TI THS1215IPW

THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
3.3-V, 12-BIT, 15 MSPS, LOW-POWER ANALOG-TO-DIGITAL
CONVERTER WITH POWER DOWN
FEATURES
•
•
•
•
•
Input Configurations:
– Differential 0.5x Gain
– Differential 1x Gain
3.3-V Supply Operation
Internal Voltage Reference
Out-of-Range Indicator
Power-Down Mode
APPLICATIONS
•
•
•
•
•
•
Camcorders
Digital Cameras
Copiers
Communications
Test Instruments
Baseband Digitization
DW OR PW PACKAGE
(TOP VIEW)
AGND
CON1
CON0
EXTREF
AIN+
AIN−
AGND
AVDD
REFT
REFB
OVRNG
D11
D10
D9
1
28
2
27
3
26
4
25
5
24
6
23
7
22
8
21
9
20
10
19
11
18
12
17
13
16
14
15
CLK
AVDD
OE
D0
D1
D2
D3
D4
DVDD
DGND
D5
D6
D7
D8
DESCRIPTION
The THS1215 is a CMOS, low-power, 12-bit, 15 MSPS analog-to-digital converter (ADC) that operates with a
3.3-V supply. The THS1215 gives circuit developers complete flexibility. The analog input to the THS1215 is
differential with a gain of 1.0 in Mode 1 and 0.5 in Mode 2. The THS1215 provides a wide selection of voltage
references to match the user's design requirements. For more design flexibility, the internal reference can be
bypassed to use an external reference to suit the dc accuracy and temperature drift requirements of the
application. The out-of-range output is used to monitor any out-of-range condition in the THS1215's input range.
The speed, resolution, and single-supply operation of the THS1215 are suited for applications in video,
multimedia, high-speed acquisition, and communications. The speed and resolution ideally suit charge-couple
device (CCD) input systems such as digital copiers, digital cameras, and camcorders. The wide input voltage
range between VREFB and VREFT allows the THS1215 to be designed into multiple systems.
The THS1215C is characterized for operation from 0°C to 70°C. The THS1215I is characterized for operation
from -40°C to 85°C.
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 © 2001–2004, Texas Instruments Incorporated
THS1215
www.ti.com
SLAS292A – MARCH 2001 – REVISED MARCH 2004
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.
ORDERING INFORMATION
(1)
PRODUCT
PACKAGELEAD
PACKAGE
DESIGNATOR (1)
SPECIFIED
TEMPERATURE
RANGE
PACKAGE
MARKING
ORDERING
NUMBER
TRANSPORT
MEDIA, QUANTITY
THS1215
TSSOP-28
PW
0°C TO 70°C
TH1215
THS1215 CPW
Tube, 50
THS1215
TSSOP-28
PW
0°C TO 70°C
TH1215
THS1215 CPWR
Tape and reel, 2000
THS1215
TSSOP-28
PW
–40°C TO 85°C
TJ1215
THS1215 IPW
Tube, 50
THS1215
TSSOP-28
PW
–40°C TO 85°C
TJ1215
THS1215 IPWR
Tape and reel, 2000
THS1215
SOP-28
DW
0°C TO 70°C
TH1215
THS1215 CDW
Tube, 20
THS1215
SOP-28
DW
0°C TO 70°C
TH1215
THS1215 CDWR
Tape and reel, 1000
THS1215
SOP-28
DW
–40°C TO 85°C
TJ1215
THS1215 IDW
Tube, 20
THS1215
SOP-28
DW
–40°C TO 85°C
TJ1215
THS1215 IDWR
Tape and reel, 1000
For the most current specifications and package information refer to our Web site at www.ti.com.
FUNCTIONAL BLOCK DIAGRAM
DVDD
CLK
Timing Circuitry
OVRNG
AIN+
AIN−
Sample
and Hold
3-State
Output
Buffers
12-Bit ADC
D[11:0]
OE
CON0
CON1
Configuration
Control
Circuit
Internal
Reference
Circuit
EXTREF REFT REFB
2
AVDD
AGND
DGND
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
TERMINAL FUNCTIONS
TERMINAL
I/O
DESCRIPTION
NAME
NO.
