ETC TSA1005-40IF

TSA1005-40
DUAL-CHANNEL, 10-BIT, 40MSPS, 150mW A/D CONVERTER
Preliminary Data
■ 10-bit, dual-channel A/D converter in deep
NC
NC
VCCBE
44 43 42
GNDBE
VCCBI
VCCBI
OEB
48 47 46 45
AVCC
AVCC
INCMI
■
■
■
■
index
corner
REFMI
■
■
REFPI
■
PIN CONNECTIONS (top view)
submicron CMOS technology
Single supply voltage: 2.5V
Independent supply for CMOS output stage
with 2.5V/3.3V capability
ENOB=9.4 @ 40Msps, Fin=10MHz
SFDR typically up to 73dB @ 40Msps,
Fin=10MHz.
40Msps sampling frequency
1GHz analog bandwidth Track-and-Hold
Common clocking between channels
Multiplexed outputs
41 40 39 38 37
36 D0(LSB)
AGND 1
2
35 D1
AGND 3
34 D2
INIB 4
33 D3
INI
AGND 5
32 D4
IPOL 6
31 D5
TSA1005-40
AVCCB 7
30 D6
29 D7
AGND 8
INQ 9
28 D8
DESCRIPTION
AGND 10
27 D9(MSB)
INBQ 11
26 VCCBE
The TSA1005-40 is a new generation of high
speed, dual-channel Analog to Digital converter
processed in a mainstream 0.25µm CMOS technology yielding high performances.
The TSA1005-40 is specifically designed for applications requiring very low noise floor, high SFDR
and good isolation between channels. It is based
on a pipeline structure and digital error correction
to provide high static linearity at Fs=40Msps, and
Fin=10MHz.
For each channel, a voltage reference is integrated to simplify the design and minimize external
components. It is nevertheless possible to use the
circuit with external references.
Each ADC outputs are multiplexed in a common
bus with small number of pins.
Differential or single-ended analog inputs can be
applied. A tri-state capability is available for the
outputs, allowing chip selection.
The TSA1005-40 is available in extended (0 to
+85°C) temperature range, in a small 48 pins
TQFP package.
AGND 12
GNDBI
DVCC
DGND
SELECT
CLK
DGND
DVCC
AVCC
Package
Condition ing
Marking
TSA1005-40IF
0°C to +85°C
TQFP48
Tray
SA1005I
0°C to +85°C
TQFP48
Tape & Reel
SA1005I
September 2002
CLK
SELECT OEB
VCCBE
Timing
VINI
AD 10
I channel
VINBI
VINCMI
10
common mode
VREFPI
REF I
VREFMI
IPOL
M
U
X
Polar.
10
10
Buffers
D0
TO
D9
VREFPQ
REF Q
VREFMQ
VINCMQ
common mode
AD 10
10
Q channel
GND
GNDBE
PACKAGE
7 × 7 mm TQFP48
TSA1005-40IFT
EVAL1005/BA
AGND
Temperature
Range
INCMQ
Part Number
REFMQ
ORDER CODE
23 24
+2.5V/3.3V
VINBQ
Medical imaging and ultrasound
I/Q signal processing applications
High speed data acquisition system
Portable instrumentation
High resolution fax and scanners
17 18 19 20 21 22
REFPQ
■
■
■
■
■
14 15 16
BLOCK DIAGRAM
VINQ
APPLICATIONS
25 GNDBE
13
Evaluation board
1/19
This is preliminary information on a new product now in development or undergoing evaluation. Details are subject to change without notice
TSA1005-40
ELECTRICAL CHARACTERISTICS
AVCC = DVCC = VCCB = 2.5V, Fs= 40Msps, Fin=10.13MHz, Vin@ -1dBFS, VREFP=0.8V, VREFM=0V
Tamb = 25°C (unless otherwise specified)
DYNAMIC CHARACTERISTICS
Symbol
Parameter
Test conditions
Min
Typ
Max
Unit
SFDR
Spurious Free Dynamic Range
-73
dBc
SNR
Signal to Noise Ratio
59
dB
THD
Total Harmonics Distortion
-73
dBc
Signal to Noise and Distortion Ratio
58.5
dB
SINAD
TIMING CHARACTERISTICS
Symbol
Parameter
Test conditio ns
Min
Typ
Max
Unit
40
MHz
55
%
FS
Sampling Frequency
0.5
DC
Clock Duty Cycle
45
TC1
Clock pulse width (high)
12.5
ns
TC2
Clock pulse width (low)
12.5
ns
Tod
Data Output Delay (Clock edge to Data Valid)
5
ns
50
10pF load capacitance
Tpd I
Data Pipeline delay for I channel
7
cycles
Tpd Q
Data Pipeline delay for Q channel
7.5
cycles
Ton
Falling edge of OEB to digital output valid data
1
ns
Toff
Rising edge of OEB to digital output tri-state
1
ns
TIMING DIAGRAM
Simultaneous sampling
on I/Q channels
N+4
N+3
I
N
N+13
N+6
N+12
N+11
N+7
N+2
N-1
N+5
N+1
N+8
N+9
Q
N+10
CLK
Tpd I + Tod
Tod
SELECT
CLOCK AND SELECT CONNECTED TOGETHER
OEB
sample N-8
I channel
sample N-6
Q channel
sample N
Q channel
sample N+1
Q channel
sample N+2
Q channel
DATA
OUTPUT
sample N-9
I channel
2/19
sample N-7
Q channel
sample N+1 sample N+2 sample N+3
I channel
I channel
I channel
TSA1005-40
ABSOLUTE MAXIMUM RATINGS
Symbol
Parameter
AVCC
Analog Supply voltage 1)
DVCC
Digital Supply voltage 1)
VCCBE
VCCBI
IDout
Tstg
ESD
Values
Unit
0 to 3.3
V
0 to 3.3
V
Digital buffer Supply voltage
1)
0 to 3.6
V
Digital buffer Supply voltage
Digital output current
Storage temperature
1)
0 to 3.3
V
-100 to 100
+150
mA
°C
HBM: Human Body Model2)
CDM: Charged Device
2
kV
1.5
Model3)
Latch-up Class 4)
A
1). All voltages values, except differential voltage, are with respect to network ground terminal . The magnitude of input and output voltages must not exceed -0.3V or VCC
2). ElectroStati cDischarge pu lse (ESD pulse) simulating a human bod y discharge of 100 pF through 1.5kΩ
3). Discharge to Ground of a device that has been previously charged.
