MAX1247BCPE+ Maxim Integrated Products, MAX1247BCPE+ Datasheet - Page 18

• Manufacturer Part Number: MAX1247BCPE+
• Description: IC ADC SRL 4CH 12BIT 2.7V 16-DIP
• Manufacturer: Maxim Integrated Products

Specifications of MAX1247BCPE+

• Number Of Bits: 12
• Sampling Rate (per Second): 133k
• Data Interface: MICROWIRE™, QSPI™, Serial, SPI™
• Number Of Converters: 1
• Power Dissipation (max): 842mW
• Voltage Supply Source: Single Supply
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Through Hole
• Package / Case: 16-DIP (0.300", 7.62mm)
• Number Of Adc Inputs: 4
• Architecture: SAR
• Conversion Rate: 133 KSPs
• Resolution: 12 bit
• Input Type: Voltage
• Interface Type: 4-Wire (SPI, QSPI, MICROWIRE, TMS320)
• Supply Voltage (max): 5.25 V
• Supply Voltage (min): 2.7 V
• Maximum Power Dissipation: 842 mW
• Maximum Operating Temperature: + 70 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: 0 C
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

+2.7V, Low-Power, 4-Channel,
Serial 12-Bit ADCs in QSOP-16
The MAX1246/MAX1247 auto power-down modes can
save considerable power when operating at less than
maximum sample rates. Figures 12, 13a, and 13b show
the average supply current as a function of the sam-
pling rate. The following discussion illustrates the vari-
ous power-down sequences.
The following examples show two different power-down
sequences. Other combinations of clock rates, compen-
sation modes, and power-down modes may give lowest
power consumption in other applications.
Figure 12. Average Supply Current vs. Conversion Rate with
External Reference
Figure 13b. MAX1246 Supply Current vs. Conversion Rate,
FASTPD
18
______________________________________________________________________________________
10,000
10,000
1000
1000
100
100
0.1
10
10
1
1
0.1
0.1
V REF = V
R
CODE = 101010100000
R
CODE = 101010100000
LOAD
LOAD
WITH EXTERNAL REFERENCE
1
AVERAGE SUPPLY CURRENT
1
AVERAGE SUPPLY CURRENT
= ∞
= ∞
vs. CONVERSION RATE
vs. CONVERSION RATE
4 CHANNELS
DD
10
CONVERSION RATE (Hz)
CONVERSION RATE (Hz)
Power-Down Sequencing
10
= 3.0V
Conversions/Channel/Second
(USING FASTPD)
100
100
Lowest Power at up to 500
4 CHANNELS
1k
1k
1 CHANNEL
10k
10k
1 CHANNEL
100k
100k
1M
1M
Figure 13a depicts the MAX1246 power consumption
for one or four channel conversions utilizing full power-
down mode and internal-reference compensation. A
0.047µF bypass capacitor at REFADJ forms an RC filter
with the internal 20kΩ reference resistor with a 0.9ms
time constant. To achieve full 12-bit accuracy, 10 time
constants or 9ms are required after power-up. Waiting
this 9ms in FASTPD mode instead of in full power-up
can reduce power consumption by a factor of 10 or
more. This is achieved by using the sequence shown in
Figure 14.
Figure 13a. MAX1246 Supply Current vs. Conversion Rate,
FULLPD
Figure 13c. Typical Reference-Buffer Power-Up Delay vs. Time
in Shutdown
100
1.0
0.0
2.0
1.5
0.5
10
1
0.001
TYPICAL REFERENCE-BUFFER POWER-UP
0.01
R
CODE = 101010100000
LOAD
DELAY vs. TIME IN SHUTDOWN
AVERAGE SUPPLY CURRENT
0.1
= ∞
vs. CONVERSION RATE
0.01
TIME IN SHUTDOWN (sec)
CONVERSION RATE (Hz)
(USING FULLPD)
1
4 CHANNELS
0.1
10
1 CHANNEL
1
100
1k
10