Datasheet ADG3243 Datasheet (Analog Devices)

Page 1
2.5 V/3.3 V, 2-Bit, Individual Control Level Translator Bus Switch
ADG3243
FEATURES 225 ps Propagation Delay through the Switch
4.5 Switch Connection between Ports Data Rate 1.5 Gbps
2.5 V/3.3 V Supply Operation Level Translation
3.3 V to 2.5 V
2.5 V to 1.8 V Small Signal Bandwidth 710 MHz 8-Lead SOT-23 Package

APPLICATIONS

3.3 V to 2.5 V Voltage Translation
2.5 V to 1.8 V Voltage Translation Bus Switching Bus Isolation Hot Swap Hot Plug Analog Switch Applications

GENERAL DESCRIPTION

The ADG3243 is a 2.5 V or 3.3 V, 2-bit, 2-port digital switch with individual channel control. It is designed on a low voltage CMOS process, which provides low power dissipation yet gives high switching speed and very low on resistance. This allows the inputs to be connected to the outputs without additional propa­gation delay or generating additional ground bounce noise.
The switches are enabled by means of the bus enable (BEx) input signal. This digital switch allows a bidirectional signal to be switched when ON. In the OFF condition, signal levels up to the supplies are blocked.
This device is ideal for applications requiring level translation. When operated from a 3.3 V supply, level translation from 3.3 V inputs to 2.5 V outputs is allowed. Similarly, if the device is operated from a 2.5 V supply and 2.5 V inputs are applied, the device will translate the outputs to 1.8 V. This makes the device suited to applications requiring level translation between different supplies, such as converter to DSP/microcontroller interfacing.

FUNCTIONAL BLOCK DIAGRAM

A0
BE0
A1
BE1

PRODUCT HIGHLIGHTS

1. 3.3 V or 2.5 V supply operation.
2. Extremely low propagation delay through switch.
3. 4.5 Ω switches connect inputs to outputs.
4. Level/voltage translation.
5. Tiny SOT-23 package.
B0
B1
REV. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other rights of third parties that may result from its use. No license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective companies.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Tel: 781/329-4700 www.analog.com Fax: 781/326-8703 © 2003 Analog Devices, Inc. All rights reserved.
Page 2
ADG3243–SPECIFICATIONS
(VCC = 2.3 V to 3.6 V, GND = 0 V, all specifications T
1
unless otherwise noted.)
MIN
to T
MAX
,
B Version
Parameter Symbol Conditions Min Typ2Max Unit
DC ELECTRICAL CHARACTERISTICS
Input High Voltage V
Input Low Voltage V
Input Leakage Current I OFF State Leakage Current I
INH
V
INH
INL
V
INL
I
OZ
ON State Leakage Current 0 A, B ≤ V Maximum Pass Voltage V
P
VCC = 2.7 V to 3.6 V 2.0 V VCC = 2.3 V to 2.7 V 1.7 V VCC = 2.7 V to 3.6 V 0.8 V VCC = 2.3 V to 2.7 V 0.7 V
± 0.01 ± 1 µA
0 A, B V
CC
CC
± 0.01 ± 1 µA ± 0.01 ± 1 µA
VA/VB = VCC = 3.3 V, IO = –5 µA 2.0 2.5 2.9 V VA/VB = VCC = 2.5 V, IO= –5 µA 1.5 1.8 2.1 V
CAPACITANCE
3
A Port Off Capacitance CA OFF f = 1 MHz 3.5 pF B Port Off Capacitance C A, B Port On Capacitance C Control Input Capacitance C
SWITCHING CHARACTERISTICS
Propagation Delay A to B or B to A, t Propagation Delay Matching Bus Enable Time BEx to A or B Bus Disable Time BEx to A or B Bus Enable Time BEx to A or B Bus Disable Time BEx to A or B
3
5
6
6
6
6
Maximum Data Rate V Channel Jitter V
OFF f = 1 MHz 3.5 pF
B
, CB ON f = 1 MHz 7 pF
PD
A
IN
4
t
, t
PHL
t
, t
PZH
t
, t
PHZ
t
, t
PZH
t
, t
PHZ
f = 1 MHz 4 pF
CL = 50 pF, VCC = 3 V 225 ps
PLH
VCC = 3.0 V to 3.6 V 1 3.2 4.6 ns
PZL
VCC = 3.0 V to 3.6 V 1 3 4 ns
PLZ
VCC = 2.3 V to 2.7 V 1 3 4 ns
PZL
VCC = 2.3 V to 2.7 V 1 2.5 3.4 ns
PLZ
= 3.3 V; VA/VB = 2 V 1.5 Gbps
CC
= 3.3 V; VA/VB = 2 V 45 ps p-p
CC
5ps
DIGITAL SWITCH
On Resistance R
ON
VCC = 3 V, VA = 0 V, IBA = 8 mA 4.5 8 VCC = 3 V, VA = 1.7 V, IBA = 8 mA 12 28
= 2.3 V, VA = 0 V, IBA = 8 mA 5 9
V
CC
= 2.3 V, VA = 1 V, IBA = 8 mA 9 18
V
On Resistance Matching ⌬R
ON
CC
VCC = 3 V, VA = 0 V, IA = 8 mA 0.1 0.5
POWER REQUIREMENTS
V
CC
Quiescent Power Supply Current I Increase in ICC per Input
NOTES
1
Temperature range is as follows: B Version: –40°C to +85°C.
2
Typical values are at 25°C, unless otherwise stated.
3
Guaranteed by design, not subject to production test.
4
The digital switch contributes no propagation delay other than the RC delay of the typical RON of the switch and the load capacitance when driven by an ideal voltage source. Since the time constant is much smaller than the rise/fall times of typical driving signals, it adds very little propagation delay to the system. Propagation delay of the digital switch when used in a system is determined by the driving circuit on the driving side of the switch and its interaction with the load on the driven side.
5
Propagation delay matching between channels is calculated from the on resistance matching and load capacitance of 50 pF.
6
See Timing Measurement Information section.
7
This current applies to the control pin BEx only. The A and B ports contribute no significant ac or dc currents as they transition.
Specifications subject to change without notice.
7
I
CC
CC
Digital Inputs = 0 V or V
CC
VCC = 3.6 V, BE0 = 3.0 V, BE1 = VCC or GND 0.15 8 µA
2.3 3.6 V
0.01 1 µA
REV. 0–2–
Page 3
ADG3243
TOP VIEW
(Not to Scale)
8
7
6
5
1
2
3
4
ADG3243
GND
A1
BE0
B0
BE1
V
CC
A0
B1

