MAX1226BEEE-T Maxim Integrated, MAX1226BEEE-T Datasheet - Page 12

• Manufacturer Part Number: MAX1226BEEE-T
• Description: Analog to Digital Converters - ADC
• Manufacturer: Maxim Integrated

Specifications of MAX1226BEEE-T

• Number Of Channels: 8/4
• Architecture: SAR
• Conversion Rate: 300 KSPs
• Resolution: 12 bit
• Input Type: Single-Ended/Differential
• Snr: 70 dB
• Interface Type: Serial
• Operating Supply Voltage: 4.75 V to 5.25 V
• Maximum Operating Temperature: + 85 C
• Package / Case: QSOP-16
• Maximum Power Dissipation: 667 mW
• Minimum Operating Temperature: - 40 C
• Number Of Converters: 1
• Voltage Reference: Internal 4.096 V or External

12-Bit 300ksps ADCs with FIFO,
Temp Sensor, Internal Reference
The conversion time for each scan is based on a num-
ber of different factors: conversion time per sample,
samples per result, results per scan, if a temperature
measurement is requested, and if the external refer-
ence is in use.
Use the following formula to calculate the total conver-
sion time for an internally timed conversion in clock
modes 00 and 10 (see the Electrical Characteristics
section as applicable):
where:
t
n
n
by number of channels being scanned by NSCAN1,
NSCAN0
t
to zero if temp measurement is not requested
t
reference is already powered up or external reference is
being used
12
Table 1. Input Data Byte (MSB First)
* Unipolar/bipolar channels 8–15 are only valid on the MAX1228 and MAX1230.
** Unipolar/bipolar channels 12–15 are only valid on the MAX1230.
X = Don’t care.
cnv
TS
RP
total conversion time = t
avg
result
Conversion
Setup
Averaging
Reset
Unipolar mode (setup)
Bipolar mode (setup)
REGISTER NAME
= time required for temperature measurement; set
= internal reference wake-up; set to zero if internal
= t
______________________________________________________________________________________
= samples per result (amount of averaging)
= number of FIFO results requested; determined
acq
(max) + t
conv
Conversion Time Calculations
(max)
UCH0/1
BCH0/1
cnv
BIT 7
1
0
0
0
✕
n
avg
CHSEL3
UCH2/3
x n
BCH1/2
BIT 6
1
0
0
result
+ t
CHSEL2
CKSEL1
UCH4/5
BCH4/5
TS
BIT 5
1
0
+ t
RP
CHSEL1
CKSEL0
AVGON
UCH6/7
BCH6/7
BIT 4
1
In clock mode 01, the total conversion time depends on
how long CNVST is held low or high, including any time
required to turn on the internal reference. Conversion
time in externally clocked mode (CKSEL1, CKSEL0 = 11)
depends on the SCLK period and how long CS is held
high between each set of eight SCLK cycles.
Select active analog input channels, scan modes, and
a single temperature measurement per scan by writing
to the conversion register. Table 2 details channel
selection, the four scan modes, and how to request a
temperature measurement. Request a scan by writing
to the conversion register when in clock mode 10 or 11,
or by applying a low pulse to the CNVST pin when in
clock mode 00 or 01.
A conversion is not performed if it is requested on a
channel that has been configured as CNVST or REF-.
Do not request conversions on channels 8–15 on the
MAX1226 and channels 12–15 on the MAX1228. Set
CHSEL3:CHSEL0 to the lower channel’s binary value. If
the last two channels are configured as a differential
pair and one of them has been reconfigured as CNVST
or REF-, the pair is ignored.
REFSEL1
UCH8/9*
BCH8/9*
CHSEL0
NAVG1
RESET
BIT 3
UCH10/11*
BCH10/11*
REFSEL0
SCAN1
NAVG0
BIT 2
X
UCH12/13**
BCH12/13**
DIFFSEL1
NSCAN1
SCAN0
BIT 1
Conversion Register
X
UCH14/15**
BCH14/15**
DIFFSEL0
NSCAN0
TEMP
BIT 0
X