AGND
1, 7
I
Analog ground
AVDD
8, 27
I
Analog supply
AIN+
5
I
Positive analog input
AIN-
6
I
Negative analog input
CLK
28
I
ADC conversion clock
CON1
2
I
Configuration input 1
CON0
3
I
Configuration input 0
DGND
19
I
Digital ground
DVDD
20
I
Digital supply
D11
12
O
ADC data bit 11
D10
13
O
ADC data bit 10
D9
14
O
ADC data bit 9
D8
15
O
ADC data bit 8
D7
16
O
ADC data bit 7
D6
17
O
ADC data bit 6
D5
18
O
ADC data bit 5
D4
21
O
ADC data bit 4
D3
22
O
ADC data bit 3
D2
23
O
ADC data bit 2
D1
24
O
ADC data bit 1
D0
25
O
ADC data bit 0
EXTREF
4
I
Reference select input (high = external, low = internal)
OVRNG
11
O
Out of range indicator (high = out of range)
OE
26
I
Output enable (high = disable, low = enable)
REFT
9
I/O
Upper ADC reference voltage
REFB
10
I/O
Lower ADC reference voltage
ABSOLUTE MAXIMUM RATINGS (1)
over operating free-air temperature range (unless otherwise noted)
UNIT
Supply voltage range
AVDD to AGND, DVDD to DGND
AGND to DGND
–0.3 V to 4 V
–0.3 V to 0.3 V
Reference voltage input range, REFT, REFB to AGND
–0.3 to AVDD + 0.3 V
Analog input voltage range, AIN+, AIN– to AGND
–0.3 to AVDD + 0.3 V
Clock input voltage range, CLK to AGND
–0.3 to AVDD + 0.3 V
Digital input voltage range, digital input to DGND
–0.3 to DVDD + 0.3 V
Digital output voltage range, digital output to DGND
–0.3 to DVDD + 0.3 V
Operating junction temperature range, TJ
–40°C to 150°C
Storage temperature range, TSTG
–65°C to 150°C
Lead temperature 1,6 mm (1/16 in) from case for 10 seconds
(1)
300°C
Stresses beyond 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 affect device reliability.
3
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
RECOMMENDED OPERATING CONDITIONS
over operating free-air temperature range, TA (unless otherwise noted)
MIN
NOM
MAX
3.0
3.3
3.6
UNIT
POWER SUPPLY
Supply voltage
AVDD
DVDD
V
ANALOG AND REFERENCE INPUTS
Reference input voltage
VREFT
fCLK = 5 MHz to 15 MHz
2.0
2.15
2.5
VREFB
fCLK = 5 MHz to 15 MHz
1.05
1.15
1.3
fCLK = 5 MHz to 15 MHz
0.95
1.0
1.05
V
CON1 = 0, CON0 = 1
–1.0
1.0
V
CON1 = 1, CON0 = 0
–2.0
2.0
V
10
pF
AVDD
V
Reference voltage differential, VREFT – VREFB
Analog input voltage differential, (AIN+) – (AIN–) (1)
Analog input capacitance, Ci
Clock input (2)
0
V
DIGITAL OUTPUTS
Minimum digital output load resistance, RL
100
Maximum digital output load capacitance, Ci
0
kΩ
10
15
pF
V
DIGITAL INPUTS
High-level input voltage, VIH
Low-level input voltage, VIL
Clock frequency, fCLK, See Note
(3)
Clock pulse duration, tW(CLKL), tW(CLKH)
Operating free-air temperature, TA
(1)
(2)
(3)
4
fCLK = 15 MHz
2.4
DVDD
DGND
0.8
V
5
30
MHz
36.7
ns
TH1215
30
0
33.3
70
°C
TJ1215
–40
85
Based on VREFT – VREFB = 1.0 V, varies proportional to the VREFT – VREFB value. AIN+ and AIN– inputs must always be greater than 0 V
and less than AVDD.
Clock pin is referenced to AGND and powered by AVDD.
Clock frequency can be extended to this range without degradation of performance.
