TI THS1240CPHP

THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
D
D
D
D
D
D
D
D
VCM
AVDD
48 47 46 45 44 43 42 41 40 39 38 37
AVSS
AVDD
VIN+
VIN–
AVDD
1
36
2
35
3
34
4
33
5
32
VREFOUT–
VREFIN–
VREFIN+
VREFOUT+
VBG
AVSS
AVDD
6
31
7
30
8
29
9
28
10
27
11
26
12
25
D0
D1
D2
D3
D4
D5
D6
D7
D8
D9
D10
D11
13 14 15 16 17 18 19 20 21 22 23 24
DV SS
CLK+
CLK–
DV DD
DV SS
DV SS
DV DD
DV SS
DV DD
DRVSS
DRVDD
D
D
40-MSPS Sample Rate
12-Bit Resolution
No Missing Codes
On-Chip Sample and Hold
77-dB Spurious Free Dynamic Range at
fIN = 15.5 MHz
5-V Analog and Digital Supply
3-V and 5-V CMOS Compatible Digital
Output
10.4 Bit ENOB at fIN = 31 MHz
65 dB SNR at fIN = 15.5 MHz
120-MHz Bandwidth
Internal or External Reference
Buffered Differential Analog Input
2s Complement Digital Outputs
Typical 380 mW Power Consumption
Single-Ended or Differential Low-Level
Clock Input
AV SS
D
D
D
D
D
AVSS
AVDD
AVSS
AVDD
AVSS
AVSS
DRVSS
DRVSS
DRVDD
DRVDD
48 PHP PACKAGE
(TOP VIEW)
features
applications
D
D
D
D
D
Wireless Local Loop
Wireless Internet Access
Cable Modem Receivers
Medical Ultrasound
Magnetic Resonant Imaging
description
The THS1240 is a high-speed low noise 12-bit CMOS pipelined analog-to-digital converter. A differential sample
and hold minimizes even order harmonics and allows for a high degree of common mode rejection at the analog
input. A buffered analog input enables operation with a constant analog input impedance, and prevents transient
voltage spikes from feeding backward to the analog input source. Full temperature DNL performance allows
for industrial application with the assurance of no missing codes. The THS1240 can operate with either internal
or external references. Internal reference usage selection is accomplished simply by externally connecting
reference output terminals to reference input terminals.
AVAILABLE OPTIONS
PACKAGE
TA
48-TQFP
(PHP)
– 40°C to 85°C
THS1240I
0°C to 70°C
THS1240C
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.
Copyright  2001, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
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1
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
functional block diagram
AVDD DVDD DRVDD
VIN+
1 kΩ
S/H
Σ
VIN–
A/D
VREFIN+
VREFOUT+
Σ
D/A
A/D
D/A
A/D
1
1
2
3.0 V
Reference
AVDD/2
2.0 V
VREFOUT–
VREFIN–
Stage 11
Stage 10
Stages 2 – 9
Stage 1
Buffer
Digital Error Correction
VCM
CLK+
Timing
CLK–
AVSS
DVSS DRVSS
D11 D10 D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
Terminal Functions
TERMINAL
NAME
NO.
I/O
DESCRIPTION
AVDD
2, 5, 12, 43,
45, 47
I
Analog power supply
AVSS
1, 11, 13, 41,
42, 44, 46
I
Analog ground return for internal analog circuitry
CLK+
15
I
Clock input
CLK–
16
I
Complementary clock input
D11–D0
25–36
O
Digital data output bits; LSB= D0, MSB = D11 (2s complement output format)
DRVDD
DRVSS
24, 37, 38
I
Digital output driver supply
23, 39, 40
I
Digital output driver ground return
DVDD
17, 20, 22
I
Positive digital supply
DVSS
18, 19, 21
I
Digital ground return
VBG
VCM
10
O
Band gap reference. Bypass to ground with a 1-µF and a 0.01-µF chip capacitor.
48
O
Common mode voltage output. Bypass to ground with a 0.1-µF and a 0.01-µF chip capacitor.
VIN+
VIN–
3
I
Analog signal input
4
I
Complementary analog signal input
VREFIN –
VREFIN+
7
I
External reference input low
8
I
External reference input high
VREFOUT+
VREFOUT –
9
O
Internal reference output. Compensate with a 1-µF and a 0.01-µF chip capacitor.
