CADEKA TMC1175AM7C30

www.cadeka.com
TMC1175A
Video A/D Converter
8 bit, 40 Msps
Features
Description
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The TMC1175A analog-to-digital (A/D) converter employs
a two-step flash architecture to convert analog signals into
8-bit digital words at sample rates of up to 40 Msps
(Megasamples per second). An integral Track/Hold circuit
delivers excellent performance on signals with full-scale frequency components up to 12 MHz. Innovative architecture
and submicron CMOS technology limit typical power dissipation to 100 mW.
8-Bit resolution
40 Msps conversion rate
Low power: 100mW at 20 Msps
Integral track/hold
Integral and differential linearity error 0.5 LSB
Single or dual +5 Volt supplies
Differential phase 0.5 degree
Differential gain 1.5%
Three-state TTL/CMOS-compatible outputs
Low cost
Power may be derived from either single or dual +5V
supplies. Internal voltage reference resistors allow self-bias
operation. Input capacitance is very low, simplifying or
eliminating input driving amplifiers. All digital three-state
outputs are TTL- and CMOS-compatible.
Applications
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Video digitizing
VGA and CCD digitizing
LCD projection panels
Image scanners
Personal computer video boards
Multimedia systems
Low cost, high speed data conversion
The TMC1175A is available in 24-lead plastic SOIC, and
28-lead J-lead PLCC packages. Performance specifications
are guaranteed from -20°C to 75°C.
Block Diagram
VIN
VR+
RT
RB
VR–
Track/
Hold
Coarse
Quantizer
Reference
Matrix
Fine
Quantizer
Digital
ErrorCorrector
D7-0
OE
CONV
24453A
REV. 1.3.3 2/28/02
TMC1175A
PRODUCT SPECIFICATION
Functional Description
The TMC1175A 8-bit A/D converter uses a two-step architecture to perform analog-to-digital conversion at rates up to
40 Msps. The input signal is held in an integral track/hold
stage during the conversion process. Operation is pipelined,
with one input sample taken and one output word provided
for each CONVert cycle.
The first step in the conversion process is a coarse 4-bit
quantization. This determines the range of the subsequent
fine 4-bit quantization step. To eliminate spurious codes, the
fine 4-bit A/D quantizer output is gray-coded and converted
to binary before it is combined with the coarse result to form
a complete 8-bit result.
Analog Input and Voltage References
The TMC1175A converts analog signals in the range RB to
RT into digital data. Input signals outside that range produce
“saturated” 00h or FFh output codes. The device will not be
damaged by signals within the range AGND to VDDA.
Input voltage range is very flexible and extends from the +5
Volt power supply to ground. Performance is specified over
the optimom 2 volt input range: 0.6V to 2.6V. However, the
part will function with a full-scale range from 1.0V to 5.0V.
A reduced input range may simplify analog signal conditioning circuitry, at the expense of additional noise sensitivity
and reduced differential linearity. Increasing the range can
improve differential linearity, but imposes a greater burden
on the input signal conditioning circuitry.
In many applications, external voltage reference sources are
connected to the RT and RB pins. RB can be grounded. Gain
and offset errors are directly related to the accuracy and stability of the applied reference voltages.
Two reference pull-up and pull-down resistors connected to
VR+ and VR– are provided internally for operation without
external voltage reference circuitry (Figure 1). The reference
voltages applied to RT and RB may be generated by connecting VR+ to RT and VR- to RB. The power supply voltage is
divided by the on-chip resistors to bias the RT and RB points.
This sets-up the converter for operation in its nominal range
from 0.6V to 2.6V.
2
V DDA
VR+
R+
324Ω
+2.6V
RT
RREF
270Ω
+0.6V
RB
VR–
R–
81Ω
27010A
Figure 1. Reference Resistors
With VDDA at 5.0V, connecting VR+ to RT and grounding
RB will provide an input range from 0.0V to 2.27V, while
connecting RT to VDDA and RB to VR- produces a full scale
range of 3.85V referenced to VDDA. External resistors may
also be employed to provide arbitrary reference voltages, but
they will not match the temperature coefficient of the onchip resistors as well as R+ and R-, and will cause the converter transfer function to vary with temperature.