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
ELECTRICAL CHARACTERISTICS
over recommended operating conditions (AVDD = DVDD = 3.3 V, fs = 15 MHz/50% duty cycle, MODE = 1, 1-V input span,
internal reference, Tmin to Tmax) (unless otherwise noted)
DIGITAL INPUTS AND OUTPUTS (all supplies = 3.3 V)
PARAMETER
TEST CONDITION
MIN
TYP
MAX
UNIT
DIGITAL INPUTS
VIH
High level input voltage
All other inputs
0.8 × DVDD
CLK
0.8 × AVDD
All other inputs
0.2 × DVDD
CLK
0.2 × AVDD
VIL
Low level input voltage
IIH
High level input current
1
IIL
Low level input current
–1
Ci
Input capacitance
5
V
µA
pF
DIGITAL OUTPUTS
VOH
High level output voltage
Iload = 50 µA
VOL
Low level output voltage
Iload = –50 µA
DVDD–0.4
V
High impedance output current
tr/tf
Rise/fall time
CL = 10 pF
0.4
V
±1
µA
4.5
ns
ANALOG INPUTS
Ci
Switched input capacitance
6
pF
td(ap)
Aperture delay time
2
ns
Aperture uncertainty (jitter)
2
ns
10
µA
DC leakage current (input = ±FS)
POWER SUPPLY (CLK = 15 MHz)
XVDD
Supply voltage (all supplies)
3.3
3.6
V
IDD
Supply current active - total
3
45
53.5
mA
I(analog)
Supply current active - analog
34
I(digital)
Supply current active - digital
II(standby)
Standby supply current
mA
11
CLK = 0 MHz
1 µF bypass (1)
mA
10
µA
770
µs
t(PU)
Power-up time for references from standby
6.2
ms
t(PUconv)
Power-up time for valid ADC conversion
1 µF bypass (2)
820
ns
148
Power dissipation
Clock = 15 MHz,
AIN+ and AIN– at Common
Mode or 1.65 V dc
Clock = 15 MHz,
fin = 3.58 MHz at –1 dBFS
167
PD
PD(STBY)
Standby power dissipation
PSRR
Power supply rejection ratio
(1)
(2)
10 µF
bypass (1)
177
mW
CLK = 0 MHz
36
±0.1
µW
%FS
Time for reference to recover to 1% of its final voltage level.
Time for ADC conversions to be accurate to within 0.1% of fullscale.
5
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
ELECTRICAL CHARACTERISTICS (CONTINUED)
over recommended operating conditions (AVDD = DVDD = 3.3 V, fs = 15 MHz/50% duty cycle, MODE = 1, 1-V input span,
internal reference, Tmin to Tmax) (unless otherwise noted)
REFT, REFB REFERENCE VOLTAGE (all supplies = 3.3 V)
PARAMETER
TEST CONDITION
MIN
TYP
MAX
UNIT
INTERNAL REFERENCE (1)
VREFT
Upper reference voltage
2.15
V
VREFB
Lower reference voltage
VREF
Differential reference voltage, VREFT – VREFB
0.95
Differential reference voltage, VREFT – VREFB accuracy
–5%
5%
Externally applied VREFT reference voltage range
2
2.5
V
Externally applied VREFB reference voltage range
1.05
1.3
V
Externally applied (VREFT – VREFB) reference voltage range
0.75
1.05
V
1.15
1
V
1.05
V
EXTERNAL REFERENCE
External mode VREFT to VREFB impedance
9
kΩ
INTERNAL EXTERNAL REFERENCE
CT
VREFT decoupling capacitor value
0.1
µF
CB
VREFB decoupling capacitor value
0.1
µF
CTB
Decoupling capacitor VREFT to VREFB
10
µF
DC ACCURACY (LINEARITY)
Number of missing codes
All modes
DNL
Differential nonlinearity
All modes
±0.43
±0.9
0
codes
INL
Integral nonlinearity
All modes
±0.6
±2.5
LSB
Offset error
All modes
1.4
2.2
%FSR
Gain error
All modes
2.2
3.5
%FSR
LSB
DYNAMIC PERFORMANCE (all supplies = 3.3 V)
ENOB Effective number of bits
fi = 3.58 MHz
THD
Total harmonic distortion
fi = 3.58 MHz
SNR
Signal-to-noise ratio
fi = 3.58 MHz
67.4
SINA
D
Signal-to-noise + distortion
fi = 3.58 MHz
SFDR
Spurious free dynamic range
fi = 3.58 MHz
G(diff)
10.7
11.1
Bits
–81.2
dB
68.9
dB
66
68.6
dB
72
81.7
dB
Analog input bandwidth
180
MHz
Differential phase, DP
0.12
degree
Differential gain
0.01%
TIMING (all supplies = 3.3 V)
Clock frequency (2)
fCLK
Clock duty cycle
5
45%
15
50%
55%
6
19
MHz
td(O)
Output delay time
td(PZ)
Delay time, output disable to Hi-Z output
3.2
td(EN)
Delay time, output enable to output valid
16
19
ns
4
5
cycles
Latency
(1)
(2)
6
The internal reference voltage is not intended for use driving off chip.
