TI ADS5294

ADS5294
www.ti.com
SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
Octal Channel 14-Bit, 80 MSPS High-SNR and Low-Power ADC
Check for Samples: ADS5294
FEATURES
DESCRIPTION
•
•
Using CMOS process technology and innovative
circuit techniques, the ADS5294 is a low power
80MSPS 8-Channel ADC. Low power consumption,
high SNR, low SFDR, and consistent overload
recovery allow users to design high performance
systems.
1
•
•
•
•
•
•
•
•
Maximum Sample Rate: 80 MSPS/14-Bit
High Signal-to-Noise Ratio
– 75.5-dBFS SNR at 5 MHz/80 MSPS
– 78.2-dBFS SNR at 5 MHz/80 MSPS and
Decimation Filter Enabled
– 84-dBc SFDR at 5 MHz/80 MSPS
Low Power Consumption
– 58 mW/CH at 50 MSPS
– 77 mW/CH at 80 MSPS (2 LVDS Wire Per
Channel)
Digital Processing Block
– Programmable FIR Decimation Filter and
Oversampling to Minimize Harmonic
Interference
– Programmable IIR High Pass Filter to
Minimize DC Offset
– Programmable Digital Gain: 0 dB to 12 dB
– 2- or 4- Channel Averaging
Flexible Serialized LVDS Outputs:
– One or Two Wires of LVDS Output Lines
per Channel Depending on ADC Sampling
Rate
– Programmable Mapping Between ADC
Input Channels and LVDS Output PinsEases Board Design
– Variety of Test Patterns to Verify Data
Capture by FPGA/Receiver
Internal and External References
1.8V Operation for Low Power Consumption
Low-Frequency Noise Suppression
Recovery From 6-dB Overload within 1 Clock
Cycle
Package: 12-mm × 12-mm 80-Pin QFP
APPLICATIONS
•
•
•
Ultrasound Imaging
Communication Applications
Multi-channel Data Acquisition
The ADS5294 has a digital processing block that
integrates several commonly used digital functions for
improving system performance. It includes a digital
filter module that has built-in decimation filters (with
low-pass, high-pass and band-pass characteristics).
The decimation rate is also programmable (by 2, by
4, or by 8). This makes it useful for narrow-band
applications, where the filters can be used
conveniently to improve SNR and knock-off
harmonics, while at the same time reducing the
output data rate. The device includes an averaging
mode where two channels (or even four channels)
can be averaged to improve SNR.
Serial LVDS outputs reduce the number of interface
lines and enable the highest system integration. The
digital data from each channel ADC can be output
over one or two wires of LVDS output lines
depending on the ADC sampling rate. This 2-wire
interface helps keep the serial data rate low, allowing
low cost FPGA based receivers to be used even at
high sample rate. The ADC resolution can be
programmed to 12 bit or 14 bit through registers. A
very unique feature is the programmable mapping
module that allows flexible mapping between the
input channels and the LVDS output pins. This helps
greatly reduce the complexity of LVDS output routing
and can potentially result in cheaper system boards
by reducing the number of PCB layers.
The device integrates an internal reference trimmed
to accurately match across devices. Best
performance is expected to be achieved through the
internal reference mode. The device can be driven
with external references as well.
The device is available in a 12 mm × 12 mm 80-pin
QFP. It is specified over a –40°C to 85°C operating
temperature range. ADS5294 is completely pin-to-pin
and register compatible to ADS5292.
1
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2011–2012, Texas Instruments Incorporated
ADS5294
SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
www.ti.com
This integrated circuit can be damaged by ESD. Texas Instruments recommends that all integrated circuits be handled with
appropriate precautions. Failure to observe proper handling and installation procedures can cause damage.
ESD damage can range from subtle performance degradation to complete device failure. Precision integrated circuits may be more
susceptible to damage because very small parametric changes could cause the device not to meet its published specifications.
Figure 1. Block Diagram
2
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PACKAGING/ORDERING INFORMATION (1)
(1)
PRODUCT
PACKAGE TYPE
OPERATING
ORDERING NUMBER
TRANSPORT MEDIA, QUANTITY
ADS5294IPFP
Tray, 480 (MOQ)
ADS5294
PFP
–40°C to 85°C
ADS5294IPFPR
Tape and Reel, 1000
ADS5294IPFPT
Tape and Reel, 250
For the most current package and ordering information see the Package Option Addendum at the end of this document, or see the TI
web site at www.ti.com.
PIN CONFIGURATION
IN8p
65
AGND
66
SDOUT
67
IN8n
68
AVDD
69
SYNC
70
VCM
71
NC
72
REFT
73
REFB
74
CLKp
75
AVDD
76
AVDD
77
CLKn
78
SDATA
79
CSZ
IN2n
SCLK
80
1
IN1n
IN2p
IN1p
AGND
80-PIN TQFP WITH THERMAL PAD
PFP PACKAGE (TOP VIEW)
64
63
62
61
60
IN7n
2
59
IN7p
AGND
3
58
AGND
IN3p
4
57
IN6n
IN3n
5
56
IN6p
AGND
6
55
AGND
IN4p
7
54
IN5n
IN4n
8
53
IN5p
AVDD
9
52
AVDD
51
RESET
50
LGND
Thermal Pad
OUT1A_n
14
47
OUT8A_p
OUT1B_p
15
46
OUT8B_n
OUT1B_n
16
45
OUT8B_p
OUT2A_p
17
44
OUT7A_n
OUT2A_n
18
43
OUT7A_p
OUT2B_p
19
42
OUT7B_n
OUT2B_n
20
21
22
23
24
25
26
27
39
41
40
OUT7B_p
OUT3A_n
OUT3B_p
OUT3B_n
OUT4A_p
OUT4A_n
OUT4B_p
OUT6A_p
OUT6A_n
30
31
32
33 34
35
36
OUT5A_n
29
OUT5B_n
28
37
38
OUT6B_p
OUT8A_n
OUT6B_n
48
OUT5A_p
13
OUT5B_p
LVDD
OUT1A_p
LCLK_p
49
LCLK_n
12
ACLK_p
LGND
ACLK_n
11
OUT4B_n
10
LVDD
OUT3A_p
ADS529X
80 TQFP
PD
PIN FUNCTIONS
PIN
NUMBER
OF PINS
NAME
5
AVDD
9, 52, 66, 71, 74
6
AGND
3, 6, 55, 58, 61, 80
1
VCM
68
Common-mode output pin, 0.95 V output. This pin can be configured as the external reference
voltage (1.5 V) input pin as well. See Reg 0x42.
1
CLKN
73
Negative differential clock –Tie CLKN to GND for single-ended clock
1
CLKP
72
Positive differential clock
2
IN1P, IN1N
78, 79
Differential input signal, Channel 1
2
IN2P, IN2N
1, 2
Differential input signal, Channel 2
2
IN3P, IN3N
4, 5
Differential input signal, Channel 3
DESCRIPTION
NUMBER
Analog power supply, 1.8V
Analog ground
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PIN FUNCTIONS (continued)
NUMBER
OF PINS
4
PIN
NAME
DESCRIPTION
NUMBER
2
IN4P, IN4N
7, 8
Differential input signal, Channel 4
2
IN5P, IN5N
53, 54
Differential input signal, Channel 5
2
IN6P, IN6N
56, 57
Differential input signal, Channel 6
2
IN7P, IN7N
59, 60
Differential input signal, Channel 7
2
IN8P, IN8N
62, 63
Differential input signal, Channel 8
2
LCLKP, LCLKN
31, 32
Differential LVDS bit clock (7X)
2
ACLKP, ACLKN
29, 30
Differential LVDS frame clock (1X)
2
OUT1A_P, OUT1A_N
13, 14
Differential LVDS data output, wire 1, channel 1
2
OUT1B_P, OUT1B_N
15, 16
Differential LVDS data output, wire 2, channel 1
2
OUT2A_P, OUT2A_N
17, 18
Differential LVDS data output, wire 1, channel 2
2
OUT2B_P, OUT2B_N
19, 20
Differential LVDS data output, wire 2, channel 2
2
OUT3A_P, OUT3A_N
21, 22
Differential LVDS data output, wire 1, channel 3
2
OUT3B_P, OUT3B_N
23, 24
Differential LVDS data output, wire 2, channel 3
2
OUT4A_P, OUT4A_N
25, 26
Differential LVDS data output, wire 1, channel 4
2
OUT4B_P, OUT4B_N
27, 28
Differential LVDS data output, wire 2, channel 4
2
OUT5A_P, OUT5A_N
35, 36
Differential LVDS data output, wire 1, channel 5
2
OUT5B_P, OUT5B_N
33, 34
Differential LVDS data output, wire 2, channel 5
2
OUT6A_P, OUT6A_N
39, 40
Differential LVDS data output, wire 1, channel 6
2
OUT6B_P, OUT6B_N
37, 38
Differential LVDS data output, wire 2, channel 6
2
OUT7A_P, OUT7A_N
43, 44
Differential LVDS data output, wire 1, channel 7
2
OUT7B_P, OUT7B_N
41, 42
Differential LVDS data output, wire 2, channel 7
2
OUT8A_P, OUT8A_N
47, 48
Differential LVDS data output, wire 1, channel 8
2
OUT8B_P, OUT8B_N
45, 46
Differential LVDS data output, wire 2, channel 8
1
PD
10
Power down control input. Active High. The pin has an internal 220-kΩ pulldown resistor.
1
REFB
69
Negative reference input/ output
1
REFT
70
Positive reference input/ output
1
RESET
51
Active HIGH RESET input. The pin has an internal 220-kΩ pulldown resistor.
1
SCLK
77
Serial clock input. The pin has an internal 220-kΩ pulldown resistor.
1
SDATA
76
Serial data input. The pin has an internal 220-kΩ pulldown resistor.
1
SDOUT
64
Serial data readout. This pin is in the high-impedance state after reset. When the <READOUT> bit
is set, the SDOUT pin becomes active. This is a CMOS digital output running from the AVDD
supply.
1
CSZ
75
Serial enable chip select – active low digital input
1
SYNC
65
Input signal to synchronize channels and chips when used with reduced output data rates. If it is
not used, add a ≤ 10 KΩ pull-down resistor.
2
LVDD
11, 49
Digital and I/O power supply, 1.8V
2
LGND
12, 50
Digital ground
1
NC
67
No Connection. Must leave floated
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ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
VALUE
UNIT
MIN
MAX
Supply voltage AVDD
–0.3
2.2
V
LVDD
–0.3
2.2
V
between AGND and LGND
–0.3
0.3
V
at analog inputs
–0.3
min[2.2, AVDD+0.3]
V
at digital inputs, CLKN, CLKP (2), RESET, SCLK, SDATA, CSZ
–0.3
min[2.2, AVDD+0.3]
V
at digital outputs
–0.3
min[2.2,LVDD+0.3]
V
Voltage
Maximum junction temperature (TJ), any condition
105
°C
Storage temperature range
–55
150
°C
Operating temperature range
-40
85
°C
Human Body Model (HBM)
2000
V
Charged Device Model (CDM)
500
V
ESD Ratings
(1)
(2)
Stresses above those listed under absolute maximum ratings may cause permanent damage to the device. These are stress ratings
only and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating
conditions” is not implied Exposure to absolute maximum rated conditions for extended periods may degrade device reliability.
When AVDD is turned off, it is recommended to switch off the input clock (or ensure the voltage on CLKP, CLKN is < |0.3V|. This
prevents the ESD protection diodes at the clock input pins from turning on.
THERMAL INFORMATION
THERMAL METRIC (1)
ADS5294
PFP (80 PINS)
θJA
Junction-to-ambient thermal resistance
30.8
θJCtop
Junction-to-case (top) thermal resistance
6.3
θJB
Junction-to-board thermal resistance
8.3
ψJT
Junction-to-top characterization parameter
0.2
ψJB
Junction-to-board characterization parameter
8.2
θJCbot
Junction-to-case (bottom) thermal resistance
0.3
(1)
UNITS
°C/W
For more information about traditional and new thermal metrics, see the IC Package Thermal Metrics application report, SPRA953.
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RECOMMENDED OPERATING CONDITIONS
MIN
TYP
MAX
UNIT
SUPPLIES
AVDD
Analog supply voltage
1.7
1.8
1.9
V
LVDD
Digital supply voltage
1.7
1.8
1.9
V
ANALOG INPUTS/OUTPUTS
Differential input voltage range
2
Input common-mode voltage
VPP
0.95±0.05
V
REFT
External reference mode
1.45
V
REFB
External reference mode
0.45
V
VCM
Common-mode voltage output
0.95
V
External Reference mode Input
Maximum Input Frequency
(1)
2 VPP amplitude
1.5
V
80
MHz
CLOCK INPUTS
ADC Clock input sample rate
Input Clock amplitude differential (V(CLKP) V(CLKN)) peak-to-peak
VIL
10
Sine wave, AC-coupled
0.2
1.5
LVPECL, AC-coupled
0.2
1.6
LVDS, AC-coupled
0.2
0.7
V
>1.5
Input clock duty cycle
35%
50%
MSPS
VPP
<0.3
Input Clock CMOS single-ended (V(CLKP))
VIH
80
V
65%
DIGITAL OUTPUTS
ACLKP and ACLKN outputs (LVDS), 1-wire interface
1x (sample
rate)
MSPS
LCLKP and LCLKN outputs (LVDS), 1-wire interface
7x (sample
rate)
MSPS
ACLKP and ACLKN outputs (LVDS), 2-wire interface
0.5x (sample
rate)
MSPS
LCLKP and LCLKN outputs (LVDS), 2-wire interface
3.5x (sample
rate)
MSPS
Maximum data rate, 2-wire interface
560
Mbps
Maximum data rate, 1-wire interface
700
Mbps
CLOAD
Maximum external capacitance from each output pin to LGND
RLOAD
Differential load resistance between the LVDS output pairs
TA
Operating free-air temperature
(1)
6
5
pF
Ω
100
-40
85
°C
See the Large and Small Signal Input Bandwidth section.
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
ELECTRICAL CHARACTERISTICS DYNAMIC PERFORMANCE
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8 V, 50% clock duty cycle, –1 dBFS differential analog input, Sample
rate = 80 MSPS, ADC is configured in internal reference mode (unless otherwise noted). MIN and MAX values are across the
full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = 1.8 V, LVDD = 1.8 V.