6
O
Internal reference output. Compensate with a 1-µF and a 0.01-µF chip capacitor.
2
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THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
functional description
The THS1240 uses a differential pipeline architecture and assures no missing codes over the full operating
temperature range. The device uses a 1 bit per stage architecture in order to achieve the highest possible
bandwidth. The differential analog inputs are terminated with a 1-kΩ resistor. The inputs are then fed to a unity
gain buffer followed by the S/H (sample and hold) stage. This S/H stage is a switched capacitor operational
amplifier-based circuit, see Figure 3. The pipeline is a typical 1 bit per stage pipeline as shown in the functional
block diagram. The digital output of the 12 stages is sent to a digital correction logic block which then outputs
the final 12 bits.
absolute maximum ratings over operating free-air temperature (unless otherwise noted)†
Supply voltage range: AVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
DVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
DRVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 7 V
Voltage between AVSS and DVSS and DRVSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to 0.5 V
Voltage between DRVDD and DVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 5 V
Voltage between AVDD and DVDD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.5 V to 5 V
Digital data output . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 0.3 V to DVDD + 0.3 V
CLK peak input current, Ip(CLK) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 mA
Peak total input current (all inputs), Ip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 30 mA
Operating free-air temperature range, TA: THS1240C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0°C to 70°C
THS1240I . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 40°C to 85°C
Storage temperature range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . – 65°C to 150°C
Lead temperature 1,6 mm (1/16 inch) from the case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . . 260°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.
recommended operating conditions
MIN
Sample rate
NOM
MAX
UNIT
40
MSPS
1
Analog supply voltage, AVDD
4.75
5
5.25
V
Digital supply voltage, DVDD
4.75
5
5.25
V
Digital output driver supply voltage, DRVDD
CLK + high level input voltage, VIH‡
3
3.3
5.25
V
3.5
5
5.25
V
CLK + low-level input voltage, VIL‡
CLK pulse-width high, tp(H)
10
12.5
ns
CLK pulse-width low, tp(L)
10
12.5
ns
Operating free-air
free air temperature range,
range TA
0
THS1240C
THS1240I
1.5
0
70
– 40
85
V
°C
‡ CLK– Input tied to ground with 0.01 µF capacitor for single-ended clock source.
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THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
electrical characteristics over recommended operating free-air temperature range,
AVDD = DVDD = 5 V, DRVDD = 3.3 V, internal references, CLK = 40 MHz, single-ended clock source
at 40 MHz with 50% duty cycle (unless otherwise noted)
dc accuracy
PARAMETER
DNL
TEST CONDITIONS
Differential nonlinearity
fIN = 15.5 MHz
MIN
TYP†
MAX
UNIT
–1
± 0.6
1.25
LSB
No missing codes
INL
Assured
Integral nonlinearity
±2
fIN = 15.5 MHz
V(VIN+) = V(VIN_) = VCM
EO
Offset error
EG
Gain error
† All typical values are at TA = 25°C.
LSB
14
70
–7
– 10
%FSR
mV
TYP†
MAX
UNIT
V(VIN) = (VCM)
V(VIN) = (VCM)
V(VIN) = (VCM)
73
110
mA
2
4
mA
2
7
V(VIN) = (VCM)
380
power supply
PARAMETER
I(AVDD)
I(DVDD)
TEST CONDITIONS
Analog supply current
Digital supply current
Output driver supply current‡
I(DRVDD)
PD
Power dissipation
† All typical values are at TA = 25°C.
‡ 15 pF load on digital outputs
MIN
mA
mW
reference
PARAMETER
TEST CONDITIONS
MIN
TYP†
MAX
UNIT
VREFOUT –
VREFOUT+
Negative reference output voltage
1.9
2
2.1
V
Positive reference output voltage
2.9
3
3.1
V
VREFIN –
VREFIN+
External reference supplied
2
V
External reference supplied
3
V
V(VCM)
Common mode output voltage
AVDD/2
I(VCM)
Common mode output current
† All typical values are at TA = 25°C.
V
µA
80
analog input
PARAMETER
TEST CONDITIONS
MIN
TYP†
MAX
UNIT
RI
Differential input resistance
1
kΩ
CI
Differential input capacitance
4
pF
VI
VID
Analog input common mode range
VCM ± 0.05
2
Differential input voltage range
BW Analog input bandwidth (large signal)
† All typical values are at TA = 25°C.
