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1
2109876543212109876543210987654321098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432
21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
PS323/PS324/PS325
Precision, Single-Supply
SPST Analog Switches
Features
•
Low On-Resistance (33-Ohm typ.) Minimizes Distortion
and Error Voltages
•
Low Glitching Reduces Step Errors in Sample-and-Holds.
Charge Injection, 2pC typ.
•
Single-Supply Operation (+2.5V to +16V)
•·
Improved Second Sources for MAX323/MAX324/MAX325
•
On-Resistance Matching Between Channels, <2-Ohm
•
On-Resistance Flatness, <6-Ohm max.
•
Low Off-Channel Leakage, <5nA @ +85oC
•
TTL/CMOS Logic Compatible
•
Fast Switching Speed, tON <150ns
•
Guaranteed Break-Before-Make action (PS325 only)
eliminates momentary crosstalk
v Rail-to-Rail Analog Signal Dynamic Range
•
Low Power Consumption, <5mW
•
MSOP Package Minimizes Board Area
Description
The PS323/PS324/PS325 are improved high-precision, medium-
voltage analog switches designed to operate with single power
supplies. The PS323 is a dual, single-pole single-throw (SPST),
normally open (NO) switch. The PS324 has the same pinout as the
PS323 but it has two normally closed (NC) switches. The PS325 has
one normally open (NO) and one normally closed (NC) switch per
package. Each switch conducts current equally well in either
direction when on. In the off state, each switch blocks voltages up
to the power-supply rail.
With a +5V power supply, PS323/PS324/PS325 guarantee <60-ohm
ON-resistance. ON-resistance matching between channels is within
2W. ON-resistance flatness is less than 6W over the specified
range. All three devices guarantee low leakage currents (<100 pA
@ 25oC, <10nA @ +85oC) and fast switching speeds (tON <150ns).
Break-before-make switching action protects against momentary
crosstalk (PS325).
For single-supply operation below 5V, PI5A317/318/319 are also
recommended.
Applications
•
•
•
•
•
•
Audio Switching and Routing
Portable Instruments
Data Acquisition Systems
Sample-and-Holds
Telecommunication Systems
Battery-Powered Systems
Functional Diagrams, Pin Configurations, and Truth Tables
PS323
NO1
COM1
IN2
GND
1
2
3
4
8
7
6
5
V+
IN1
COM2
NO2
NC1
COM1
IN2
GND
1
2
3
4
PS324
8
7
6
5
V+
IN1
COM2
NC2
NC1
COM1
IN2
GND
1
2
3
4
PS325
8
7
6
5
V+
IN1
COM2
NC2
Top View
Top View
Switches shown for logic “0” input
Top View
PS323
Logic
0
1
Switch
O FF
ON
PS324
Logic
0
1
Switch
ON
O FF
Logic
0
1
PS325
Switch 1
O FF
ON
Switch 2
ON
O FF
1
PS8188C
10/24/02
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21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
PS323/PS324/PS325
Precision, Single Supply SPST Analog Switches
Absolute Maximum Ratings
Voltages Referenced to GND .......................................................
V+ ........................................................................... -0.3V to +17V
V
IN
, V
COM
, V
NC
, V
NO (1) ................................................
–2V to (V+) +2V
or 30mA, whichever occurs first
Current (any terminal) ........................................................ 30mA
Peak Current, COM, NO, NC
(pulsed at 1ms, 10% duty cycle) ....................................... 100mA
ESD per Method 3015.7 ................................................... >2000V
Thermal Information
Continuous Power Dissipation
Plastic DIP (derate 6mW/
º
C above +70
º
C) ...................... 500mW
Narrow SO (derate 6mW/
º
C above +70
º
C) ...................... 450mW
MSOP (derate 4mW/
º
C above +70
º
C) ............................ 330mW
Storage Temperature ........................................ –65
º
C to +150
º
C
Lead Temperature (soldering, 10s) .................................. +300
º
C
Note 1:
Signals on NC, NO, COM, or IN exceeding V+ or GND
are clamped by internal diodes. Limit forward diode current to
30mA maximum.
