MAX11600 Datasheet, PDF (11/23 Pages) Maxim Integrated Products – 2.7V to 3.6V and 4.5V to 5.5V, Low-Power, 4-/8-/12-Channel 2-Wire Serial 8-Bit ADCs

2.7V to 3.6V and 4.5V to 5.5V, Low-Power,
4-/8-/12-Channel 2-Wire Serial 8-Bit ADCs
Table 1. Setup Byte Format
BIT 7
(MSB)
REG
BIT 6
SEL2
BIT 5
SEL1
BIT 4
SEL0
BIT 3
CLK
BIT 2
BIP/UNI
BIT 1
RST
BIT 0
(LSB)
X
BIT
NAME
DESCRIPTION
7
REG
Register bit. 1 = setup byte, 0 = configuration byte (Table 2).
6
SEL2
Three bits select the reference voltage and the state of AIN_/REF
5
SEL1
(MAX11600/MAX11601/MAX11604/MAX11605) or REF (MAX11602/MAX11603) (Table 6).
4
SEL0
Default to 000 at power-up.
3
CLK
1 = external clock, 0 = internal clock. Defaulted to zero at power-up.
2
BIP/UNI
1 = bipolar, 0 = unipolar. Defaulted to zero at power-up (see the Unipolar/Bipolar section).
1
RST
1 = no action, 0 = resets the configuration register to default. Setup register remains unchanged.
0
X
Don’t care; can be set to 1 or 0.
Single-Ended/Pseudo-Differential Input
The SGL/DIF bit of the configuration byte configures the
MAX11600–MAX11605 analog input circuitry for single-
ended or pseudo-differential inputs (Table 2). In single-
ended mode (SGL/DIF = 1), the digital conversion results
are the difference between the analog input selected by
CS[3:0] and GND (Table 3). In pseudo-differential mode
(SGL/DIF = 0), the digital conversion results are the differ-
ence between the positive and the negative analog inputs
selected by CS[3:0] (Table 4). The negative analog input
signal must remain stable within ±0.5 LSB (±0.1 LSB for
best results) with respect to GND during a conversion.
Unipolar/Bipolar
When operating in pseudo-differential mode, the BIP/
UNI bit of the setup byte (Table 1) selects unipolar or
bipolar operation. Unipolar mode sets the differential
analog input range from zero to V_REF. A negative differ-
ential analog input in unipolar mode causes the digital
output code to be zero. Selecting bipolar mode sets the
differential input range to ±V_REF/2, with respect to the
negative input. The digital output code is binary in
unipolar mode and two’s complement binary in bipolar
mode (see the Transfer Functions section).
In single-ended mode, the MAX11600–MAX11605
always operate in unipolar mode regardless of the
BIP/UNI setting, and the analog inputs are internally ref-
erenced to GND with a full-scale input range from zero
to V_REF.
Digital Interface
The MAX11600–MAX11605 feature a 2-wire interface
consisting of a serial-data line (SDA) and a serial-clock
line (SCL). SDA and SCL facilitate bidirectional communi-
cation between the MAX11600–MAX11605 and the mas-
ter at rates up to 1.7MHz. The MAX11600–MAX11605 are
slaves that transmit and receive data. The master (typical-
ly a microcontroller) initiates data transfer on the bus and
generates SCL to permit that transfer.
SDA and SCL must be pulled high. This is typically
done with pullup resistors (500Ω or greater) (see
Typical Operating Circuit). Series resistors (R_S) are
optional. They protect the input architecture of the
MAX11600–MAX11605 from high-voltage spikes on the
bus lines and minimize crosstalk and undershoot of the
bus signals.
Bit Transfer
One data bit is transferred during each SCL clock
cycle. Nine clock cycles are required to transfer the
data in or out of the MAX11600–MAX11605. The data
on SDA must remain stable during the high period of
the SCL clock pulse. Changes in SDA while SCL is high
are control signals (see the START and STOP
Conditions section). Both SDA and SCL idle high when
the bus is not busy.
START and STOP Conditions
The master initiates a transmission with a START condi-
tion (S), a high-to-low transition on SDA with SCL high.
The master terminates a transmission with a STOP
condition (P), a low-to-high transition on SDA, while
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