PARAMETERS
CONDITIONS
MIN
TYP
MAX
UNITS
AC PERFORMANCE
fin = 10 MHz, 65 MSPS
SNR
SINAD
Signal-to-noise ratio
Signal-to-noise and distortion ratio
fin = 5 MHz, TA = 25°C
72.8
fin = 5 MHz, Across temperatures
71.8
dBFS
78.2
dBFS
fin = 30 MHz
74.2
dBFS
fin = 65 MHz
71.7
dBFS
fin = 5 MHz
74.8
dBFS
fin = 30 MHz
73.4
dBFS
fin = 65 MHz
70
dBFS
DNL
Differential nonlinearity
fin = 5 MHz
INL
Integral nonlinearity
fin = 5 MHz
12.2
–0.96
fin = 5 MHz
72
Second-harmonic distortion
Third-harmonic distortion
Worse spur excluding HD2, HD3
IMD3
XTALK
LSB
2.2
5.5
LSB
dBc
81
dBc
fin = 65 MHz
74
dBc
82
dBc
fin = 30 MHz
80
dBc
fin = 65 MHz
73.5
dBc
70.5
93
dBc
fin = 30 MHz
73
88
dBc
fin = 65 MHz
85
dBc
84
dBc
fin = 30 MHz
81
dBc
fin = 65 MHz
74
dBc
fin = 5 MHz
91
dBc
fin = 30 MHz
83
dBc
fin = 65 MHz
76
dBc
84.5
dBc
fin = 5 MHz
HD3
1.7
fin = 30 MHz
fin = 5 MHz
HD2
Bits
±0.5
84
fin = 5 MHz
Total harmonic distortion
dBFS
fin = 5 MHz, Decimation by two enabled
fin = 5 MHz
THD
dBFS
77.3
Effective number of bits
Spurious-free dynamic range
dBFS
75.5
fin = 5 MHz, -60 dBFS Input signal amplitude
ENOB
SFDR
75.6
72
Intermodualtion distortion
fin = 8 MHz at –7 dBFS, f2 = 10 MHz at –7 dBFS
Overload recovery
Recovery to within 1% of full-scale for 6-dB overload with
sine wave input
Cross-talk
fin = 10 MHz, -1 dBFS signal applied on
aggressor channel no signal applied on
victim channel
Phase noise
5 MHz, 1 kHz off carrier
far channel
near channel
1
Clock Cycle
90
dBc
85
–138
dBc
dBc/Hz
ANALOG INPUT / OUTPUT
Differential input voltage range
(0-dB gain)
2
VPP
kΩ
RIN
Differential Input Resistance
At DC
2
CIN
Differential Input Capacitance
At DC
3.2
pF
Analog input bandwidth
With a 50 Ωsource impedance
550
MHz
Analog input common-mode current
(per input pin)
1.6
µA/MSPS
VCM common-mode output voltage
0.95
V
VCM output current capability
5
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ELECTRICAL CHARACTERISTICS DYNAMIC PERFORMANCE (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8 V, 50% clock duty cycle, –1 dBFS differential analog input, Sample
rate = 80 MSPS, ADC is configured in internal reference mode (unless otherwise noted). MIN and MAX values are across the
full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = 1.8 V, LVDD = 1.8 V.
PARAMETERS
CONDITIONS
MIN
TYP
MAX
UNITS
DC ACCURACY
Offset error
Across devices and across channels within a device
–15
Temperature coefficient of offset error
E(GREF)
Gain error due to internal reference
inaccuracy alone
E(GCHAN)
Gain error of channel alone
15
<0.01
Across devices
-2
2
0.5
Temperature coefficient of E(GCHAN)
mV
mV/ °C
%FS
%FS
<0.01
%FS/ °C
80 MSPS, 14 Bit, 2-wire LVDS
77
mW/CH
50 MSPS, 1-wire LVDS
58
mW/CH
40 MSPS, 14 Bit, 1-wire LVDS
52
mW/CH
10 MSPS, 14 Bit, 1-wire LVDS
33
mW/CH
fin = 10 MHz, 80 MSPS, 14 Bit,
Decimation filter = 2, 1-wire LVDS
100
mW/CH
14 Bit, 80 MSPS
230
14 Bit, 65 MSPS
200
14 Bit, 40 MSPS
155
80 MSPS, 14 Bit, 2-wire LVDS
111
50 MSPS, 14 Bit, 1-wire LVDS
80
mA
40 MSPS, 14 Bit, 1-wire LVDS
73
mA
80 MSPS, 1 Bit, Decimation filter = 2,
1-wire LVDS
210
mA
Partial Power Down (80 MSPS, 2-wire)
175
POWER SUPPLY
Power consumption
AVDD
LVDD
Power-down power consumption
8
Complete Power Down
265
mA
mA
mA
122
mA
mW
60
mW
Power supply modulation ratio
Carrier = 5 MHz, f(PSRR) = 10 kHz, 50 mVpp on AVDD
35
dB
Power supply rejection ratio
AC power supply rejection ratio f = 10 kHz
55
dB
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DIGITAL CHARACTERISTICS
The DC specifications refer to the condition where the digital outputs are not switching, but are permanently at a valid logic
level 0 or 1. AVDD = 1.8V, LVDD = 1.8V
PARAMETERS
CONDITION
MIN
TYP
MAX
UNITS
DIGITAL INPUTS/OUTPUTS
All digital inputs support 1.8-V and 3.3-V CMOS
logic levels.
VIH
Logic high input voltage
VIL
Logic low input voltage
IIH
Logic high input current
VHIGH = 1.8 V
IIL
Logic low input current
VLOW = 0 V
VOH
Logic high output voltage
VOL
Logic low output voltage
1.3
V
0.4
V
6
µA
< 0.1
µA
AVDD - 0.1
V
0.2
V
LVDS OUTPUTS
VODH
High-level output differential
voltage
100 Ω external termination
245
350
405
mV
VODL
Low-level output differential
voltage
100 Ω external termination
–245
–350
–405
mV
VOCM
Output common-mode voltage
900
1100
1300
mV
OUTP
Logic
Logic
0 0
VODL = -350 mV*
Logic 0
VODH = +350 mV*
OUTM
VOCM
GND
GND
*With external 100-W termination
Figure 2. LVDS Output Voltage Levels
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TIMING REQUIREMENTS (1) (2) (3)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8 V, sampling frequency = 80 MSPS, 14-bit, sine wave input clock = 1.5
Vpp clock amplitude, CLOAD = 5 pF, RLOAD = 100 Ω, unless otherwise noted. MIN and MAX values are across the full
temperature range TMIN = –40°C to TMAX = 85°C, AVDD = 1.8 V, LVDD = 1.7 V to 1.9 V
PARAMETERS
ta
CONDITIONS
Aperture delay
The delay in time between the rising edge of the input
sampling clock and the actual time at which the sampling
occurs
Aperture delay variation
Across channels within the same device
MIN
Across devices at the same temperature and LVDD supply
tj
Aperture jitter RMS
td
Data latency
TYP
MAX
UNITS
4
ns
±175
ps
2.5
ns
320
fs rms
1-wire LVDS output interface
11
Clock
cycles
2-wire LVDS output interface
15
Clock
cycles
tSU
Data setup time
80 MSPS, 2 wire LVDS, 7x serialization
0.34
0.57
ns
tH
Data hold time
80 MSPS, 2 wire LVDS, 7x serialization
0.55
0.8
ns
Clock propagation delay
Input clock rising edge(zero cross) to frame clock rising
edge(zero cross)
Variation of tPROP
Between two devices at same temperature and LVDD supply
tPROP
See Table 1 and Table 2
LVDS bit clock duty cycle
±0.75
ns
48%
tRISE
Data rise time
Rise time is from -100 mV to + 100 mV, 10 ≤ Fs ≤ 80 MSPS
0.24
ns
tFALL
Data fall time
Fall time is from +100 mV to -100 mV, 10 ≤ Fs ≤ 80 MSPS
0.24
ns
tCLKRISE
Output clock rise time
Rise time is from -100 mV to +100 mV, 10 ≤ Fs ≤ 80 MSPS
0.20
ns
tCLKFALL
Output clock fall time
Fall time is from +100 mV to -100 mV, 10 ≤ Fs ≤ 80 MSPS
0.20
ns
Wake-up Time
Time to valid data after coming out of COMPLETE POWERDOWN mode
100
µs
5
µs
tWAKE
Time to valid data after coming out of PARTIAL POWERDOWN mode (with clock continuing to run during powerdown)
(1)
(2)
(3)
10
Timing parameters are ensured by design and characterization and not tested in production.
Measurements are done with a transmission line of 100-Ω characteristic impedance between the device and the load. Setup and hold
time specifications take into account the effect of jitter on the output data and clock.
Data valid refers to logic HIGH of 100 mV and logic LOW of –100 mV.
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
Table 1. LVDS Timing at Different Sampling Frequencies - 2 Wire Interface, 7x Serialization
(1)
(2)
LVDS Output Rate (MSPS)
Setup Time (tsu), ns
Hold Time (tH), ns
tPROG = (6/7) × T + tdelay, ns (2)
Fs = 1/T
Data Valid to ZeroCrossing of LCLKP
(both edges)
Zero-Crossing of LCLKP to
Data Becoming Invalid
(both edges)
tPROG = delay from Input clock zero-cross
rising edge to frame clock zero cross (rising
edge)
MIN
TYP
MIN
TYP
MIN
TYP
MAX
80
0.34
0.57
MAX
0.55
0.8
MAX
8
9.5
11
65
0.35
0.64
0.8
1.1
8
9.5
11
50
0.7
0.9
1.2
1.5
8
9.5
11
40
1
1.3
1.6
1.85
8
9.5
11
30
1.7
2
2
2.3
8
9.5
11
20
2.9
3.2
3.2
3.5
8
9.5
11
10
6.5
6.7
6.7
7
8
9.5
11
Bit clock and Frame clock jitter has been included in the Setup and hold timing.
Values below correspond to tdelay, NOT tPROG
Table 2. LVDS Timing at Different Sampling Frequencies - 1 Wire Interface, 14x Serialization
(1)
(2)
(1)
(1)
LVDS Output Rate (MSPS)
Setup Time (tsu), ns
Hold Time (tH), ns
tPROG = (5/7) × T + tdelay, ns (2)
Fs = 1/T
Data Valid to ZeroCrossing of LCLKP
(both edges)
Zero-Crossing of LCLKP to
Data Becoming Invalid
(both edges)
tPROG = delay from Input clock zero-cross
rising edge to frame clock zero cross (rising
edge)
MIN
TYP
MIN
TYP
MIN
TYP
MAX
50
0.28
0.48
MAX
0.28
0.6
MAX
7.5
9
10.5
40
0.5
0.68
0.54
0.8
7.5
9
10.5
30
0.62
0.8
1
1.25
7.5
9
10.5
20
1.2
1.4
1.6
1.9
7.5
9
10.5
10
3.1
3.3
3.3
3.5
7.5
9
10.5
Bit clock and Frame clock jitter has been included in the Setup and hold timing.
Values below correspond to tdelay, NOT tPROG
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12
Output Data
CHnOUT
Data rate = 14 x fCLKIN
Bit Clock
LCLK
Freq = 7 x fCLKIN
Frame Clock
ACLK
Freq = fCLKIN
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
D0
D1
(D12) (D13)
D13
(D0)
D12
(D1)
D11
(D2)
D13
(D0)
D10
(D3)
D9
(D4)
D7
(D6)
D6
(D7)
D5
(D8)
D4
(D9)
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Data bit in LSB First mode
Data bit in MSB First mode
SAMPLE N-td
D8
(D5)
ta
Sample N
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
td clock cycles
latency
D13
(D0)
D12
(D1)
D11
(D2)
D10
(D3)
D9
(D4)
D7
(D6)
SAMPLE N-1
D8
(D5)
D6
(D7)
Sample
N+td
ta
D5
(D8)
D4
(D9)
tPROG
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D13
(D0)
D12
(D1)
D11
(D2)
D10
(D3)
D9
(D4)
D7
(D6)
SAMPLE N
D8
(D5)
Sample
N+td+1
D6
(D7)
T
D5
(D8)
D4
(D9)
D0
D1
D3
D2
(D10) (D11) (D12) (D13)
D11
(D0)
D10
(D1)
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LVDS TIMING DIAGRAM
Figure 3. 14-Bit 1 wire LVDS Timing Diagram
Copyright © 2011–2012, Texas Instruments Incorporated
Output Data
CHnOUT
Data rate = 14 x fCLKIN
Bit Clock
LCLK
Freq = 7 x fCLKIN
Frame Clock
ACLK
Freq = fCLKIN
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
D0
D1
(D12) (D13)
D13
(D0)
D12
(D1)
D11
(D2)
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D13
(D0)
D10
(D3)
D9
(D4)
D7
(D6)
D6
(D7)
D5
(D8)
D4
(D9)
Data bit in LSB First mode
Data bit in MSB First mode
SAMPLE N-td
D8
(D5)
ta
Sample N
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
td clock cycles
latency
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Figure 4. Enlarged 1 wire LVDS Timing Diagram (14bit)
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13
14
D1
D0
(D12) (D13)
Output Data
CHnOUT A
Data rate = 7 x fCLKIN
D7
(D6)
D8
(D5)
Output Data
CHnOUT B
Data rate = 7 x fCLKIN
Bit Clock
DCLK
Freq = 3.5 x fCLKIN
Frame Clock
FCLK
Freq = fCLKIN/2
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
D13
(D0)
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
Sample N-1
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
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Data bit in LSB First mode
Data bit in MSB First mode
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
D9
(D4)
D8
(D5)
D7
(D6)
td cycles latency
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
SAMPLE N-td
D4
(D9)
D11
(D2)
ta
Sample N
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
D9
(D4)
D8
(D5)
D7
(D6)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
SAMPLE N-1
D4
(D9)
D11
(D2)
Sample
N+td
ta
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
SAMPLE N
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
tPROP
Sample
N+td+1
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
D9
(D4)
D8
(D5)
D7
(D6)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
SAMPLE N+1
D4
(D9)
D11
(D2)
D6
(D7)
D13
(D0)
T
D5
(D8)
D12
(D1)
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
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Figure 5. 14-Bit 2 wire LVDS Timing Diagram
Copyright © 2011–2012, Texas Instruments Incorporated
D1
D0
(D12) (D13)
Output Data
CHnOUT A
Data rate = 7 x fCLKIN
D7
(D6)
D8
(D5)
Output Data
CHnOUT B
Data rate = 7 x fCLKIN
Bit Clock
DCLK
Freq = 3.5 x fCLKIN
Frame Clock
FCLK
Freq = fCLKIN/2
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
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D13
(D0)
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
Sample N-1
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
Data bit in LSB First mode
Data bit in MSB First mode
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
D6
(D7)
D13
(D0)
D5
(D8)
D12
(D1)
D9
(D4)
D8
(D5)
D7
(D6)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D10
(D3)
SAMPLE N-td
D4
(D9)
D11
(D2)
ta
Sample N
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Figure 6. Enlarged 2 wire LVDS Timing Diagram (14bit)
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Figure 7. Definition of Setup and Hold Times tSU = min(tSU1, tSU2); tH = min(tH1, tH2)