With this implementation, errors in the power supply voltage
end up on the conversion data output.
Because a two-step conversion process is employed, it is
important that the references remain stable during the
ENTIRE conversion process (two clock cycles). The reference voltage can then be changed, but any conversion in
progress during a reference change is invalid.
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
Table 1. Output Coding
remain valid for tHO (Output Hold Time), satisfying any
hold time requirement of the receiving circuit. The new data
become valid tDO (Output Delay Time) after this rising edge
of CONV.
Input Voltage
Output
RT + 1 LSB
FF
RT
FF
RT – 1 LSB
FE
•••
•••
RB + 128 LSB
80
RB + 127 LSB
7F
•••
•••
Power and Ground
RB + 1 LSB
01
RB
00
RB – 1 LSB
00
To minimize noise injection into the analog section, VDDA
may be connected to a separate regulated +5 volt supply.
VDDD may be connected to a digital supply. Power up
sequence is immaterial. Latch-up will not occur.
The outputs of the TMC1175A are CMOS- and TTL-compatible, and are capable of driving four low-power Schottky
TTL (54/74LS) loads. An Output Enable control, OE, places
the outputs in a high-impedance state when HIGH. The outputs are enabled when OE is LOW.
Note:
1. LSB = (RT – RB) / 255
AGND and DGND pins should be connected to a common
ground plane. For optimum performance treat analog and
digital PWB traces as transmission lines. Route analog
connections cleanly to the TMC1175A. Segregate digital
connections and if necessary terminate clocks to eliminate
ringing. Prevent digital returm currents from flowing across
analog input sections of the TMC1175A.
Digital Inputs and Outputs
Sampling of the applied input signal takes place on the falling edge of the CONV signal (Figure 2). The output word is
delayed by 2 1/2 CONV cycles. It is then available after the
rising edge of CONV. The previous data on the output
tSTO
VIN
Sample N+3
Sample N
Sample N+2
Sample N+1
tPWL
1/fS
tPWH
CONV
tDO
D7-0
ORP
ORN
tHO
Data N–3
Data N–2
Hi-Z
tDIS
Data N–1
Data N
tENA
OE
24455A
Figure 2. Conversion Timing
REV. 1.3.3 2/28/02
3
TMC1175A
PRODUCT SPECIFICATION
V(1)
V(2)
V(3)
V(4)
Analog input
External Clock
S (1)
Upper comparators block
C (1) S (2)
C (2) S (3)
C (3)
S (4)
C (4)
Upper data
MD (0)
MD (1)
MD (2)
MD (3)
Lower reference voltage
RV (0)
RV (1)
RV (2)
RV (3)
Lower comparators A block
S (1)
H (1)
H (0)
H (3)
C (0)
Out(-2)
Digital output
C (3)
LD (1)
S (2)
LD(-2)
Lower data B
S (3)
LD (-1)
Lower data A
Lower comparators B block
C (1)
H (2)
C (2)
S (4)
LD(0)
Out(-1)
H (94)
LD(2)
Out(0)
Out(1)
65-7568
Figure 3. Internal Timing
M7 Package
DGND
RB
VR–
AGND
AGND
VIN
VDDA
RT
VR+
VDDA
VDDA
VDDD
25
24
23
22
21
20
19
24
23
22
21
20
19
18
17
16
15
14
13
18
17
16
15
14
13
VR– 26
RB 27
DGND 28
N/C 1
OE 2
DGND 3
D0 4
N/C
CONV
VDDD
12 D7
R3 Package
4
VDDA
VDDA
VDDD
D1 5
D2 6
D3 7
N/C 8
D4 9
D5 10
D6 11
OE 1
DGND 2
D0 3
D1 4
D2 5
D3 6
D4 7
D5 8
D6 9
D7 10
VDDD 11
CONV 12
A GND
A GND
VIN
N/C
VDDA
RT
VR+
Pin Assignments
24454A
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
Pin Descriptions
Pin Number
Pin Name
M7
R3
Pin Type Pin Function Description
VIN
19
23
RT – RB Analog Input. The input voltage conversion range lies between the
voltages applied to the RT and RB pins.