The clock frequency may be extended down to 5 MHz without degradation in specified performance.
ns
ns
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
PARAMETER MEASUREMENT INFORMATION
TIMING DIAGRAM
S1
S2
S3
Analog
1
2
3
4
5
6
7
8
9
10
CLK
t PIPELINE
t d(O)
D[9:0]
S1
S2
S3
Figure 1. Analog Input and Data Output Timing
OE
t d(EN)
t d(PZ)
Hi−Z
Hi−Z
D[9:0]
Data
Data
Data
Figure 2. Output Enable Timing
THS1215
REFT
CT
1.5 V
BAND
GAP
CTB
REFB
CB
Figure 3. Reference Generation
7
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
TYPICAL CHARACTERISTICS
POWER
vs
TEMPERATURE
SIGNAL-TO-NOISE
vs
TEMPERATURE
152
71
DVDD = AVDD = 3.3 V,
AIN+ = AIN− = 1.65 V,
fs = 15 MSPS
SNR − Signal-to-Noise − dB
151
Power − mW
150
149
148
147
146
70
AVDD = DVDD = 3.3 V,
fIN = 3.58 MHz, −1dBFS,
fs = 15 MSPS,
Mode = 1
69
68
67
145
144
−40
−15
10
35
60
66
−40
85
TA − Temperature − °C
SPURIOUS FREE DYNAMIC RANGE
vs
TEMPERATURE
TOTAL HARMONIC DISTORTION
vs
TEMPERATURE
85
−78
THD − Total Harmonic Distortion − dB
SFDR − Spurious Free Dynamic Range − dB
60
Figure 5.
80
78
76
74
AVDD = DVDD = 3.3 V,
fIN = 3.58 MHz, −1dBFS
fs = 15 MSPS
−15
10
35
TA − Temperature − °C
Figure 6.
8
35
Figure 4.
82
70
−40
10
TA − Temperature − °C
84
72
−15
60
85
AVDD = DVDD = 3.3 V,
fIN = 3.58 MHz, −1dBFS
fs = 15 MSPS
−80
−82
−84
−86
−88
−40
−15
10
35
TA − Temperature − °C
Figure 7.
60
85
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
TYPICAL CHARACTERISTICS (continued)
SIGNAL-TO-NOISE AND DISTORTION
vs
TEMPERATURE
SINAD − Signal-to-Noise and Distortion − dB
69.0
68.5
68.0
67.5
67.0
AVDD = DVDD = 3.3 V,
fIN = 3.58 MHz, −1dBFS
fs = 15 MSPS
66.5
66.0
−40
−15
10
35
60
85
TA − Temperature − °C
Figure 8.
DNL − Differential Nonlinearity − LSB
DIFFERENTIAL NONLINEARITY (DNL)
1.0
0.8
0.6
0.4
0.2
−0.0
−0.2
−0.4
−0.6
−0.8
−1.0
DVDD = AVDD = 3.3 V,
fs = 15 MSPS
0
512
1024
1536
2048
2560
3072
3584
4096
3072
3584
4096
ADC Code
Figure 9.
INL − Integral Nonlinearity − LSB
INTEGRAL NONLINEARITY (INL)
1.5
DVDD = AVDD = 3.3 V,
fs = 15 MSPS
1.0
0.5
0.0
−0.5
−1.0
−1.5
0
512
1024
1536
2048
2560
ADC Code
Figure 10.
9
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
TYPICAL CHARACTERISTICS (continued)
FAST FOURIER TRANSFORM-MODE 1
0
AVDD = DVDD = 3.3 V,
fs = 15 MSPS,
fi = 3.58 MHz, −1dBFS
Mode 1 Differential
Power − dBFS
−20
−40
−60
−80
−100
5.73
6.17
6.61
7.05
7.49
5.73
6.17
6.61
7.05
7.49
5.29
4.85
4.41
3.97
3.53
3.08
2.64
2.2
1.76
1.32
0.88
0.44
−140
0
−120
f − Frequency − MHz
Figure 11.