16
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
TYPICAL CHARACTERISTICS
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
0
0
SNR = 76.1 dBFS
SINAD = 75.7 dBFS
SFDR = 87 dBc
THD =84.7 dBc
−10
−20
−30
−30
−40
−40
−50
−50
Amplitude (dB)
Amplitude (dB)
−20
−60
−70
−80
−60
−70
−80
−90
−90
−100
−100
−110
−110
−120
−120
−130
−130
−140
10
20
Frequency (MHz)
30
−140
40
Figure 8. FFT for 5 MHz Input Signal,
Sample Rate = 80 MSPS
20
Frequency (MHz)
30
40
0
SNR = 70.7 dBFS
SINAD =69.5 dBFS
SFDR = 74.9 dBc
THD =74.55 dBc
−20
−20
−30
−30
−40
−40
−50
−50
−60
−70
−80
−60
−70
−80
−90
−90
−100
−100
−110
−110
−120
−120
−130
−130
10
20
Frequency (MHz)
30
40
SNR = 76.5 dBFS
SINAD = 76.5 dBFS
SFDR = 90.23 dBc
THD = 87 dBc
−10
Amplitude (dB)
Amplitude (dB)
10
Figure 9. FFT for 15 MHz Input Signal,
Sample Rate = 80 MSPS
0
−10
−140
SNR = 75.5 dBFS
SINAD = 74.4 dBFS
SFDR = 80.3 dBc
THD =79.7 dBc
−10
−140
Figure 10. FFT for 65 MHz Input Signal,
Sample Rate = 80 MSPS
5
10
Frequency (MHz)
15
Figure 11. FFT for 5 MHz Input Signal,
Sample Rate = 40 MSPS
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
0
0
SNR = 76.5 dBFS
SINAD = 76.5 dBFS
SFDR = 88.4 dBc
THD = 87 dBc
−10
−20
−30
−30
−40
−40
−50
−50
Amplitude (dB)
Amplitude (dB)
−20
−60
−70
−80
−60
−70
−80
−90
−90
−100
−100
−110
−110
−120
−120
−130
−130
−140
5
10
Frequency (MHz)
fIN1 = 8 MHz
fIN2 = 10 MHz
Each Tone at −7dBFS Amplitude
Two Tone IMD = −91.4 dBFS
−10
15
−140
20
10
Figure 12. FFT for 15 MHz Input Signal,
Sample Rate = 40 MSPS
20
Frequency (MHz)
30
40
Figure 13. Two Tone Intermodulation
77
86
76
84
82
75
SFDR (dBc)
SNR (dBFS)
80
74
73
78
76
72
74
71
70
72
5
15
25
35
45
55
65
Input Signal frequency (MHz)
75
85
Figure 14. Signal -To-Noise Ratio vs. Input Signal
Frequency
18
70
5
15
25
35
45
55
65
Input Signal frequency (MHz)
75
85
Figure 15. Spurious-Free Dynamic Range vs. Input Signal
Frequency
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
80
90
Input frequency = 10 MHz
Input frequency = 70 MHz
76
86
72
82
SFDR (dBc)
68
64
60
78
74
0
1
2
3
4
5
6
7
8
Digital gain (dB)
9
10
11
70
12
0
1
2
3
4
5
6
7
8
Digital gain (dB)
9
10
11
G001
G001
Figure 16. SNR vs. Digital Gain
Figure 17. SFDR vs. Digital Gain
80
79.5
100
79
90
78.5
80
78
70
77.5
60
77
50
76.5
40
76
30
75.5
SNR
SFDR(dBc)
SFDR(dBFS)
10
0
−96
−86
−76
−66 −56 −46 −36 −26
Input amplitude (dBFS)
−16
−6 0
75
SFDR
SNR
SFDR (dBc)
110
78
88
SNR (dBFS)
SFDR (dBFS,dBc)
120
20
12
87
77
86
76
85
75
84
74
83
73
SNR (dBFS)
SNR (dBFS)
Input frequency = 10 MHz
Input frequency = 70 MHz
74.5
74
Figure 18. Performance vs. Input Amplitude
82
0.2
0.4
0.6 0.8 1 1.2 1.4 1.6 1.8 2
Input Clock Amplitude, differential (Vp−p)
2.2
72
2.4
Figure 19. Performance vs. Clock Input Amplitudes
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
77
86
77.5
88
77
87
76.5
86
76
85
75.5
74.5
83.5
84
75
83
74.5
82
74
81
73.5
SNR (dBFS)
SFDR (dBc)
75
84
SNR (dBFS)
SFDR (dBc)
89
75.5
84.5
74
83
73.5
82.5
35
40
45
50
55
Input Clock Duty Cycle (%)
60
65
73
80
0.80
Figure 20. Performance vs. Input Clock Duty Cycle
73
1.10
0.85
0.90
0.95
1.00
1.05
Analog Input Common−mode voltage (V)
Figure 21. Performance vs. Input VCM
77.0
88
AVDD=1.65V
AVDD=1.7V
AVDD=1.8V
AVDD=1.9V
AVDD=1.95V
76.5
AVDD=1.65V
AVDD=1.7V
AVDD=1.8V
AVDD=1.9V
AVDD=1.95V
87
86
85
SFDR (dBc)
76.0
SNR (dBFS)
SFDR
SNR
76
85
82
Fin = 5 MHz
76.5
85.5
78
90
SFDR
SNR
75.5
75.0
84
83
82
81
80
74.5
79
74.0
−40
−20
0
20
40
Temperature (°C)
60
80
Figure 22. Signal -To-Noise Ratio vs. Temperature
20
78
−40
−20
0
20
40
Temperature (°C)
60
80
Figure 23. Spurious-Free Dynamic Range vs. Temperature
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
100
−110
Far Channel
Near Channel
95
Phase Noise (dBc/Hz)
−120
Crosstalk (dB)
90
85
80
−140
−150
75
70
−130
10
20
30
40
50
60
Frequency of Aggressor Channel (MHz)
−160
0.01
70
Figure 24. Crosstalk vs. Frequency
0.1
1
Frequency Offset (kHz)
10
100
Figure 25. Phase Noise for 5 MHz Input Signal,
Sample Rate = 80 MSPS
0.3
0.8
0.7
0.6
0.2
0.5
0.4
0.3
0.1
DNL (LSB)
INL (LSB)
0.2
0.1
0.0
−0.1
0.0
−0.2
−0.1
−0.3
−0.4
−0.5
−0.2
−0.6
−0.7
−0.8
900
3900
6900
9900
Output_codes (dB)
12900
15900
−0.3
900
Figure 26. Integral Non-Linearity
3900
6900
9900
Output_codes (LSB)
12900
Figure 27. Differential Non-Linearity
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
80
With 50mVpp signal superimposed on input common−mode
Fin = 3 MHz
45.5
70
CMRR (dB)
31.53
16.18
60
50
40
5.55
0.03
0.1
0.11
30
Figure 28. Histogram of Output Code with Analog Inputs
Shorted
20
30
40
50
Frequency of CMRR signal (MHz)
60
70
20
With 50mVpp signal
superimposed on AVDD supply
PSMR: 3MHz input signal applied
PSRR: No input signal applied
PSMR
PSRR
Low Pass
High pass
10
0
−30
Normalized Amplitude (dB)
Power Supply Rejection (dB)
10
Figure 29. Common Mode Rejection Ratio vs. Frequency
−10
−20
0
−40
−50
−60
−10
−20
−30
−40
−50
−60
−70
−70
−80
0.01
0.1
1
10
Frequency of signal on supply (MHz)
70
Figure 30. Power Supply Rejection Ratio vs. Frequency
22
−80
0.0
0.1
0.2
0.3
0.4
Normalized Frequency (fin/fs)
0.5
Figure 31. Filter Response, Decimate by 2
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
40
0
Low Pass
Band−Pass1
Band−Pass2
High Pass
30
20
SNR = 78.2 dBFS
SINAD = 78.2 dBFS
Decimate by 2 Filter Enabled
−10
−20
−30
−40
0
−50
Amplitude (dB)
Normalized Amplitude (dB)
10
−10
−20
−30
−60
−70
−80
−90
−40
−100
−50
−110
−60
−120
−70
−130
−80
0.0
0.1
0.2
0.3
Normalized frequency (fin/fs)
0.4
−140
0.5
Figure 32. Filter Response, Decimate by 4
5
10
Frequency (MHz)
15
3
SNR = 77.9 dBFS
SINAD = 77.9 dBFS
SFDR = 93.13 dBc
THD = −96 dBc
2 Channels averaged
−20
−30
0
−3
−6
−9
Normalized Amplitude (dB)
−40
−50
−60
−70
−80
−90
−100
−12
−15
−18
−21
−24
K=2
K=3
K=4
K=5
K=6
K=7
K=8
K=9
K=10
−27
−30
−33
−110
−36
−120
−39
−130
−42
−140
20
Figure 33. FFT for 5 MHz Input Signal, Sample
Rate = 80 MSPS with Decimation Filter = 2
0
−10
Amplitude (dB)
0
0
5
10
15
20
25
Frequency (MHz)
30
35
Figure 34. FFT for 5 MHz Input Signal, Sample
Rate = 80 MSPS by Averaging 2 Channels
40
−45
0.02
0.1
1
Input Signal Frequency (MHz)
10 15
Figure 35. Digital High-Pass Filter Response
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
0
0
−5
HPF_DISABLED
HPF_ENABLED
−10
−20
−15
−30
−25
−40
−35
−45
Amplitude (dB)
Amplitude (dB)
−50
−60
−70
−80
−90
−55
−65
−75
−100
−85
−110
−95
−120
−105
−130
−115
−140
−150
0
0.5
1
1.5
2
2.5
3
3.5
Input Signal Frequency (MHz)
4
4.5
−125
5
Figure 36. FFT with HPF Enabled and Disabled, No Signal
15
20
25
Frequency (MHz)
30
35
40
−20
−20
−30
−30
−40
−40
−50
−50
−60
−70
−80
−60
−70
−80
−90
−90
−100
−100
−110
−110
−120
−120
−130
−130
0
0.1
0.2
0.3
0.4 0.5 0.6 0.7
Frequency (MHz)
0.8
0.9
LF noise suppression enabled
LF noise suppression disabled
−10
Amplitude (dB)
Amplitude (dB)
10
0
LF noise suppression enabled
LF noise suppression disabled
1
Figure 38. FFT (0 to 1 MHz) for 5 MHz Input Signal, Sample
Rate = 80 MSPS with Low Frequency Noise Suppression
Enabled
24
5
Figure 37. FFT (Full-Band) for 5 MHz Input Signal, Sample
Rate = 80MSPS with Low Frequency Noise Suppression
Enabled
0
−10
−140
0
−140
39
39.1 39.2 39.3 39.4 39.5 39.6 39.7 39.8 39.9
Frequency (MHz)
40
Figure 39. FFT (39 MHz to 40 MHz) for 5 MHz Input Signal,
Sample Rate = 80 MSPS with Low Frequency Noise
Suppression Enabled
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TYPICAL CHARACTERISTICS (continued)
Typical values are at 25°C, AVDD = 1.8 V, LVDD = 1.8V, 50% clock duty cycle, –1 dBFS differential analog input, 14 Bit/80
MSPS, ADC is configured in the internal reference mode, unless otherwise noted.
450
350
2−wire
1−wire
1−wire Decimate by 2
325
400
300
350
Digital Power (mW)
Analog Power (mW)
275
300
250
250
225
200
175
150
125
200
100
75
150
10
20
30
40
50
60
Sampling Frequency (MSPS)
70
50
80
Figure 40. Power Consumption on Analog Supply
Figure 41. Power Consumption on Digital Supply
190
220
170
200
150
Digital Current (mA)
Analog Current (mA)
240
180
160
140
110
90
70
100
50
10
20
30
40
50
60
Sampling Frequency (MSPS)
70
Figure 42. Supply Current on Analog Supply
80
2−wire
1−wire
1−wire Decimate by 2
130
120
80
10 15 20 25 30 35 40 45 50 55 60 65 70 75 80
Sampling Frequency (MSPS)
30
10
20
30
40
50
60
Sampling Frequency (MSPS)
70
80
Figure 43. Supply Current on Digital Supply
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SERIAL INTERFACE
ADS5294 has a set of internal registers that can be accessed by the serial interface formed by pins CSZ (Serial
interface Enable – Active Low), SCLK (Serial Interface Clock) and SDATA (Serial Interface Data).
When CSZ is low,
• Serial shift of bits into the device is enabled.
• Serial data (SDATA) is latched at every rising edge of SCLK.
• SDATA is loaded into the register at every 24th SCLK rising edge
If the word length exceeds a multiple of 24 bits, the excess bits are ignored. Data can be loaded in multiples of
24-bit words within a single active CSZ pulse. The first eight bits form the register address and the remaining 16
bits the register data. The interface can work with SCLK frequencies from 15 MHz down to very low speeds (few
Hertz) and also with non-50% SCLK duty cycle.
Register Initialization
After power-up, the internal registers must be initialized to the respective default values. Initialization can be done
in one of two ways:
1. Through a hardware reset, by applying a high pulse on the RESET pin; or
2. Through a software reset; using the serial interface, set the RST bit high. Setting this bit initializes the
internal registers to the respective default values and then self-resets the bit low. In this case, the RESET pin
stays low (inactive).
REGISTER DATA
REGISTER ADDRESS
SDATA
A7
A6
A5
A4
A3
A2
A1
A0
D15
D14
D13
D12
tDSU
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
tDH
SCLK
tSLOADH
tSCLK
CSZ
tSLOADS
RESET
Figure 44. Serial Interface Timing
SERIAL INTERFACE TIMING CHARACTERISTICS
Typical values at 25°C, MIN and MAX values across the full temperature range TMIN = –40°C to TMAX = 85°C, AVDD = 1.8 V,
LVDD = 1.8 V, unless otherwise noted.
PARAMETER
MIN
MAX
UNIT
15
MHz
fSCLK
SCLK frequency (= 1/ tSCLK)
tSLOADS
CS to SCLK setup time
33
ns
tSLOADH
SCLK to CS hold time
33
ns
tDS
SDATA setup time
33
ns
tDH
SDATA hold time
33
ns
26
> DC
TYP
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RESET TIMING
Typical values at 25°C, MIN and MAX values across the full temperature range TMIN = –40°C to TMAX = 85°C (unless
otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
t1
Power-on delay
Delay from power up of AVDD and LVDD to RESET pulse active
t2
Reset pulse duration
Pulse duration of active RESET signal
t3
Register write delay
Delay from RESET disable to CSZ active
TYP MAX
1
50
UNIT
ms
ns
100
ns
POWER SUPPLY
AVDD, LVDD
t1
RESET
t2
t3
SEN
NOTE: A high-going pulse on RESET pin is required in serial interface mode in case of initialization through hardware reset.
For parallel interface operation, RESET has to be tied permanently HIGH.
Figure 45. Reset Timing Diagram
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Serial Register Readout
The device includes a mode where the contents of the internal registers can be read back on SDOUT pin. This
may be useful as a diagnostic check to verify the serial interface communication between the external controller
and the ADC.
By default, after power up and device reset, the SDOUT pin is in the high-impedance state. When the readout
mode is enabled using the register bit <READOUT>, SDOUT outputs the contents of the selected register
serially, described as follows.
• Set register bit <READOUT> = 1 to put the device in serial readout mode. This disables any further writes
into the internal registers, EXCEPT the register at address 1. Note that the <READOUT> bit itself is also
located in register 1.
The device can exit readout mode by writing <READOUT> to 0.
Only the contents of register at address 1 cannot be read in the register readout mode.
• Initiate a serial interface cycle specifying the address of the register (A7-A0) whose content is to be read.
• The device serially outputs the contents (D15–D0) of the selected register on the SDOUT pin.
• The external controller can latch the contents at the rising edge of SCLK.
