• High signal-to-noise ratio over a large analog input
frequency range (7.3 effective bits at 4.43 MHz
full-scale input at f
• CMOS compatible digital inputs
• External reference voltage regulator
• Power dissipation only 53 mW (typical)
• Standby mode (only 1.2 mW typical)
• Low analog input capacitance, no buffer amplifier
required
• No sample-and-hold circuit required.
QUICK REFERENCE DATA
= 25 MHz)
clk
TDA8792
APPLICATIONS
Analog-to-digital conversion for:
• General purpose
• Hand-held equipment
• Mobile telecommunication
• Instrumentation
• Video.
GENERAL DESCRIPTION
The TDA8792 is a 8-bit analog-to-digital converter (ADC)
for low-voltage, portable applications. It operates at 3.3 V
and converts the analog input signal into 8-bit
binary-coded digital words at a maximum sampling rate of
25 MHz. The output data is valid after a delay of 6 clock
cycles.
SYMBOLPARAMETERCONDITIONSMIN.TYP.MAX.UNIT
V
DDA
V
DDD
V
DDO
I
DDA
I
DDD
I
DDO
analog supply voltage2.853.33.6V
digital supply voltage2.703.33.6V
output stages supply voltage2.53.33.6V
analog supply current−1220mA
digital supply current−36mA
output stages supply currentf
= 25 MHz; CL= 15 pF;
clk
−12mA
ramp input
INLintegral non-linearityf
DNLdifferential non-linearityf
f
clk(max)
P
tot
maximum clock frequency25−−MHz
total power dissipationf
= 25 MHz; ramp input−±0.4±0.8LSB
clk
= 25 MHz; ramp input−±0.3±0.75LSB
clk
= 25 MHz; CL= 15 pF;
clk
−53100mW
ramp input
ORDERING INFORMATION
TYPE
NUMBER
NAMEDESCRIPTIONVERSION
PACKAGE
TDA8792MSSOP24plastic shrink small outline package; 24 leads; body width 5.3 mmSOT340-1
D014data output; bit 0 (LSB)
D115data output; bit 1
D216data output; bit 2
D317data output; bit 3
D418data output; bit 4
D519data output; bit 5
D620data output; bit 6
D721data output; bit 7 (MSB)
V
DDO
V
SSO
CLK24clock input
2digital supply voltage (+3.3 V)
3digital ground 2
4analog ground 1
5analog input voltage
6analog supply voltage (+3.3 V)
7bias current input
8reference voltage TOP input
9reference voltage MIDDLE
10reference voltage BOTTOM input
12analog ground 2
output enable input (CMOS level
13
input, active LOW)
positive supply voltage for output
22
stage (+3.3 V)
23output ground
handbook, halfpage
V
DDD
V
SSD2
SSA1
V
DDA
I
bias
V
V
RM
V
SSA2
RT
RB
n.c.
1
2
3
4
V
5
I
6
TDA8792
7
8
9
10
11
12
MLD120 - 1
STDBY
V
V
Fig.2 Pin configuration.
TDA8792
CLK
24
V
23
SSO
22
V
DDO
21
D7
20
D6
D5
19
D4
18
17
D3
D2
16
D1
15
D0
14
OE
13
1996 Feb 214
Page 5
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
TDA8792
analog-to-digital converter (ADC)
LIMITING VALUES
In accordance with the Absolute Maximum Rating System (IEC 134).
SYMBOLPARAMETERCONDITIONSMIN.MAX.UNIT
V
DDA
V
DDD
V
DDO
∆V
∆V
∆V
V
I
V
clk(p-p)
I
O
T
stg
T
amb
T
j
DD1
DD2
DD3
analog supply voltagenote 1−0.5+5.0V
digital supply voltagenote 1−0.5+5.0V
output stages supply voltagenote 1−0.5+5.0V
supply voltage differences between
∆V
DD1=VDDA
− V
DDD
supply voltage differences between
∆V
DD2=VDDD
− V
DDO
supply voltage differences between
∆V
DD3=VDDA
− V
DDO
input voltagereferenced to V
AC input voltage for switching
may have any value between −0.5 V and +5.0 V provided that the
HANDLING
Inputs and outputs are protected against electrostatic discharges in normal handling. However, to be totally safe, it is
desirable to take normal precautions appropriate to handling integrated circuits.