ABSOLUTE MAXIMUM RATINGS*

(TA = 25°C, unless otherwise noted.)
VCC to GND . . . . . . . . . . . . . . . . . . . . . . . . . –0.5 V to +4.6 V
Digital Inputs to GND . . . . . . . . . . . . . . . . . –0.5 V to +4.6 V
DC Input Voltage . . . . . . . . . . . . . . . . . . . . . –0.5 V to +4.6 V
DC Output Current . . . . . . . . . . . . . . . . . 25 mA per Channel
Operating Temperature Range
Industrial (B Version) . . . . . . . . . . . . . . . . –40°C to +85°C
Storage Temperature Range . . . . . . . . . . . . –65°C to +150°C
Junction Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . 150°C
Thermal Impedance . . . . . . . . . . . . . . . . . . . . . 206°C/Ω
JA
Lead Temperature, Soldering (10 sec) . . . . . . . . . . . . . 300°C
IR Reflow, Peak Temperature (<20 sec) . . . . . . . . . . . . 235°C
*Stresses above those listed under Absolute Maximum Ratings may cause perma-
nent damage to the device. This is a stress rating only; functional operation of the device at these or any other conditions above those listed in the operational sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods may affect device reliability. Only one absolute maximum rating may be applied at any one time.

PIN CONFIGURATION

8-Lead SOT-23

PIN FUNCTION DESCRIPTIONS

Pin No. Mnemonic Description
1 BE0 Bus Enable (Active Low) 2A0 Port A0, Input or Output 3A1 Port A1, Input or Output 4GND Ground Reference 5B1 Port B1, Input or Output 6B0 Port B0, Input or Output 7 BE1 Bus Enable (Active Low) 8VCCPositive Power Supply Voltage
Table I. Truth Table
BEx Function
LAx = Bx, 3.3 V to 2.5 V/2.5 V to 1.8 V Level Shifting H Disconnect

ORDERING GUIDE

Model Temperature Range Package Description Package Branding
ADG3243BRJ-R2 –40°C to +85°CSOT-23 (Small Outline Transistor Package) RJ-8 SFA ADG3243BRJ-REEL –40°C to +85°CSOT-23 (Small Outline Transistor Package) RJ-8 SFA ADG3243BRJ-REEL7 –40°C to +85°CSOT-23 (Small Outline Transistor Package) RJ-8 SFA
CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on the human body and test equipment and can discharge without detection. Although the ADG3243 features proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
REV. 0
–3–
Page 4
ADG3243