• To exit the serial readout mode, reset register bit <READOUT> = 0, which enables writes into all registers of
the device. At this point, the SDOUT pin enters the high-impedance state.
A) Enable Serial Readout (<READOUT> = 1)
REGISTER DATA (D15:D0) = 0x0001
REGISTER ADDRESS (A7:A0) = 0x01
SDATA
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
SCLK
CSZ
Pin SDOUT Becomes
Active and Forces Low
Pin SDOUT is tri-stated
SDOUT
B) Read Contents of Register 0x0F.
This Register has been Initialized with 0x0200
(The Device was earlier put in global power down)
REGISTER DATA (D15:D0) = XXXX (don’t care)
REGISTER ADDRESS (A7:A0) = 0x0F
SDATA
A7
A6
A5
A4
A3
A2
0
0
0
0
0
0
A1
A0
0
0
D15 D14 D13 D12 D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
0
0
0
0
0
0
0
0
SCLK
CSZ
SDOUT
0
0
0
0
0
0
1
SDOUT Output Contents of Register 0x0F in the same cycle, MSB first
Figure 46. Serial Readout Timing
28
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DEFAULT STATES AFTER RESET
•
•
•
•
•
•
Device is in normal operation mode with 14-bit ADC enabled for all channels.
Output interface is 1-wire, 14× serialization with 7×bit clock and 1×frame clock frequency
Serial readout is disabled
PDN pin is configured as global power-down pin
Digital gain is set to 0 dB.
Digital modes such as LFNS, digital filters, and so on, are disabled.
Register Map
Table 3. Summary of Functions Supported by Serial Interface
ADDR.
(HEX)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
00
D0
(1) (2) (3) (4)
NAME
X
RST
X
EN_READOUT
01
X
02
0A
EN_HIGH_ADDRS
X
X
X
X
EN_SYNC
X
X
X
X
X
DESCRIPTION
1: Self-clearing software RESET; . After reset, this bit is set to 0
0: Normal operation.
1: READOUT of registers mode;0: Normal operation
0 – Disable access to register at address 0xF0
1 – Enable access to register at address 0xF0
1:Enable SYNC feature to synchronize the test patterns;
0: Normal operation, SYNC feature is disabled for the test patterns.
Note: this bit needs to be set as 1 when software or hardware SYNC
feature is used. see Reg.0x25[8] and 0x25[15]
X
X
X
X
X
X
X
X
RAMP_PAT_RESET_VAL
X
X
X
X
X
X
X
X
PDN_CH<8:1>
1:Channel-specific ADC power-down mode;
0: Normal operation
PDN_PARTIAL
1:Partial power-down mode - fast recovery from power-down;
0: Normal operation
PDN_COMPLETE
1:Register mode for complete power-down - slower recovery;
0: Normal operation
X
Ramp pattern reset value
0F
X
X
14
X
X
X
X
X
X
X
X
X
PDN_PIN_CFG
1:Configures PD pin for partial power-down mode;
0:Configures PD pin for complete power-down mode
LFNS_CH<8:1>
1: Channel-specific low frequency noise suppression mode enable;
0: LFNS disabled
EN_FRAME_PAT
1: Enables output frame clock to be programmed through a pattern;
0: Normal operation on frame clock
1C
23
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
ADCLKOUT<13:0>
14-bit pattern for frame clock on ADCLKP/ADCLKN pins
X
X
X
X
X
X
X
X
X
X
X
X
X
X
PRBS_SEED<15:0>
PRBS pattern starting seed value lower 16 bits
X
X
X
X
X
X
X
X
INVERT_CH<8:1>
24
X
(1)
(2)
(3)
(4)
X
X
X
X
X
X
PRBS_SEED<22:16>
1: Swaps the polarity of the analog input pins electrically;
0: Normal configuration
PRBS seed starting value upper 7 bits
The unused bits in each register (identified as blank table cells) must be programmed as '0'.
X = Register bit referenced by the corresponding name and description
Bits marked as '0' should be forced to 0, and bits marked as '1' should be forced to 1 when the particular register is programmed.
Multiple functions in a register can be programmed in a single write operation.
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Table 3. Summary of Functions Supported by Serial Interface (1)(2)(3)(4) (continued)
ADDR.
(HEX)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
X
0
0
EN_RAMP
0
X
0
DUALCUSTOM_PAT
0
0
X
SINGLE_CUSTOM_PAT
1: Enables mode wherein output is a constant specified code;
0: Normal operation
BITS_CUSTOM1<13:12>
2 MSBs for single custom pattern (and for the first code of the dual
custom patterns)
BITS_CUSTOM2<13:12>
2 MSBs for second code of the dual custom patterns
X
X
D0
NAME
X
X
25
X
TP_SOFT_SYNC
X
PRBS_TP_EN
X
PRBS_MODE_2
X
PRBS_SEED_FROM_REG
X
DESCRIPTION
1: Enables a repeating full scale ramp pattern on the outputs;
0: Normal operation
1:Enables mode wherein output toggles between 2 defined codes;
0: Normal operation
1: Software sync bit for test patterns on all 8 CHs;
0: No sync. Note: in order to synchronize the digital filters using the
SYNC pin, this bit must be set as 0.
1: PRBS test pattern enable bit;
0: PRBS test pattern disabled
PRBS 9 bit LFSR (23bit LFSR is default)
1: Enable PRBS seed to be chosen from register 0x23 and 0x24;
0: Disabled
TP_HARD_SYNC
1: Enable the external SYNC feature for syncing test patterns.
0: Inactive. Note: in order to synchronize the digital filters using the
SYNC pin, this bit must be set as 0.
26
X
X
X
X
X
X
X
X
X
X
X
X
BITS_CUSTOM1<11:0>
12 lower bits for single custom pattern (and for the first code of the
dual custom pattern).
27
X
X
X
X
X
X
X
X
X
X
X
X
BITS_CUSTOM2<11:0>
12 lower bits for second code of the dual custom pattern
X
EN_BITORDER
0
X
BIT_WISE
28
1
X
X
X
X
X
X
X
X
EN_WORDWISE__BY_CH<7:0>
Enables the bit order output.
0 = Byte wise, 1 = Word wise
Selects between bytewise and bit wise
1: bit-wise, odd bits come out on one wire and even bits come out on
other wire
0: byte-wise, upper bits on one wire and lower bits on other wire
Note: D15 must be set to '0' for this mode
1: Output format is one sample on one LVDS wire and next sample
on other LVDS wire.
0: Data comes out in two-wire mode with upper set of bits on one
channel and lower set of bits on the other.
Note: D15 must set '1' for this mode.
GLOBAL_EN_FILTER
1: Enables filter blocks - global control;
0: Inactive
X
EN_CHANNEL_AVG
1: Enables channel averaging mode;
0: Inactive
X
GAIN_CH1<3:0>
Programmable gain - Channel 1
GAIN_CH2<3:0>
Programmable gain - Channel 2
GAIN_CH3<3:0>
Programmable gain - Channel 3
GAIN_CH4<3:0>
Programmable gain - Channel 4
X
29
X
X
X
X
X
X
X
2A
X
X
30
X
X
X
X
X
X
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Table 3. Summary of Functions Supported by Serial Interface (1)(2)(3)(4) (continued)
ADDR.
(HEX)
D15
D14
D13
D12
X
X
X
X
D11
D10
D9
D8
X
X
X
X
D7
D6
D5
D4
D3
D2
D1
D0
NAME
DESCRIPTION
GAIN_CH5<3:0>
Programmable gain - Channel 5
GAIN_CH6<3:0>
Programmable gain - Channel 6
GAIN_CH7<3:0>
Programmable gain - Channel 7
GAIN_CH8<3:0>
Programmable gain - Channel 8
2B
X
X
X
X
X
X
X
X
X
X
X
X
AVG_CTRL4<1:0>
1: Averaging control for what comes out on LVDS output OUT4
AVG_CTRL3<1:0>
Averaging control for what comes out on LVDS output OUT3
AVG_CTRL2<1:0>
Averaging control for what comes out on LVDS output OUT2
AVG_CTRL1<1:0>
Averaging control for what comes out on LVDS output OUT1
AVG_CTRL8<1:0>
Averaging control for what comes out on LVDS output OUT8
AVG_CTRL7<1:0>
Averaging control for what comes out on LVDS output OUT7
AVG_CTRL6<1:0>
Averaging control for what comes out on LVDS output OUT6
AVG_CTRL5<1:0>
Averaging control for what comes out on LVDS output OUT5
2C
X
X
X
X
X
X
X
X
2D
X
X
X
X
X
X
X
FILTER1_COEFF_SET<2:0>
X
X
X
FILTER1_RATE<2:0>
X
2E
ODD_TAP1
X
X
X
X
X
X
X
X
X
X
X
2F
X
X
X
X
X
X
X
X
X
X
30
X
X
USE_FILTER2
X
X
Select stored coefficient set for filter 2
Set decimation factor for filter 2
Use odd tap filter 2
1: Enables filter for channel 2;
0: Disables
HPF_CORNER _CH2
HPF corner in values k from 2 to 10
HPF_EN_CH2
1: HPF filter enabled for the channel;
0: Disabled
FILTER3_COEFF_SET<2:0>
Select stored coefficient set for filter 3
ODD_TAP3
X
X
1: HPF filter enable for the channel;
0: Disables
FILTER3_RATE<2:0>
X
1: Enables filter for channel 1;
0: Disables
HPF_EN_CH1
ODD_TAP2
X
Use odd tap filter 1
HPF corner in values k from 2 to 10
FILTER2_RATE<2:0>
X
Set decimation factor for filter 1
HPF_CORNER _CH1
FILTER2_COEFF_SET<2:0>
X
X
USE_FILTER1
Select stored coefficient set for filter 1
USE_FILTER3
Set decimation factor for filter 3
Use odd tap filter 3
1: Enables filter for channel 3;
0: Disables
HPF_CORNER _CH3
HPF corner in values k from 2 to 10
HPF_EN_CH3
1: HPF filter enabled for the channel;
0: Disabled
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Table 3. Summary of Functions Supported by Serial Interface (1)(2)(3)(4) (continued)
ADDR.
(HEX)
D15
D14
D13
D12
D11
D10
D9
D8
D7
X
X
X
D6
D5
D4
X
X
X
D3
D2
D1
D0
FILTER4_COEFF_SET<2:0>
FILTER4_RATE<2:0>
X
ODD_TAP4
31
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
33
X
X
X
X
Select stored coefficient set for filter 5
USE_FILTER5
X
X
X
34
1: HPF filter enabled for the channel;
0: Disabled
FILTER_TYPE6<2:0>
Select stored coefficient set for filter 6
USE_FILTER6
FILTER_MODE7<1:0>
X
ODD_TAP7
X
X
X
X
X
USE_FILTER7
HPF_CORNER _CH7
X
HPF_EN_CH7
X
X
X
FILTER_TYPE8<2:0>
X
DECBY8_8
X
X
FILTER_MODE8<1:0>
X
ODD_TAP8
35
X
X
X
X
X
X
38
32
X
X
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1: Enables filter for channel 5;
0: Disables
HPF corner in values k from 2 to 10
DECBY8_7
X
Use odd tap filter 5
HPF_EN_CH5
FILTER_TYPE7<2:0>
X
Set decimation factor for filter 5
HPF_CORNER _CH5
HPF_EN_CH6
X
1: Enables filter for channel 4;
0: Disables
FILTER5_COEFF_SET<2:0>
HPF_CORNER _CH6
X
Use odd tap filter 4
1: HPF filter enabled for the channel;
0: Disabled
ODD_TAP6
X
Set decimation factor for filter 4
HPF_EN_CH4
FILTER_MODE6<1:0>
X
Select stored coefficient set for filter 4
HPF corner in values k from 2 to 10
DECBY8_6
X
DESCRIPTION
HPF_CORNER _CH4
ODD_TAP5
32
X
USE_FILTER4
FILTER5_RATE<2:0>
X
X
NAME
USE_FILTER8
Enables decimate by 8 filter 6
Set decimation factor for filter 6
Use odd tap filter 6
Enables filter for channel 6
HPF corner in values k from 2 to 10
Hpf filter enable for the channel
Select stored coefficient set for filter 7
Enables decimate by 8 filter 7
Set decimation factor for filter 7
Use odd tap filter 7
Enables filter for channel 7
HPF corner in values k from 2 to 10
Hpf filter enable for the channel
Select stored coefficient set for filter 8
Enables decimate by 8 filter 8
Set decimation factor for filter 8
Use odd tap filter 8
1: Enables filter for channel 8;
0: Disables
HPF_CORNER_CH8
HPF corner in values k from 2 to 10
HPF_EN_CH8
1: HPF filter enable for the channel;
0: Disables
DATA_RATE<1:0>
Select output frame clock rate
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Table 3. Summary of Functions Supported by Serial Interface (1)(2)(3)(4) (continued)
ADDR.
(HEX)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
X
D3
D2
D1
D0
X
NAME
EXT_REF_VCM
42
X
X
PHASE_DDR<1:0>
DESCRIPTION
Drive external reference mode through:
D15=D3=1: the VCM pin;
D15=D3=0: REFT/REFB pins.
Note: 0xF[15] should be set as '1' to enable the external reference
mode
Controls phase of LCLK output relative to data
1: Enable deskew pattern mode;
0: Inactive
0
X
PAT_DESKEW
X
0
PAT_SYNC
1: Enable sync pattern mode;
0: Inactive
X
EN_2WIRE
1: 2 wire LVDS output;
0: 1 wire LVDS output
BTC_MODE
1: 2's complement; (ADC data output format)
0: Binary Offset (ADC data output format)
MSB_FIRST
1: MSB First;
0: LSB First
45
1
1
X
1
X
1
46
1:SDR Bit Clock;
0: DDR Bit Clock
0
0
X
EN_12BIT
1: Enable 12 bit serialization mode;
0: Inactive
1
0
X
0
EN_14BIT
1: Enable 14 bit serialization mode;
0: Inactive
1
X
0
0
EN_16BIT
1: Enable 16 bit serialization mode;
0: Inactive
Note: 16 bit can be used when average mode or decimation mode is
enabled for better SNR.
FALL_SDR
1: Controls LCLK rising or falling edge comes in the middle of data
window when operating in SDR output mode; 0: At the edge of data
window.
X
1
X
1
1
51
EN_SDR
1
1
50
X
X
X
X
X
X
X
X
1
X
X
X
X
X
X
X
1
1
X
X
X
X
X
X
X
X
X
1
X
X
X
X
MAP_Ch1234_to_OUT1A
OUT1A Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT1B
OUT1B Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT2A
OUT2A Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT2B
OUT2B Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT3A
OUT3A Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT3B
OUT3B Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT4A
OUT4A Pin pair to channel data mapping selection
MAP_Ch1234_to_OUT4B
OUT4B Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT5B
OUT5B Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT5A
OUT5A Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT6B
OUT6B Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT6A
OUT6A Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT7B
OUT7B Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT7A
OUT7A Pin pair to channel data mapping selection
52
1
X
X
X
X
1
53
X
1
1
X
X
X
X
X
X
X
X
X
X
X
X
X
1
1
X
X
1
54
X
X
X
X
X
X
X
X
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Table 3. Summary of Functions Supported by Serial Interface (1)(2)(3)(4) (continued)
ADDR.