THERMAL CHARACTERISTICS
SYMBOLPARAMETERVALUEUNIT
R
th j-a
thermal resistance from junction to ambient in free air119K/W
1996 Feb 215
Page 6
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
TDA8792
analog-to-digital converter (ADC)
CHARACTERISTICS
V
DDA=V6
V
SSA,VSSD
VIH=V
unless otherwise specified.
SYMBOLPARAMETERCONDITIONSMIN.TYP.MAX.UNIT
Supply
V
DDA
V
DDD
V
DDO
I
DDA
I
DDD
I
DDO
Inputs
LOCK INPUT CLK (REFERENCED TO V
C
V
IL
V
IH
I
IL
I
IH
C
I
INPUTS OE AND STDBY (REFERENCED TO V
V
IL
V
IH
I
IL
I
IH
VI(ANALOG INPUT VOLTAGE REFERENCED TO V
I
IL
I
IH
Z
I
C
I
Reference voltages for the resistor ladder; see Table 1
V
RB
V
RT
V
diff
I
ref
R
LAD
TC
DDD
RLAD
to V
; CL= 15 pF; T
= 2.85 to 3.6 V; V
4,12
and V
SSO
DDD=V2
shorted together; V
= 0 to +70 °C; typical values measured at V
amb
to V3and V1= 2.7 to 3.6 V; V
DDA
to V
= −0.15 to +0.15 V; f
DDD
DDO=V22
= 25 MHz; 50% duty factor; VIL=0V;
clk
DDA=VDDD=VDDO
to V23= 2.5 to 3.6 V;
= 3.3 V and T
amb
=25°C;
analog supply voltage2.853.33.6V
digital supply voltage2.73.33.6V
output stages supply voltage2.53.33.6V
analog supply current−1220mA
digital supply current−36mA
output stages supply currentCL= 15 pF; ramp input−12mA
); note 1
SSD
LOW level input voltage0−0.8V
HIGH level input voltage2.0−V
LOW level input currentV
HIGH level input currentV
= 0.4 V−10−−µA
clk
= 2.7 V−−10µA
clk
DDD
V
input capacitance−10−pF
); see Tables 2 and 3
SSD
LOW level input voltage0−0.8V
HIGH level input voltage2.0−V
DDD
V
LOW level input currentVIL= 0.4 V−10−−µA
HIGH level input currentVIH= 2.7 V−−+10µA
analog input settling time LOW-to-HIGH full-scale square wave;
analog input settling time HIGH-to-LOW full-scale square wave;
HARMONICS
h
1
h
all
fundamental harmonics (full scale)fi= 4.43 MHz−−0dB
harmonics (full scale); all componentsfi= 4.43 MHz
second harmonics−−61−dB
third harmonics−−61−dB
THDtotal harmonic distortionf
SIGNAL-TO-NOISE RATIO; see Figs 6 and 11; note 4
S/Nsignal-to-noise ratio (full scale)without harmonics;
)
SSO
DDO
= 3.15 TO 3.45 V); see Fig.3 and note 1
DDD
=25°C
AMB
note 2
small signal at mid-scale;
Vi= ±10 LSB at
code 128; note 2
Fig.5; note 3
Fig.5; note 3
= 4.43 MHz−−58−dB
i
= 25 MHz;
f
clk
fi= 4.43 MHz
− 0.4 −V
DDO
DDO
V
−10−+10µA
2030−MHz
−35−MHz
−812ns
−812ns
−46−dB
1996 Feb 217
Page 8
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
TDA8792
analog-to-digital converter (ADC)
SYMBOLPARAMETERCONDITIONSMIN.TYP.MAX.UNIT
E
FFECTIVE BITS; see Figs 6 and 11;note4
EBeffective bitsf
DIFFERENTIAL GAIN; see note 5
G
diff
differential gainf
DIFFERENTIAL PHASE; see note 5
ϕ
diff
Timing (f
t
ds
t
h
t
d
differential phasef
= 25 MHz); see Fig.3 and note 6
clk
sampling delay time−−2ns
output hold time6−−ns
output delay time81325ns
3-state output delay times; see Fig.4
t
dZH
t
dZL
t
dHZ
t
dLZ
enable HIGH−1728ns
enable LOW−2230ns
disable HIGH−2028ns
disable LOW−2230ns
Standby mode output delay times
t
dSTBLH
t
dSTBHL
standby (LOW-to-HIGH transition)−−200ns
start-up (HIGH-to-LOW transition)−−note 7 ns
Notes
1. In addition to a good layout of the digital and analog ground, it is recommended that the rise and fall times of the clock
must not be less than 1 ns.