4). Corporate ST Microelectronics procedu renumber 0018695
PIN CONNECTIONS (top view)
NC
NC
44
VCCBE
AVCC
45
NDBE
AVCC
46
VCCBI
INCMI
47
OEB
REFMI
48
VCCBI
REFPI
i nd ex
c or ner
43
42
41
40
39
38
37
36 D 0( L SB )
A GND 1
3 5 D1
INI
2
A GND
3
34 D 2
INIB
4
33 D 3
A GND
5
3 2 D4
IPO L
6
31 D 5
T S A1 00 5-40
A V CC B 7
A GND
8
INQ
9
30 D 6
29 D 7
28 D 8
A GND 10
2 7 D 9( M SB )
INB Q
2 6 VC C B E
11
25 GND BE
A GND 12
19
20
21
AGND
AVCC
DVCC
DGND
CLK
SELECT
22
23
24
GNDBI
18
DVCC
17
DGND
16
INCMQ
REFPQ
14 1 5
REFMQ
13
PIN DESCRIPTION
Pin No
N ame
1
AGND
2
IN I
3
AGND
Pin No
Name
Analog ground
D escription
0V
Observation
25
GNDBE
Description
I channel analog input
1Vpp
26
VCCB E
D igital Buffer power supply
2.5V/3.3V
Analog ground
0V
27
D9(MSB)
Most Significant Bit output
CMOS output (2.5V/3.3V)
D igital buffer ground
Observation
0V
4
INB I
I channel inverted analog input
1Vpp
28
D8
D igital output
CMOS output (2.5V/3.3V)
5
AGND
Analog ground
0V
29
D7
D igital output
CMOS output (2.5V/3.3V)
6
IPOL
Analog bias current input
30
D6
D igital output
CMOS output (2.5V/3.3V)
7
AVCC
Analog power supply
2.5V
31
D5
D igital output
CMOS output (2.5V/3.3V)
8
AGND
Analog ground
0V
32
D4
D igital output
CMOS output (2.5V/3.3V)
9
IN Q
Q channel analog input
1Vpp
33
D3
D igital output
CMOS output (2.5V/3.3V)
10
AGND
Analog ground
0V
34
D2
D igital output
CMOS output (2.5V/3.3V)
11
IN BQ
Q channel inverted analog input
1Vpp
35
D1
D igital output
CMOS output (2.5V/3.3V)
12
AGND
Analog ground
0V
36
D0(LSB)
Least Significant Bit output
CMOS output (2.5V/3.3V)
13
RE FPQ
Q channel top reference voltage
1V
37
NC
N on connected
14
REFMQ
Q channel bottom reference voltage
0V
38
NC
N on connected
15
INCM Q
Q channel input common mode
0.5V
39
VCCB E
D igital Buffer power supply
16
AGND
Analog ground
0V
40
GNDBE
D igital buffer ground
0V
17
AVCC
Analog power supply
2.5V
41
VCCB I
D igital Buffer power supply
2.5V
18
DV CC
Digital power supply
2.5V
42
VCCB I
D igital Power Supply
2.5V
19
D GND
Digital ground
0V
43
OEB
Output Enable input
2.5V/3.3V CMOS input
Clock input
2.5V CMOS input
44
AVCC
Analog power supply
2.5V
Channel selection
2.5V CMOS input
45
AVCC
Analog power supply
2.5V
I channel input common mode
0.5V
2.5V/3.3V - See Application Note
20
CLK
21
SELECT
22
D GND
Digital ground
0V
46
IN CMI
23
DV CC
Digital power supply
2.5V
47
RE FMI
I channel bottom reference voltage
0V
24
GND BI
Digital buffer ground
0V
48
REFP I
I channel top reference v oltage
1V
3/19
TSA1005-40
CONDITIONS
AVCC = DVCC = VCCB = 2.5V, Fs= 40Msps, Fin=2MHz, Vin@ -1dBFS, VREFM=0V
Tamb = 25°C (unless otherwise specified)
OPERATING CONDITIONS
Symbol
Parameter
Typ
Max
Unit
AVCC
Analog Supply voltage
2.25
2.5
2.7
V
DVCC
Digital Supply voltage
2.25
2.5
2.7
V
VCCBE
External Digital buffer Supply voltage
2.25
2.5
3.5
V
VCCBI
Internal Digital buffer Supply voltage
2.25
2.5
2.7
V
Forced top voltage reference 1)
0.6
0.88
1.4
V
Forced bottom reference voltage 1)
0
0
0.4
V
Forced input common mode voltage
0.2
0.46
1
V
VREFPI
VREFPQ
VREFMI
VREFMQ
INCMI
INCMQ
1)
Min
Condition VRefP-VRefM>0.3V
ANALOG INPUTS
Symbol
Parameter
Test conditions
VIN-VINB Full scale reference voltage
Cin
Input capacitance
Req
Equivalent input resistor
BW
Analog Input Bandwidth
ERB
Effective Resolution Bandwidth
Min
Typ
Max
Unit
0.3
2.0
2.8
Vpp
Vin@Full Scale, Fs=40Msps
7
pF
1.6
KΩ
1000
MHz
70
MHz
DIGITAL INPUTS AND OUTPUTS
Symbol
Parameter
Test conditions
Min
Typ
Max
Unit
0
0.8
V
Clock and Select inputs
VIL
Logic ”0” voltage
VIH
Logic ”1” voltage
2.0
2.5
V
OEB inpu t
VIL
Logic ”0” voltage
VIH
Logic ”1” voltage
0
0.25 x
VCCBE
0.75 x VCCBE
VCCBE
V
V
Digital Outputs
VOL
Logic ”0” voltage
Iol=10µA
VOH
Logic ”1” voltage
Ioh=10µA
IOZ
High Impedance leakage current OEB set to VIH
CL
Output Load Capacitance
4/19
0
0.9 x VCCBE
VCCBE
-1.67
0
0.1 x
VCCBE
V
V
1.67
µA
15
pF
TSA1005-40
CONDITIONS
AVCC = DVCC = VCCB = 2.5V, Fs= 40Msps, Fin=2MHz, Vin@ -1dBFS, VREFP=0.8V, VREFM=0V
Tamb = 25°C (unless otherwise specified)
REFERENCE VOLTAGE
Symbol
VREFPI
VREFPQ
VINCMI
VINCMQ
Parameter
Test conditions
Min
Typ
Max