RT
17
20
2.6V
Reference Voltage Top Input. RT is the top input to the reference
resistor ladder. A DC voltage applied to RT defines the positive end
of the VIN conversion range.
RB
23
27
0.6V
Reference Voltage Bottom Input. RB is the bottom input to the
reference resistor ladder. A DC voltage applied to RB defines the
negative end of the VIN conversion range.
VR+
16
19
Reference Voltage Top Source. VR+ is the internal pull-up
reference resistor for self-bias operations.
VR–
22
26
Reference Voltage Bottom Source. VR- is the internal pull-down
reference resistor for self-bias operations.
OE
1
2
CMOS
Output Enable. (CMOS-compatible) When LOW, D7-0 are enabled.
When HIGH, D7-0 are in a high-impedance state.
CONV
12
14
CMOS
Convert (Clock) Input. (CMOS-compatible) VIN is sampled on the
falling edge of CONV.
10–3
12–9,
7–4
CMOS/
TTL
Data Outputs (D7 = MSB). Eight-bit CMOS- and TTL-compatible
digital outputs. Data is output following the rising edge of CONV.
VDDA
14, 15, 18
17, 18,
21
+5V
Analog Supply Voltage. Independent +5 volt power connection to
analog comparator circuits.
VDDD
11, 13
13, 16
+5V
Digital Supply Voltage. Independent +5 volt power connection to
digital error correction and output drivers.
AGND
20, 21
24, 25
0.0V
Analog Ground. Connect to the system analog ground plane.
DGND
2, 24
3, 28
0.0V
Digital Ground. Connect to the system analog ground plane.
1, 8, 15,
22
open
Not Connected.
Inputs
Outputs
D7-0
Power
No Connect
N/C
Bandwidth Specification Notes
The specification for bandwidth of an A/D converter is somewhat different from the normal frequency-response specification used in amplifiers and filters. An understanding of the
differences will help in selecting converters properly for particular applications.
A/D conversion comprises two distinct processes: sampling
and quantizing. Sampling is “grabbing” a snapshot of the
input signal and holding it steady for quantizing. The quantizing process is approximating the analog input, which may
be any value within the conversion range, with its nearest
numerical value. While sampling is a high-frequency process, quantizing operates on a dc signal, held steady by the
track/hold circuit. Therefore, the sampling process is what
relates to the dynamic characteristics of the converter.
REV. 1.3.3 2/28/02
Sampling involves an aperture time, the time during which
the track/hold is trying to capture the input signal and settle
on a dc value to hold. It is analogous to the shutter speed of a
camera: the shorter the aperture (or faster the shutter) the less
the signal will be blurred, and the less uncertainty there will
be in the quantized value.
For example, a 10 MHz sinewave with a 1V peak amplitude
(2Vp-p) has a maximum slew rate of 2πfA at zero crossing,
or 62.8V/µs. With an 8-bit A/D converter, q (the quantization
step size) = 2V/255 = 7.8mV. The input signal will slew one
LSB in 124ps. To limit the error (and noise) contribution due
to aperture effects to 1/2LSB, the aperture must be shorter
than 62ps.
5
TMC1175A
PRODUCT SPECIFICATION
This is the primary reason that the signal to noise ratio drops
off as full scale frequency increases. Note, also, that the slew
rate is directly proportional to signal amplitude, A. A/Ds will
handle lower-amplitude signals of higher bandwidth.
All this is of particular interest in applications such as digitizing analog VGA RGB signals, or the output of a CCD
imaging chip. These data are effectively pre-sampled: there
is a period of rapid slewing from one pixel value to another,
followed by a relatively stable dc level before the signal
slews to the next pixel value. The goal is, of course, to
sample on these pixel values, not on the slewing between
pixels. During the aperture time, the A/D sees essentially a
dc signal, and classic bandwidth considerations are not
important. As long as the input circuit can slew and settle to
the new value in the prescribed period, an accurate conversion will be made.
