1.8 V CMOS or LVDS output supply
Integer 1-to-8 input clock divider
IF sampling frequencies to 300 MHz
−152.8 dBm/Hz small signal input noise with 200 Ω input
impedance @ 70 MHz and 125 MSPS
Optional on-chip dither
Programmable internal ADC voltage reference
Integrated ADC sample-and-hold inputs
Flexible analog input range: 1 V p-p to 2 V p-p
Differential analog inputs with 650 MHz bandwidth
ADC clock duty cycle stabilizer
95 dB channel isolation/crosstalk
Serial port control
User-configurable, built-in self-test (BIST) capability
Energy-saving power-down modes
APPLICATIONS
Communications
Diversity radio systems
Multimode digital receivers (3G)
GSM, EDGE, W-CDMA, LTE,
CDMA2000, WiMAX, TD-SCDMA
I/Q demodulation systems
Smart antenna systems
General-purpose software radios
Broadband data applications
Ultrasound equipment
Analog-to-Digital Converter (ADC)
AD9258
FUNCTIONAL BLOCK DIAGRAM
SDIO/
SCLK/
DCS
DFS
AD9258
VIN+A
VIN–A
VREF
ENSE
SELECT
VCM
RBIAS
VIN–B
VIN+B
NOTES
1. PIN NAMES ARE FOR THE CMOS PIN CONFIGURATION ONLY;
SEE FIGURE 7 FORLVDS PIN NAMES.
REF
MULTICHIP
ADC
ADC
SYNC
SYNCAGND
SPI
PROGRAMMI NG DATA
CMOS/LVDS
OUTPUT BUFFER
DIVIDE 1
TO 8
DUTY CYCLE
STABILIZER
CMOS/LVDS
OUTPUT BUFFER
PDWNOEB
Figure 1.
PRODUCT HIGHLIGHTS
1. On-chip dither option for improved SFDR performance
with low power analog input.
2. Proprietary differential input that maintains excellent SNR
performance for input frequencies up to 300 MHz.
3. Operation from a single 1.8 V supply and a separate digital
output driver supply accommodating 1.8 V CMOS or
LVDS outputs .
4. Standard serial port interface (SPI) that supports various
product features and functions, such as data formatting
(offset binary, twos complement, or gray coding), enabling
the clock DCS, power-down, test modes, and voltage
reference mode.
5. Pin compatibility with the AD9268, allowing a simple
migration from 14 bits to 16 bits. The AD9258 is also pin
compatible with the AD9251, AD9231, and AD9204 family
of products for lower sample rate, low power applications.
DRVDDCSBAVDD
DCO
GENERATION
ORA
D13A (MSB)
14
TO
D0A (LSB)
CLK+
CLK–
DCOA
DCOB
ORB
D13B (MSB)
14
TO
D0B (LSB)
08124-001
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.
Changes to Features List .................................................................. 1
Changes to Specifications Section .................................................. 4
Changes to Table 5 ............................................................................ 9
Changes to Typical Performance Characteristics Section ......... 17
5/09—Revision 0: Initial Version
Rev. A | Page 2 of 44
AD9258
GENERAL DESCRIPTION
The AD9258 is a dual, 14-bit, 80 MSPS/105 MSPS/125 MSPS
analog-to-digital converter (ADC). The AD9258 is designed to
support communications applications where high performance,
combined with low cost, small size, and versatility, is desired.
The dual ADC core features a multistage, differential pipelined
architecture with integrated output error correction logic. Each
ADC features wide bandwidth differential sample-and-hold
analog input amplifiers that support a variety of user-selectable
input ranges. An integrated voltage reference eases design considerations. A duty cycle stabilizer is provided to compensate for
variations in the ADC clock duty cycle, allowing the converters
to maintain excellent performance.
The ADC output data can be routed directly to the two external
14-bit output ports. These outputs can be set to either 1.8 V CMOS
or LVDS.
Flexible power-down options allow significant power savings,
when desired.
Programming for setup and control is accomplished using a 3-wire
SPI-compatible serial interface.
The AD9258 is available in a 64-lead LFCSP and is specified over
the industrial temperature range of −40°C to +85°C.
See the AN-835 Application Note, Understanding High Speed ADC Testing and Evaluation, for a complete set of definitions.