FAST FOURIER TRANSFORM-MODE 2
0
AVDD = DVDD = 3.3 V,
fs = 15 MSPS,
fi = 3.58 MHz, −1dBFS
Mode 2 Differential
Power − dBFS
−20
−40
−60
−80
−100
5.29
4.85
4.41
3.97
3.53
3.08
2.64
2.2
1.76
1.32
0.88
0.44
−140
0
−120
f − Frequency − MHz
Figure 12.
BANDWIDTH
3
0
Amplitude − dB
−3
−6
−9
−12
AVDD = DVDD = 3.3 V,
fs = 15 MSPS
−15
−18
2
20
f − Frequency − MHz
Figure 13.
10
200
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
PRINCIPLES OF OPERATION
ANALOG INPUT
The analog input AIN is sampled in the sample and hold unit, the output of which feeds the ADC CORE, where
the process of analog-to-digital conversion is performed against ADC reference voltages, VREFT and VREFB.
Connecting the EXTREF pin to one of two voltages, DGND or DVDD selects one of the two configurations of ADC
reference generation. The ADC reference voltages come from either the internal reference buffer or completely
external sources. Connect EXTREF to DGND for internal reference generation or to DVDD for external reference
generation.
CON0 and CON1 as described below, select the input configuration mode or place the device in power-down
state. The ADC core drives out through output buffers to the data pins D0 to D11. The output buffers can be
disabled by the OE pin.
A single, sample-rate clock (15 MHz maximum) is required at pin CLK. The analog input signal is sampled on the
rising edge of CLK, and corresponding data is output after the fifth following rising edge.
The THS1215 can operate in differential Mode 1 or differential Mode 2, controlled by the configuration pins
CON0 and CON1 as shown in Table 1. Mode 0 places the THS1215 in power-down or standby state for reduced
power consumption.
Table 1. Input Modes of Operation
MODE
CON1
CON0
0
0
0
Device powered down
MODE OF OPERATION
1
0
1
Differential mode × 1
2
1
0
Differential mode × 0.5
3
1
1
Not used
Modes 1 and 2 are shown in Figure 14.
AIN−
1V
AIN+
OUTPUT
CODE
4095
0
AIN−
2V
AIN+
OUTPUT CODE
4095
0
MODE 2, CON[1:0] = 10
MODE 1, CON[1:0] = 01
Figure 14. Input Mode Configurations
The gain of the sample and hold changes with the CON1 and the CON0 inputs. Table 2 shows the gain of the
sample and hold and the levels applied at the AIN+ and AIN– analog inputs for Mode 1 and Mode 2. The
common mode level for the two analog inputs is at AVDD/2.
Table 2. Input Mode Switching
MODE
CON1
CON0
(AIN+) – (AIN-)
MIN
(AIN+) – (AIN-)
MAX
S/H GAIN
1
0
1
–1 V
1V
×1
2
1
0
-2 V
2V
×0.5
11
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
Table 2 assumes that the delta in ADC reference voltages VREFT and VREFB is set to 1 V, i.e., VREFT – VREFB = 1
V. Note that VREFB and VREFT can be set externally, which will scale the numbers given in this table.
The user-chosen operating configuration and reference voltages determine what input signal voltage range the
THS1215 can handle.
The following sections explain both the internal signal flow of the device and how the input signal span is related
to the ADC reference voltages, as well as the ways in which the ADC reference voltages can be buffered
internally or externally applied.
SIGNAL PROCESSING CHAIN (Sample and Hold, ADC)
Figure 15 shows the signal flow through the sample and hold unit and the PGA to the ADC core.
REFT
AIN+
AIN−
+1
VP+
SAMPLE
AND
−1
HOLD
ADC
CORE
VP−
REFB
Figure 15. Analog Input Signal Flow
Sample and Hold
The differential sample and hold processes AIN with respect to the voltages applied to the REFT and REFB pins,
to give a differential output (VP+) – (VP–) = VP given by:
• VP = (AIN+) – ( AIN–)
Analog-to-Digital Converter
No matter what operating configuration is chosen, VP is digitized against ADC reference voltages VREFT and
VREFB. The VREFT and VREFB voltages set the analog input span limits FS+ and FS–, respectively. Any voltages at
AIN greater than REFT or less than REFB causes ADC over-range, which is signaled by OVR going high when
the conversion result is output.