Unit
Top internal reference voltage
0.81
0.88
0.94
V
Input common mode voltage
0.41
0.46
0.50
V
POWER CONSUMPTION
Symbol
Parameter
Min
Typ
Max
Unit
ICCA
Analog Supply current
50
mA
ICCD
Digital Supply Current
4
mA
ICCBE
Digital Buffer Supply Current (10pF load)
6
mA
ICCBI
Digital Buffer Supply Current
274
uA
Power consumption in normal operation mode
150
mW
Thermal resistance (TQFP48)
80
°C/W
Pd
Rthja
ACCURACY
Symbol
Parameter
Min
Typ
Max
Unit
OE
Offset Error
LSB
GE
Gain Error
%
DNL
Differential Non Linearity
±0.5
LSB
INL
Integral Non Linearity
±0.7
LSB
-
Monotonicity and no missing codes
Guaranteed
MATCHING BETWEEN CHANNELS
Symbol
Parameter
Min
Typ
Max
Unit
1
%
GM
Gain match
0.04
OM
Offset match
0.5
LSB
PHM
Phase match
1
dg
XTLK
Crosstalk rejection
85
dB
5/19
TSA1005-40
Static parameter: Integral Non Linearity
Fs=40MSPS; Icca=45mA; Fin=10MHz
2
1.5
INL (LSBs)
1
0.5
0
-0.5
-1
-1.5
-2
0
200
400
600
800
1000
800
1000
Output Code
Static parameter: Differential Non Linearity
Fs=40MSPS; Icca=45mA; Fin=10MHz
1
0.8
DNL (LSBs)
0.6
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-1
0
200
400
600
Output Code
Linearity vs. Fin
Fs=40MHz; Icca=45mA
Distortion vs. Fin
Fs=40MHz; Icca=45mA
9
ENOB_I
ENOB_Q
80
8
70
SNR_Q
SINAD_Q
7
60
6
50
SNR_I
SINAD_I
5
40
4
0
20
40
Fin (MHz)
60
Dynamic parameters (dBc)
90
30
6/19
0
10
ENOB (bits)
Dynamic parameters (dB)
100
-20
-40
THD_I
SFDR_I
-60
-80
SFDR_Q
THD_Q
-100
-120
0
20
40
Fin (MHz)
60
TSA1005-40
10
9.5
90
9
ENOB_Q
ENOB_I
8.5
80
8
70
7.5
SNR_Q
SINAD_Q
7
60
50
40
2.25
6.5
ENOB (bits)
Dynamic parameters (dB)
100
6
SNR_I
SINAD_I
5.5
Dynamic Parameters (dBc)
Distortion vs. AVCC
Fs=40MSPS; Icca=45mA; Fin=5MHz
Linearity vs. AVCC
Fs=40MSPS; Icca=45mA; Fin=5MHz
2.45
2.55
-40
-50
2.65
-70
-80
SFDR_I
-90
THD_I
-100
-110
2.35
2.45
Linearity vs. DVCC
Fs=40MSPS; Icca=45mA; Fin=10MHz
9
ENOB_I
8.5
80
8
7.5
70
SINAD_Q
7
60
6.5
SINAD_I
SNR_I
6
5.5
40
2.25
Dynamic Parameters (dBc)
ENOB_Q
ENOB (bits)
Dynamic parameters (dB)
9.5
50
2.45
2.55
0
-20
-40
2.65
-80
-100
THD_I
THD_Q
2.35
2.45
10
85
9.5
9
ENOB_Q
8.5
75
8
70
7.5
65
7
SNR_Q
6.5
60
6
55
SINAD_I
5.5
SNR_I
50
2.25
5
2.35
2.45
-40
2.55
VCCBI (V)
2.65
Dynamic Parameters (dBc)
90
SINAD_Q
2.65
Distortion vs. VCCBI
Fs=40MSPS; Icca=45mA; Fin=10MHz
ENOB (bits)
Dynamic parameters (dB)
Linearity vs. VCCBI
Fs=40MSPS; Icca=45mA; Fin=10MHz
ENOB_I
2.55
DVCC (V)
DVCC (V)
80
SFDR_I
SFDR_Q
-60
-120
2.25
5
2.35
2.65
Distortion vs. DVCC
Fs=40MSPS; Icca=45mA; Fin=10MHz
10
100
SNR_Q
2.55
AVCC (V)
AVCC (V)
90
SFDR_Q
THD_Q
-60
-120
2.25
5
2.35
-30
-50
THD_Q
-60
SFDR_Q
-70
-80
-90
THD_I
SFDR_I
-100
-110
-120
2.25
2.35
2.45
2.55
2.65
VCCBI (V)
7/19
TSA1005-40
90
10
85
9.8
Dynamic Parameters (dBc)
Distortion vs. VCCBE
Fs=40MSPS; Icca=45mA; Fin=10MHz
9.6
80
ENOB_Q
ENOB_I
9.4
75
9.2
70
9
65
8.8
SNR_I
SINAD_I
8.6
60
ENOB (bits)
Dynamic parameters (dB)
Linearity vs. VCCBE
Fs=40MSPS; Icca=45mA; Fin=10MHz
8.4
55
SINAD_Q
SNR_Q
50
2.25
8.2
-40
-50
3.25
-70
-80
THD_I
-90
SFDR_I
-100
-110
2.75
Linearity vs. Duty Cycle
Fs=40MHz; Icca=45mA; Fin=5MHz
Distortion vs. Duty Cycle
Fs=40MHz; Icca=45mA; Fin=5MHz
Dynamic parameters (dBc)
9.5
90
9
ENOB
8.5
80
8
SNR
7.5
SINAD
7
60
6.5
ENOB (bits)
Dynamic parameters (dB)
-40
10
100
6
50
5.5
40
5
45
47
49
3.25
VCCBE (V)
VCCBE (V)
70
SFDR_Q
THD_Q
-60
-120
2.25
8
2.75
-30
51
53
-50
SFDR
-60
-70
-80
THD
-90
-100
-110
-120
55
45
47
Positive Duty Cycle (%)
49
51
53
Positive Duty Cycle (%)
Single-tone 8K FFT at 39.7Msps - Q Channel
Fin=10MHz; Icca=45mA, Vin@-1dBFS
Power spectrum (dB)
0
-20
-40
-60
-80
-100
-120
-140
2
4
6
8
10
12
Frequency (MHz)
8/19
14
16
18
20
55
TSA1005-40
DEFINITIONS OF SPECIFIED PARAMETERS
STATIC PARAMETERS
Signal to Noise Ratio (SNR)
Static measurements are performed through
method of histograms on a 2MHz input signal,
sampled at 40Msps, which is high enough to fully
characterize the test frequency response. The
input level is +1dBFS to saturate the signal.
The ratio of the rms value of the fundamental
component to the rms sum of all other spectral
components in the Nyquist band (fs/2) excluding
DC, fundamental and the first five harmonics.