–3 dB
120
V
Vp-p
MHz
digital outputs
PARAMETER
VOH
VOL
TEST CONDITIONS
IOH = – 50 µA
IOL = 50 µA
High-level output voltage
Low-level output voltage
CL
Output load capacitance
† All typical values are at TA = 25°C.
4
POST OFFICE BOX 655303
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MIN
TYP†
MAX
0.8DRVDD
UNIT
V
0.2DRVDD
VDD
15
pF
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
ac specifications over recommended operating free-air temperature range, AVDD = DVDD = 5 V,
DRVDD = 3.3 V, internal references, CLK = 40 MHz, analog input at –2 dBFS, single-ended clock
source at 40 MHz with 50% duty cycle (unless otherwise noted)
PARAMETER
TEST CONDITIONS
MIN
fIN = 2.2 MHz
fIN = 15.5 MHz
SNR
Signal-to-noise ratio
fIN = 15.5 MHz, V(IN) = –0.5 dBFS
fIN = 31 MHz
Signal-to-noise and distortion
fIN = 15.5 MHz
fIN = 15.5 MHz, V(IN) = –0.5 dBFS
ENOB
Effective number of bits
THD
Total harmonic distortion
fIN = 15.5 MHz
fIN = 15.5 MHz, V(IN) = –0.5 dBFS
fIN = 2.2 MHz
fIN = 15.5 MHz
SFDR
d Harmonic
2nd
d Harmonic
3rd
Spurious-free dynamic range
Distortion
Distortion
dB
65.5
64
64
63.3
64
62
dB
64.5
63.2
55.7
10.2
10
bits
10.4
–72
–68
–71
dBc
73
70
77
dBc
72
fIN = 15.5 MHz, V(IN) = –0.5 dBFS
fIN = 31 MHz
77
fIN = 70 MHz
fIN = 2.2 MHz
59.6
fIN = 15.5 MHz
fIN = 31 MHz
–87
82
–70
–77
fIN = 70 MHz
fIN = 2.2 MHz
–60.5
fIN = 15.5 MHz
fIN = 31 MHz
–80.4
dBc
–73
–70
–77
fIN = 70 MHz
F1 = 14.9 MHz,
F2 = 15.6 MHz,
Analog inputs at – 8 dBFS each
Two tone SFDR
UNIT
64
63
fIN = 31 MHz
fIN = 70 MHz
fIN = 15.5 MHz
fIN = 15.5 MHz, V(IN) = –0.5 dBFS
MAX
64.6
fIN = 70 MHz
fIN = 2.2 MHz
SINAD
TYP†
dBc
–60
72
dBc
† All typical values are at TA = 25°C.
operating characteristics over recommended operating conditions, AVDD = DVDD = 5 V,
DRVDD = 3.3 V
switching specifications
PARAMETER
TEST CONDITIONS
Aperture delay, td(A)
TYP†
MAX
120
Aperture jitter
Output delay td(O), after falling edge of CLK+
MIN
ps
1
Digital outputs driving a 15 pF load each
Pipeline delay td(PIPE)
ps RMS
13
6.5
UNIT
ns
CLK
Cycle
† All typical values are at TA = 25°C.
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5
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
definitions of specifications
analog bandwidth
The analog input frequency at which the spectral power of the fundamental frequency of a large input signal
is reduced by 3 dB.
aperture delay
The delay between the 50% point of the rising edge of the clock and the instant at which the analog input is
sampled.
aperture uncertainity (jitter)
The sample-to-sample variation in aperture delay
differential nonlinearity
The deviation of any output code from the ideal width of 1 LSB.
integral nonlinearity
The deviation of the transfer function from an end-point adjusted reference line measured in fractions of 1 LSB.