Analog input
A first-order approximation for the equivalent analog input circuit of the THS1215 is shown in Figure 16. The
equivalent input capacitance CI is 5 pF typical. The input must charge/discharge this capacitance within the
sample period of one half of a clock cycle. When a full-scale voltage step is applied, the input source provides
the charging current through the switch resistance RSW (200 Ω) of S1 and quickly settles. In this case the input
impedance is low. Alternatively, when the source voltage equals the value previously stored on CI, the hold
capacitor requires no input current and the equivalent input impedance is high.
12
THS1215
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SLAS292A – MARCH 2001 – REVISED MARCH 2004
VS+
VS −
VCM
RS
THS1215
RSW
RS
RSW
CI
CI
+
_
VCM
+
_
Figure 16. Simplified Equivalent Input Circuit
To maintain the frequency performance outlined in the specifications, the total source impedance should be
limited to the following equation with fCLK = 15 MHz, CI = 5 pF, RSW = 200 Ω:
R S
2f
1
–R
C In(256) SW
CLK
I
So, for applications running at a lower fCLK, the total source resistance can increase proportionally.
The analog input of the THS1215 is a differential input that can be configured in various ways depending on the
signal source and the required level of performance. A fully differential connection (see Figure 17) delivers the
best performance from the converter.
AVDD
2
R2
VIN+
C1
THS1215
R1
−
AIN+
+
R2
C2
VIN−
C1
R1
−
+
AIN−
C2
REFT
REFB
Figure 17. AC-Coupled Differential Input
The analog input can be dc-coupled (see Figure 18) as long as the inputs are within the analog input common
mode voltage range. For example (see Figure 18), VIN+ and VIN- are signals centered on GND with a
peak-to-peak voltage of 2 V, and the circuit in Figure 18 is used to interface it with the THS1215. Assume AVDD
13
THS1215
www.ti.com
SLAS292A – MARCH 2001 – REVISED MARCH 2004
of the converter is 3 V. Two problems have to be solved. The first is to shift common mode level (CML) from 0 V
to 1.5 V (AVDD/2). To do that, a V bias voltage and an adequate ratio of R1 and R2 have to be selected. For
instance, if V bias = AVDD = 3 V, then R1 = R2. The second is that the differential voltage has to be reduced from
4 V (2 x 2 V) to 1 V, and for that an attenuation of 4 to1 is needed. The attenuation is determined by the relation:
(R3||2R2)/((R3||2R2) + 2R1). One possible solution is R1 = R2 = R3 = 150 Ω. In this case, moreover, the input
impedance (2R1 + (R3||2R2)) is 400 Ω. The values can be changed to match any other input impedance. A
capacitor, C, connected from AIN+ to AIN- helps filter any high frequency noise on the inputs, also improving
performance. Note that the chosen value of capacitor C must take into account the highest frequency component
of the analog input signal.
VBIAS
THS1215
VIN+
R1
R2
AIN+
R3
VIN−
R1
AIN−
R2
REFT
VBIAS
REFB
Figure 18. DC-Coupled Differential Input Circuit
A single-ended source may give better overall system performance when it is converted to a differential signal
before driving the THS1215. The configuration in Figure 19 takes a VIN of 1 V and drives the 1:1 transformer
ratio so that value of AIN+ and AIN– converts to full-scale value at the ADC digital output. With VIN at –1 V the
value at AIN+ and AIN– converts to 0 at the ADC digital outputs.
AV DD
2
THS1215
V IN
AIN+
AIN−
REFT
REFB
Figure 19. Transformer Coupled Single-Ended Input
14
THS1215
www.ti.com
SLAS292A – MARCH 2001 – REVISED MARCH 2004
Digital Outputs
The output of THS1215 is in unsigned binary code. The ADC input over-range indicator is output on pin OVRNG.
Capacitive loading on the output should be kept as low as possible (a maximum loading of 10 pF is
recommended) to ensure best performance. Higher output loading causes higher dynamic output currents and
can therefore increase noise coupling into the part's analog front-end. To drive higher loads, the use of an output
buffer is recommended.
When clocking output data from THS1215, it is important to observe its timing relation to CLK. The pipeline ADC
delay is 5 clock cycles to which the maximum output propagation delay needs to be added.