(HEX)
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
X
X
X
X
1
D3
D2
D1
D0
NAME
DESCRIPTION
X
X
X
X
MAP_Ch5678_to_OUT8B
OUT8B Pin pair to channel data mapping selection
MAP_Ch5678_to_OUT8A
OUT8A Pin pair to channel data mapping selection
55
1
F0
34
X
EN_EXT_REF
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1: Enable external reference mode. the voltage reference can be
applied on either REFP/B pins or VCM pin.
0: Default: internal reference mode.
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DESCRIPTION OF SERIAL REGISTERS
POWER-DOWN MODES
ADDR.
(HEX)
0F
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
PDN_CH<8:1>
PDN_PARTIAL
PDN_COMPLETE
PDN_PIN_CFG
X
X
X
Each of the 8 channels can be individually powered down. PDN_CH<N> controls the power-down mode for ADC
channel <N>. In addition to channel-specific power-down, the ADS5294 also has two global power-down modes:
1. The partial power-down mode. It partially powers down the chip; recovery time from the partial power-down
mode is about 10 µs provided that the clock has been running for at least 50 µs before exiting this mode.
2. The complete power-down mode. It completely powers down the chip, and involves a much longer recovery
time 100 µs.
In addition to programming the chip in either of these two power-down modes (through either the PDN_PARTIAL
or PDN_COMPLETE bits), the PD pin itself can be configured as either a partial power-down pin or a complete
power-down pin control. For example, if PDN_PIN_CFG=0 (default), when the PD pin is high, the device enters
complete power-down mode. However, if PDN_PIN_CFG=1, when the PD pin is high, the device enters partial
power-down mode.
LOW FREQUENCY NOISE SUPPRESSION MODE
ADDR.
(HEX)
14
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
LFNS_CH<8:1>
The low frequency noise suppression mode is specifically useful in applications where good noise performance is
desired in the frequency band of 0 to 1 MHz (around DC). Setting this mode shifts the low-frequency noise of the
ADS5294 to approximately Fs/2, thereby, moving the noise floor around DC to a much lower value.
LFNS_CH<8:1> enables this mode individually for each channel. See Figure 38 and Figure 39.
ANALOG INPUT INVERT
ADDR.
(HEX)
24
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
INVERT_CH<8:1>
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Normally, INP pin represents the positive analog input pin, and INN represents the complementary negative input.
Setting the bits marked INVERT_CH<8:1> (individual control for each channel) causes the inputs to be swapped.
INN now represents the positive input, and INP the negative input.
LVDS TEST PATTERNS
ADDR.
(HEX)
23
D15 D14 D13 D12 D11 D10
X
X
X
X
X
X
X
X
X
X
X
X
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
X
X
X
X
0
0
0
X
0
0
0
X
X
X
X
X
0
X
X
0
PRBS_SEED<15:0>
PRBS_SEED<22:16>
EN_RAMP
DUALCUSTOM_PAT
SINGLE_CUSTOM_PAT
BITS_CUSTOM1<13:12>
BITS_CUSTOM2<13:12>
TP_SOFT_SYNC
PRBS_TP_EN
PRBS_MODE_2
PRBS_SEED_FROM_REG
TP_HARD_SYNC
BITS_CUSTOM1<11:0>
BITS_CUSTOM2<11:0>
PAT_DESKEW
PAT_SYNC
24
X
25
X
X
X
26
27
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
45
The ADS5294 can output a variety of test patterns on the LVDS outputs. These test patterns replace the normal
ADC data output. All these patterns can be synchronized across devices by the sync function either through the
hardware SYNC pin or the software sync bit TP_SOFT_SYNC bit in register 0x25. TP_HARD_SYNC bit when
set enables the Test patterns to be synchronized by the hardware SYNC Pin. When the software sync bit
TP_SOFT_SYNC bit is set, special timing is needed.
• Setting EN_RAMP to 1 causes all the channels to output a repeating full-scale ramp pattern. The ramp
increments from zero code to full-scale code in steps of 1 LSB every clock cycle. After hitting the full scale
code, it returns back to zero code and ramps again.
• The device can also be programmed to output a constant code by setting SINGLE_CUSTOM_PAT to 1, and
programming the desired code in BITS_CUSTOM1<13:0>. In this mode, BITS_CUSTOM1<13:0> take the
place of the 14-bit ADC data at the output, and are controlled by LSB-first and MSB-first modes the same way
as normal ADC data are.
• The device may also be made to toggle between two consecutive codes, by programming
DUAL_CUSTOM_PAT to 1. The two codes are represented by the contents of BITS_CUSTOM1<13:0> and
BITS_CUSTOM2<13:0>.
• In addition to custom patterns, the device may also be made to output two preset patterns:
– Deskew patten – Set using PAT_DESKEW, this mode replaces the 14-bit ADC output D<13:0> with the
0101010101010101 word.
– Sync pattern – Set using PAT_SYNC, the normal ADC word is replaced by a fixed 11111110000000
word.
– PRBS patterns: The device can give 9 bit or 23 bit LFSR Pseudo random pattern on the channel outputs
that are controlled by the register 0x25. To enable the PRBS pattern PRBS_TP_EN bit in the register
0x25 needs to be set. Default is the 23 bit LFSR but 9 bit LFSR can be chosen by setting
PRBS_MODE_2 bit. The seed value for the PRBS patterns can be chosen by enabling the
PRBS_SEED_FROM_REG bit to 1 and the value written to the PRBS_SEED registers in 0x24 and 0x23.
Note that only one of the above patterns should be active at any given instant.
36
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D11
(D0)
D11
(D0)
D1
D0
(D10) (D11)
D1
D0
(D10) (D11)
D8
(D3)
D9
(D2)
D7
(D4)
D7
(D4)
D5
(D6)
D5
(D6)
D11
(D0)
D4
(D7)
D4
(D7)
D9
(D2)
D8
(D3)
D3
(D8)
D3
(D8)
D7
(D4)
D6
(D5)
D2
(D9)
D2
(D9)
D5
(D6)
D4
(D7)
D1
(D10)
D0
(D11)
D1
D0
(D10) (D11)
D1
D0
(D10) (D11)
D3
(D8)
D2
(D9)
x
X
X
Data bit in LSB First mode
D6
(D5)
D6
(D5)
D1
(D10)
D10
(D1)
X
D1
Data bit in MSB First mode
D8
(D3)
D9
(D2)
D3
(D8)
D0
(D11)
X
D2
D10
(D1)
D5
(D6)
D7
(D4)
D2
(D9)
D6
(D5)
D1
D0
(D10) (D11)
D7
(D4)
X
D3
D10
(D1)
D9
(D2)
D4
(D7)
D2
(D9)
D8
(D3)
D4
D11
(D0)
D11
(D0)
D1
(D10)
D6
(D5)
D3
(D8)
D9
(D2)
X
D3
(D8)
D8
(D3)
D4
(D7)
D10
(D1)
D5
Output Data
CHnOUT A
Bit-wise
Output Data
CHnOUT B
Word-wise
(Sample N)
Output Data
CHnOUT A
Word-wise
(Sample N-1)
D10
(D1)
D5
(D6)
D11
(D0)
X
D0
(D11)
D1
D0
(D10) (D11)
D6
(D5)
X
D6
D2
(D9)
D2
(D9)
D7
(D4)
D7
Output Data
CHnOUT B
Bit-wise
D3
(D8)
D8
(D3)
x
0
1
D8
D4
(D7)
D9
(D2)
D9
D5
(D6)
D10
(D1)
D10
D1
D0
(D10) (D11)
D11
(D0)
D11
Output Data
CHnOUT A
Byte-wise
D6
(D5)
D12
D7
(D4)
D13
Output Data
CHnOUT B
Byte-wise
td cycles latency
D14
ta
Sample N
28
D15
Frame Clock
FCLK
Freq = f CLKIN/2
Sample N-1
ADDR.
(HEX)
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
ADS5294
BIT-BYTE-WORD WISE OUTPUT
D0
NAME
EN_BITORDER
BIT_WISE
EN_WORDWISE_B
Y_CH<7:>
Register 0x28 can select the LVDS ADC output as bit-wise,byte-wise or word-wise in the two wire mode.
Figure 47 and Figure 48 illustrate the details.
Figure 47. 12-Bit Word Wise
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37
38
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Output Data
CHnOUT B
Word-wise
(Sample N)
Output Data
CHnOUT A
Word-wise
(Sample N-1)
Output Data
CHnOUT A
Bit-wise
Output Data
CHnOUT B
Bit-wise
D11
(D2)
D11
(D2)
D9
(D4)
D8
(D5)
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
D10
(D3)
D10
(D3)
D7
(D6)
D6
(D7)
D8
(D5)
D8
(D5)
D9
(D4)
Data bit in LSB First mode
D7
(D6)
D7
(D6)
D3
D1
(D10) (D12)
D2
D0
(D11) (D13)
D9
(D4)
D5
(D8)
D4
(D9)
D2
D1
D0
D3
(D10) (D11) (D12) (D13)
D10
(D3)
Data bit in MSB First mode
D12
(D1)
D13
(D0)
D1
D0
(D12) (D13)
D13
(D0)
D12
(D1)
D11
(D2)
D10
(D3)
D5
(D8)
D12
(D1)
D13
(D0)
D13
(D0)
D12
(D1)
D6
(D7)
D13
(D0)
Sample N-1
D1
D0
(D12) (D13)
D3
D1
(D10) (D12)
D2
D0
(D11) (D13)
D1
D0
(D12) (D13)
Output Data
CHnOUT A
Byte-wise
D7
(D6)
D8
(D5)
Output Data
CHnOUT B
Byte-wise
Frame Clock
FCLK
Freq = fCLKIN/2
Input Clock
CLKIN
Freq = fCLKIN
Input Signal
D6
(D7)
D6
(D7)
D13
(D0)
D12
(D1)
D6
(D7)
D13
(D0)
D5
(D8)
D5
(D8)
D11
(D2)
D10
(D3)
D5
(D8)
D12
(D1)
D4
(D9)
D4
(D9)
D9
(D4)
D8
(D5)
D4
(D9)
D11
(D2)
D9
(D4)
D8
(D5)
D7
(D6)
td cycles latency
D5
(D8)
D4
(D9)
D3
D1
(D10) (D12)
D2
D0
(D11) (D13)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D3
D2
D1
D0
(D10) (D11) (D12) (D13)
D7
(D6)
D6
(D7)
D2
D1
D0
D3
(D10) (D11) (D12) (D13)
D10
(D3)
ta
Sample N
ADS5294
SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
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Figure 48. 14-Bit Word Wise
DIGITAL PROCESSING BLOCKS
The ADS5294 integrates a set of commonly useful digital functions that can be used to ease system design.
These functions are shown in the digital block diagram of Figure 49 and described in the following sections.
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ADS5294
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SLAS776B – NOVEMBER 2011 – REVISED JULY 2012
LVDS OUTPUTS
Test Patterns
Channel 1 ADC Data
-
14-BIT
Ramp
Average of 2
channels
OUT 1A
Serializer
Wire 2
OUT 1B
Channel 2
Serializer
Wire 1
OUT 2A
Built-in Coefficients
24-tap filter
(Even Tap)
Decimation
by 2 or
by 4
23-tap filter
(Odd Tap)
Channel 2 ADC Data
Channel 3 ADC Data
Channel 4 ADC Data
Channel 1
Serializer
Wire 1
Average of 4
channels
Serializer
Wire 2
Custom Coefficients
Decimation
by 2 or
by 4 or
by 8
24-tap filter
(Even Tap)
23-tap filter
(Odd Tap)
Channel 3
Serializer
Wire 1
GAIN
(0 to 12 dB ,
1 dB steps )
12-tap filter
OUT 2B
MAPPER
MULTIPLEXER
8:8
OUT 3A
OUT 3B
Serializer
Wire 2
OUT 4A
Channel 4
Serializer
Wire 1
DIGITAL PROCESSING BLOCK for
OUT 4B
Serializer
Wire 2
CHANNEL 1
½ ADS529x
Figure 49. Digital Processing Block Diagram
PROGRAMMABLE DIGITAL GAIN
ADDR.
(HEX)
2A
2B
D15
X
X
D14
X
X
D13
X
X
D12
D11
D10
D9
D8
X
X
X
X
X
X
X
X
D7
D6
D5
D4
X
X
X
X
X
X
X
X
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
GAIN_CH1<3:0>
GAIN_CH2<3:0>
GAIN_CH3<3:0>
GAIN_CH4<3:0>
GAIN_CH5<3:0>
GAIN_CH6<3:0>
GAIN_CH7<3:0>
GAIN_CH8<3:0>
X
X
In applications where the full scale swing of the analog input signal is much less than the 2 VPP range supported
by the ADS5294, a programmable gain can be set to achieve the full-scale output code even with a lower analog
input swing. The programmable gain for each channel can be individually set using a set of four bits, indicated as
GAIN_CHN<3:0> for Channel N. The gain setting is coded in binary from 0-12 dB as shown in Table 4.
Table 4. Gain Setting for Channel N
GAIN_CHN<3>
GAIN_CHN<2>
GAIN_CHN<1>
GAIN_CHN<0>
CHANNEL N GAIN SETTING
0
0
0
0
0 dB
0
0
0
1
1 dB
0
0
1
0
2 dB
0
0
1
1
3 dB
0
1
0
0
4 dB
0
1
0
1
5 dB
0
1
1
0
6 dB
0
1
1
1
7 dB
1
0
0
0
8 dB
1
0
0
1
9 dB
1
0
1
0
10 dB
1
0
1
1
11 dB
1
1
0
0
12 dB
1
1
0
1
Do not use
1
1
1
0
Do not use
1
1
1
1
Do not use
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CHANNEL AVERAGING
ADDR.