SNR is reported in dB.
Differential Non Linearity (DNL)
The average deviation of any output code width
from the ideal code width of 1 LSB.
Integral Non linearity (INL)
An ideal converter presents a transfer function as
being the straight line from the starting code to the
ending code. The INL is the deviation for each
transition from this ideal curve.
DYNAMIC PARAMETERS
Dynamic measurements are performed by
spectral analysis, applied to an input sine wave of
various frequencies and sampled at 40Msps.
The input level is -1dBFS to measure the linear
behavior of the converter. All the parameters are
given without correction for the full scale amplitude performance except the calculated ENOB
parameter.
Spurious Free Dynamic Range (SFDR)
The ratio between the power of the worst spurious
signal (not always an harmonic) and the amplitude
of fundamental tone (signal power) over the full
Nyquist band. It is expressed in dBc.
Total Harmonic Distortion (THD)
The ratio of the rms sum of the first five harmonic
distortion components to the rms value of the
fundamental line. It is expressed in dB.
Signal to Noise and Distortion Ratio (SINAD)
Similar ratio as for SNR but including the harmonic
distortion components in the noise figure (not DC
signal). It is expressed in dB.
From the SINAD, the Effective Number of Bits
(ENOB) can easily be deduced using the formula:
SINAD= 6.02 × ENOB + 1.76 dB.
When the applied signal is not Full Scale (FS), but
has an A0 amplitude, the SINAD expression
becomes:
SINAD2Ao=SINADFull Scale+ 20 log (2A0/FS)
SINAD2Ao=6.02 × ENOB + 1.76 dB + 20 log (2A0/
FS)
The ENOB is expressed in bits.
Analog Input Bandwidth
The maximum analog input frequency at which the
spectral response of a full power signal is reduced
by 3dB. Higher values can be achieved with
smaller input levels.
Effective Resolution Bandwidth (ERB)
The band of input signal frequencies that the ADC
is intended to convert without loosing linearity i.e.
the maximum analog input frequency at which the
SINAD is decreased by 3dB or the ENOB by 1/2
bit.
Pipeline delay
Delay between the initial sample of the analog
input and the availability of the corresponding
digital data output, on the output bus. Also called
data latency. It is expressed as a number of clock
cycles.
9/19
TSA1005-40 APPLICATION NOTE
DETAILED INFORMATION
The TSA1005-40 is a dual-channel, 10-bit resolution analog to digital converter based on a pipeline
structure and the latest deep sub micron CMOS
process to achieve the best performances in
terms of linearity and power consumption.
Each channel achieves 10-bit resolution through
the pipeline structure. A latency time of 7 clock periods is necessary to obtain the digitized data on
the output bus.
The input signals are simultaneously sampled on
both channels on the rising edge of the clock. The
output data is valid on the rising edge of the clock
for I channel and on the falling edge of the clock
for Q channel. The digital data out from the different stages must be time delayed depending on
their order of conversion. Then a digital data correction completes the processing and ensures the
validity of the ending codes on the output bus.
The structure has been specifically designed to
accept differential signals. In this case, you will obtain the best performances. Nevertheless, single-ended signals can drive the ADC with few linearity degradation.
The TSA1005-20 is pin to pin compatible with the
dual 10bits/40Msps TSA1005, the dual 12bits/
20Msps TSA1204 and the dual 12bits/40Msps
TSA1203.
COMPLEMENTARY FUNCTIONS
Some functionalities have been added in order to
simplify as much as possible the application
board. These operational modes are described as
followed.
Output Enable (OEB)
When set to low level (VIL), all digital outputs
remain active and are in low impedance state.
When set to high level (VIH), all digital outputs
buffers are in high impedance state while the
converter goes on sampling. When OEB is set to a
low level again, the data are then present on the
output with a very short Ton delay.