Caution:
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. This is a stress only
rating and operation of the device at these or any other conditions beyond those indicated in the operational sections of this specification is not
implied.
Electrical Specifications - Single +5V Supply
(V+ = 5V +10%, GND = 0V, V
INH
= 2.4V, V
INL
= 0.8V)
Parame te r
Analog Switch
Analog Signal Range
(3 )
On- Resistance
V
A N A LO G
R
O N
V+ = 4.5V,
V
N O
or V
N C
= +3.5V
I
C O M
= 1mA,
V
N O
or V
N C
= +3V,
I
C O M
= 1mA,
V+ = 5V,
V+ = 5V,
I
C O M
= 1mA,
or V
N C
= 1V, 2V, 3V
25
Full
25
Full
25
Full
25
Full
25
Full
25
Full
–0.1
–5
–0.1
–5
–0 . 2
–10
–0 . 0 4
–0.01
–0.01
2
0
20
30
0.8
V+
35
60
2
4
6
8
0.1
5
0.1
5
0.2
10
nA
ohm
V
Symbol
Conditions
Te mp (°C)
M in
(1 )
Typ
(2 )
M ax
(1 )
Units
On- Resistance Match
Between Channels
(4 )
∆
R
O N
On- Resisatance Flatness
(5 )
R
F LAT(O N )
I
N O (O F F )
or
I
N C (O F F )
V
N O
NO or NC Off Leakage
Current(6)
V+ = 5.5V,
V
C O M
= 1V,
V
N O
or V
N C
= 4.5V
V+ = 5.5V
V
C O M
= 4.5V
V
N O
or V
N C
= 1V
V+ = 5.5V
V
C O M
= 5V
V
N O
or V
N C
= 5V
COM Off Leakage Current
(6 )
I
C O M (O F F )
COM On Leakage Current
(6 )
I
C O M (O N )
2
PS8188C
10/24/02
21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
PS323/PS324/PS325
Precision, Single Supply SPST Analog Switches
Electrical Specifications - Single +5V Supply
(continued)
(V + = 5V ±10%, GND = 0V, V
INH
=2.4V, V
INL
= 0.8V)
Parame te r
Logic Input
Input Current with Input Voltage High
Input Current with Input Voltage High
Logic High Input Voltage
Logic Low Input Voltage
Dynamic
Turn- On Time
(3 )
t
O N
V
NO
or V
NC
= 3V, Figure 2
Turn- Off Time
(3 )
Break- Before- Make Time Delay
(3 )
Charge Injection
(3 )
Off Isolation
(7 )
Crosstalk
NC or NO Off Capacitance
COM Off Capacitance
COM Off Capacitance
Supply
Power- Supply Range
Positive Supply Current
V+
I+
V+ = 5.5V, V
IN
= 0V or V+,
all channels on or off
Full
2.7
–1
16
1
V
µA
t
O F F
t
D
Q
OIRR
X
TA LK
C
(O F F )
C
C O M (O F F )
C
C O M (O N )
f =1MHz, Figure 8
P S 3 2 5 o nly, RL = 3 0 0 o hm, C L = 3 5 p F,
F igure 3
C
L
= 1nF, V
G E N
= 0 V,
R
G E N =
0 o hm, F igure 4
R
L
= 5 0 0 o hm, C
L
= 5 p F, f =1MHz, F igure 5
R
L
= 5 0 0 o hm, C
L
= 5 p F, f =1MHz, F igure 6
f =1MHz, Figure 7
9
22
pF
25
25
25
Full
25
Full
2
30
60
25
50
5
1
–72
dB
–85
9
5
pC
75
150
50
100
ns
I
IN H
I
IN L
V
IN H
V
IN L
V
IN
= 2.4V, all others = 0.8V
V
IN
= 2.4V, all others = 2.4V
Full
–0.5
–0.5
2.4
0.8
0.005
0.005
0.5
0.5
µA
Symbol
Conditions
Te mp (°C)
M in
(1 )
Typ
(2 )
M ax
(1 )
Units
V
Notes:
1. The algebraic convention, where the most negative value is a minimum and the most positive is a maximum, is used in
this data sheet.
