MAX14777 Datasheet, PDF (12/16 Pages) Maxim Integrated Products – Quad Beyond-the-Rails -15V to +35V Analog Switch

MAX14777
Quad Beyond-the-Rails -15V to +35V
Analog Switch
Pin Description (continued)
PIN
NAME
FUNCTION
12
EN2
Switch 2 Control Input. Drive EN2 high to close switch 2. Drive EN2 low to open switch 2.
13
V_L
Logic Interface Reference Supply Input. Bypass V_L to GND with a 1µF ceramic capacitor.
14
EN3
Switch 3 Control Input. Drive EN3 high to close switch 3. Drive EN3 low to open switch 3.
15
EN4
Switch 4 Control Input. Drive EN4 high to close switch 4. Drive EN4 low to open switch 4.
16
N.C.
No Connection. Not internally connected.
17
B4
Analog Switch 4 Terminal B. Switch 4 is open when EN4 is low.
18
B3
Analog Switch 3 Terminal B. Switch 3 is open when EN3 is low.
19
B2
Analog Switch 2 Terminal B. Switch 2 is open when EN2 is low.
20
B1
Analog Switch 1 Terminal B. Switch 1 is open when EN1 is low.
—
EP
Exposed Pad. Connect EP to V_N. Do not connect to ground. EP is not intended as an electrical
connection point.
Detailed Description
The MAX14777 quad SPST switch supports analog
signals above and below the rails with a single 3.0V to
5.5V supply. The device features up to -15V/+35V analog
signal range for all switches when pin SEL35 is high.
When pin SEL35 is low, the analog signal range reduces
to -15V/+15V signal range, also resulting in a lower V_CC
supply current. SEL35 trades off high-side analog signal
range for supply current. Each switch has a separate con-
trol input to allow independent switching.
The MAX14777 features 10Ω (max) on-resistance, and
9mΩ (typ) R_ON flatness, along with a 50nA (max at
+85°C) on-leakage. For maximum signal integrity, the IC
keeps this performance over the entire common-mode
voltage range. Each switch can carry up to 60mA (max)
of continuous current in either direction.
Integrated Bias Generation
The MAX14777 contains a total of three charge pumps to
generate bias voltages for the internal switches: a 5V reg-
ulated charge pump, a positive high-voltage charge pump
(V_P), and a negative high-voltage charge pump (V_N).
When V_CC is above 4.75V (typ), the 5V charge pump is
bypassed and V_CC provides the input for the high-voltage
charge pumps, reducing overall supply current.
The voltage at V_N is always -16V (typ); however, the
MAX14777 features a pin-selectable (SEL35) voltage-
high range for the analog signal. When the SEL35 input is
low, the voltage on V_P is +26V (typ) and the analog signal
range is -15V/+15V. When the SEL35 input is high, the
voltage on V_P is +46V (typ) and the analog signal range
is extended to -15V/+35V.
An external 10nF capacitor is required for each high-
voltage charge pump between V_P/V_N and GND. Use a
50V-rated capacitor on V_N. On V_P use a 50V capacitor
if SEL35 = low or use a 100V capacitor if SEL35 = high.
Never use V_P or V_N to power external circuitry.
Analog Signal Levels
The MAX14777 transmits signals above and below the
rails with a single 3.0V to 5.5V supply due to its integrated
bias circuitry. The analog signal range is pin selectable
using the SEL35 input. Drive SEL35 low to switch signals
between -15V and +15V. Drive SEL35 high to switch
signals between -15V and +35V.
Setting SEL35 low reduces both turn-on delay and V_CC
supply current.
The MAX14777 features 10Ω (max) on-resistance and
9mΩ (typ) R_ON flatness for analog signals between -15V
and +35V. The current flow through the switches can be
bidirectional.
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