THS1215
SN74ALVCH16841
DA11
DA0
12
1D9
1Q9
1D0
1Q0
2D1
2Q1
2D0
2Q0
2D7
2Q9
2D2
2Q2
ASIC
or
DSP
12
LE
OE
Figure 20. Buffered Output Connection
THS1215
FIFO
DA11
DA0
CLK
12
DSP
D11
1Q15
D0
D15
1Q0
D12
HF flag
16
INTR
WRTCLK
15 MHz
Clock
Figure 21. FIFO Connection
Layout, Decoupling, and Grounding Rules
Proper grounding and layout of the PCB on which THS1215 is populated is essential to achieve the stated
performance. It is advised to use separate analog and digital ground planes that are spliced underneath the IC.
THS1215 has digital and analog pins on opposite sides of the package to make this easier. Because there is no
connection internally between analog and digital grounds, they have to be joined on the PCB. It is advised to do
this at one point in close proximity to THS1215.
Because of the high sampling rate and switched-capacitor architecture, THS1215 generates transients on the
supply and reference lines. Proper decoupling of these lines is therefore essential. EVM decoupling is
recommended as shown in Figure 22.
15
THS1215
www.ti.com
SLAS292A – MARCH 2001 – REVISED MARCH 2004
+3.3VA
+3.3VD
+3.3VD +3.3VA
U1
THS1215PW
+3.3VD
8
LNK3
LNK4
OEB
EXTREF
OEB
R2
R23
47K
47K
AGND
DVDD
DGND
27
CLKVDD AGND
EXTREF
D0
ADCCLK
28
OEB
26
ADCCLK
OEB
CON0
3
CON1
2
EXTREF
4
CON0
CON1
EXTREF
+3.3VD
AVDD
20
CLK
D1
LNK2
CON1
VINP
47K
VINM
CON0
CON1
R1
47K
VINP
5
VINM
6
9
10
LNK5
TP1
25
ADCD00
24
ADCD01
23
ADCD02
CON0
D3
22
ADCD03
CON1
D4
21
ADCD04
EXTREF
D5
18
ADCD05
D6
17
ADCD06
D7
16
ADCD07
AIN+
D8
15
ADCD08
AIN−
D9
14
ADCD09
13
ADCD10
REFT
D11
REFB
OVRNG
12
11
TP2
C28
ADCD11
ADCOVRNG
ADCD [00:11]
VRB
+
VRT
VRT
1
D2
D10
CON0
19
OE
+3.3VD
R24
7
VRB
10uF
24
AVDD
AGND
27
DVDD
14
D0
13
12
ADCDB01
11
ADCDB02
10
D4
ADCDB03
9
D5
ADCDB04
8
ADCDB05
7
ADCDB06
6
ADCDB07
5
ADCDB08
4
ADCDB09
3
ADCDB10
2
ADCDB11
1
DACCLK 28
25
DGND
26
IOUT1
22
IOUT1
IOUT2
21
IOUT2
D2
C26
0.1uF
_3.3VA
IOUT1
D3
+3.3VD
C62
470pF
C63
0.1uF
C64
470pF
C65
0.1uF
C66
470pF
C67
0.1uF
IOUT2
D6
D7
EXTLO
+3.3VA
16
D8
+3.3VD
D9
REFIO
D10
FSADJ
17
C16
C5
0.01uF
0.1uF
D12
+
C17
C18
0.1uF
0.1uF
10uF
R10
2K
D13
+3.3VA
CLK
C15
MODE
SLEEP
C19
18
D11
COMP1
15
0.1uF
C25
0.1uF
20
D1
ADCDB00
DACCLK
C27
U3
THS5671AIPW
+3.3VD +3.3VA
COMP2
ADCDB[00:11]
19
23
0.1uF
C6
0.1uF
Figure 22. EVM Schematic
DEFINITIONS OF SPECIFICATIONS AND TERMINOLOGY
Integral Nonlinearity (INL)
Integral nonlinearity refers to the deviation of each individual code from a line drawn from zero through full scale.
The point used as zero occurs 1/2 LSB before the first code transition. The full-scale point is defined as level 1/2
LSB beyond the last code transition. The deviation is measured from the center of each particular code to the
true straight line between these two end-points.
Differential Nonlinearity (DNL)
An ideal ADC exhibits code transitions that are exactly 1 LSB apart. DNL is the deviation from this ideal value.
Therefore, this measure indicates how uniform the transfer function step sizes are. The ideal step size is defined
here as the step size for the device under test, i.e., (last transition level - first transition level)/(2n -2). Using this
definition for DNL separates the effects of gain and offset error. A minimum DNL better than -1 LSB ensures no
missing codes.