Also the integral of the DNL curve.
clock pulse width/duty cycle
Pulse width high is the minimum amount of time that the clock pulse should be left in logic 1 state to achieve
rated performance; pulse width low is the minimum time clock pulse should be left in low state. At a given clock
rate, these specs define acceptable clock duty cycles.
offset error
The difference between the analog input voltage at which the ADC output changes from mid-scale to 1 LSB
above mid-scale, and the ideal voltage at which this transition should occur.
gain error
The difference between the analog input voltage at which the ADC output changes from full-scale to 1 LSB below
full scale, and the ideal voltage at which this transition should occur, minus the offset error
Gain Error
ǒ
+ 100%x 2 * V2 )V* V
IN
IN_
Ǔ @Code 4096
total harmonic distortion
The ratio of the power of the fundamental to a given harmonic component reported in dBc.
output delay
The delay between the 50% point of the falling edge of the clock and the time when all output data bits are within
valid logic levels (not including pipeline delay).
signal-to-noise-and distortion (SINAD)
When tested with a single tone, the ratio of the signal power to the sum of the power of all other spectral
components, excluding dc, referenced to full scale.
signal-to-noise ratio (SNR)
When tested with a single tone, the ratio of the signal power to the sum of the power of all other power spectral
components, excluding dc and the first 9 harmonics, referenced to full scale.
effective number of bits (ENOB)
For a sine wave, SINAD can be expressed in terms of the effective number of bits, using the following formula,
ENOB
+ (SINAD6.02* 1.76)
spurious-free dynamic range (SFDR)
The ratio of the signal power to the power of the worst spur, excluding dc. The worst spurious component may
or may not be a harmonic. The ratio is reported in dBc (that is, degrades as signal levels are lowered).
6
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THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
Sample N
V(VIN)
td(A)
td(Pipe)
tp(H)
tP(L)
CLK+
tc
Digital Output
(D0 – D11)
td(O)
Data N–7
Data N–6
Data N–5
Data N–4
Data N–3
Data N–2
Data N–1
Data N
Data N+1
Data N+2
Figure 1. Timing Diagram
equivalent circuits
R2
BAND
GAP
φ2
R1
VREFOUT+
VCM
VREFOUT–
R1
R2
φ1′
VIN+
AVDD
φ1
1 kΩ
φ1
VIN–
600 Ω
φ1′
VCM
VCM
600 Ω
φ2
AVSS
Figure 2. References
Figure 3. Analog Input Stage
VDD
DVDD
To
Timing
Circuits
R1
5 kΩ
DRVDD
R1
5 kΩ
DVDD
CLK+
10 Ω
CLK–
DVSS
R2
5 kΩ
R2
5 kΩ
D0–D11
DVSS
DRVSS
Figure 5. Digital Outputs
GND
Figure 4. Clock Inputs
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7
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
APPLICATION INFORMATION
using the THS1240 references
The option of internal or external reference is provided by allowing for an external connection of the internal
reference to the reference inputs. This type of reference selection offers the lowest noise possible by not relying
on any active switch to make the selection. Compensating each reference output with a 1-µF and 0.01-µF chip
capacitor is required as shown in Figure 6. The differential analog input range is equal to 2 (VREFOUT+ –
VREFOUT–). When using external references, it is best to decouple the reference inputs with a 0.1-µF and
0.01-µF chip capacitor as shown in Figure 7.
VREFIN+
VREFOUT+
0.01 µF
VREFIN+
External Reference +
0.01 µF
1 µF
0.1 µF
VREFIN–
VREFOUT–
0.01 µF
VREFIN–
External Reference –
0.01 µF
1 µF
Figure 6. Internal Reference Usage
0.1 µF
Figure 7. External Reference Usage
using the THS1240 clock input
The THS1240 clock input can be driven with either a differential clock signal or a single ended clock input with
little or no difference in performance between the single-ended and differential-input configurations. The
common mode of the clock inputs is set internally to VDD/2 using 5-kΩ resistors (Figure 4).
The THS1240 clock input requires a common mode voltage or dc component of VDD/2. It is possible for the
common mode voltage of the clock source to differ from VDD/2 by as much as 10% with little or no performance
degradation. The clock input should be either a sinewave or a square wave having a 50% duty cycle.
When driven with a single-ended CMOS clock input, it is best to connect the CLK– input to ground with a 0.01 µF
capacitor (see Figure 8).
CLK+
Square Wave or Sine Wave
2 V p-p to 5 V p-p
Common Mode Voltage = VDD/2
THS1240
CLK–
0.01 µF
Figure 8. Driving the Clock From a Single-Ended Clock Source
8
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THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
APPLICATION INFORMATION
using the THS1240 clock input (continued)
If the dc component of the input clock differs from VDD/2 by more than 10%, it is best to connect the CLK+ input
to the clock source through a 0.01 µF capacitor. In this mode, the converter can operate with a clock having a
peak-to-peak voltage of as little as 2 V with little or no performance degradation (see Figure 9).