Therefore, this allows the chip select of the device.
The timing diagram summarizes this functionality.
In order to remain in the normal operating mode,
this pin should be grounded through a low value of
resistor.
SELECT
The digital data out from each ADC core are multiplexed together to share the same output bus.
This prevents from increasing the number of pins
and enables to keep the same package as single
channel ADC like TSA1002.
The selection of the channel information is done
through the ”SELECT” pin. When set to high level
(VIH), the I channel data are present on the bus
D0-D9. When set to low level (VIL), the Q channel
data are on the output bus D0-D9.
Connecting SELECT to CLK allows I and Q channels to be simultaneously present on D0-D9; I
channel on the rising edge of the clock and Q
channel on the falling edge of the clock. (see timing diagram page 2).
REFERENCES AND COMMON MODE
CONNECTION
VREFM must be always connected externally.
Internal reference and common mode
In the default configuration, the ADC operates with
its own reference and common mode voltages
generated by its internal bandgap. VREFM pins
are connected externally to the Analog Ground
while VREFP (respectively INCM) are set to their
internal voltage of 0.88V (respectively 0.46V). It is
recommended to decouple the VREFP and INCM
in order to minimize low and high frequency noise
(refer to Figure 1)
Figure 1 : Internal reference and common mode
setting
VIN
330pF 10nF
4.7 uF
330pF 10nF
4.7uF
VREFP
TSA1005
VINB
INCM
VREFM
10/19
TSA1005-40
External reference and common mode
Each of the voltages VREFP and INCM can be
fixed externally to better fit to the application
needs
(Refer
to
table
’OPERATING
CONDITIONS’ page 4 for min/max values).
The VREFP, VREFM voltages set the analog
dynamic at the input of the converter that has a full
scale amplitude of 2*(VREFP-VREFM). Using
internal references, the dynamic range is 1.8V.
The INCM is the mid voltage of the analog input
signal.
might also use a higher impedance ratio (1:2 or
1:4) to reduce the driving requirement on the
analog signal source.
Each analog input can drive a 1Vpp amplitude input signal, so the resultant differential amplitude is
2Vpp.
Figure 3 : Differential input configuration with
transformer
Analog source
ADT1-1
1:1
VIN
50Ω
33pF
VINB
It is possible to use an external reference voltage
device for specific applications requiring even
better
linearity,
accuracy
or
enhanced
temperature behavior.
Using the STMicroelectronics TS821 or
TS4041-1.2 Vref leads to optimum performances
when configured as shown on Figure 2 .
Figure 2 : External reference setting
1kΩ
330pF 10nF 4.7uF
VCCA VREFP
VIN
TSA1005
VINB
VREFM
TS821
TS4041
INCM
330pF
10nF
470nF
Figure 4 represents the biasing of a differential
input signal in AC-coupled differential input
configuration. Both inputs VIN and VINB are
centered around the common mode voltage, that
can be let internal or fixed externally.
Figure 4 : AC-coupled differential input
external
reference
50Ω
VIN
10nF
100kΩ
33pF
common
mode
DRIVING THE ANALOG INPUT
TSA1005
I or Q ch.
50Ω
INCM
100kΩ
TSA1005
VINB
10nF
Differential inputs
The TSA1005-40 has been designed to obtain
optimum performances when being differentially
driven. An RF transformer is a good way to
achieve such performances.
Figure 3 describes the schematics. The input
signal is fed to the primary of the transformer,
while the secondary drives both ADC inputs. The
common mode voltage of the ADC (INCM) is
connected to the center-tap of the secondary of
the transformer in order to bias the input signal
around this common voltage, internally set to
0.46V. It determines the DC component of the
analog signal. As being an high impedance input,
it acts as an I/O and can be externally driven to
adjust this DC component. The INCM is
decoupled to maintain a low noise level on this
node. Our evaluation board is mounted with a 1:1
ADT1-1WT transformer from Minicircuits. You
11/19
Figure 5 shows a DC-coupled configuration with
forced VREFP and INCM to the 1V DC analog
input while VREFM is connected to ground; we
achieve a 2Vpp differential amplitude.
Figure 5 : DC-coupled 2Vpp differential analog
input
analog
AC+DC
DC
VREFP
VIN
TSA1005
VINB
analog
VREFM
INCM
DC
VREFP-VREFM = 1 V
330pF 10nF
4.7uF
TSA1005-40
Single-ended input configuration
The single-ended input configuration of the
TSA1005-40 requires particular biasing and driving. The structure being fully differential, care has
to be taken in order to properly bias the inputs in
single-ended mode. Figure 6 summarizes the link
from the differential configuration to the single-ended one; a wrong configuration is also presented.
- With differential driving, both inputs are centered
around the INCM voltage.
- The transition to single-ended configuration
implies to connect the unused input (VINB for
instance) to the DC component of the single input
(VIN) and also to the input common mode in order
to be well balanced. The mid-code is achieved at
the crossing between VIN and VINB, therefore
inputs are conveniently biased.
- Unlikely other structures of converters in which
the unused input can be grounded; in our case it
will end with unbalanced inputs and saturation of
the internal amplifiers leading to a non respect of
the output codes.
Figure 6 : Input dynamic range for the various configurations
Differential configura tion
Single-ended configuration:
balanced inputs
Single-end ed configuration:
unbalanced input s
+FS : code 1023
+FS + offset : code > 1023
+FS : code 1023
VIN - VINB
VIN - VINB
VIN - VINB
VIN
VINB
VIN
INCM
0 : code 511
INCM
INCM
VIN
0 : code 511
-FS : code 0
-FS + offset : code > 0
-FS : code 0
Ao + ac
Ao + ac
Ao + ac
VIN
VINB
VINB
INCM
Ao
Ao + ac
VIN
VINB
INCM
INCM
Ao
Wrong configuratio n !