2. Typical values are for DESIGN AID ONLY, not guaranteed or subject to production testing.
3. Guaranteed by design
4.
∆R
ON
= R
ON
max - R
ON
min
5. Flatness is defined as the difference between the maximum and minimum value of ON-resistance measured.
6. Leakage parameters are 100% tested at maximum rated hot temperature and guaranteed by correlation at +25ºC.
7. Off Isolation = 20log
10
[ V
COM
/ (V
NC
or V
NO
) ]. See Figure 5.
3
PS8188C
10/24/02
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21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
PS323/PS324/PS325
Precision, Single Supply SPST Analog Switches
Electrical Specifications - Single +3.3V Supply
(V+ = 3.3V ±10%, GND = 0V, V
INH
= 2.4V, V
INL
= 0.8V)
Parame te r
Analog Switch
Analog Signal Range
(3 )
On- Resistance
Dynamic
Turn- On Time
(3 )
t
O N
V
NO
or V
NC
= 1.5V, Figure 2
Turn- Off Time
(3 )
Break- Before- Make Time Delay
(3 )
Charge Injection
(3 )
Supply
Positive Supply Current
I+
V+ = 3.6V, V
IN
= 0V or V+,
all channels on or off
Full
–1
0.01
1
µA
t
O F F
t
D
Q
PS325 only
C
L
= 1nF, V
G EN
= 0V,
R
G EN =
0ohm, Figure 4
25
Full
25
Full
25
25
2
50
10 0
30
60
5
1
5
pC
125
250
75
150
ns
V
A N A LO G
R
O N
V+ = 3V,
I
C O M
= 1mA,
V
N O
or V
N C
= 1.5V
25
Full
0
40
50
V+
70
80
V
ohm
Symbol
Conditions
Te mp (°C)
M in
(1 )
Typ
(2 )
M a x
( 1 )
Units
Electrical Specifications - Single +12V Supply
(V+ = 12V ±10%, GND = 0V, V
INH
= 4V, V
INL
= 0.8V)
Parame te r
Analog Switch
Analog Signal Range
(3 )
O n- Resistance
D ynamic
Turn- O n Time
(3 )
t
O N
V
NO
or V
NC
= 1.5V, Figure 2
Turn- O ff Time
(3 )
Break- Before- Make Time Delay
(3 )
Charge Injection
(3 )
Supply
Positive Supply Current
I+
V+ = 13V, V
IN
= 0V or V+,
all channels on or off
Full
–1
0.01
1
µA
t
O F F
t
D
Q
PS325 only
C
L
= 1nF, V
G EN
= 0V,
R
G EN =
0ohm, Figure 4
25
Full
25
Full
25
25
2
25
50
20
40
5
1
5
pC
50
100
40
75
ns
V
A N A LO G
R
O N
V+ = 10.8V
I
C O M
= 1mA,
V
N O
or V
N C
= 10V
25
Full
0
15
20
V+
25
40
V
ohm
Symbol
Conditions
Te mp (°C)
M in
(1 )
Typ
(2 )
M a x
( 1 )
Units
4
PS8188C
10/24/02
Application Information
The PS323, PS324, & PS325 dual analog switches precisely switch
inputs with a single 2.7V to 12V supply, low on-resistance (30Ohm)
and high speed operation (tON = 85ns, tOFF = 25ns). The devices
are suited to portable battery powered equipment due to a low
supply voltage (2.7V), low power consumption (5mW), and low
leakage currents (0.1nA). High frequency applications benefit from
the high bandwidth, high off isolation, and low crosstalk.