Square Wave or
Sine Wave
2 V p-p to 5 V p-p
CLK+
0.01 µF
THS1240
CLK–
0.01 µF
Figure 9. AC-Coupled Single-Ended Clock Input
The THS1240 clock input can also be driven differentially. If the common mode of the clock input is VDD/2, then
the clock inputs can be driven directly (see Figure 10)
CLK+
Differential Square Wave or
Sine Wave 2 V p-p to 5 V p-p
Common Mode Voltage = VDD/2
THS1240
CLK–
Figure 10. Differential Clock Input
If the clock input is driven differentially with a clock signal having a common mode voltage that is different from
VDD/2, then it is best to connect both clock inputs to the differential input clock signal with 0.01 µF capacitors
(see Figure 11). The differential input swing can vary between 2 V and 5 V with little or no performance
degradation.
Differential Square Wave or
Sine Wave
2 V p-p to 5 V p-p
CLK+
0.01 µF
THS1240
CLK–
0.01 µF
Figure 11. AC-Coupled Differential Clock Input
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9
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
APPLICATION INFORMATION
using the analog input
The THS1240 obtains optimum performance when the analog signal inputs are driven differentially. The circuit
below shows the optimum configuration, see Figure 12. The signal is fed to the primary of an RF transformer.
Since the input signal must be biased around the common mode voltage of the internal circuitry, the common
mode (VCM) reference from the THS1240 is connected to the center-tap of the secondary. To ensure a steady
low noise VCM reference, the best performance is obtained when the VCM output is connected to ground with
a 0.1-µF and 0.01-µF low inductance capacitor.
R0
Z0 = 50 Ω
1:1
VIN+
50 Ω
R
50 Ω
AC Signal Source
THS1240
VIN–
T1-1T
VCM
0.01 µF
0.1 µF
Figure 12. Driving the THS1240 Analog Input With Impedance Matched Transmission Line
When it is necessary to buffer or apply a gain to the incoming analog signal, it is also possible to combine a
single-ended amplifier with an RF transformer as shown in Figure 13. For this application, a wide-band current
mode feedback amplifier such as the THS3001 is best. The noninverting input to the operational amplifier is
terminated with a resistor having an impedance equal to the characteristic impedance of the trace that sources
the IF input signal. The single-ended output allows the use of standard passive filters between the amplifier
output and the primary. In this case, the SFDR of the operational amplifier is not as critical as that of the A/D
converter. While harmonics generated from within the A/D converter fold back into the first Nyquist zone,
harmonics generated externally in the operational amplifier can be filtered out with passive filters.
1 kΩ
1 kΩ
Impedance Ratio = 1:n
10 Ω
_
RT
VIN+
BPF
+
IF Input
THS3001
THS1240
VIN–
VCM
0.1 µF
0.01 µF
Figure 13. IF Input Buffered With THS3001 Operational Amplifier
10
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THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
APPLICATION INFORMATION
digital outputs
The digital outputs are in 2s complement format and can drive either TTL, 3-V CMOS, or 5-V CMOS logic. The
digital output high voltage level is equal to DRVDD. Table 1 shows the value of the digital output bits for full scale
analog input voltage, midrange analog input voltage, and negative full scale input voltage. To reduce capacitive
loading, each digital output of the THS1240 should drive only one digital input. The CMOS output drivers are
capable of handling up to a 15-pF load. For better SNR performance, use 3.3 V for DRVDD. Resistors of 200 Ω
in series with the digital output can be used for optimizing SNR performance.
Table 1. Digital Outputs
ANALOG INPUT
VIN+
Vref+
VIN–
Vref–
VCM
Vref–
VCM
Vref+
D11
D10
D9
D8
D7
D6
D5
D4
D3
D2
D1
D0
0
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
0
0
0
0
0
0
0
0
0
0
0
power supplies
Best performance is obtained when AVDD is kept separate from DVDD. Regulated or linear supplies, as opposed
to switched power supplies, must be used to minimize supply noise. It is also recommended to partition the
analog and digital components on the board in such a way that the analog supply plane does not overlap with
the digital supply plane in order to limit dielectric coupling between the different supplies.
package
The THS1240 is packaged in a small 48-pin quad flat-pack PowerPAD package. The die of the THS1240 is
bonded directly to copper alloy plate which is exposed on the bottom of the package. Although, the PowerPAD
provides superior heat dissipation when soldered to a ground land, it is not necessary to solder the bottom of
the PowerPAD to anything in order to achieve minimum performance levels indicated in this specification over
the full recommended operating temperature range.