(HEX)
29
2C
D15
D14
D13
D12
D11
D10
D9
X
X
D8
D7
X
D6
D5
D4
X
D2
D1
D0
NAME
X
EN_CHANNEL_AVG
AVG_CTRL4<1:0>
AVG_CTRL3<1:0>
AVG_CTRL2<1:0>
AVG_CTRL1<1:0>
AVG_CTRL8<1:0>
AVG_CTRL7<1:0>
AVG_CTRL6<1:0>
AVG_CTRL5<1:0>
X
X
2D
D3
X
X
X
X
X
X
X
X
X
X
In the default mode of operation, the LVDS outputs <8..1> contain the data of the ADC Channels <8..1>. By
setting the EN_CHANNEL_AVG bit to ‘1’, the outputs from multiple channels can be averaged. The resulting
outputs from the Channel averaging block (which is bypassed in the default mode) are referred to as Bins. The
contents of the Bins <8..1> come out on the LVDS outputs <8..1>. The contents of each of the 8 bins are
determined by the register bits marked AVG_CTRLn<1:0> where n stands for the Bin number. The different
settings are shown below:
40
AVG_CTRL1<1>
AVG_CTRL1<0>
Contents of Bin 1
0
0
Zero
0
1
ADC Channel 1
1
0
Average of ADC Channel 1, 2
1
1
Average of ADC Channel 1, 2, 3, 4
AVG_CTRL2<1>
AVG_CTRL2<0>
Contents of Bin 2
0
0
Zero
0
1
ADC Channel 2
1
0
ADC Channel 3
1
1
Average of ADC Channel 3, 4
AVG_CTRL3<1>
AVG_CTRL3<0>
Contents of Bin 3
0
0
Zero
0
1
ADC Channel 3
1
0
ADC Channel 2
1
1
Average of ADC Channel 1, 2
AVG_CTRL4<1>
AVG_CTRL4<0>
Contents of Bin 4
0
0
Zero
0
1
ADC Channel 4
1
0
Average of ADC Channel 3, 4
1
1
Average of ADC Channel 1, 2, 3, 4
AVG_CTRL5<1>
AVG_CTRL5<0>
Contents of Bin 5
0
0
Zero
0
1
ADC Channel 5
1
0
Average of ADC Channel 5, 6
1
1
Average of ADC Channel 5, 6, 7, 8
AVG_CTRL6<1>
AVG_CTRL6<0>
Contents of Bin 6
0
0
Zero
0
1
ADC Channel 6
1
0
ADC Channel 7
1
1
Average of ADC Channel 7, 8
AVG_CTRL7<1>
AVG_CTRL7<0>
Contents of Bin 7
0
0
Zero
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AVG_CTRL1<1>
AVG_CTRL1<0>
Contents of Bin 1
0
1
ADC Channel 7
1
0
ADC Channel 6
1
1
Average of ADC Channel 6, 5
AVG_CTRL8<1>
AVG_CTRL8<0>
Contents of Bin 8
0
0
Zero
0
1
ADC Channel 8
1
0
Average of ADC Channel 7, 8
1
1
Average of ADC Channel 5, 6, 7, 8
When the contents of a particular bin is set to Zero, then the LVDS buffer corresponding to that bin gets
automatically powered down.
DECIMATION FILTER
ADDR.
D15 D14 D13 D12 D11 D10
(HEX)
29
2E
D9
D8
D7
X
X
X
D6
D5
D4
D3
D2
D1
D0
X
X
X
X
X
X
2F
X
X
X
X
X
X
X
X
30
X
X
X
X
X
X
X
X
31
X
X
X
X
X
X
X
X
32
X
X
X
X
X
X
X
X
33
X
X
X
X
X
X
X
X
34
X
X
X
X
X
X
X
X
35
X
X
X
X
X
X
X
X
NAME
GLOBAL_EN_FILTER
FILTER1_COEFF_SET<2:0>
FILTER1_RATE<2:0>
ODD_TAP1
USE_FILTER1
FILTER2_COEFF_SET<2:0>
FILTER2_RATE<2:0>
ODD_TAP2
USE_FILTER2
FILTER3_COEFF_SET<2:0>
FILTER3_RATE<2:0>
ODD_TAP3
USE_FILTER3
FILTER4_COEFF_SET<2:0>
FILTER4_RATE<2:0>
ODD_TAP4
USE_FILTER4
FILTER5_COEFF_SET<2:0>
FILTER5_RATE<2:0>
ODD_TAP5
USE_FILTER5
FILTER6_COEFF_SET<2:0>
FILTER6_RATE<2:0>
ODD_TAP6
USE_FILTER6
FILTER7_COEFF_SET<2:0>
FILTER7_RATE<2:0>
ODD_TAP7
USE_FILTER7
FILTER8_COEFF_SET<2:0>
FILTER8_RATE<2:0>
ODD_TAP8
USE_FILTER8
The decimation filter is implemented as 24-tap FIR with symmetrical coefficients (each coefficient is 12-bit
signed). The filter equation is:
æ 1 ö
y(n) = ç
÷ ´ ëé(h0 ´ x(n)+h1 ´ x(n - 1)+h2 ´ x(n - 2)+...+h11 ´ x(n - 11)+h11 ´ x(n - 12)...+h1 ´ x(n - 22)+h0 ´ x(n - 23)ûù
è 211 ø
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By setting the register bit <ODD_TAPn> = 1, a 23-tap FIR is implemented:
æ 1 ö
y(n)= çç
÷ ´ é(h ´ x(n)+h1 ´ x(n - 1)+h2 ´ x(n - 2)+...+h10 ´ x(n - 10)+h11 ´ x(n - 11)+h10 ´ x(n - 12)...+h1 ´ x(n - 21)+h0 ´ x(n - 22)ùû
11 ÷ ë 0
è2 ø
(2)
In Equation 1 and Equation 2, h0, h1 …h11 are 12 bit signed representation of the coefficients, x(n) is the input
data sequence to the filter and y(n) is the filter output sequence.
A decimation filter can be introduced at the output of each channel. To enable this feature, the
GLOBAL_EN_FILTER should be set to ‘1’. Setting this bit to ‘1’ increases the overall latency of each channel to
20 clock cycles irrespective of whether the filter for that particular channel has been chosen or not (using the
USE_FILTER bit). The bits marked FILTERn_COEFF_SET<2:0>, FILTERn_RATE<2:0>, ODD_TAPn and
USE_FILTERn represent the controls for the filter for Channel n. Note that these bits are functional only when
the GLOBAL_EN_FILTER gets set to ‘1’. For illustration, the controls for channel 1 are listed in Table 5:
The USE_FILTER1 bit determines whether the filter for Channel 1 is used or not. When this bit is set to ‘1’, the
filter for channel 1 is enabled. When this bit is set to ‘0’, the filter for channel 1 is disabled but the channel data
passes through a dummy delay so that the overall latency of channel 1 is 20 clock cycles. With the
USE_FILTER1 bit set to ‘1’, the characteristics of the filter can be set by using the other sets of bits.
The ADS5294 has 6 sets of filter coefficients stored in memory. Each of these sets define a unique pass band in
the frequency domain and contain 12 coefficients (each coefficient is 12-bit long). These 12 coefficients are used
to implement either a symmetric 24-tap (even-tap) filter, or a symmetric 23-tap (odd-tap) filter. Setting the register
bit ODD_TAP1 to ‘1’ enables the odd-tap configuration (the default is even tap with this bit set to ‘0’) for Channel
1. The bits FILTER1_COEFF_SET<2:0> can be used to choose the required set of coefficients for Channel 1.
The passbands corresponding to of each of these filter coefficient sets is shown in Figure 50
Set 1
H(f)
H(f)
0.2*Fs
0.3*Fs
f
0.2*Fs
Set 3
H(f)
H(f)
0.1*Fs
Set 2
f
0.125*Fs
Set 5
H(f)
H(f)
0.275*Fs
0.225*Fs
0.5*Fs
f
Set 4
0.075*Fs
0.15*Fs
0.3*Fs
0.275*Fs
0.225*Fs
f
Set 6
f
0.375*Fs
0.4*Fs 0.5*Fs
f
0.35*Fs
Figure 50. Filter Types
42
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Coefficient Sets 1 and 2 are the most appropriate when Decimation by a factor of 2 is required, whereas
Coefficient Sets 3,4,5,6 are appropriate when Decimation by a factor of 4 is desired. The computation rate of the
filter output can be independently set using the bits FILTERn_RATE<2:0>. The settings are shown in Table 5.
Table 5. Digital Filters
<DATA
RATE>
FILTERn
RATE>
<FILTERn
COEFF SET>
<ODD TAP>
<USE
FILTER
CHn>
<EN CUSTOM
FILT>
Built-in low-pass odd-tap filter (pass band = 0 to fS/4)
001
000
000
1
1
0
Built-in high-pass odd-tap filter (pass band = 0 to fS/4)
001
000
001
1
1
0
Built-in low-pass even-tap filter (pass band = 0 to fS/8)
010
001
010
0
1
0
Built-in first band pass even tap filter(pass band = fS/8 to fS/4)
010
001
011
0
1
0
Built-in second band pass even tap filter(pass band = fS/4 to 3
fS/8)
010
001
100
0
1
0
DECIMATION
Decimate by 2
Decimate by 4
TYPE OF FILTER
Built-in high pass odd tap filter (pass band = 3 fS/8 to fS/2)
010
001
101
1
1
0
Decimate by 2
Custom filter (user programmablecoefficients)
001
000
000
0 and 1
1
1
Decimate by 4
Custom filter (user programmablecoefficients)
010
001
000
0 and 1
1
1
Decimate by 8
Custom filter (user programmablecoefficients)
011
100
000
0 and 1
1
1
Bypass decimation
Custom filter (user programmablecoefficients)
0 and 1
1
1
The choice of the odd/even tap setting, filter coefficient set and the filter rate uniquely determines the filter to be
used. In addition to the preset filter coefficients, the coefficients for each of the eight filter channels can be
programmed by the user. Each of the eight channels has 12 programmable coefficients, each 12-bit long. The 96
registers with addresses from 5A (Hex) to B9 (Hex) are used to program these 8 sets of 12 programmable
coefficients. Registers 5A to 65 are used to program the 1st filter, with the 1st coefficient occupying the bits
D11..D0 of register 5A, the 2nd coefficient occupying the bits D11..D0 of register 5B, and so on. Similarly
registers 66(Hex) to 71(Hex) are used to program the 2nd filter, and so on.
When programming the filter coefficients, the D15 bit of each of the 12 registers corresponding to that filter
should be set to ‘1’. If the D15 bit of these 12 registers is set to ‘0’, then the preset coefficient (as programmed by
FILTERn_COEFF_SET<2:0>) is used even if the bits D11..D0 get programmed. By setting or not setting the D15
bits of individual filter channels to ‘1’, some filters can be made to operate with preset coefficient sets, and some
others can be made to simultaneously operate with programmed coefficient sets.
HIGH PASS FILTER
ADDR.
(HEX)
2E
2E
2F
2F
30
30
31
31
32
32
33
33
34
34
35
35
D15
D14
D13
D12
D11
D10
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
NAME
HPF_corner_CH1
HPF_EN_CH1
HPF_corner_CH2
HPF_EN_CH2
HPF_corner_CH3
HPF_EN_CH3
HPF_corner_CH4
HPF_EN_CH4
HPF_corner_CH5
HPF_EN_CH5
HPF_corner_CH6
HPF_EN_CH6
HPF_corner_CH7
HPF_EN_CH7
HPF_corner_CH8
HPF_EN_CH8
X
X
X
X
X
X
X
X
This group of registers controls the characteristics of a digital high pass transfer function applied to the output
data, useing Equation 3:
y(n) =
2
k
k
2 +1
[x(n) - x(n - 1)+y(n - 1)]
(3)
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Where k is set as described by the HPF_corner registers (one for each channel). Also the HPF_EN bit in each
register needs to be set to enable the HPF feature for each channel.
BIT CLOCK PROGRAMMABILITY
ADDR.
(HEX)
42
46
46
D15
D14
1
1
D13
D12
D11
D10
D9
D8
D7
D6
D5
X
X
D4
D3
D2
D1
D0
NAME
PHASE_DDR<1:0>
EN_SDR
FALL_SDR
X
X
The output interface of the ADS5294 is normally a DDR interface, with the LCLK rising edge and falling edge
transitions in the middle of alternate data windows. This default phase is shown in Figure 51.
PHASE_DDR<1:0> = 10
ADCLKp
LCLKp
OUTp
Figure 51. Default Phase of LCLK
The phase of LCLK can be programmed relative to the output frame clock and data using bits
PHASE_DDR<1:0>. The LCLK phase modes are shown in Figure 52.
PHASE_DDR<1:0> = 00
PHASE_DDR<1:0> = 10
ADCLKp
ADCLKp
LCLKp
LCLKp
OUTp
OUTp
PHASE_DDR<1:0> = 01
PHASE_DDR<1:0> = 11
ADCLKp
ADCLKp
LCLKp
LCLKp
OUTp
OUTp
Figure 52. Phase Programmability Modes for LCLK
44
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In addition to programming the phase of the LCLK in the DDR mode, the device can also be made to operate in
SDR mode by setting bit EN_SDR to 1. In the mode, the bit clock (LCLK) is output at 14X times the input clock,
or twice the rate as in DDR mode. Depending on the state of FALL_SDR, the LCLK may be output in either of
the two manners shown in Figure 53. As can be seen in Figure 53, only the LCLK rising (or falling edge) is used
to capture the output data in SDR mode. The SDR mode does not work well beyond 40 MSPS because the
LCLK frequency will become very high.
EN_SDR = 1, FALL_SDR = 0
ADCLKp
LCLKp
OUTp
EN_SDR = 1, FALL_SDR = 1
ADCLKp
LCLKp
OUTp
Figure 53. SDR Interface Modes
OUTPUT DATA RATE CONTROL
ADDR.
(HEX)
38
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
DATA_RATE<1> DATA_RATE<0>
In the default mode of operation, the data rate at the output of the ADS5294 is at the sampling rate of the ADC.
This is true even when the custom pattern generator is enabled. In addition, both output data rate and sampling
rate can also be configured to a sub-multiple of the input clock rate.
With the DATA_RATE<1:0> control, the output data rate can be programmed to be a sub-multiple of the ADC
sampling rate. This feature can be used to lower the output data rate, for example when the decimation filter is
used. Without enabling the decimation filter, the sub-multiple ADC sampling rate feature still can be used.
The different settings are listed below:
DATA_RATE<1>
DATA_RATE<0>
Output data rate
0
0
Same as ADC sampling rate
0
1
1/2 of ADC sampling rate
1
0
1/4 of ADC sampling rate
1
1
1/8 of ADC sampling rate
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SYNCHRONIZATION PULSE
ADDR.
(HEX)
25
02
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
TP_HARD_SYNC
EN_SYNC
The SYNC pin can be used to synchronize the data output from channels within the same chip or from channels
across chips when decimation filters are used with reduced output data rate.
When the decimation filters are used (for example, the decimate by two filter is enabled), then, effectively, the
device outputs one digital code for every two analog input samples. If the SYNC function is not enabled, then the
filters are not synchronized (even within a chip) – this means that one channel may be sending out codes
corresponding to input samples N, N+1 and so on, while another may be sending out code corresponding to
N+1, N+2 and so on.
To achieve synchronization, the SYNC pulse must arrive at all the ADS529x chips at the same time instant (as
shown in the timing diagram of Figure 54
The ADS5294 generates an internal synchronization signal which is used to reset the internal clock dividers used
by the decimation filter.
Using the SYNC signal in this way ensures that all channels will output digital codes corresponding to the same
set of input samples.
SYNC Timings:
Synchronizing the filters using the SYNC pin is enabled by default. No register bits are required to be
written. Even EN_SYNC bit is not required.It is important for register bit TP_HARD_SYNC to be 0 for
this mode to work. As shown by Figure 54, the SYNC rising edge can be positioned anywhere within the
window. The width of the SYNC must be at least one clock cycle.
0ns
ADC Input
Clock
t CLK/2
-1ns
t CLK/2
td: -1 ns< td < t CLK/2
SYNC
twidth >
1clock cycle
Figure 54. Synchronization Pulse Timing
Note that the SYNC DOES NOT synchronize the sampling instants of the ADC across chips. All channels within
a single chip sample their analog inputs simultaneously. To ensure that channels across two chips will sample
their analog inputs simultaneously, the input clock needs to be routed to both chips with identical length. This
ensuring that the input clocks arrive at both the chips at the same time. This needs to be taken care of in the
board design and routing. The SYNC pin cannot be used to synchronize the sampling instants.