The TMC1175A is capable of slewing a full 2V and settling
between samples taken as little as 25ns apart, making it ideal
for digitizing analog VGA and CCD outputs.
Equivalent Circuits and Threshold Level
VDD
VDD
p
p
Data or
Control
Input
Output
n
GND
n
27011B
GND
27014B
Figure 5. Equivalent Digital Output Circuit
Figure 4. Equivalent Digital Input Circuit
VDDA
tENA
VIN
OE
tDIS
0.5V
2.0V
0.8V
Three-State
Outputs
AGND
Figure 6. Equivalent Analog Input Circuit
6
65-1175A-07
0.5V
27052A
High Impedance
Figure 7. Threshold Levels for Three-State Measurements
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
Absolute Maximum Ratings
(beyond which the device may be damaged)1
Parameter
Conditions
Min
Typ
Max
Unit
V
Power Supply Voltages
VDDA
Measured to AGND
-0.5
7.0
VDDD
Measured to DGND
-0.5
7.0
VDDA
Measured to VDDD
-0.5
0.5
AGND
Measured to DGND
-0.5
0.5
V
Digital Inputs
Applied Voltage2
Measured to DGND
Forced Current3,4
-0.5
VDDD + 0.5
V
-10.0
10.0
mA
-0.5
VDDA + 0.5
V
-10.0
10.0
mA
-0.5
VDDD + 0.5
V
-6.0
6.0
mA
1
sec
Analog Inputs
Applied Voltage2
Measured to AGND
3,4
Forced Current
Outputs
Applied Voltage2
Forced
Measured to DGND
Current3,4
Short Circuit Duration
Single output in HIGH state to ground
Temperature
Operating, Ambient
-20
Junction
Storage
-65
110
°C
150
°C
150
°C
Lead Soldering
10 seconds
300
°C
Vapor Phase Soldering
1 minute
220
°C
Notes:
1. Functional operation under any of these conditions is NOT implied. Performance and reliability are guaranteed only if
operating conditions are not exceeded.
2. Applied voltage must be current limited to specified range.
3. Forcing voltage must be limited to specified range.
4. Current is specified as conventional current flowing into the device
REV. 1.3.3 2/28/02
7
TMC1175A
PRODUCT SPECIFICATION
.
Operating Conditions
Parameter
Min
Nom
Max
Units
VDDD
Digital Power Supply Voltage
4.75
5.0
5.25
V
VDDA
Analog Power Supply Voltage
4.75
5.0
5.25
V
AGND
Analog Ground (Measured to
DGND)
-0.1
0
0.1
V
fS
Conversion Rate
TMC1175A-20
20
Msps
TMC1175A-30
30
Msps
40
Msps
TMC1175A-40
CONV Pulsewidth, HIGH
tPWH
CONV Pulsewidth, LOW
tPWL
VRT
Reference Voltage, Top
VRB
Reference Voltage, Bottom
VRT-VRB
Reference Voltage Differential
TMC1175A-20
15
ns
TMC1175A-30
13
ns
TMC1175A-40
12
ns
TMC1175A-20
15
ns
TMC1175A-30
12
ns
TMC1175A-40
12
ns
2.0
2.6
VDDA
V
0
0.6
3.0
V
5.0
V
1.0
VIN
Analog Input Range
VRB
VRT
V
VIH
Input Voltage, Logic HIGH
0.7 x
VDDD
VDDD
V
VIL
Input Voltage, Logic LOW
GND
0.3 x
VDDD
V
IOH
Output Current, Logic HIGH
-4.0
mA
IOL
Output Current, Logic LOW
4.0
mA
TA
Ambient Temperature, Still Air
75
°C
-20
Electrical Characteristics
Parameter
IDD
IDDQ
PD
CAI
RIN
8
Power Supply
Conditions
Current1
Power Supply Current,
Quiescent
