MAX1091BEEI+ Maxim Integrated Products, MAX1091BEEI+ Datasheet - Page 15

• Manufacturer Part Number: MAX1091BEEI+
• Description: IC ADC 10BIT 250KSPS 28-QSOP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1091BEEI+

• Number Of Bits: 10
• Sampling Rate (per Second): 250k
• Data Interface: Parallel
• Number Of Converters: 1
• Power Dissipation (max): 667mW
• Voltage Supply Source: Single Supply
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 28-QSOP
• Number Of Adc Inputs: 8
• Architecture: SAR
• Conversion Rate: 250 KSPs
• Resolution: 10 bit
• Input Type: Differential
• Interface Type: Parallel
• Voltage Reference: Internal 2.5 V or External
• Supply Voltage (max): 3 V
• Maximum Power Dissipation: 762 mW
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

When power is first applied, internal power-on reset cir-
cuitry activates the MAX1091/MAX1093 in external
clock mode and sets INT high. After the power supplies
stabilize, the internal reset time is 10µs, and no conver-
sions should be attempted during this phase. When
using the internal reference, 500µs is required for V
to stabilize.
The MAX1091/MAX1093 can be used with an internal
or external reference voltage. An external reference
can be connected directly to REF or REFADJ.
An internal buffer is designed to provide +2.5V at REF for
the both the MAX1091 and the MAX1093. The internally
trimmed +1.22V reference is buffered with a +2.05V/V
gain.
Table 4. Channel Selection for Pseudo-Differential Operation (SGL/DIF = 0)
*Channels CH4–CH7 apply to MAX1091 only.
Table 5. Data-Bus Output (8 + 2 Parallel
Interface)
PIN
D0
D1
D2
D3
D4
D5
D6
D7
A2
0
0
0
0
1
1
1
1
Bit 0 (LSB)
HBEN = 0
Bit 1
Bit 2
Bit 3
Bit 4
Bit 5
Bit 6
Bit 7
with +2.5V Reference and Parallel Interface
Internal and External Reference
A1
0
0
1
1
0
0
1
1
Applications Information
______________________________________________________________________________________
Bit 8
Bit 9 (MSB)
250ksps, +3V, 8-/4-Channel, 10-Bit ADCs
(UNI/BIP = 0)
BIPOLAR
A0
Bit 9
Bit 9
Bit 9
Bit 9
Bit 9
Bit 9
0
1
0
1
0
1
0
1
HBEN = 1
Power-On Reset
CH0
+
-
(UNI/BIP = 1)
UNIPOLAR
CH1
0
0
0
0
0
0
+
-
REF
CH2
+
-
With the internal reference, the full-scale range is +2.5V
with unipolar inputs and ±1.25V with bipolar inputs. The
internal reference buffer allows for small adjustments
(±100mV) in the reference voltage (Figure 7).
Note: The reference buffer must be compensated with
an external capacitor (4.7µF min) connected between
REF and GND to reduce reference noise and switching
spikes from the ADC. To further minimize noise on the
reference, connect a 0.01µF capacitor between
REFADJ and GND.
With both the MAX1091 and MAX1093, an external ref-
erence can be placed at either the input (REFADJ) or
the output (REF) of the internal reference buffer amplifier.
Using the REFADJ input makes buffering the external
reference unnecessary. The REFADJ input impedance
is typically 17kΩ.
Figure 7. Reference Voltage Adjustment with External
Potentiometer
50kΩ
50kΩ
V
DD
CH3
+
= +3V
-
GND
CH4*
330kΩ
+
-
0.01µF
GND
CH5*
+
-
4.7µF
External Reference
Internal Reference
CH6*
+
REFADJ
REF
-
MAX1091
MAX1093
CH7*
+
-
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