MAX110 Maxim, MAX110 Datasheet - Page 10

• Manufacturer Part Number: MAX110
• Description: Low-Cost / 2-Channel / 14-Bit Serial ADCs
• Manufacturer: Maxim

XCLK internally connects to a clock-frequency divider
network, whose output is the ADC oversampling clock,
f
oscillator or external clock applied to XCLK) to be
divided by one, two, or four (see Clock Divider-Ratio
Control Bits ).
Figure 3 shows the two methods for providing the over-
sampling clock to the MAX110/MAX111. In external-
clock mode (Figure 3a), the internal RC oscillator is
disabled and XCLK accepts a TTL/CMOS-level clock to
provide the oversampling clock to the ADC.
Select external-clock mode (Figure 3a) by connecting
RCSEL to GND and a TTL/CMOS-compatible clock to
XCLK (see Selecting the Oversampling Clock
Frequency ).
In RC-oscillator mode (Figure 3b), the internal RC oscil-
lator is active and its output is connected to XCLK
(Figure 1). Select RC-oscillator mode by connecting
RCSEL to V
connects it to XCLK for use by the ADC and external
system components. Minimize the capacitive loading on
XCLK when using the internal RC oscillator.
Low-Cost, 2-Channel, ±14-Bit Serial ADCs
Figure 1. Functional Diagram
10
OSC
. This allows the selected clock source (internal RC
______________________________________________________________________________________
DD
IN1+
IN1-
IN2+
IN2-
REF+
REF-
. This enables the internal oscillator and
INPUT
MUX
IN+
IN-
Oversampling Clock
MAX110
MAX111
Gm
Gm
GENERATOR
DITHER
-
INTEGRATOR
Figure 2. ADC Waveforms During a Conversion
OVERSAMPLING
OUTPUT FROM
DIFFERENTIAL
1-BIT DAC
ANALOG
CLOCK
INPUT
V
V
V
V
REF+
REF-
REF+
REF-
UP/DOWN
COUNTER
LOGIC + CLOCK GENERATOR
DC LEVEL AT 1/2 V
TIMER + CONTROL
OSCILLATOR
NETWORK,
DIVIDE BY
1, 2, OR 4
DIVIDER
DIN
RC
OSC
SCLK CS
REGISTER
CONTROL
REGISTER
REF
SERIAL
SHIFT
16
16
16
16
DOUT
BUSY
RCSEL
XCLK
MAX110
MAX111