In addition to the above, the SYNC can also be used to synchronize the RAMP test patterns across channels. In
order to synchronize the test patterns, TP_HARD_SYNC must be set as 1. Setting TP_HARD_SYNC =1 actually
disables the sync of the filters.
46
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External Reference Mode of Operation
The ADS5294 supports an external reference mode of operation in one of two ways:
a. By forcing the reference voltages on the REFT and REFB pins.
b. By applying the reference voltage on VCM pin.
This mode can be used to operate multiple ADS5294 chips with the same (externally applied) reference voltage.
Using the REF pins:
For normal operation, the device requires two reference voltages, REFT and REFB. By default, the device
generates these two voltages internally. To enable the external reference mode, set the register bits as shown in
Table 6 . This powers down the internal reference amplifier and the two reference voltages can be forced directly
on the REFT and REFB pins as VREFT = 1.45V ± 50mV and VREFB = 0.45 V ±50 mV.
Note that the relation between the ADC full-scale input voltage and the applied reference voltages is
Full-scale input voltage = 2 x (VREFT – VREFB)
(4)
Using the VCM pin:
In this mode, an external reference voltage VREFIN can be applied to the VCM pin such that
Full-scale input voltage = 2 x VREFIN
(5)
To enable this mode, set the register bits as shown in Table 6. This changes the function of the VCM pin to an
external reference input pin. The voltage applied on VCM must be 1.5 V ±50 mV.
Table 6. External reference function
EN_HIGH_ADDRS
EN_EXT_REF
EXT_REF_VCM
External reference using REFT/REFB pins
Function
1
1
00
External reference using VCM pin
1
1
11
DATA OUTPUT FORMAT MODES
ADDR.
(HEX)
46
46
D15
D14
D13
D12
D11
D10
D9
D8
D7
D6
D5
1
1
D4
D3
D2
X
X
D1
D0
NAME
BTC_MODE
MSB_FIRST
The ADC output, by default, is in Straight offset binary mode. Programming the BTC_MODE bit to '1' inverts the
MSB, and the output becomes Binary 2’s complement mode. Also, by default, the first bit of the frame (following
the rising edge of CLKP) is the LSB of the ADC output. Programming the MSB_FIRST mode inverts the bit order
in the word, and the MSB is output as the first bit following CLKP rising edge.
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PROGRAMMABLE MAPPING BETWEEN INPUT CHANNELS AND OUTPUT PINS
ADDR.
D15 D14 D13 D12 D11 D10
(HEX)
50
1
1
1
X
X
51
1
1
1
X
X
52
1
1
53
1
1
1
X
X
54
1
1
1
X
X
55
1
1
D9
X
X
X
X
D8
D7
D6
D5
D4
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
D3
D2
D1
D0
NAME
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
MAP_CH1234_TO_OUT1A
MAP_CH1234_TO_OUT1B
MAP_CH1234_TO_OUT2A
MAP_CH1234_TO_OUT2B
MAP_CH1234_TO_OUT3A
MAP_CH1234_TO_OUT3B
MAP_CH1234_TO_OUT4A
MAP_CH1234_TO_OUT4B
MAP_CH5678_TO_OUT5B
MAP_CH5678_TO_OUT5A
MAP_CH5678_TO_OUT6B
MAP_CH5678_TO_OUT6A
MAP_CH5678_TO_OUT7B
MAP_CH5678_TO_OUT7A
MAP_CH5678_TO_OUT8B
MAP_CH5678_TO_OUT8A
X
X
X
X
The ADS5294 has 16 pairs of LVDS channel outputs. The mapping of ADC channels to LVDS output channels is
programmable to allow for flexibility in board layout. The 16 LVDS channel outputs are split in to 2 groups of 8
LVDS pairs. Within each group 4 ADC input channels can be multiplexed in to the 8 LVDS pairs depending on
the modes of operation whether it is 1 wire mode or 2 wire mode.
Input channels 1 to 4 can be mapped to any of the LVDS outputs OUT1A/B to OUT4A/B (using the
MAP_CH1234_TO_OUTnA/B). Similarly, input channels 5 to 8 can be mapped to any of the LVDS outputs
OUT5A/B to OUT8A/B (using the MAP_CH5678_TO_OUTnA/B). The block diagram of the mapping is listed in
Figure 55.
48
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Channel 8 data
MAP_CH5678_to_OUTn<3:0> = 0000
n = 5A, 5B, 6A, 6B, 7A, 7B, 8A, 8B
Channel 7 data
MAP_CH5678_to_OUTn<3:0> = 0010
OUTn
Channel 6 data
MAP_CH5678_to_OUTn<3:0> = 0100
Channel 5 data
MAP_CH5678_to_OUTn<3:0> = 0110
MAP_CH5678_to_OUTn<3:0> = 1xxx, the
unused OUTn LVDS buffer is powered down.
Channel 4 data
MAP_CH1234_to_OUTn<3:0> = 0110
Channel 3 data
MAP_CH1234_to_OUTn<3:0> = 0100
OUTn
Channel 2 data
MAP_CH1234_to_OUTn<3:0> = 0010
Channel 1 data
MAP_CH1234_to_OUTn<3:0> = 0000
MAP_CH1234_to_OUTn<3:0> = 1xxx, the
unused OUTn LVDS buffer is powered down.
(a) 1-wire mode
Channel 1 LSB Byte data<7:0>
MAP_CH1234_to_OUTn<3:0> = 0000
Channel 1 MSB Byte data<15:8>
MAP_CH1234_to_OUTn<3:0> = 0001
Channel 2 LSB Byte data<7:0>
MAP_CH1234_to_OUTn<3:0> = 0010
n = 1A, 1B, 2A, 2B, 3A, 3B, 4A, 4B
Channel 2 MSB Byte data<15:8>
MAP_CH1234_to_OUTn<3:0> = 0011
OUTn
Channel 3 LSB Byte data<7:0>
MAP_CH1234_to_OUTn<3:0> = 0100
Channel 3 MSB Byte data<15:8>
MAP_CH1234_to_OUTn<3:0> = 0101
MAP_CH1234_to_OUTn<3:0> = 1xxx, the
unused OUTn LVDS buffer is powered down.
Channel 4 LSB Byte data<7:0>
MAP_CH1234_to_OUTn<3:0> = 0110
Channel 4 MSB Byte data<15:8>
MAP_CH1234_to_OUTn<3:0> = 0011
Channel 8 LSB Byte data<7:0>
MAP_CH5678_to_OUTn<3:0> = 0000
Channel 8 MSB Byte data<15:8>
MAP_CH5678_to_OUTn<3:0> = 0001
Channel 7 LSB Byte data<7:0>
MAP_CH5678_to_OUTn<3:0> = 0010
n = 5A, 5B, 6A, 6B, 7A, 7B, 7A, 7B
Channel 7 MSB Byte data<15:8>
MAP_CH5678_to_OUTn<3:0> = 0011
OUTn
Channel 6 LSB Byte data<7:0>
MAP_CH5678_to_OUTn<3:0> = 0100
Channel 6 MSB Byte data<15:8>
MAP_CH5678_to_OUTn<3:0> = 0101
MAP_CH5678_to_OUTn<3:0> = 1xxx, the
unused OUTn LVDS buffer is powered down.
Channel 5 LSB Byte data<7:0>
MAP_CH5678_to_OUTn<3:0> = 0110
Channel 5 MSB Byte data<15:8>
MAP_CH5678_to_OUTn<3:0> = 0011
(b) 2-wire mode
Figure 55. Input and Output Channel Mapping
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Registers 0x50 to 0x55 control the multiplexing options as below:
MAP_CH1234_to_OUTn<3:0>
Used in 1-wire mode?
Used in 2-wire mode?
ADC input channel IN1 to OUTn
Y
Y, for LSB byte
0001
ADC input channel IN1 to OUTn (2wire only)
N
Y, for MSB byte
0010
ADC input channel IN2 to OUTn
Y
Y, for LSB byte
0011
ADC input channel IN2 to OUTn (2wire only)
N
Y, for MSB byte
0100
ADC input channel IN3 to OUTn
Y
Y, for LSB byte
0101
ADC input channel IN3 to OUTn (2wire only)
N
Y, for MSB byte
0110
ADC input channel IN4 to OUTn
Y
Y, for LSB byte
0111
ADC input channel IN4 to OUTn (2wire only)
N
Y, for MSB byte
1xxx
LVDS output buffer OUTn is powered
down
MAP_CH5678_to_OUTn<3:0>
50
Mapping
0000
Used in 1-wire mode?
Used in 2-wire mode?
0000
Mapping
ADC input channel IN8 to OUTn
Y
Y, for LSB byte
0001
ADC input channel IN8 to OUTn (2wire only)
N
Y, for MSB byte
0010
ADC input channel IN7 to OUTn
Y
Y, for LSB byte
0011
ADC input channel IN7 to OUTn (2wire only)
N
Y, for MSB byte
0100
ADC input channel IN6 to OUTn
Y
Y, for LSB byte
0101
ADC input channel IN6 to OUTn (2wire only)
N
Y, for MSB byte
0110
ADC input channel IN5 to OUTn
Y
Y, for LSB byte
0111
ADC input channel IN5 to OUTn (2wire only)
N
Y, for MSB byte
1xxx
LVDS output buffer OUTn is powered
down
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The default mapping for 1-wire and 2-wire modes is:
Table 7. Mapping for 1-wire Mode
Analog Input channel
LVDS Output
Channel IN1
OUT1A
Channel IN2
OUT2A
Channel IN3
OUT3A
Channel IN4
OUT4A
Channel IN5
OUT5A
Channel IN6
OUT6A
Channel IN7
OUT7A
Channel IN8
OUT8A
Note: In the single wire mode with default register settings, ADC data is available only on OUTnA.
Table 8. Mapping for 2-wire Mode
Analog Input channel
LVDS Output
Channel IN1
OUT1A, OUT1B
Channel IN2
OUT2A, OUT2B
Channel IN3
OUT3A, OUT3B
Channel IN4
OUT4A, OUT4B
Channel IN5
OUT5A, OUT5B
Channel IN6
OUT6A, OUT6B
Channel IN7
OUT7A, OUT7B
Channel IN8
OUT8A, OUT8B
Note: In the 2-wire mode, the ADC data is available on both OUTnA and OUTnB.
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APPLICATION INFORMATION
THEORY OF OPERATION
The ADS5294 is an octal channel, 14-bit high-speed ADC with sample rate up to 80 MSPS that runs off a single
1.8 V supply. All eight channels of the ADS5294 simultaneously sample their analog inputs at the rising edge of
the input clock. The sampled signal is sequentially converted by a series of small resolution stages, with the
outputs combined in a digital correction logic block. At every clock, edge the sample propagates through the
pipeline resulting in a data latency of 11 clock cycles.
The 14 data bits of each channel are serialized and sent out in either 1-wire (one pair of LVDS pins are used) or
2-wire (two pairs of LVDS pins are used) mode, depending on the LVDS output rate. When the data is output in
the 2-wire mode, it can reduce the serial data rate of the outputs, especially at higher sampling rates. Hence, low
cost FPGAs can be used to capture 80 MSPS/14bit data. Alternately, at lower sample rates, the 14-bit data can
be output as a single data stream over one pair of LVDS pins (1-wire mode). The device outputs a bit clock at 7x
and frame clock at 1x times the sample frequency in the 14-bit mode.
This 14-bit ADC achieves approximately 76 dBFS SNR at 80 MSPS. Its output resolution can be configured as
12-bit and 10-bit if necessary. 70 dBFS and 61 dBFS SNRs are achieved when the ADS5294’s output resolution
is 12-bit and 10-bit respectively.
ANALOG INPUT
The analog inputs consist of a switched-capacitor based, differential sample and hold architecture. This
differential topology results in very good AC performance even for high input frequencies at high sampling rates.
The INP and INM pins are internally biased around a common-mode voltage of Vcm (0.95 V). For a full-scale
differential input, each input pin (INP and INM) must swing symmetrically between Vcm + 0.5V and Vcm - 0.5V,
resulting in a 2 VPP differential input swing. Figure 56 illustrates the equivalent circuit of the input sampling circuit.
Figure 56. Analog Input Circuit Model
DRIVE CIRCUIT
For optimum performance, the analog inputs must be driven differentially. This improves the common-mode
noise immunity and even order harmonic rejection. A 5 Ω to 15 Ω resistor in series with each input pin is
recommended to damp out ringing caused by package parasitic.
The drive circuit shows an R-C filter across the analog input pins. The purpose of the filter is to absorb the
glitches caused by the opening and closing of the sampling capacitors.
52
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0.1 mF
10 W
INP
Differential
Input
2 pF
INM
ADS259x
10 W
0.1 mF
Figure 57. Analog Input Drive Circuit
Large and Small Signal Input Bandwidth
The small signal bandwidth of the analog input circuit is high, around 550 MHz. When using an amplifier to drive
the ADS5294, the total noise of the amplifier up to the small signal bandwidth must be considered. The large
signal bandwidth of the device depends on the amplitude of the input signal. The ADS5294 supports 2 VPP
amplitude for input signal frequency up to 80 MHz. For higher frequencies (80 MHz), the amplitude of the input
signal must be decreased proportionally. For example, at 160 MHz, the device supports a maximum of 1 VPP
signal.
INPUT CLOCK
The ADS5294 is configured by default to operate with a single-ended input clock – CLKP is driven by a CMOS
clock and CLKM is tied to GND. The device can automatically detect a single-ended or differential clock. If CLKM
is grounded, the device treats clock as a single-ended clock. Operating with a low-jitter differential clock usually
gives better SNR performance, especially at input frequencies greater than 30 MHz. Typical clock termination
structures are listed in Figure 58 andFigure 59.
Clock buffer
Lpkg
~ 2 nH
5Ω
CLKP
Ceq
Cbond
~ 0.5 pF
Resr
~ 200 Ω
6 pF
VCM
6 pF
Lpkg
~ 2 nH
Ceq
5 kΩ
5 kΩ
5Ω
CLKM
Cbond
~ 0.5 pF
Resr
~ 200 Ω
Ceq is approximately 1 to 3 pF, equivalent input capacitance of clock buffer.
Figure 58. Equivalent Circut of the Input Clock Circuit
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SINGLE-ENDED CLOCK CONNECTIONS
CMOS
CLOCK IN
CLKP
VCM
CLKM
ADS529x
Figure 59. Single-Ended Clock Drive Circuit
DIFFERENTIAL CLOCK CONNECTIONS
DIFFERENTIAL CLOCK CONNECTIONS
0.1 mF
0.1 mF
CLKP
CLKP
Differential
LVPECL
clock input
Differential sinewave clock input
Rterm
0.1 mF
CLKM
0.1 mF
CLKM
Rterm
ADS529x
ADS529x
0.1 mF
CLKP
Differential
LVDS
clock input
Rterm
CLKM
0.1 mF
54
ADS529x
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DIGITAL HIGH PASS IIR FILTER
DC offset is often observed at ADC input signals. For example, in ultrasound applications, the DC offset from
VGA (variable Gain amplifier) varies at different gains. Such a variable offset can introduce artifacts in ultrasound
images especially in Doppler modes. Analog filter between ADC and VGA can be used with added noise and
power. Digital filter achieves the same performance as analog filters and has more flexibility in fine tuning
multiple characteristics.