Proper Power Supply Sequencing & Over-voltage
Protection
With any CMOS device, proper power supply sequencing is needed
to protect the device from excessive input currents, which may
permanently damage the IC. All I/O pins contain ESD protection
diodes from the pin to V+ and to GND (see Figure 9 below).
To prevent forward biasing of these diodes, V+ must be applied
before any input signals, and input signals must swing between
V+ and GND. If these conditions cannot be guaranteed, then one
of two suggested protection methods must be employed. Protect
the logic inputs by adding a 1kOhm resistor in series with the input
(see Figure 9). The resistor limits the currents below the threshold
that can cause permanent damage to sub-micro Amp levels. This
reduced input current produces an insignificant voltage drop during
normal operation. A series resistor is not desirable, but small-signal
diodes can be added in series with the supply pins to provide
over-voltage protection for the IC. The diodes limit the analog
signal from 1V below V+ to 1V above GND. The leakage current will
remain low, but the switch resistance may increase at low supply voltages.
Positive Supply
21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
21098765432121098765432109876543210987654321210987654321098765432109876543212109876543210987654321098765432121098765432109876543210987654321
PS323/PS324/PS325
Precision, Single Supply SPST Analog Switches
Power-Supply Considerations
The PS32X construction is typical of most CMOS analog switches,
except that they have voltage supply pins: V+ and GND. These
pins power the internal CMOS switches and set the analog voltage
limits. Unlike switches with a 12V maximum supply voltage, the
PS32X series is made from a 17V-supply voltage technology that
provides room for 10-20% tolerance on 12V supplies. This
technology gives room for overshoot and noise spikes. While the
minimum recommended supply voltage is 2.7V, it is important to
note that the input signal-range, switching times, and on-resistance
degrade at lower supply voltages. Refer to the electrical
specifications for details. V+ and GND also power the internal
logic drivers (turn the switch on & off). These switches can be
operated with bipolar supplies if the voltage range from V- (at the
GND pin) to V+ does not exceed a total of 12V.
Logic-Level Thresholds
The switch logic is TTL compatible (0.8V & 2.4V) over a supply
range of 3V to 11V. At 12V the VIH level is about 2.5V. This is below
the TTL guaranteed high output minimum level of 2.8V, but noise
margin is reduced. For best results with a 12V supply, use logic
drive that provides a VOH greater than 3V. The digital input stages
draw supply current whenever the digital input voltage is not at
one of the supply rails. Driving the digital input signals from GND
to V+ with a fast transition time minimizes power dissipation.
High-Frequency Signal Passing/Isolation
In 50Ohm systems, signal response is flat even past 300MHz.
An OFF switch is like a capacitor and passes high frequencies
with low attenuation, resulting in signal passing from the switch
input to output. OFF Isolation is the resistance to passing signals
while the switch is OFF, while Crosstalk indicates the amount of
signal noise that crosses over from one switch to another. The
OFF Isolation is about 50dB in 50Ohm systems. Larger load
impedances reduce Off Isolation and Crosstalk due to the voltage
divider action of the switch OFF impedance and the load.
V+
Leakage Current
NO
COM
Vg
V-
Figure 1. Overvoltage Protection
Reverse ESD protection diodes are internally connected between
each analog-signal pin and both V+ and GND. One of these diodes
conducts if any analog signal exceeds V+ or GND.
Most of the analog leakage current comes from the ESD diodes to
V+ or GND. Although the ESD diodes on a given signal pin are
identical and therefore fairly well balanced, they are reverse biased
differently. Either V+ or GND and the analog signal bias each
diode. Hence, leakage currents will vary as the signal varies. The
difference in the diode leakage currents to the V+ and GND pins
creates the analog signal-path leakage current. Also, analog leakage
currents flow between each pin and one of the supply terminals,
not to the other switch terminal. This is why both sides of a given
switch can show leakage currents of the same or opposite polarity. There
is no connection between the analog-signal paths and V+ or GND.
5
PS8188C
10/24/02
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