Only if the device is to be used at ambient temperatures above the recommended operating temperatures, use
of the PowerPAD is suggested.
The copper alloy plate or PowerPAD is exposed on the bottom of the device package for a direct solder
attachment to a PCB land or conductive pad. The land dimensions should have minimum dimensions equal to
the package dimensions minus 2 mm, see Figure 14.
For a multilayer circuit board, a second land having dimensions equal to or greater than the land to which the
device is soldered should be placed on the back of the circuit board (see Figure 15). A total of 9 thermal vias
or plated through-holes should be used to connect the two lands to a ground plane (buried or otherwise) having
a minimum total area of 3 inches square in 1 oz. copper. For the THS1240 package, the thermal via centers
should be spaced at a minimum of 1 mm. The ground plane need not be directly under or centered around the
device footprint if a wide ground plane thermal run having a width on the order of the device is used to channel
the heat from the vias to the larger portion of the ground plane. The THS1240 package has a standoff of 0.19
mm or 7.5 mils. In order to apply the proper amount of solder paste to the land, a solder paste stencil with a 6
mils thickness is recommended for this device. Too thin a stencil may lead to an inadequate connection to the
land. Too thick a stencil may lead to beading of solder in the vicinity of the pins which may lead to shorts. For
more information, refer to Texas Instruments literature number SLMA002 PowerPAD Thermally Enhanced
Package.
PowerPAD is a trademark of Texas Instruments.
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
11
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
APPLICATION INFORMATION
package (continued)
1,25 mm
2 x 1,25 mm
1,25 mm
5 mm
2 x 1,25 mm
0,33 mm Diameter
Plated Through Hole
5 mm
Figure 14. Thermal Land (top view)
PHP (S-PQFP-G48)
Thermal
Land
ÏÏÏÏÌÌÎÎ
ÎÎÎÎÎ
ÌÌÌÌ
ÎÎÌÌ
ÎÎÎÎÎÎ
ÏÏÏÏÏ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎÎÎÎÎÎÎÎÎÎÎ
ÎÎÎÎÎ
ÎÎÌÌ
ÎÎÎÎÎÎ
ÌÌÎÎ
ÌÌÌÌ
Plated Through Hole
PWB
Figure 15. Top and Bottom Thermal Lands With Plated Through Holes (side view)
12
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
TYPICAL CHARACTERISTICS
Power – dBFS
OUTPUT POWER SPECTRUM
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
FS = 40 MSPS
fIN = 2.2 MHz
VIN = –2 dBFS
8K Point Discrete
Fourier Transform
0
5
10
15
20
15
20
15
20
f – Frequency – MHz
Figure 16
Power – dBFS
OUTPUT POWER SPECTRUM
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
FS = 40 MSPS
fIN = 15.5 MHz
VIN = –2 dBFS
8K Point Discrete
Fourier Transform
0
5
10
f – Frequency – MHz
Figure 17
Power – dBFS
OUTPUT POWER SPECTRUM
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
FS = 40 MSPS
fIN = 31 MHz
VIN = –2 dBFS
8K Point Discrete
Fourier Transform
0
5
10
f – Frequency – MHz
Figure 18
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
13
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
TYPICAL CHARACTERISTICS
Power – dBFS
OUTPUT POWER SPECTRUM
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
FS = 40 MSPS
fIN = 69 MHz
VIN = –2 dBFS
8K Point Discrete
Fourier Transform
0
5
10
15
20
f – Frequency – MHz
Figure 19
Power – dBFS
TWO-TONE OUTPUT POWER SPECTRUM
0
–10
–20
–30
–40
–50
–60
–70
–80
–90
–100
–110
FS = 40 MSPS
fIN = 14.9 MHz and 15.6 MHz