2
Crosstalk is measured at 100 MHz with −1.0 dBFS on one channel and no input on the alternate channel.
1
Temp Min Typ Max Min Typ Max Min Typ Max Unit
fIN = 2.4 MHz 25°C −100 −100 −99 dBc
fIN = 70 MHz 25°C −100 −96 −99 −94 −98 −94 dBc
Full −96 −94 −94 dBc
fIN = 140 MHz 25°C −97 −97 −97 dBc
fIN = 200 MHz 25°C −95 −95 −95 dBc
fIN = 2.4 MHz 25°C −109 −107 −107 dBc
fIN = 70 MHz 25°C −105 −96 −106 −95 −105 −95 dBc
Full −96 −95 −95 dBc
fIN = 140 MHz 25°C −106 −104 −103 dBc
fIN = 200 MHz 25°C −102 −104 −97 dBc
2
Full −95 −95 −95 dB
DIGITAL SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.0 V internal reference, and DCS enabled, unless
otherwise noted.
Table 3.
Parameter Temperature Min Typ Max Unit
DIFFERENTIAL CLOCK INPUTS (CLK+, CLK−)
Logic Compliance CMOS/LVDS/LVPECL
Internal Common-Mode Bias Full 0.9 V
Differential Input Voltage Full 0.3 3.6 V p-p
Input Voltage Range Full AGND AVDD V
Input Common-Mode Range Full 0.9 1.4 V
High Level Input Current Full −100 +100 μA
Low Level Input Current Full −100 +100 μA
Input Capacitance Full 4 pF
Input Resistance Full 8 10 12 kΩ
SYNC INPUT
Logic Compliance CMOS
Internal Bias Full 0.9 V
Input Voltage Range Full AGND AVDD V
High Level Input Voltage Full 1.2 AVDD V
Low Level Input Voltage Full AGND 0.6 V
High Level Input Current Full −100 +100 μA
Low Level Input Current Full −100 +100 μA
Input Capacitance Full 1 pF
Input Resistance Full 12 16 20 kΩ
Rev. A | Page 7 of 44
AD9258
Parameter Temperature Min Typ Max Unit
LOGIC INPUT (CSB)1
High Level Input Voltage Full 1.22 2.1 V
Low Level Input Voltage Full 0 0.6 V
High Level Input Current Full −10 +10 μA
Low Level Input Current Full 40 132 μA
Input Resistance Full 26 kΩ
Input Capacitance Full 2 pF
LOGIC INPUT (SCLK/DFS)2
High Level Input Voltage Full 1.22 2.1 V
Low Level Input Voltage Full 0 0.6 V
High Level Input Current (VIN = 1.8 V) Full −92 −135 μA
Low Level Input Current Full −10 +10 μA
Input Resistance Full 26 kΩ
Input Capacitance Full 2 pF
LOGIC INPUT/OUTPUT (SDIO/DCS)
High Level Input Voltage Full 1.22 2.1 V
Low Level Input Voltage Full 0 0.6 V
High Level Input Current Full −10 +10 μA
Low Level Input Current Full 38 128 μA
Input Resistance Full 26 kΩ
Input Capacitance Full 5 pF
LOGIC INPUTS (OEB, PDWN)
High Level Input Voltage Full 1.22 2.1 V
Low Level Input Voltage Full 0 0.6 V
High Level Input Current (VIN = 1.8 V) Full −90 −134 μA
Low Level Input Current Full −10 +10 μA
Input Resistance Full 26 kΩ
Input Capacitance Full 5 pF
DIGITAL OUTPUTS
CMOS Mode—DRVDD = 1.8 V
High Level Output Voltage
IOH = 50 μA Full 1.79 V
IOH = 0.5 mA Full 1.75 V
Low Level Output Voltage
IOL = 1.6 mA Full 0.2 V
IOL = 50 μA Full 0.05 V
LVDS Mode—DRVDD = 1.8 V
Differential Output Voltage (VOD), ANSI Mode Full 290 345 400 mV
Output Offset Voltage (VOS), ANSI Mode Full 1.15 1.25 1.35 V
Differential Output Voltage (VOD), Reduced Swing Mode Full 160 200 230 mV
Output Offset Voltage (VOS), Reduced Swing Mode Full 1.15 1.25 1.35 V
1
Pull up.