2. The analog bandwidth is defined as the maximum full-scale input sine wave frequency which can be applied to the
device. No glitches greater than 8 LSBs are observed in the reconstructed signal neither is there any significant
attenuation.
3. The analog input settling time is the minimum time required for the input signal to be stabilized after a sharp full-scale
input (square-wave signal) in order to sample the signal and obtain correct output data.
4. Effective bits are obtained via a Fast Fourier Transform (FFT) treatment taking 8K acquisition points per equivalent
fundamental period. The calculation takes into account all harmonics and noise up to half of the clock frequency
(NYQUIST frequency). Conversion to signal-to-noise ratio: S/N = EB × 6.02 + 1.76 dB.
5. Measurement carried out using video analyser VM700A, where the video analog signal is reconstructed through a
digital-to-analog converter.
6. Output data acquisition: the output data is available after the maximum delay time of t
operation, the hardware design must be taken into account the td and th limits with respect to the input characteristics
of the acquisition circuit.
7. Maximum value standby mode start-up output delay time (HIGH-to-LOW transition):.
= 25 MHz
clk
= 2.0 MHz−7.4−bits
f
i
= 4.43 MHz−7.3−bits
f
i
= 7.5 MHz−7.2−bits
f
i
= 10 MHz−7.0−bits
f
i
= 25 MHz;
clk
−1.5−%
PAL modulated ramp
= 25 MHz;
clk
−0.5−deg
PAL modulated ramp
. In the event of 25 MHz clock
d
100
7000
+
-----------------------f
(MHz)
clk
1996 Feb 218
Page 9
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
TDA8792
analog-to-digital converter (ADC)
Table 1 Output coding and input voltage (typical values; referenced to V
BINARY OUTPUT BITS
STEPV
I(p-p) (V)
D7D6D5D4D3D2D1D0
Underflow<000000000
0000000000
1.00000001
..........
..........
254.11111110
2551.5 11111111
Overflow>1.5 11111111
Table 2 Mode selection
OED7 TO D0
1high impedance
0active; binary
Table 3 Standby selection
STDBYD7 TO D0I
1LOW0.4 mA
0active15 mA
SSA
)
DDA+IDDD
(typ.)
CLK
V
l
DATA
D0 to D7
t
CPH
sample N 1
DATA
N 6
t
CPL
1.4 V
sample N 2
t
ds
DATA
N 5
t
d
sample N 6
DATA
N 1
t
h
V
0.4 V
DATA
N
MLD121
DDO
50%
0.4 V
Fig.3 Timing diagram.
1996 Feb 219
Page 10
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
analog-to-digital converter (ADC)
V
handbook, full pagewidth
DDD
OE
output
data
output
data
LOW
t
dLZ
10 %
TDA8792
HIGH
OE
TDA8792
50 %
LOW
V
S1
DDD
t
dZH
50 %
TEST
t
dLZ
t
dZL
t
dHZ
t
dZH
V
DDD
V
DDD
GND
GND
S1
MLD122
t
dHZ
HIGH
t
dZL
50 %
3.3 kΩ
15 pF
90 %
fOE= 100kHz.
Fig.4 Timing diagram and test conditions of 3-state output delay time.
The analog and digital supplies should be separated and decoupled.
The external voltage generator must be built such that a good supply voltage ripple rejection is achieved with respect to the LSB value. The reference
ladder voltages can also be derived from a well regulated V
For applications where the input signal must remain well centred around middle scale, VRM must be decoupled and connected to analog input signal
(pin 5) through a resistor. The values must be defined in accordance with the input signal frequency in order to avoid direct coupling into the ADC ladder
(e.g. R = 5 kΩ and C = 100 nF).
, VRM and VRT are decoupled to V
(1) V
RB
(2) Pin 11 should be connected to V
.
SSA
in order to prevent noise influence.
SSA
supply through a resistor bridge and a decoupled capacitor.
There is no soldering method that is ideal for all IC
packages. Wave soldering is often preferred when
through-hole and surface mounted components are mixed
on one printed-circuit board. However, wave soldering is
not always suitable for surface mounted ICs, or for
printed-circuits with high population densities. In these
cases reflow soldering is often used.
This text gives a very brief insight to a complex technology.
A more in-depth account of soldering ICs can be found in
our
“IC Package Databook”
Reflow soldering
Reflow soldering techniques are suitable for all SSOP
packages.
Reflow soldering requires solder paste (a suspension of
fine solder particles, flux and binding agent) to be applied
to the printed-circuit board by screen printing, stencilling or
pressure-syringe dispensing before package placement.