Total Power Dissipation
Input Capacitance, Analog
Input Resistance
Min
Typ1
Max
Units
VDDD = VDDA = Max, CLOAD = 35pF
fS = 20Msps
20
30
mA
fS = 30Msps
25
35
mA
fS = 40Msps
30
40
mA
CONV = LOW
7
18
mA
CONV = HIGH
10
20
mA
fS = 20Msps
100
160
mW
fS = 30Msps
125
185
mW
fS = 40Msps
150
210
mW
VDDD = VDDA = Max
VDDD = VDDA = Max, CLOAD = 35pF
CONV = LOW
4
pF
CONV = HIGH
12
pF
1000
kΩ
500
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
Electrical Characteristics (continued)
Parameter
Conditions
Typ1
Min
Max
Units
±1
µA
340
Ω
VDDD = Max, VIN = VDDD
±5
µA
Input Current, LOW
VDDD = Max, VIN = 0V
±5
µA
IOZH
Hi-Z Output Leakage
VDDD = Max, VIN = VDDD
±5
µA
IOZL
Hi-Z Output Leakage
VDDD = Max, VIN = 0V
±5
µA
IOS
Short-Circuit Current
-30
mA
VOH
Output Voltage, HIGH
ICB
Input Current, Analog
RREF
Reference Resistance
IIH
Input Current, HIGH
IIL
200
270
IOH = -100µA
VDDD-0.3
V
IOH = -2.5mA
3.5
V
IOH = Max
2.4
V
VOL
Output Voltage, LOW
CDI
Digital Input Capacitance
IOL = Max
4
CDO
Digital Output Capacitance
10
0.4
V
10
pF
pF
Note:
1. Typical values with VDDD = VDDA = Nom and TA = Nom, Minimum/Maximum values with VDDD = VDDA = Max and TA = Min.
Switching Characteristics
Parameter
tSTO
Sampling Time Offset
Conditions
tHO
Output Hold Time
CLOAD = 15pF
tDO
Output Delay Time
CLOAD = 15pF
tENA
tDIS
Min
Typ
Max
Units
2
5
8
ns
5
ns
20
ns
Output Enable Time
27
ns
Output Disable Time
42
ns
REV. 1.3.3 2/28/02
9
TMC1175A
PRODUCT SPECIFICATION
System Performance Characteristics
Parameter
Conditions
Min
Typ1
Max
Units
ELI
Integral Linearity Error,
Independent
VRT = 2.6V
VRB = 0.6V
±0.5
±1
LSB
ELD
Differential Linearity Error
VRT = 2.6V
VRB = 0.6V
±0.3
±1
LSB
BW
Bandwidth2
TMC1175A-20
TMC1175A-30
TMC1175A-40
10
12
12
MHz
MHz
MHz
EAP
Aperture Error
EOT
Offset Voltage, Top
RT – VIN for most positive code transition
-8
-25
30
-42
mV
ps
EOB
Offset Voltage, Bottom
RB – VIN for most negative code transition
30
40
60
mV
dg
Differential Gain
fS = 14.3Msps
NTSC 40 IRE Mod Ramp
VDDA = +5.0V, TA=25°C
VRT = 2.6V, VRB = 0.6V
1.5
2.7
%
dp
Differential Phase
fS = 14.3Msps
NTSC 40 IRE Mod Ramp
VDDA = +5.0V, TA=25°C
VRT = 2.6V, VRB = 0.6V
0.5
1.0
deg
SNR3
Signal-to-Noise Ratio
fS = 20Msps, VRT = 2.6V, VRB = 0.6V
fIN = 1.24MHz
44
48
dB
fIN = 2.48MHz
43
47
dB
fIN = 6.98MHz
41
45
dB
fIN = 10.0MHz
37
42
dB
fIN = 1.24MHz
42
47
dB
fIN = 2.48MHz
40
45
dB
fIN = 6.98MHz
38
43
dB
fIN = 10.0MHz
33
39
dB
fIN = 12.0MHz
30
37
dB
fS = 30Msps, VRT = 2.6V, VRB = 0.6V
fS = 40Msps, VRT = 2.6V, VRB = 0.6V
10
fIN = 1.24MHz
40
45
dB
fIN = 2.48MHz
38
43
dB
fIN = 6.98MHz
36
41
dB
fIN = 10.0MHz
34
38
dB
fIN = 12.0MHz
32
36
dB
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
System Performance Characteristics (continued)
Min
Typ1
fIN = 1.24MHz
46
52