2
Pull down.
1
2
Rev. A | Page 8 of 44
AD9258
SWITCHING SPECIFICATIONS
AVDD = 1.8 V, DRVDD = 1.8 V, maximum sample rate, VIN = −1.0 dBFS differential input, 1.0 V internal reference, and DCS enabled, unless
otherwise noted.
Table 4.
AD9258BCPZ-80 AD9258BCPZ-105 AD9258BCPZ-125
Parameter Temperature Min Typ Max Min Typ Max Min Typ Max Unit
CLOCK INPUT PARAMETERS
Input Clock Rate Full 625 625 625 MHz
Conversion Rate1
DCS Enabled Full 20 80 20 105 20 125 MSPS
DCS Disabled Full 10 80 10 105 10 125 MSPS
CLK Period—Divide-by-1 Mode (t
CLK Pulse Width High (tCH)
Divide-by-1 Mode, DCS Enabled Full
Divide-by-1 Mode, DCS Disabled Full
Divide-by-2 Mode Through
Divide-by-8 Mode
Aperture Delay (tA) Full 1.0 1.0 1.0 ns
Aperture Uncertainty (Jitter, tJ) Full 0.07 0.07 0.07
DATA OUTPUT PARAMETERS
CMOS Mode
Data Propagation Delay (tPD) Full 2.8 3.5
DCO Propagation Delay (t
DCO to Data Skew (t
SKEW
LVDS Mode
Data Propagation Delay (tPD Full 2.9 3.7 4.5 2.9 3.7 4.5 2.93.7 4.5 ns
DCO Propagation Delay (t
DCO to Data Skew (t
SKEW
CMOS Mode Pipeline Delay
(Latency)
LVDS Mode Pipeline Delay
(Latency) Channel A/Channel B
Wake-Up Time3 Full 500 500 500 μs
Out-of-Range Recovery Time Full 2 2 2 Cycles
1
Conversion rate is the clock rate after the divider.
2
Additional DCO delay can be added by writing to Bit 0 through Bit 4 in SPI Register 0x17 (see Table 17).
3
Wake-up time is defined as the time required to return to normal operation from power-down mode.
SYNC to rising edge of CLK+ setup time 0.30 ns typ
SSYNC
t
SYNC to rising edge of CLK+ hold time 0.40 ns typ
HSYNC
SPI TIMING REQUIREMENTS
tDS Setup time between the data and the rising edge of SCLK 2 ns min
tDH Hold time between the data and the rising edge of SCLK 2 ns min
t
Period of the SCLK 40 ns min
CLK
tS Setup time between CSB and SCLK 2 ns min
tH Hold time between CSB and SCLK 2 ns min
t
SCLK pulse width high 10 ns min
HIGH
t
SCLK pulse width low 10 ns min
LOW
t
EN_SDIO
t
DIS_SDIO
Timing Diagrams
CH A/CH B DATA
CH A/CH B DATA
VIN
CLK+
CLK–
DCOA/DCOB
VIN
CLK+
CLK–
DCOA/DCOB
Time required for the SDIO pin to switch from an input to an output relative to the SCLK
falling edge
Time required for the SDIO pin to switch from an output to an input relative to the SCLK
rising edge
N – 1
t
CH
t
A
N
N + 1
t
CLK
t
DCO
t
SKEW
N – 12N – 13
t
PD
N + 2
N – 11N – 10N – 9N – 8
Figure 2. CMOS Default Output Mode Data Output Timing
N – 1
t
CH
t
DCO
t
A
N
N + 1
t
CLK
t
SKEW
t
PD
CH A
CH B
N – 12
N – 12
CH A
N – 11
N + 2
CH B
N – 11
CH A
N – 10
Figure 3. CMOS Interleaved Output Mode Data Output Timing
N + 3
N + 3
CH B
N – 10
CH A
N – 9
N + 4
N + 4
CH B
N – 9
CH A
N – 8
N + 5
N + 5
10 ns min
10 ns min
08124-002
08124-057
Rev. A | Page 10 of 44
AD9258
VIN
CLK+
CLK–
DCOA/DCOB
CH A/CH B DATA
N – 1
CH A
N – 9
N + 4
CH B
N – 9
CH A
N – 8
N + 5
08124-003
t
A
N
N + 1
t
CH
t
DCO
t
CLK
t
t
SKEW
PD
CH A
CH B
N – 12
N – 12
CH A
N – 11
N + 2
CH B
N – 11
CH A
N – 10
N + 3
CH B
N – 10
Figure 4. LVDS Mode Data Output Timing
CLK+
SYNC
t
SSYNC
t
HSYNC
08124-004
Figure 5. SYNC Input Timing Requirements
Rev. A | Page 11 of 44
AD9258
ABSOLUTE MAXIMUM RATINGS
Table 6.
