MAX1167/MAX1168
Multichannel, 16-Bit, 200ksps Analog-to-Digital
Converters
10 ______________________________________________________________________________________
Pin Description
PIN
MAX1167 MAX1168
NAME FUNCTION
1 3 DOUT
Serial Data Output. Data changes state on SCLK’s falling edge in SPI/QSPI/MICROWIRE
mode and on SCLK’s rising edge in DSP mode (MAX1168 only). DOUT is high impedance
when CS is high.
2 4 SCLK
Serial Clock Input. SCLK drives the conversion process in external clock mode and clocks
data out.
3 5 DIN
Serial Data Input. Use DIN to communicate with the command/configuration/control
register. In SPI/QSPI/MICROWIRE mode, the rising edge of SCLK clocks in data at DIN. In
DSP mode, the falling edge of SCLK clocks in data at DIN.
46EOC
End-of-Conversion Output. In internal clock mode, a logic low at EOC signals the end of a
conversion with the result available at DOUT. In external clock mode, EOC remains high.
5 7 AIN0 Analog Input 0
6 8 AIN1 Analog Input 1
7 9 AIN2 Analog Input 2
8 10 AIN3 Analog Input 3
9 15 REF
Reference Voltage Input/Output. V
REF
sets the analog voltage range. Bypass to AGND
with a 10µF capacitor. Bypass with a 1µF (min) capacitor when using internal reference.
10 16 REFCAP
Refer ence Byp ass C ap aci tor C onnecti on. Byp ass to AG N D w i th a 0.F cap aci tor w hen
usi ng i nter nal r efer ence. Inter nal r efer ence and b uffer shut d ow n i n exter nal r efer ence m od e.
11 17 AGND Analog Ground. Connect to pin 18 (MAX1168) or pin 12 (MAX1167).
12 18 AGND Primary Analog Ground (Star Ground). Power return for AV
DD
.
13 19 AV
DD
Analog Supply Voltage. Bypass to AGND with a 0.1µF capacitor.
14 20 CS
Active-Low Chip-Select Input. Forcing CS high places the MAX1167/MAX1168 in shutdown
with a typical supply current of 0.6µA. In SPI/QSPI/MICROWIRE mode, a high-to-low
transition on CS activates normal operating mode. In DSP mode, after the initial CS
transition from high to low, CS can remain low for the entire conversion process (see the
Operating Modes section).
15 21 DGND Digital Ground
16 22 DV
DD
Digital Supply Voltage. Bypass to DGND with a 0.1µF capacitor.
1 DSPR
DSP Frame-Sync Receive Input. A frame-sync pulse received at DSPR initiates a
conversion. Connect to logic high when using SPI/QSPI/MICROWIRE mode.
2 DSEL
Data-Bit Transfer-Select Input. Logic low on DSEL places the device in 8-bit-wide data-
transfer mode. Logic high places the device in 16-bit-wide data-transfer mode. Do not
leave DSEL unconnected.
11 AIN4 Analog Input 4
12 AIN5 Analog Input 5
Detailed Description
The MAX1167/MAX1168 low-power, multichannel, 16-bit
ADCs feature a successive-approximation ADC, auto-
matic power-down, integrated +4.096V reference, and a
high-speed SPI/QSPI/MICROWIRE-compatible interface.
A DSPR input and DSPX output allow the MAX1168 to
communicate with digital signal processors (DSPs) with
no external glue logic. The MAX1167/MAX1168 operate
with a single +5V analog supply and feature a separate
digital supply, allowing direct interfacing with +2.7V to
+5.5V digital logic.
Figures 3 and 4 show the functional diagrams of the
MAX1167/MAX1168, and Figures 5 and 6 show the
MAX1167/MAX1168 in a typical operating circuit. The
serial interface simplifies communication with micro-
processors (µPs).
In external reference mode, the MAX1167/MAX1168
have two power modes: normal mode and shutdown
mode. Driving CS high places the MAX1167/MAX1168 in
shutdown mode, reducing the supply current to 0.6µA
(typ). Pull CS low to place the MAX1167/MAX1168 in
normal operating mode. The internal reference mode
offers software-programmable, power-down options as
shown in Table 5.
In SPI/QSPI/MICROWIRE mode, a falling edge on CS
wakes the analog circuitry and allows SCLK to clock in
data. Acquisition and conversion are initiated by SCLK.