VIN = –8 dBFS Each
8K Point Discrete
Fourier Transform
0
5
10
15
20
f – Frequency – MHz
Figure 20
Dynamic Power Performance – dB
DYNAMIC POWER PERFORMANCE
vs
ANALOG INPUT POWER
D
100
90
FS = 40 MSPS
fIN = 15.5 MHz
80
SNR (dB)
3rd Harmonic (dBc)
70
60
SFDR (dBc)
50
SINAD (dB)
40
30
–60
2nd Harmonic (dBc)
–50
–40
–30
–20
Analog Input Power – dBFS
Figure 21
14
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
–10
0
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
Dynamic Power Performance – dB
TYPICAL CHARACTERISTICS
DYNAMIC POWER PERFORMANCE
vs
SAMPLING RATE
3rd Harmonic (dBc)
100
2nd Harmonic (dBc)
SNR (dB)
90
3rd Harmonic (dBc)
80
70
60
SFDR (dBc)
SINAD (dB)
50
fIN = 15.5 MHz
VIN = –2 dBFS
40
30
0
10
20
30
40
50
60
Sampling Rate – MSPS
Dynamic Power Performance – dB, dBc
Figure 22
DYNAMIC POWER PERFORMANCE
vs
DUTY CYCLE
100
fIN = 15.5 MHz
VIN_ –2 dBFS
90
SFDR (dBc)
SNR (dB)
80
70
60
50
SINAD (dB)
40
30
40
50
60
70
Duty Cycle – %
Figure 23
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
15
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
Dynamic Power Performance – dB, dBc
TYPICAL CHARACTERISTICS
DYNAMIC POWER PERFORMANCE
vs
ANALOG INPUT FREQUENCY
100
2nd Harmonic (dBc)
3rd Harmonic (dBc)
90
SNR (dB)
80
70
60
FS = 40 MSPS
VIN = –2 dBFS
50
SFDR (dBc)
SINAD (dB)
40
0
10
20
30
40
50
60
70
80
3072
3584
4096
Analog Input Frequency – MHz
Figure 24
Differential Nonlinearity – LSB
DIFFERENTIAL NONLINEARITY
vs
OUTPUT CODE
1
fIN = 15.5 MHz
0
–1
0
512
1024
1536
2048
2560
Output Code
Figure 25
16
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
TYPICAL CHARACTERISTICS
INTEGRAL NONLINEARITY
vs
OUTPUT CODE
Integral Nonlinearity – LSB
2
fIN = 15.5 MHz
1
0
–1
–2
0
512
1024
1536
2048
2560
3072
3584
4096
Output Code
Figure 26
ANALOG INPUT POWER BANDWIDTH
0
Power – dBFS
–5
–10
–15
–20
–25
FS = 40 MSPS
VIN = –2 dBFS
–30
0
20
40
60
80
100
120
140
160
180
200
f – Frequency – MHz
Figure 27
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
17
THS1240
12-BIT 40 MSPS IF SAMPLING COMMUNICATIONS
ANALOG-TO-DIGITAL CONVERTER
SLAS279D – JUNE 2000 – REVISED JANUARY 2001
MECHANICAL DATA
PHP (S-PQFP-G48)
PowerPAD PLASTIC QUAD FLATPACK
0,27
0,17
0,50
36
0,08 M
25
37
24
Thermal Pad
(see Note D)
48
13
0,13 NOM
1
12
5,50 TYP
Gage Plane
7,20
SQ
6,80
9,20
SQ
8,80
0,25
0,15
0,05
1,05
0,95
0°– 7°
0,75
0,45
Seating Plane
0,08
1,20 MAX
4146927/A 01/98
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 protrusions.
The package thermal performance may be enhanced by bonding the thermal pad to an external thermal plane. This pad is electrically
and thermally connected to the backside of the die and possibly selected leads.
E. Falls within JEDEC MO-153
PowerPAD is a trademark of Texas Instruments.
18
POST OFFICE BOX 655303
• DALLAS, TEXAS 75265
PACKAGE OPTION ADDENDUM
www.ti.com
30-Mar-2005
PACKAGING INFORMATION
Orderable Device
Status (1)
Package
Type
Package
Drawing
Pins Package Eco Plan (2)
Qty
THS1240CPHP
OBSOLETE
HTQFP
PHP
48
TBD
Call TI
Call TI
THS1240IPHP
OBSOLETE
HTQFP
PHP
48
TBD
Call TI
Call TI
Lead/Ball Finish
MSL Peak Temp (3)
(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) 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.
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.
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Addendum-Page 1
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