Several techniques exist for reflowing; for example,
thermal conduction by heated belt. Dwell times vary
between 50 and 300 seconds depending on heating
method. Typical reflow temperatures range from 215 to
250 °C.
Preheating is necessary to dry the paste and evaporate
the binding agent. Preheating duration: 45 minutes at
45 °C.
Wave soldering
Wave soldering isnot recommended for SSOP packages.
This is because of the likelihood of solder bridging due to
closely-spaced leads and the possibility of incomplete
solder penetration in multi-lead devices.
(order code 9398 652 90011).
TDA8792
If wave soldering cannot be avoided, the following
conditions must be observed:
• A double-wave (a turbulent wave with high upward
pressure followed by a smooth laminar wave)
soldering technique should be used.
• The longitudinal axis of the package footprint must
be parallel to the solder flow and must incorporate
solder thieves at the downstream end.
Even with these conditions, only consider wave
soldering SSOP packages that have a body width of
4.4 mm, that is SSOP16 (SOT369-1) or
SSOP20 (SOT266-1).
During placement and before soldering, the package must
be fixed with a droplet of adhesive. The adhesive can be
applied by screen printing, pin transfer or syringe
dispensing. The package can be soldered after the
adhesive is cured.
Maximum permissible solder temperature is 260 °C, and
maximum duration of package immersion in solder is
10 seconds, if cooled to less than 150 °C within
6 seconds. Typical dwell time is 4 seconds at 250 °C.
A mildly-activated flux will eliminate the need for removal
of corrosive residues in most applications.
Repairing soldered joints
Fix the component by first soldering two diagonallyopposite end leads. Use only a low voltage soldering iron
(less than 24 V) applied to the flat part of the lead. Contact
time must be limited to 10 seconds at up to 300 °C. When
using a dedicated tool, all other leads can be soldered in
one operation within 2 to 5 seconds at between 270 and
320 °C.
1996 Feb 2115
Page 16
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
TDA8792
analog-to-digital converter (ADC)
DEFINITIONS
Data sheet status
Objective specificationThis data sheet contains target or goal specifications for product development.
Preliminary specificationThis data sheet contains preliminary data; supplementary data may be published later.
Product specificationThis data sheet contains final product specifications.
Limiting values
Limiting values given are in accordance with the Absolute Maximum Rating System (IEC 134). Stress above one or
more of the limiting values may cause permanent damage to the device. These are stress ratings only and operation
of the device at these or at any other conditions above those given in the Characteristics sections of the specification
is not implied. Exposure to limiting values for extended periods may affect device reliability.
Application information
Where application information is given, it is advisory and does not form part of the specification.
LIFE SUPPORT APPLICATIONS
These products are not designed for use in life support appliances, devices, or systems where malfunction of these
products can reasonably be expected to result in personal injury. Philips customers using or selling these products for
use in such applications do so at their own risk and agree to fully indemnify Philips for any damages resulting from such
improper use or sale.
1996 Feb 2116
Page 17
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
analog-to-digital converter (ADC)
TDA8792
NOTES
1996 Feb 2117
Page 18
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
analog-to-digital converter (ADC)
TDA8792
NOTES
1996 Feb 2118
Page 19
Philips SemiconductorsProduct specification
3.3 V, 25 MHz 8-bit
analog-to-digital converter (ADC)
TDA8792
NOTES
1996 Feb 2119
Page 20
Philips Semiconductors – a worldwide company
Argentina: IEROD, Av. Juramento 1992 - 14.b, (1428)
BUENOS AIRES, Tel. (541)786 7633, Fax. (541)786 9367
Australia: 34 Waterloo Road, NORTH RYDE, NSW 2113,
Tel. (02)805 4455, Fax. (02)805 4466
Austria: Triester Str. 64, A-1101 WIEN, P.O. Box 213,
Tel. (01)60 101-1236, Fax. (01)60 101-1211
Belgium: Postbus 90050, 5600 PB EINDHOVEN, The Netherlands,
All rights are reserved. Reproduction in whole or in part is prohibited without the
prior written consent of the copyright owner.
The information presented in this document does not form part of any quotation
or contract, is believed to be accurate and reliable and may be changed without
notice. No liability will be accepted by the publisher for any consequence of its
use. Publication thereof does not convey nor imply any license under patent- or
other industrial or intellectual property rights.
Printed in The Netherlands
537021/1100/02/pp20Date of release: 1996 Feb 21
Document order number:9397 750 00675
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