MAX5165MECM-T Maxim Integrated, MAX5165MECM-T Datasheet - Page 7

• Manufacturer Part Number: MAX5165MECM-T
• Description: Sample & Hold Amplifiers
• Manufacturer: Maxim Integrated
• Series: MAX5165r

Specifications of MAX5165MECM-T

• Number Of Channels: 32
• Acquisition Time: 4 us
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Package / Case: TQFP-48
• Minimum Dual Supply Voltage: - 4.75 V, + 9.5 V

Table 1. Output Selection
0 = Logic Low, 1 = Logic High
Table 2. Mode Selection
0 = Logic Low, 1 = Logic High
* Only one M_ input asserted low; all others must be logic high
to meet the timing specification (see Single vs. Simultaneous
Sampling section).
Driving M3–M0 low (one at a time) selects sample
mode (Tables 1, 2). During sample mode, the selected
multiplexer channel connects to IN, allowing the hold
capacitor to acquire the input signal. To guarantee an
accurate sample, maintain sample mode for at least
4µs. The output of the S/H amplifier tracks the input
after 4µs. Only the addressed channel on the selected
multiplexer samples the input; all other channels remain
in hold mode.
Driving M3–M0 high selects hold mode. Hold mode dis-
ables the multiplexer and disconnects all eight chan-
nels on the 1-to-8 multiplexer from the input. When a
channel is disconnected, the hold capacitor maintains
the sampled voltage at the output with a 1mV/sec
droop rate (towards V
INPUTS (M3–M0)
MODE-SELECT
A2
0
0
0
0
1
1
1
1
0
1
ADDRESS
_______________________________________________________________________________________
A1
0
0
1
1
0
0
1
1
DD
Sample mode enabled on selected
analog multiplexer and channel
(Table 1).
Hold mode enabled on selected
analog multiplexer and channel
(Table 1).
).
32-Channel Sample/Hold Amplifier
A0
ACTION
0
1
0
1
0
1
0
1
with a Single Multiplexed Input
Sample Mode
Hold Mode
MUX0
OUT0
OUT1
OUT2
OUT3
OUT4
OUT5
OUT6
OUT7
When switching between sample mode and hold mode,
the voltage of the hold capacitor changes due to
charge injection from stray capacitance. This voltage
change, called hold step, is minimized by limiting the
amount of stray capacitance seen by the hold capaci-
tor. The MAX5165 limits the hold step to 0.25mV (typ).
An output capacitor to ground can be used to filter out
this small hold-step error.
The MAX5165 contains an output buffer for each multi-
plexer channel (32 total), so the hold capacitor sees a
high-impedance input, reducing the droop rate. The
capacitor droops at a 1mV/sec (typ) rate while in hold
mode. The buffer also provides a low output imped-
ance; however, the device contains output resistors in
series with the buffer output (Figure 1) for selected out-
put filtering. To provide greater design flexibility, the
MAX5165 is available with an R
Note: Output loads increase the analog supply cur-
rent (I
damages the device by consuming more power than the
device will dissipate (see Absolute Maximum Ratings).
The resistor-divider formed by the output resistor (R
and load impedance (R
(V
The maximum output voltage range depends on the
analog supply voltages available, and the scaling factor
used:
when R
SAMP
(V
OUT10
OUT11
OUT12
OUT13
OUT14
OUT15
MUX1
OUT8
OUT9
DD
SS
). Determine the output voltage (V
L
OUTPUT SELECTED
Voltage Gain = A
= ∞, then A
(V
+ 0.75V) · A
and I
SS
+ 0.75V) ≤ V
SS
V
). Excessive loading of the output(s)
OUT_
V
V
= 1 and this equation becomes:
≤ V
OUT16
OUT17
OUT18
OUT19
OUT20
OUT21
OUT22
OUT23
L
= V
MUX2
) scales the sampled voltage
V
OUT_
OUT
= R
SAMP
O
L
≤ (V
≤ (V
/ (R
of 50Ω, 500Ω, or 1kΩ.
· A
DD
DD
L
V
+ R
OUT_
- 2.4V)
- 2.4V) · A
OUT
OUT24
OUT25
OUT26
OUT27
OUT28
OUT29
OUT30
OUT31
MUX3
) as follows:
Hold Step
)
Output
V
OUT
7
)