Ao
The applications requiring single-ended inputs
can be configured like reported on Figure 7 for an
AC-coupled input or on Figure 8 for a DC-coupled
input.
VIN
Figure 7 : AC-coupled Single-ended input
Signal source
10nF
In the case of AC-coupled analog input, the
analog inputs VIN and VINB are biased to the
same voltage that is the common mode voltage of
the circuit (INCM). The INCM and reference
voltages may remain at their internal level but can
also be fixed externally.
In the case of DC-coupled analog input with 1V
DC signal, the DC component of the analog input
VIN
100kΩ
50Ω
INCM
33pF
TSA1005
100kΩ
VINB
set the common mode voltage. As an example
figure 8, VREFP and INCM are set to the 1V DC
12/19
TSA1005-40
Figure 8 : DC-coupled 2Vpp analog input
The figure 9 sums up the relevant data.
Figure 9 : analog current consumption
optimization depending on Rpol value
250
100
AC+DC
VIN
DC
VREFM
INCM
330pF
200
80
TSA1005
VINB
VREFP-VREFM = 1 V
90
VREFP
Icca (mA)
Analog
70
150
60
ICCA
50
100
40
30
10nF
4.7uF
Rpol (kOhms)
analog input while VREFM is connected to
ground; we achieve a 2Vpp differential amplitude.
50
20
10
RPOL
0
0
5
15
25
Dynamic characteristics, while not being as
remarkable as for differential configuration, are
still of very good quality.
35
45
55
Fs (MHz)
APPLICATION
Clock input
Layout precautions
The TSA1005-40 performance is very dependant
on your clock input accuracy, in terms of aperture
jitter; the use of low jitter crystal controlled
oscillator is recommended.
The duty cycle must be between 45% and 55%.
The clock power supplies must be separated from
the ADC output ones to avoid digital noise
modulation at the output.
It is recommended to always keep the circuit
clocked, even at the lowest specified sampling
frequency of 0.5Msps, before applying the supply
voltages.
Power consumption
So as to optimize both performance and power
consumption of the TSA1005-40 according the
sampling frequency, a resistor is placed between
IPOL and the analog Ground pins. Therefore, the
total dissipation is adjustable from 35Msps up to
50Msps.
The TSA1005-40 will combine highest performances and lowest consumption at 40Msps when
Rpol is equal to 30kΩ. This value is nevertheless
dependant on application and environment.
At lower sampling frequency range, this value of
resistor may be adjusted in order to decrease the
analog current without any degradation of
dynamic performances.
13/19
To use the ADC circuits in the best manner at high
frequencies, some precautions have to be taken
for power supplies:
- First of all, the implementation of 4 separate
proper supplies and ground planes (analog,
digital, internal and external buffer ones) on the
PCB is recommended for high speed circuit
applications to provide low inductance and low
resistance common return.
The separation of the analog signal from the
digital part is mandatory to prevent noise from
coupling onto the input signal. The best
compromise is to connect from one part AGND,
DGND, GNDBI in a common point whereas
GNDBE must be isolated. Similarly, the power
supplies AVCC, DVCC and VCCBI must be
separated from the VCCBE one.
- Power supply bypass capacitors must be placed
as close as possible to the IC pins in order to
improve high frequency bypassing and reduce
harmonic distortion.
- Proper termination of all inputs and outputs must
be incorporated with output termination resistors;
then the amplifier load will be only resistive and
the stability of the amplifier will be improved. All
leads must be wide and as short as possible
especially for the analog input in order to decrease
parasitic capacitance and inductance.
- To keep the capacitive loading as low as
possible at digital outputs, short lead lengths of
routing are essential to minimize currents when
the output changes. To minimize this output
TSA1005-40
capacitance, buffers or latches close to the output
pins will relax this constraint.
- Choose component sizes as small as possible
(SMD).
Digital Interface application
Thanks to its wide external buffer power supply
range, the TSA1005-40 is perfectly suitable to
plug in to 2.5V low voltage DSPs or digital interfaces as well as to 3.3V ones.
Medical Imaging application
Driven by the demand of the applications requiring
nowadays either portability or high degree of parallelism (or both), this product has been developed to satisfy medical imaging, and telecom infrastructures needs.
As a typical system diagram shows figure 10, a
narrow input beam of acoustic energy is sent into
a living body via the transducer and the energy reflected back is analyzed.
Figure 10 : Medical imaging application
HV TX amps
The transducer is a piezoelectric ceramic such as
zirconium titanate. The whole array can reach up
to 512 channels.
The TX beam former, amplified by the HV TX
amps, delivers up to 100V amplitude excitation
pulses with phase and amplitude shifts.
The mux and T/R switch is a two way input signal
transmitter/ output receiver.
To compensate for skin and tissues attenuation
effects, The Time Gain Compensation (TGC) amplifier is an exponential amplifier that enables the
amplification of low voltage signals to the ADC input range. Differential output structure with low
noise and very high linearity are mandatory factors.
These applications need high speed, low power
and high performance ADCs. 10-12 bit
resolution is necessary to lower the quantification
noise. As multiple channels are used, a dual converter is a must for room saving issues.
The input signal is in the range of 2 to 20MHz
(mainly 2 to 7MHz) and the application uses mostly a 4 over-sampling ratio for Spurious Free Dynamic Range (SFDR) optimization.
The next RX beam former and processing blocks
enable the analysis of the outputs channels versus the input beam.
TX
beamformer
Mux and
T/R
switches
ADC
RX
beamformer
TGC amplifie r
Processing
and disp lay
14/19
TSA1005-40
EVAL1005/BA evaluation board
The EVAL1005/BA is a 4-layer board with high
decoupling and grounding level. The schematic of
the evaluation board is reported figure 14 and its
top overlay view figure 13.The characterization of
the board has been made with a fully ADC
devoted test bench as shown on Figure 11. The
analog input signal must be filtered to be very
pure.