dB
fIN = 2.48MHz
44
51
dB
fIN = 6.98MHz
41
45
dB
fIN = 10.0MHz
38
43
dB
fIN = 1.24MHz
42
49
dB
fIN = 2.48MHz
40
45
dB
fIN = 6.98MHz
37
41
dB
fIN = 10.0MHz
35
40
dB
fIN = 12.0MHz
34
39
dB
fIN = 1.24MHz
40
44
dB
fIN = 2.48MHz
39
43
dB
fIN = 6.98MHz
38
41
dB
fIN = 10.0MHz
36
40
dB
fIN = 12.0MHz
36
39
dB
Parameter
SFDR4
Spurious-Free Dynamic
Range
Conditions
Max
Units
fS = 20Msps, VRT = 2.6V, VRB = 0.6V
fS = 30Msps, VRT = 2.6V, VRB = 0.6V
fS = 40Msps, VRT = 2.6V, VRB = 0.6V
Notes:
1. Values shown in Typ column are typical for VDDD = VDDA = +5V and TA = 25°C.
2. Bandwidth is the frequency up to which a full-scale sinewave can be digitized without spurious codes.
3. SNR values do not include the harmonics of the fundamental frequency.
4. SFDR is the ratio in dB of fundamental amplitude to the harmonic with the highest amplitude.
REV. 1.3.3 2/28/02
11
TMC1175A
PRODUCT SPECIFICATION
Typical Performance Characteristics
60
30
50
25
40
SFDR
IDD (mA)
20
15
30
10
20
5
10
fs = 20 Msps
fs = 30 Msps
fs = 40 Msps
0
0
0
10
20
30
0
40
Figure 8. Typical IDD vs fS
40
40
30
30
SNR
SNR
50
fs = 20 Msps
fs = 30 Msps
fs = 40 Msps
10
0
2
4
6
8
8
6
20
10
12
10
fs = 20 Msps
fs = 33 Msps
10
0
0
4
Figure 9. Typical SFDR vs fIN and fS
50
20
2
12
Figure 10. Typical SNR vs fIN and fS
0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
Figure 11. Typical SNR vs Full Scale Input Range
Applications Discussion
The circuit in Figure 12 employs a band-gap reference to
generate a variable RT reference voltages for the
TMC1175A as well as a bias voltage to offset the wideband
input amplifier to mid-range. An "offset adjust"
is also shown for varying the mid-range voltage level.
The operational amplifier in the reference circuitry is a
standard 741-type.
The voltage reference at RT can be adjusted from 0.0 to 2.4
volts while RB is grounded. Diodes are used to restrict the
wideband amplifier output to between -0.7V and VDD
+0.7V. Diode protection is good practice to limit the analog
input voltage at VIN to the safe operating range.
12
The circuit in Figure 13 shows self-bias of RT and RB by
connection to VR+ and VR-. This sets up a 0.6 to 2.6 Volt
input range for VIN. The input range is susceptible to power
supply variation since the voltages on RT and RB are directly
derived from VDDA. The video input is AC-coupled and
biased at a adjustable midpoint of the A/D input range.
This circuit offers the advantage of minimum support
circuitry for the most cost-sensitive applications.
In Figure 14, an external band-gap reference sets RT to +1.2
Volts while RB is grounded. The internal pull-up resistor,
R+, provides the bias current for the band-gap reference. The
A/D converter input is biased to the mid-point of the input
range.
