MX7575SQ/883B Maxim Integrated, MX7575SQ/883B Datasheet - Page 9

• Manufacturer Part Number: MX7575SQ/883B
• Description: Analog to Digital Converters - ADC 8-Bit Precision DAC
• Manufacturer: Maxim Integrated

Specifications of MX7575SQ/883B

• Number Of Channels: 1
• Architecture: SAR
• Conversion Rate: 200 KSPs
• Resolution: 8 bit
• Input Type: Single-Ended
• Snr: 45 dB
• Interface Type: Parallel
• Operating Supply Voltage: 5 V
• Maximum Operating Temperature: + 125 C
• Package / Case: CDIP N
• Maximum Power Dissipation: 842 mW
• Minimum Operating Temperature: - 55 C
• Number Of Converters: 1
• Voltage Reference: External

Figure 13. MX7575 SNR vs. Input Frequency
Figure 14. MX7575 Accuracy vs. Conversion Time
Figure 15. External Reference Circuit
ICL8069
3.3k
CMOS, µP-Compatible, 5µs/10µs, 8-Bit ADCs
2.5
2.0
1.5
1.0
0.5
40
42
44
46
48
50
52
54
0
+5V
100
T
A: T
B: T
C: T
10
A
= +25°C
A
A
A
_______________________________________________________________________________________
= +125°C
= +85°C
= +25°C
INPUT FREQUENCY (Hz)
CONVERSION TIME ( s)
1k
100
1.23V
A
47 F
B
10k
1000
C
0.1 F
10000
100k
REF
The decoupling capacitors are necessary to provide a
low AC source impedance.
The MX7575/MX7576 can be run with either an exter-
nally applied clock or their internal clock. In either case,
the signal appearing at the clock pin is internally divid-
ed by two to provide an internal clock signal that is rela-
tively insensitive to the input clock duty cycle.
Therefore, a single conversion takes 20 input clock
cycles, which corresponds to 10 internal clock cycles.
The internal oscillator frequency is set by an external
capacitor, C
are connected as shown in Figure 16a. During a con-
version, a sawtooth waveform is generated on the CLK
pin by charging C
through an internal switch. At the end of a conversion,
the internal oscillator is shut down by clamping the CLK
pin to V
internal oscillator can easily be overdriven with an
external clock source.
The internal oscillator provides a convenient clock
source for the MX7575. Figure 17 shows typical conver-
sion times versus temperature for the recommended
R
tions, the oscillation frequency for this R
bination may vary by as much as ±50% from the
nominal value shown in Figure 17. Therefore, an exter-
nal clock should be used in the following situations:
1) Applications that require the conversion time to be
2) Applications in which time-related software con-
The CLK input of the MX7575/MX7576 may be driven
directly by a 74HC or 4000B series buffer (e g., 4049),
or by an LS TTL output with a 5.6kΩ pull-up resistor. At
the end of a conversion, the device ignores the clock
input and disables its internal clock signal. Therefore,
the external clock may continue to run between conver-
sions without being disabled. The duty cycle of the
external clock may vary from 30% to 70%. As dis-
cussed previously, in order to maintain accuracy, clock
rates significantly lower than the data sheet limits
(4MHz for MX7575 and 2MHz for MX7576) should not
be used.
CLK
within 50% of the minimum conversion time for the
specified accuracy (5µs MX7575/10µs MX7576).
straints cannot accommodate conversion-time differ-
ences that may occur from unit to unit or over
temperature for a given device.
and C
DD
through an internal switch. The circuit for the
CLK
CLK
, and an external resistor, R
combination. Due to process varia-
CLK
through R
Internal/External Clock
CLK
and discharging it
CLK
External Clock
Internal Clock
/C
CLK
CLK
, which
com-
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