MAX14800 Datasheet, PDF (9/17 Pages) Maxim Integrated Products – Low-Charge Injection, 16-Channel, High-Voltage Analog Switches

Low-Charge Injection, 16-Channel,
High-Voltage Analog Switches
Detailed Description
The MAX14800–MAX14803 provide high-voltage
switching on 16 channels for ultrasound imaging and
printer applications. The devices utilize HVCMOS
process technology to provide 16 high-voltage low-
charge-injection SPST switches, controlled by a digital
interface. Data is clocked into an internal 16-bit shift
register and retained by a programmable latch with
enable and clear inputs. A power-on-reset function
ensures that all switches are open on power-up.
The MAX14800–MAX14803 operate with a wide range
of high-voltage supplies including: V_PP/V_NN = +100V/
-100V, +200V/0V, or +40V/-160V. The digital interface
operates from a separate +2.7V to +5.5V V_DD supply.
Digital inputs DIN, CLK, LE, and CLR operate on the
V_DD supply voltage. The MAX14801/MAX14803
provide integrated 35kΩ bleed resistors on each switch
terminal to discharge capacitive loads. The MAX14802/
MAX14803 provide integrated clamping diodes for
overvoltage protection against positive overshoot. The
MAX14802/MAX14803 feature clamping diodes (at the
COM_). These clamping diodes provide overvoltage
protection against positive overshoot.
Analog Switch
The MAX14800–MAX14803 allow a peak-to-peak analog
signal range from V_NN to the minimum of either V_NN +
200V or V_DD. Analog switch inputs must be unconnect-
ed, or satisfy V_NN ≤ (V_{COM_}, V_{NO_}) ≤ V_PP during power-
up and power-down.
High-Voltage Supplies
The MAX14800–MAX14803 allow a wide range of high-
voltage supplies. The devices operate with V_NN from
-160V to 0 and V_PP from +40V to V_NN + 250V. When
V_NN is connected to GND (single-supply applications),
the devices operate with V_PP up to +200V. The V_PP
and V_NN high-voltage supplies are not required to be
symmetrical, but the voltage difference (V_PP - V_NN)
must not exceed 250V.
Bleed Resistors (MAX14801/MAX14803)
The MAX14801/MAX14803 feature integrated 35kΩ
bleed resistors to discharge capacitive loads such as
piezoelectric transducers. Each analog switch terminal
is connected to GND with a bleed resistor.
Overvoltage Protection
(MAX14802/MAX14803)
The MAX14802/MAX14803 feature clamping diodes (at
the COM_). These clamping diodes provide overvolt-
age protection against positive overshoot.
Serial Interface
The MAX14800–MAX14803 are controlled by a serial
interface with a 16-bit serial shift register and transpar-
ent latch. Each of the sixteen data bits controls a single
analog switch (see Table 1). Data on DIN is clocked
with the most significant bit (MSB) first into the shift reg-
ister on the rising edge of CLK. Data is clocked out of
the shift register onto DOUT on the rising edge of CLK.
DOUT reflects the status of DIN, delayed by 16 clock
cycles (see Figures 1 and 2).
Latch Enable (LE)
Drive LE logic-low to change the contents of the latch
and update the state of the high-voltage switches
(Figure 2). Drive LE logic-high to freeze the contents of
the latch and prevent changes to the switch states. To
reduce noise due to clock feedthrough, drive LE logic-
high while data is clocked into the shift register. After
the data shift register is loaded with valid data, pulse
LE logic-low to load the contents of the shift register
into the latch.
Latch Clear (CLR)
The MAX14800–MAX14803 feature a latch clear input.
Drive CLR logic-high to reset the contents of the latch
to zero and open all switches. CLR does not affect the
contents of the data shift register. Pulse LE logic-low to
reload the contents of the shift register into the latch.
Power-On Reset
The MAX14800–MAX14803 feature a power-on-reset
circuit to ensure all switches are open at power-on. The
internal 16-bit serial shift register and latch are set to
zero on power-up.
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