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
+5V
Regulated +5V
0.1µF
LM385
1kΩ
V DDA
+5V
0.1µF
0.1µF
Gain Adjust
2kΩ
0.1mF
20Ω
+
2V
1kΩ
V DDD
VR+
RT
TMC1175A
0.1µF
RB
1kΩ
+
Video
Input
OE
V IN
75Ω
D 7-0
VR-
Wideband
Op-amp
455Ω
455Ω
CONV
A GND
D GND
+5V
27056A
Figure 12. Typical Interface Circuit-High Performance
Grounding
The TMC1175A has separate analog and digital
circuits. To keep digital system noise from the A/D
converter, it is recommended that power supply voltages
(VDDD and VDDA) originate from separate sources with
VDDA regulated, and that ground connections (DGND and
AGND) be made to the analog ground plane. Power supply
pins should be individually decoupled at the pin. The digital
circuitry that gets its input from the TMC1175A should be
referred to the system digital ground plane.
Printed Circuit Board Layout
Designing with high performance mixed-signal circuits
demands printed circuits with ground planes. Wire-wrap is
not an option, even for breadboarding. Overall system performance is strongly influenced by the board layout. Capacitive coupling from digital to analog circuits may result in
poor A/D conversion. Consider the following suggestions
when doing the layout:
1.
2.
3.
Offset
Adjust
The ground plane should be solid, not cross-hatched.
Connections to the ground plane should have very
short leads.
REV. 1.3.3 2/28/02
V DDA
+5V
0.1µF
Video
Input
0.1µF
V DDD
VR+
RT
2.2kΩ
0.1µF
TMC1175A
2kΩ
RB
560Ω
VR0.1µF
D 7-0
OE
V IN
10µF
75Ω
A GND
CONV
D GND
24458A
Figure 13. Typical Interface Circuit – Low Cost
+5V
0.1µF
Keep the critical analog traces (VIN, RT, RB, VR+,
VR-) as short as possible and as far as possible from all
digital signals. The TMC1175A should be located near
the board edge, close to the analog input connectors.
The power plane for the TMC1175A should be separate from that which supplies the rest of the digital circuitry. A single power plane should be used for all of
the VDD pins. If the power supply for the TMC1175A
is the same as that of the system's digital circuitry,
power to the TMC1175A should be decoupled with
ferrite beads and 0.1µF capacitors to reduce noise.
+5V
0.1µF
V DDA
0.1µF
V DDD
VR+
RT
0.1µF
LM385
RB
1kΩ
RF
Input
TMC1175A
VR-
10µF
V IN
56Ω
1kΩ
A GND
D 7-0
OE
CONV
D GND
24457A
Figure 14. Typical Interface Circuit – Stabilized Reference
13
TMC1175A
4.
5.
14
Decoupling capacitors should be applied liberally to
VDD pins. Remember that not all power supply pins are
created equal. They supply different circuits on the integrated circuit, each of which generate varying amounts
and types of noise. For best results, use 0.1µF ceramic
capacitors. Lead lengths should be minimized. Ceramic
chip capacitors are the best choice.
If the digital power supply has a dedicated power plane
layer, it should not be placed under the TMC1175A, the
voltage reference, or the analog inputs. Capacitive coupling of digital power supply noise from this layer to the
TMC1175A and its related analog circuitry can have an
adverse effect on performance.
PRODUCT SPECIFICATION
6.
CONV should be handled carefully. Jitter and noise on
this clock may degrade performance. Terminate the
clock line at the CONV input, if required, to eliminate
overshoot and ringing.
Evaluation Board
An evaluation board is available that implements good interface practices and provide a convenient testbed for developing system applications and circuit variations. An on-board
D/A converter is provided to reconstruct the digitized signal
and to evaluate converter performance.
Contact your sales representative for information.
REV. 1.3.3 2/28/02
PRODUCT SPECIFICATION
TMC1175A
Mechanical Dimensions
24 Lead SOIC (5.4 mm) Package
Symbol
Inches
Millimeters
Min.
Max.
Min.
Max.