The conversion result is available at DOUT in unipolar
serial format. DOUT is held low until data becomes
available (MSB first) on the 8th falling edge of SCLK
when in 8-bit transfer mode, and on the 16th falling
edge when in 16-bit transfer mode (see the
Operating
Modes
section). Figure 8 shows the detailed SPI/QSPI/
MICROWIRE serial-interface timing diagram.
In external clock mode, the MAX1168 also interfaces
with DSPs. In DSP mode, a frame-sync pulse from the
DSP initiates a conversion that is driven by SCLK. The
MAX1168 formats a frame-sync pulse to notify the DSP
that the conversion results are available at DOUT in
MSB-first, unipolar, serial-data format. Figure 16 shows
the detailed DSP serial-interface timing diagram (see the
Operating Modes
section).
Analog Input
Figure 7 illustrates the input-sampling architecture of
the ADC. The voltage applied at REF or the internal
+4.096V reference sets the full-scale input voltage.
MAX1167/MAX1168
Multichannel, 16-Bit, 200ksps Analog-to-Digital
Converters
______________________________________________________________________________________ 11
Pin Description (continued)
PIN
MAX1167 MAX1168
NAME FUNCTION
13 AIN6 Analog Input 6
14 AIN7 Analog Input 7
23 DSPX
DSP Frame-Sync Transmit Output. A frame-sync pulse at DSPX notifies the DSP that the
MSB data is available at DOUT. Leave DSPX unconnected when not in DSP mode.
24 N.C. No Connection. Not internally connected.
DGND
1mA
C
LOAD
= 30pF
DOUT
DOUT
C
LOAD
= 30pF
1mA
DGND
DV
DD
a) V
OL
TO V
OH
b) HIGH-Z TO V
OL
AND V
OH
TO V
OL
Figure 1. Load Circuits for DOUT Enable Time and SCLK-to-
DOUT Delay Time
DGND
1mA
C
LOAD
= 30pF
DOUT
DOUT
C
LOAD
= 30pF
1mA
DGND
DV
DD
a) V
OH
TO HIGH-Z
b) V
OL
TO HIGH-Z
Figure 2. Load Circuits for DOUT Disable Time
MAX1167/MAX1168
Track/Hold (T/H)
In track mode, the analog signal is acquired on the
internal hold capacitor. In hold mode, the T/H switches
open and the capacitive digital-to-analog converter
(DAC) samples the analog input.
During the acquisition, the analog input (AIN_) charges
capacitor C
DAC
. At the end of the acquisition interval
the T/H switches open. The retained charge on C
DAC
represents a sample of the input.
In hold mode, the capacitive DAC adjusts during the
remainder of the conversion cycle to restore node
ZERO to zero within the limits of 16-bit resolution. At the
end of the conversion, force CS high and then low to
reset the T/H switches back to track mode (AIN_),
where C
DAC
charges to the input signal again.
The time required for the T/H to acquire an input signal
is a function of how quickly its input capacitance is
charged. If the input signal’s source impedance is high,
the acquisition time lengthens and more time must be
allowed between conversions. The acquisition time
(t
ACQ
) is the maximum time the device takes to acquire
the signal. Use the following formula to calculate acqui-
sition time:
t
ACQ
= 11(R
S
+ R
IN
+ R
DS(ON)
) 45pF + 0.3µs
where R
IN
= 340Ω, R
S
= the input signal’s source
impedance, R
DS(ON)
= 60Ω, and t
ACQ
is never less
than 729ns. A source impedance of less than 200Ω
does not significantly affect the ADC’s performance.
Multichannel, 16-Bit, 200ksps Analog-to-Digital
Converters
12 ______________________________________________________________________________________
REFERENCE
REF
REFCAP
AV
DD
DV
DD
AGND
AGND DGND
AIN0
AIN1
AIN2
AIN3
SCLK
CS
DIN
ANALOG-INPUT
MULTIPLEXER
MULTIPLEXER
CONTROL
ACCUMULATOR
MEMORY
INPUT REGISTER
BIAS
OSCILLATOR
OUTPUT DOUT
EOC
ANALOG-SWITCH FINE TIMING
SUCCESSIVE-APPROXIMATION
REGISTER
MAX1167
DAC
BUFFER
AZ
RAIL
COMPARATOR
Figure 3. MAX1167 Functional Diagram

MAX1167CCEE+

Mfr. #:
Manufacturer:
Maxim Integrated
Description:
Analog to Digital Converters - ADC Integrated Circuits (ICs) Analog to Digital Converters - IC ADC 16BIT 200KSPS 16-QSOP
Lifecycle:
New from this manufacturer.
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