Offset and Gain Error
Offset error (in LSBs) is defined as the average offset for all inputs, and gain error is defined as the maximum
error (in LSBs) caused by the angular deviation from the offset corrected straight line.
16
THS1215
www.ti.com
SLAS292A – MARCH 2001 – REVISED MARCH 2004
Analog Input Bandwidth
The analog input bandwidth is defined as the maximum frequency of a 1-dBFS input sine wave that can be
applied to the device for which an extra 3-dB attenuation is observed in the reconstructed output signal.
Output Timing
Output timing td(O) is measured from the 50% level of the CLK input falling edge to the 10%/90% level of the
digital output. The digital output load is not higher than 10 pF.
Output hold time th(O) is measured from the 50% level of the CLK input falling edge to the10%/90% level of the
digital output. The digital output load is not less than 2 pF.
Aperture delay td(A) is measured from the 50% level of the CLK input to the actual sampling instant.
The OE signal is asynchronous.
OE timing td(PZ) is measured from the VIH(min) level of OE to the high-impedance state of the output data. The
digital output load is not higher than 10 pF.
OE timing td(EN) is measured from the VIL(max) level of OE to the instant when the output data reaches VOH(min) or
VOL(max) output levels. The digital output load is not higher than 10 pF.
Signal-to-Noise Ratio + Distortion (SINAD)
SINAD is the ratio of the rms value of the measured input signal to the rms sum of all other spectral components
below the Nyquist frequency, including harmonics but excluding dc. The value for SINAD is expressed in
decibels.
Effective Number of Bits (ENOB)
For a sine wave, SINAD can be expressed in terms of the number of bits. Using the following formula,
• N = (SINAD – 1.76)/6.02
it is possible to get a measure of performance expressed as N, the effective number of bits. Thus, effective
number of bits for a device for sine wave inputs at a given input frequency can be calculated directly from its
measured SINAD.
Total Harmonic Distortion (THD)
THD is the ratio of the rms sum of the first six harmonic components to the rms value of the measured input
signal and is expressed as a percentage or in decibels.
Spurious Free Dynamic Range (SFDR)
SFDR is the difference in dB between the rms amplitude of the input signal and the peak spurious signal.
17
PACKAGE OPTION ADDENDUM
www.ti.com
12-Jan-2006
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
THS1215CDW
ACTIVE
SOIC
DW
28
THS1215CDWR
ACTIVE
SOIC
DW
THS1215CDWRG4
ACTIVE
SOIC
THS1215CPW
ACTIVE
THS1215CPWR
20
Lead/Ball Finish
MSL Peak Temp (3)
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
28
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
DW
28
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
TSSOP
PW
28
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
ACTIVE
TSSOP
PW
28
2000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215CPWRG4
ACTIVE
TSSOP
PW
28
2000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IDW
ACTIVE
SOIC
DW
28
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IDWR
ACTIVE
SOIC
DW
28
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IDWRG4
ACTIVE
SOIC
DW
28
1000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IPW
ACTIVE
TSSOP
PW
28
Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IPWR
ACTIVE
TSSOP
PW
28
2000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
THS1215IPWRG4
ACTIVE
TSSOP
PW
28
2000 Green (RoHS &
no Sb/Br)
CU NIPDAU
Level-1-260C-UNLIM
50
20
50
(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.
Addendum-Page 1
PACKAGE OPTION ADDENDUM
www.ti.com
12-Jan-2006
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 2
MECHANICAL DATA
MTSS001C – JANUARY 1995 – REVISED FEBRUARY 1999
PW (R-PDSO-G**)
PLASTIC SMALL-OUTLINE PACKAGE
14 PINS SHOWN
0,30
0,19
0,65
14
0,10 M
8
0,15 NOM
4,50
4,30
6,60
6,20
Gage Plane
0,25
1
7
0°– 8°
A
0,75
0,50
Seating Plane
0,15
0,05
1,20 MAX
PINS **
0,10
8
14
16
20
24
28
A MAX
3,10
5,10
5,10
6,60
7,90
9,80
A MIN
2,90
4,90
4,90
6,40
7,70
9,60
DIM
4040064/F 01/97
NOTES: A.
B.
C.
D.
All linear dimensions are in millimeters.
This drawing is subject to change without notice.
Body dimensions do not include mold flash or protrusion not to exceed 0,15.
Falls within JEDEC MO-153
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
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