A
.067
.004
.075
.012
1.70
A1
1.90
0.31
B
.014
.020
0.36
0.51
C
.006
.012
0.15
0.30
D
.587
.610
14.90
15.50
E
.205
.220
E1
e
.295
.319
5.20
7.50
5.60
8.10
h
.050 BSC
.010
.020
L
.016
.050
0.10
1.27 BSC
0.25
0.50
0.41
1.27
24
N
α°
ccc
24
8
0
.004
-
Notes
24
8
0
0.10
-
13
E1
E
12
1
D
h x 45°
C
A1
A
e
REV. 1.3.3 2/28/02
B
SEATING PLANE
α
-CLEAD COPLANARITY
ccc C
L
15
TMC1175A
PRODUCT SPECIFICATION
Mechanical Dimensions (continued)
28 Lead PLCC Package
Symbol
A
A1
A2
B
B1
D/E
D1/E1
D3/E3
e
J
ND/NE
N
ccc
Inches
Min.
Max.
.165
.180
.090
.120
.020
—
.013
.021
.026
.032
.485
.495
.450
.456
.300 BSC
.050 BSC
.042
.048
7
28
—
.004
Notes:
Millimeters
Min.
Max.
4.19
4.57
2.29
3.05
.51
—
.33
.53
.66
.81
12.32
12.57
11.43
11.58
7.62 BSC
1.27 BSC
1.07
1.22
7
28
—
0.10
Notes
1. All dimensions and tolerances conform to ANSI Y14.5M-1982
2. Corner and edge chamfer (J) = 45°
3. Dimension D1 and E1 do not include mold protrusion. Allowable
protrusion is .101" (.25mm)
3
2
E
E1
D
J
D1
D3/E3
B1
J
e
A
A1
A2
16
B
–C–
LEAD COPLANARITY
ccc C
REV. 1.3.3 2/28/02
TMC1175A
PRODUCT SPECIFICATION
Ordering Information
Product Number
Conversion
Rate
Temperature Range
Screening
Package
Package
Marking
TMC1175AM7C20
20 Msps
TA = -20°C to 75°C
Commercial
24-Lead SOIC
1175AM7C20
TMC1175AM7C30
30 Msps
TA = -20°C to 75°C
Commercial
24-Lead SOIC
1175AM7C30
TMC1175AM7C40
40 Msps
TA = -20°C to 75°C
Commercial
24-Lead SOIC
1175AM7C40
TMC1175AR3C20
20 Msps
TA = -20°C to 75°C
Commercial
28-Lead PLCC
1175AR3C20
TMC1175AR3C30
30 Msps
TA = -20°C to 75°C
Commercial
28-Lead PLCC
1175AR3C30
TMC1175AR3C40
40 Msps
TA = -20°C to 75°C
Commercial
28-Lead PLCC
1175AR3C40
2/28/02 0.0m 002
Stock#DS7001175A
Addendum 03/03/09
CADEKA Adds New Package Option
TMC1175AW7C20
20 Msps
TA = -20°C to 75°C
Commercial
24-Lead SOIC
(0.300 wide
body SOIC)
1175AW7C20
24 Lead SOIC, 0.300 Wide Body Package
24
13
Symbol
H
E
1
12
D
A1
A
B
e
SEATING
PLANE
–C–
LEAD
COPLANARITY
ccc C
h x 45°
C
α
L
A
A1
B
C
D
E
e
H
h
L
N
α
ccc
Inches
Min.
Millimeters
Max.
Min.
Max.
.093
.104
.004
.012
.013
.020
.009
.013
.599
.614
.290
.299
.050 BSC
.394
.419
2.35
2.65
0.10
0.30
0.33
0.51
0.23
0.32
15.20
15.60
7.36
7.60
1.27 BSC
10.00
10.65
24
24
.010
.016
0°
—
.020
.050
8°
.004
0.25
0.40
0°
—
Notes
0.51
1.27
8°
5
2
2
3
6
0.10
Notes:
1. Dimensioning and tolerancing per ANSI Y14.5M-1982.
2. "D" and "E" do not include mold flash. Mold flash or
protrusions shall not exceed .010 inch (0.25mm).
3. "L" is the length of terminal for soldering to a substrate.
4. Terminal numbers are shown for reference only.
5. "C" dimension does not include solder finish thickness.
6. Symbol "N" is the maximum number of terminals.
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CADEKA Headquarters Loveland, Colorado
T: 970.663.5452
T: 877.663.5452 (toll free)
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