Parameter Rating
ELECTRICAL
1
AVDD to AGND −0.3 V to +2.0 V
DRVDD to AGND −0.3 V to +2.0V
VIN+A/VIN+B, VIN−A/VIN−B to AGND −0.3 V to AVDD + 0.2 V
CLK+, CLK− to AGND −0.3 V to AVDD + 0.2 V
SYNC to AGND −0.3 V to AVDD + 0.2 V
VREF to AGND −0.3 V to AVDD + 0.2 V
SENSE to AGND −0.3 V to AVDD + 0.2 V
VCM to AGND −0.3 V to AVDD + 0.2 V
RBIAS to AGND −0.3 V to AVDD + 0.2 V
CSB to AGND −0.3 V to DRVDD + 0.2 V
SCLK/DFS to AGND −0.3 V to DRVDD + 0.2 V
SDIO/DCS to AGND −0.3 V to DRVDD + 0.2 V
OEB −0.3 V to DRVDD + 0.2 V
PDWN −0.3 V to DRVDD + 0.2 V
D0A/D0B through D13A/D13B to
AGND
DCOA/DCOB to AGND
−0.3 V to DRVDD + 0.2 V
−0.3 V to DRVDD + 0.2 V
ENVIRONMENTAL
Operating Temperature Range
−40°C to +85°C
(Ambient)
Maximum Junction Temperature
150°C
Under Bias
Storage Temperature Range
−65°C to +150°C
(Ambient)
1
The inputs and outputs are rated to the supply voltage (AVDD or DRVDD) +
0.2 V but should not exceed 2.1 V.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
THERMAL CHARACTERISTICS
The exposed paddle must be soldered to the ground plane for
the LFCSP package. Soldering the exposed paddle to the PCB
increases the reliability of the solder joints and maximizes the
thermal capability of the package.
Typical θ
is specified for a 4-layer PCB with a solid ground
JA
plane. As shown in Table 7, airflow improves heat dissipation,
which reduces θ
. In addition, metal in direct contact with the
JA
package leads from metal traces, through holes, ground, and
power planes, reduces θ
.
JA
Table 7. Thermal Resistance
Airflow
Packa ge Type
64-Lead LFCSP
(CP-64-6)
Veloc ity
(m/sec) θ
0 18.5 1.0 °C/W
1.0 16.1 9.2 °C/W
1, 2
JA
1, 3
θ
JC
1, 4
θ
Unit
JB
2.5 14.5 °C/W
1
Per JEDEC 51-7, plus JEDEC 25-5 2S2P test board.
2 Per JEDEC JESD51-2 (still air) or JEDEC JESD51-6 (moving air).
3 Per MIL-Std 883, Method 1012.1.
4 Per JEDEC JESD51-8 (still air).
ESD CAUTION
Rev. A | Page 12 of 44
AD9258
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
AVDD
AVDD
VIN+B
VIN–B
AVDD
AVDD
RBIAS
VCM
SENSE
VREF
AVDD
AVDD
VIN–A
VIN+A
AVDD
646362616059585756555453525150
AVDD
49
CLK+
CLK–
SYNC
NC
NC
D0B (LSB)
D1B
D2B
D3B
DRVDD
10
D4B
11
D5B
12
D6B
13
D7B
14
D8B
15
D9B
16
NOTES
1. NC = NO CONNECT.
2. THE EXPOSED THERMAL PAD ON THE BOTTOM OF THE PACKAGE
PROVIDES THE ANALOG G ROUND FOR THE P ART. THIS EXPOSED
PAD MUST BE CONNECTED TO GROUND FOR PROPE R OPERATIO N.