QFN 制造商:Intersil 功能描述:DL 14-BIT 200MSPS UNBUFRED INPUT 72PIN 制造商:Intersil Corporation 功能描述:IC, ADC, 14BIT; Resolution (Bits):14bit; Sampling Rate:200MSPS; Supply Voltage Type:Single; Supply Voltage Min:1.7V; Supply Voltage Max:1.9V; Supply Current:375mA; Digital IC Case Style:QFN; No. of Pins:72; Data Interface:SPI ;RoHS Compliant: Yes
ISLA224P25 制造商:INTERSIL 制造商全称:Intersil Corporation 功能描述:Dual 14-Bit, 250MSPS/200MSPS/130MSPS ADC