The dataready signal is the acquisition clock of the
logic analyzer.
The ADC digital outputs are latched by the octal
buffers 74LCX573.
All characterization measurements have been
made with:
- SFSR=1dB for static parameters.
- SFSR=-1dB for dynamic parameters.
Figure 11 : Analog to Digital Converter characterization bench
HP8644
Data
Vin
Sine Wave
Generator
ADC
evaluation
board
Logic
Analyzer
PC
Clk
Clk
HP8133
Pulse
Generator
HP8644
Sine Wave
Generator
Operating conditions of the evaluation board:
Find below the connections to the board for the
power supplies and other pins:
board
notation
board
notation
connection
internal
external
voltage (V)
voltage (V)
AV
AVCC
2.5
AG
AGND
0
RPI
REFPI
RMI
REFMI
CMI
INCMI
0.46
0.2 to 1
RPQ
REFPQ
0.89
0.6 to 1.4
RMQ
REFMQ
CMQ
INCMQ
DV
DVCC
2.5
DG
DGND
0
15/19
0.89
0.6 to 1.4
0 to 0.4
0 to 0.4
0.46
0.2 to 1
connection
internal
external
voltage (V)
voltage (V)
GB1
GNDBI
0
VB1
VCCBI
2.5
GB2
GNDBE
0
VB2
VCCBE
2.5/3.3
GB3
GNDB3
0
VB3
VCCB3
2.5
Care should be taken for the evaluation board
considering the fact that the outputs of the converter are 2.5V/3.3V (VB2) tolerant whereas the
74LCX573 external buffers are operating up to
2.5V.
The ADC outputs on the connector J6 are D11
(MSB) to D2 (LSB).
TSA1005-40
Single and Differential Inputs:
The ADC board components are mounted to test
the TSA1005-40 with single analog input; the
ADT1-1WT transformer enables the differential
drive into the converter; in this configuration, the
resistors RSI6, RSI7, RSI8 for I channel (respectively RSQ6, RSQ7, RSQ8 for Q one) are connected as short circuits whereas RSI5, RSI9 (respectively RSQ5, RSQ9) are open circuits.
The other way is to test it via JI1 and JI1B differential inputs. So, the resistances RSI5, RSI9 for I
channel (respectively RSQ5, RSQ9 for Q one) are
connected as short circuits whereas RSI6, RSI7,
RSI8 (respectively RSQ6, RSQ7, RSQ8 for Q
one) are open circuits.
With the strap connected:
- to the upper connectors, the I channel at the output is selected.
- horizontally, the Q channel at the output is selected.
- to the lower connectors, both channels are selected, relative to the clock edge.
Figure 12 : mode select
SELECT
I channel
SELECT
Grounding consideration
So as to better reject noise on the board, connect
on the bottom overlay AG (AGND), DG(DGND),
GB1(GNDBI) together from one part, and
GB2(GNDBE) with GB3(GNDB3) from the other
part.
Q channel
I/Q channels
CLK
DGND DVCC
schematic
board
Mode select
So as to evaluate a single channel or the dual
ones, you have to connect on the board the
relevant position for the SELECT pin.
Consumption adjustment
Before any characterization, care should be taken
to adjust the Rpol (Raj1) and therefore Ipol value
in function of your sampling frequency.
Figure 13 : Printed circuit of evaluation board.
16/19
1
JQ1B
InQB
JI1B
InIB
0
RQ19
50
RQ1
50
3
3
RSQ61
0
RI19
50
RI1
50
RSI6 1
0
AVCC
0 NC
RSQ9
4RSQ8
T2-AT1-1WT
0
0 NC RSQ7
TQ2
6
0
2
RSQ5
ANALOGIC
VCC
GND
JA
0 NC
RSI9
4 RSI8
T2-AT1-1WT0
2
RSI7
+
0NM
0NM
0 NC
TI2
6
RSI5
R22
R21
C41
C42
47µF10µF
0NM
R23
CI9
C4
470nF 10nF
JQ2
VREFQ
330pF
CQ8
NM
33pF
CQ10 CQ9
CQ6
CQ1
330pF
C2
NM
33pF
470nF 10nF
C3
CI6
330pF
CI8
CI1
470nF 10nF
CI10
0NM
R24
CI31
1K
R2
330pF
CI30
470nF 10nF
330pF
CI12
C52 10nF
C14 330pF
C51 330pF
C53 470nF
AGND
INI
AGND
INBI
AGND
IPOL
AVCC
AGND
INQ
AGND
INBQ
AGND
ADC DUAL10B
C36 47µF
C23 10µF
C22 470nF
C21 10nF
C20 330pF
AVCC
DVCC
C32 47µF
C31 10µF
C13 470nF
C11 10nF
C10 330pF
J27
2
1
DIGITAL
JD
CON2
C5
CLK
100nF
J4
50
R3
DVCC
SW1
CD3 330pF
CD2 10nF
330pF
470nF 10nF
DVcc
36
35
34
33
32
31
30
29
28
27
26
25
10µF
R5
50
J25
CKDATA
C35
VCCB2
47µF
C19 470nF
C18 10nF
C17 330pF
C29
Ra
330pF
10nF
C25
470nF
C27
VCCB2