ADS5294 includes optional 1st order digital high-pass IIR filter. Its block diagram is shown in Figure 60 as well as
its transfer function
y(n) =
2
k
k
2 +1
[x(n) - x(n - 1)+y(n - 1)]
(6)
Figure 60. HP Filter Block Diagram
Figure 61 shows its characteristics at k=2 to 10.
3
0
−3
−6
Normalized Amplitude (dB)
−9
−12
−15
−18
−21
−24
K=2
K=3
K=4
K=5
K=6
K=7
K=8
K=9
K=10
−27
−30
−33
−36
−39
−42
−45
0.02
0.1
1
Input Signal Frequency (MHz)
10 15
Figure 61. HP Filter Amplitude Response at K = 2 to 10
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DECIMATION FILTER
ADS5294 includes an option to decimate the ADC output data using filters. Once the decimation is enabled, the
decimation rate, frequency band of the filter can be programmed. In addition, the user can select either the predefined or custom coefficients.
Table 9. Digital Filters
<DATA
RATE>
FILTERn
RATE>
<FILTERn
COEFF SET>
<ODD TAP>
<USE
FILTER
CHn>
<EN CUSTOM
FILT>
Built-in low-pass odd-tap filter (pass band = 0 to fS/4)
001
000
000
1
1
0
Built-in high-pass odd-tap filter (pass band = 0 to fS/4)
001
000
001
1
1
0
Built-in low-pass even-tap filter (pass band = 0 to fS/8)
010
001
010
0
1
0
Built-in first band pass even tap filter(pass band = fS/8 to fS/4)
010
001
011
0
1
0
Built-in second band pass even tap filter(pass band = fS/4 to 3
fS/8)
010
001
100
0
1
0
Built-in high pass odd tap filter (pass band = 3 fS/8 to fS/2)
010
001
101
1
1
0
Decimate by 2
Custom filter (user programmablecoefficients)
001
000
000
0 and 1
1
1
Decimate by 4
Custom filter (user programmablecoefficients)
010
001
000
0 and 1
1
1
Decimate by 8
Custom filter (user programmablecoefficients)
011
100
000
0 and 1
1
1
Bypass decimation
Custom filter (user programmablecoefficients)
0 and 1
1
1
DECIMATION
Decimate by 2
Decimate by 4
TYPE OF FILTER
DECIMATION FILTER EQUATION
In the default setting, the decimation filter is implemented as a 24-tap FIR filter with symmetrical coefficients
(each coefficient is 12-bit signed). By setting the register bit <ODD TAPn> = 1, a 23-tap FIR is implemented
Pre-defined Coefficients
The build-in filters (low pass, high pass an band pass) use pre-defined coefficients. The frequency responses of
the build-in decimation filters with different decimation factors are shown in Figure 62.
40
20
Low Pass
High pass
10
Low Pass
Band−Pass1
Band−Pass2
High Pass
30
20
0
Normalized Amplitude (dB)
Normalized Amplitude (dB)
10
−10
−20
−30
−40
−50
0
−10
−20
−30
−40
−50
−60
−60
−70
−80
0.0
−70
0.1
0.2
0.3
0.4
Normalized Frequency (fin/fs)
Figure 62. Decimation Filter Responses
(Decimate by 2)
56
0.5
−80
0.0
0.1
0.2
0.3
Normalized frequency (fin/fs)
0.4
0.5
Figure 63. Decimation Filter Responses
(Decimate by 4)
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Custom Filter Coefficients
The filter coefficients can also be programmed by the user (customized). For custom coefficients, set the register
bit <FILTER COEFF SELECT> and load the coefficients (h0 to h11) in registers 0x5A to 0xB9, using the serial
interface as:
Register content = real coefficient value x 211, i.e., 12 bit signed representation of real coefficient.
Board Design Considerations
Grounding
A single ground plane is sufficient to give good performance, provided the analog, digital, and clock sections of
the board are cleanly partitioned. See ADS5294VM Evaluation Module (SLAU355) for placement of components,
routing and grounding.
Supply Decoupling
Because the ADS5294 already includes internal decoupling, minimal external decoupling can be used without
loss in performance. For example, the ADS5294EVM uses a single 0.1 µF decoupling capacitor for each supply,
placed close to the device supply pins.
Packaging
Exposed Pad
The exposed pad at the bottom of the package is the main path for heat dissipation. Therefore, the pad must be
soldered to a ground plane on the PCB for best thermal performance. The pad must be connected to the ground
plane through the optimum number of vias.
Also, visit TI’s thermal website at www.ti.com/thermal.
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DEFINITION OF SPECIFICATIONS
Analog Bandwidth – The analog input frequency at which the power of the fundamental is reduced by 3 dB with
respect to the low-frequency value.
Aperture Delay – The delay in time between the rising edge of the input sampling clock and the actual time at
which the sampling occurs. This delay is different across channels. The maximum variation is specified as
aperture delay variation (channel-to-channel).
Aperture Uncertainty (Jitter) – The sample-to-sample variation in aperture delay.
Clock Pulse Width/Duty Cycle – The duty cycle of a clock signal is the ratio of the time the clock signal remains
at a logic high (clock pulse width) to the period of the clock signal. Duty cycle is typically expressed as a
percentage. A perfect differential sine-wave clock results in a 50% duty cycle.
Maximum Conversion Rate – The maximum sampling rate at which specified operation is given. All parametric
testing is performed at this sampling rate unless otherwise noted.
Minimum Conversion Rate – The minimum sampling rate at which the ADC functions.
Differential Nonlinearity (DNL) – An ideal ADC exhibits code transitions at analog input values spaced exactly
1 LSB apart. The DNL is the deviation of any single step from this ideal value, measured in units of LSBs.
Integral Nonlinearity (INL) – The INL is the deviation of the ADC transfer function from a best fit line determined
by a least squares curve fit of that transfer function, measured in units of LSBs.
Gain Error – Gain error is the deviation of the ADC actual input full-scale range from its ideal value. The gain
error is given as a percentage of the ideal input full-scale range. Gain error has two components: error as a
result of reference inaccuracy and error as a result of the channel. Both errors are specified independently as
EGREF and EGCHAN.
To a first-order approximation, the total gain error is ETOTAL ~ EGREF + EGCHAN.
For example, if ETOTAL = ±0.5%, the full-scale input varies from (1 – 0.5/100) x FSideal to (1 + 0.5/100) x FSideal.
Offset Error – The offset error is the difference, given in number of LSBs, between the ADC actual average idle
channel output code and the ideal average idle channel output code. This quantity is often mapped into millivolts.
Temperature Drift – The temperature drift coefficient (with respect to gain error and offset error) specifies the
change per degree Celsius of the parameter from TMIN to TMAX. It is calculated by dividing the maximum deviation
of the parameter across the TMIN to TMAX range by the difference TMAX – TMIN.
Signal-to-Noise Ratio – SNR is the ratio of the power of the fundamental (PS) to the noise floor power (PN),
excluding the power at dc and the first nine harmonics.
SNR = 10Log10
PS
PN
(7)
SNR is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full-scale) when the power of the fundamental is extrapolated to the converter fullscale range.
Signal-to-Noise and Distortion (SINAD) – SINAD is the ratio of the power of the fundamental (PS) to the power
of all the other spectral components including noise (PN) and distortion (PD), but excluding dc.
SINAD = 10Log10
PS
PN + PD
(8)
SINAD is either given in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the
reference, or dBFS (dB to full-scale) when the power of the fundamental is extrapolated to the converter fullscale range.
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Effective Number of Bits (ENOB) – ENOB is a measure of the converter performance as compared to the
theoretical limit based on quantization noise.
ENOB =
SINAD - 1.76
6.02
(9)
Total Harmonic Distortion (THD) – THD is the ratio of the power of the fundamental (PS) to the power of the
first nine harmonics (PD).
THD = 10Log10
PS
PN
(10)
THD is typically given in units of dBc (dB to carrier).
Spurious-Free Dynamic Range (SFDR) – The ratio of the power of the fundamental to the highest other
spectral component (either spur or harmonic). SFDR is typically given in units of dBc (dB to carrier).
Two-Tone Intermodulation Distortion – IMD3 is the ratio of the power of the fundamental (at frequencies f1
and f2) to the power of the worst spectral component at either frequency 2f1 – f2 or 2f2 – f1. IMD3 is either given
in units of dBc (dB to carrier) when the absolute power of the fundamental is used as the reference, or dBFS (dB
to full-scale) when the power of the fundamental is extrapolated to the converter full-scale range.
DC Power-Supply Rejection Ratio (DC PSRR) – DC PSSR is the ratio of the change in offset error to a change
in analog supply voltage. The dc PSRR is typically given in units of mV/V.
AC Power-Supply Rejection Ratio (AC PSRR) – AC PSRR is the measure of rejection of variations in the
supply voltage by the ADC. If ΔVSUP is the change in supply voltage and ΔVOUT is the resultant change of the
ADC output code (referred to the input), then:
DVOUT
PSRR = 20Log 10
(Expressed in dBc)
DVSUP
(11)
Voltage Overload Recovery – The number of clock cycles taken to recover to less than 1% error after an
overload on the analog inputs. This is tested by separately applying a sine wave signal with 6dB positive and
negative overload. The deviation of the first few samples after the overload (from the expected values) is noted.
Common-Mode Rejection Ratio (CMRR) – CMRR is the measure of rejection of variation in the analog input
common-mode by the ADC. If ΔVCM_IN is the change in the common-mode voltage of the input pins and ΔVOUT is
the resulting change of the ADC output code (referred to the input), then:
DVOUT
CMRR = 20Log10
(Expressed in dBc)
DVCM
(12)
Crosstalk (only for multi-channel ADCs) – This is a measure of the internal coupling of a signal from an
adjacent channel into the channel of interest. It is specified separately for coupling from the immediate
neighboring channel (near-channel) and for coupling from channel across the package (far-channel). It is usually
measured by applying a full-scale signal in the adjacent channel. Crosstalk is the ratio of the power of the
coupling signal (as measured at the output of the channel of interest) to the power of the signal applied at the
adjacent channel input. It is typically expressed in dBc.
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REVISION HISTORY
Changes from Original (November 2011) to Revision A
•
Page
Changed From: Product Preview To: Production ................................................................................................................. 1
Changes from Revision A (November 2011) to Revision B
Page
•
Changed the location of OUT A and OUT B in Figure 5 and Figure 6 ............................................................................... 14
•
Added EN_HIGH_ADDRS to Table 3 ................................................................................................................................. 29
•
Moved EN_EXT_REF From: 0x0F To: 0xF0 in Table 3 ..................................................................................................... 34
•
Added the section BIT-BYTE-WORD WISE OUTPUT. Added Figure 47 and Figure 48. .................................................. 37
•
Added section DIGITAL PROCESSING BLOCKS ............................................................................................................. 38
•
Replaced Table 5 and Table 6 with new Table 5 - Digital Filters ....................................................................................... 43
•
Changed the SYNCHRONIZATION PULSE section .......................................................................................................... 46
•
Added the External Reference Mode of Operation section ................................................................................................ 47
•
Added Figure 58 ................................................................................................................................................................. 53
•
Replaced Table 9 (Decimation Filter Modes) with new Table 9 - Digital Filters ................................................................. 56
•
Deleted section: Synchronization Pulse ............................................................................................................................. 57
60
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PACKAGE OPTION ADDENDUM
www.ti.com
25-Feb-2012
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package
Drawing
Pins
Package Qty
Eco Plan
(2)
Lead/
Ball Finish
MSL Peak Temp
(3)
ADS5294IPFP
ACTIVE
HTQFP
PFP
80
96
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
ADS5294IPFPR
ACTIVE
HTQFP
PFP
80
1000
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
ADS5294IPFPT
ACTIVE
HTQFP
PFP
80
250
Green (RoHS
& no Sb/Br)
CU NIPDAU Level-3-260C-168 HR
Samples
(Requires Login)
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability
information and additional product content details.
TBD: The Pb-Free/Green conversion plan has not been defined.
Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that
lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes.
Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between
the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above.
Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight
in homogeneous material)
(3)
MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature.
Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. TI bases its knowledge and belief on information
provided by third parties, and makes no representation or warranty as to the accuracy of such information. Efforts are underway to better integrate information from third parties. TI has taken and
continues to take reasonable steps to provide representative and accurate information but may not have conducted destructive testing or chemical analysis on incoming materials and chemicals.
TI and TI suppliers consider certain information to be proprietary, and thus CAS numbers and other limited information may not be available for release.
In no event shall TI's liability arising out of such information exceed the total purchase price of the TI part(s) at issue in this document sold by TI to Customer on an annual basis.
Addendum-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jul-2012
TAPE AND REEL INFORMATION
*All dimensions are nominal
Device
Package Package Pins
Type Drawing
SPQ
Reel
Reel
A0
Diameter Width (mm)
(mm) W1 (mm)
B0
(mm)
K0
(mm)
P1
(mm)
W
Pin1
(mm) Quadrant
ADS5294IPFPR
HTQFP
PFP
80
1000
330.0
24.4
15.0
15.0
1.5
20.0
24.0
Q2
ADS5294IPFPT
HTQFP
PFP
80
250
330.0
24.4
15.0
15.0
1.5
20.0
24.0
Q2
Pack Materials-Page 1
PACKAGE MATERIALS INFORMATION
www.ti.com
14-Jul-2012
*All dimensions are nominal
Device
Package Type
Package Drawing
Pins
SPQ
Length (mm)
Width (mm)
Height (mm)
ADS5294IPFPR
HTQFP
PFP
80
1000
367.0
367.0
45.0
ADS5294IPFPT
HTQFP
PFP
80
250
367.0
367.0
45.0
Pack Materials-Page 2
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have not been so designated are neither designed nor intended for automotive use; and TI will not be responsible for any failure of such
components to meet such requirements.
Products
Applications
Audio
www.ti.com/audio
Automotive and Transportation www.ti.com/automotive
Amplifiers
amplifier.ti.com
Communications and Telecom www.ti.com/communications
Data Converters
dataconverter.ti.com
Computers and Peripherals
www.ti.com/computers
DLP® Products
www.dlp.com
Consumer Electronics
www.ti.com/consumer-apps
DSP
dsp.ti.com
Energy and Lighting
www.ti.com/energy
Clocks and Timers
www.ti.com/clocks
Industrial
www.ti.com/industrial
Interface
interface.ti.com
Medical
www.ti.com/medical
Logic
logic.ti.com
Security
www.ti.com/security
Power Mgmt
power.ti.com
Space, Avionics and Defense
www.ti.com/space-avionics-defense
Microcontrollers
microcontroller.ti.com
Video and Imaging
www.ti.com/video
RFID
www.ti-rfid.com
OMAP Mobile Processors
www.ti.com/omap
TI E2E Community
e2e.ti.com
Wireless Connectivity
www.ti.com/wirelessconnectivity
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