C28
2
1
CON2
VCCB2
J26
D0(LSB)
D1
D2
D3
D4
D5
D6
D7
D8
D9(MSB)
VCCBE
GNDBE
CD1 470nF
1
2
3
4
5
6
7
8
9
10
11
12
330pF
CI11
47µF
C43 10µF
VCCB1
C44
C15 10nF
AVCC
IN S2
Vcc D
GNDS1
STG719
CQ13 CQ12 CQ11
470nF 10nF
CI13
REFP
REFM
INCM
CQ32 CQ31 CQ30
Raj1
47K
470nF 10nF
CI32
47K
R11
U1
R12
47K
S5
SW-SPST
VCCB1
VCCB2
S4
SW-SPST
C16 470nF
+
JI2
VREFI
+
CC
ND
+
REFP
REFM
INCM
48
47
46
45
44
43
42
41
40
39
38
37
REFPI
REFMI
INCMI
AVCC
AVCC
OEB
VCCBI
VCCBI
GNDBE
VCCBE
NC
NC
17/19
+
REFPQ
REFMQ
INCMQ
AGND
AVCC
DVCC
DGND
CLK
SELECT
DGND
DVCC
GNDBI
J17
BUFPOW
1
2
3
4
5
6
7
8
9
10
1
2
3
4
5
6
7
8
9
10
470nF
10nF
330pF
C39
C26
47µF
C37
C34
C33
C40
C38
330pF
10nF
470nF
74LCX573
OEB
VCC
D0
Q0
D1
Q1
U3
D2
Q2
D3
Q3
D4
Q4
D5
Q5
D6
Q6
D7
Q7
GND
LE
74LCX573
OEB
VCC
D0
Q0
D1
Q1
D2
Q2
D3
Q3
D4
Q4
U2
D5
Q5
D6
Q6
D7
Q7
GND
LE
VCCB2
GndB1
VccB1
GndB2
VccB2
GndB3
VccB3
VCCB1
VCCB3
+
13
14
15
16
17
18
19
20
21
22
23
24
NM: non soudé
20
19
18
17
16
15
14
13
12
11
20
19
18
17
16
15
14
13
12
11
Normal mode
Test mode
Switch S5
Open
Short
VCCB3
OEB Mode
Normal mode
High Impedance output mode
Switch S4
Open
Short
analoginput with transformer (default)
single input
differential input
CLK
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
DO
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
RS5 RS6 RS7 RS8 RS9
C
C
C
C
C
C
C
J6
CLK GND
D11 GND (MSB)
D10 GND
D9 GND
D8 GND
D7 GND
D6 GND
D5 GND
D4 GND
D3 GND
D2 GND (LSB)
D1 GND
D0 GND
TSA1005-40
Figure 14 : TSA1005-40 Evaluation board schematic
+
TSA1005-40
Figure 15 : Printed circuit board - List of components
Name Part
Type
RSQ6 0
RSQ7 0
RSQ8 0
RSI6 0
RSI7 0
RSI8 0
47
R3
47
R5
RQ19 47
47
RI1
RQ1 47
RI19 47
RSI9 0NC
RSQ5 0NC
RSQ9 0NC
RSI5 0NC
R24
0NC
0NC
R23
R21
0NC
R22
0NC
1K
R2
R12
47K
47K
R11
Raj1 200K
C23
C41
C29
Footprint Name Part
Type
805
CD2
10nF
805
C40
10nF
805
C39
10nF
805
CQ12 10nF
805
CQ9
10nF
805
C52
10nF
603
C18
10nF
603
C21
10nF
603
C4
10nF
603
C15
10nF
603
C27
10nF
603
C11
10nF
805
CI9
10nF
805
CI12 10nF
805
CI31 10nF
805
CQ31 10nF
805
CQ30 330pF
805
CI11 330pF
805
C51
330pF
805
C2
330pF
603
C17
330pF
603
CD3
330pF
603
C10
330pF
CQ8
330pF
VR5
trimmer
CQ11 330pF
10µF 1210
CI8
330pF
10µF 1210
C14
330pF
10µF 1210
CI30 330pF
Footprint
Name
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
603
C26
C20
C33
C25
CI1
CQ1
C34
C42
C35
C44
C36
C32
C37
CQ10
C28
CI10
CQ32
CQ13
CI32
C13
C53
C16
C3
C22
CI13
C38
CD1
C19
Part
Type
330pF
330pF
330pF
330pF
33pF
33pF
47µF
47µF
47µF
47µF
47µF
47µF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
470nF
Footprint Name Part
Footprint
Type
603
CQ6 NC
805
603
CI6
NC
805
603
U2
74LCX573
TSSOP20
603
U3
74LCX573
TSSOP20
603
U1
STG719
SOT23-6
603
JA
ANALOGIC connector
RB.1
J17
BUFPOW
connector
RB.1
J25
CKDATA
SMA
RB.1
J4
CLK
SMA
RB.1
J27
CON2
SIP2
RB.1
J26
CON2
SIP2
RB.1
JD
DIGITAL
connector
805
JI1
InI
SMA
805
JI1B
InIB
SMA
805
JQ1
InQ
SMA
805
JQ1B InQB
SMA
805
SW1 SWITCH
connector
805
S5
SW-SPST
connector
805
S4
SW-SPST
connector
805
TI2
T2-AT1-1WT ADT
805
TQ2
T2-AT1-1WT ADT
805
JI2
VREFI
connector
805
JQ2
VREFQ
connector
805
J6
32Pin
IDC-32
805
connector
805
805
NC: non soldered
805
18/19
TSA1005
PACKAGE MECHANICAL DATA
48 PINS - PLASTIC PACKAGE
A
A2
e
48
A1
37
0,10 mm
.004 inch
36
12
25
SEATING PLANE
E
c
24
L
D3
D1
D
L1
13
E1
E3
B
1
K
0,25 mm
.010 inch
GAGE PLANE
Millimeters
Inches
Dim.
Min.
A
A1
A2
B
C
D
D1
D3
e
E
E1
E3
L
L1
K
0.05
1.35
0.17
0.09
0.45
Typ.
1.40
0.22
9.00
7.00
5.50
0.50
9.00
7.00
5.50
0.60
1.00
Max.
Min.
1.60
0.15
1.45
0.27
0.20
0.002
0.053
0.007
0.004
0.75
0.018
Typ.
0.055
0.009
0.354
0.276
0.216
0.0197
0.354
0.276
0.216
0.024
0.039
Max.
0.063
0.006
0.057
0.011
0.008
0.030
0° (min.), 7° (max.)
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