TERMINOLOGY

V
CC
Positive Power Supply Voltage.
GND Ground (0 V) Reference.
V
INH
V
INL
I
I
I
OZ
I
OL
V
P
Minimum Input Voltage for Logic 1.
Maximum Input Voltage for Logic 0.
Input Leakage Current at the Control Inputs.
OFF State Leakage Current. It is the maximum leakage current at the switch pin in the OFF state.
ON State Leakage Current. It is the maximum leakage current at the switch pin in the ON state.
Maximum Pass Voltage. The maximum pass voltage relates to the clamped output voltage of an NMOS device when the switch input voltage is equal to the supply voltage.
R
ON
Ohmic Resistance Offered by a Switch in the ON State. It is measured at a given voltage by forcing a specified amount of current through the switch.
R
ON
OFF OFF Switch Capacitance.
C
X
C
ON ON Switch Capacitance.
X
C
IN
I
CC
ON Resistance Match between Any Two Channels, i.e., RON max – R
Control Input Capacitance. This consists of BEx.
Quiescent Power Supply Current. This current represents the leakage current between the VCC and ground pins.
ON
min.
It is measured when all control inputs are at a logic high or low level and the switches are OFF.
I
t
t
PLH
PZH
CC
, t
, t
PHL
PZL
Extra power supply current component for the EN control input when the input is not driven at the supplies.
Data Propagation Delay through the Switch in the ON State. Propagation delay is related to the RC time constant R
× CL, where CL is the load capacitance.
ON
Bus Enable Times. These are the times taken to cross the VT voltage at the switch output when the switch turns on in response to the control signal, BEx.
t
PHZ
, t
PLZ
Bus Disable Times. This is the time taken to place the switch in the high impedance OFF state in response to the control signal. It is measured as the time taken for the output voltage to change by V
from the original quiescent level,
with reference to the logic level transition at the control input. (Refer to Figure 3 for enable and disable times.)
Max Data Rate Maximum Rate at which Data Can Be Passed through the Switch.
Channel Jitter Peak-to-Peak Value of the Sum of the Deterministic and Random Jitter of the Switch Channel.
REV. 0–4–
Page 5
Typical Performance Characteristics–ADG3243
40
TA = 25C
35
30
)
25
(
ON
20
R
15
10
5
0
0 0.5
1.5 2.5 3.5 VA/VB (V
)
TPC 1. On Resistance vs. Input Voltage
15
= 2.5V
V
CC
10
85C
()
ON
R
5
25C
VCC = 3V
VCC = 3.3V
VCC = 3.6V
3.02.01.0
40C
40
TA = 25C
35
30
)
25
(
ON
20
R
15
10
5
0
0 0.5
1.5 2.5
VA/VB (V
)
TPC 2. On Resistance vs. Input Voltage
3.0 TA = 25C
= –5␮A
I
O
2.5
2.0
(V)
1.5
OUT
V
1.0
0.5
VCC = 2.3V
VCC = 2.5V
= 2.7V
V
CC
VCC = 3.6V
V
CC
VCC = 3V
= 3.3V
20
= 3.3V
V
CC
15
()
10
ON
R
5
0
3.02.01.0
0 0.5
85C
40C
VA/VB (V)
25C
1.5
2.01.0
TPC 3. On Resistance vs. Input Voltage for Different Temperatures
2.5 TA = 25C I
= –5␮A
O
2.0
1.5
(V)
OUT
V
1.0
0.5
VCC = 2.7V
VCC = 2.5V
VCC = 2.3V
0
0 0.5
VA/VB(V)
1.0
TPC 4. On Resistance vs. Input Voltage for Different Temperatures
500
TA = 25C
450
400
350
300
250
(A)
CC
I
200
150
100
50
0
051015 20 25 30 35 40 45
ENABLE FREQUENCY (MHz)
VCC = 3.3V
VCC = 2.5V
TPC 7. ICC vs. Enable Frequency
1.2
0
0 0.5
TPC 5. Pass Voltage vs. V
3.0
2.5
2.0
(V)
1.5
OUT
V
1.0
0.5
50
0
1.0 2.0 3.0
1.5 2.5 3.5 VA/VB (V)
TA = 25C V
= 0V
A
BEx = 0
VCC = 3.3V
0.02 0.04 0.06 0.08 0.100
CC
VCC = 2.5V
IO (A)
TPC 8. Output Low Characteristic
0
0 0.5
TPC 6. Pass Voltage vs. V
3.0 TA = 25C V
= V
A
CC
BEx = 0
VCC = 2.5V
–0.08 –0.06 –0.04 –0.02 0
(V)
V
OUT
2.5
2.0
1.5
1.0
0.5
0
–0.10
1.5 2.5
1.0 2.0 3.0 VA/VB (V)
CC
VCC = 3.3V
IO (A)
TPC 9. Output High Characteristic
REV. 0
–5–
Page 6
ADG3243
0
TA = 25C
–0.2
ON OFF C
= InF
L
–0.4
–0.6
VCC = 2.5V
–0.8
(pC)
–1.0
INJ
Q
–1.2
–1.4
–1.6
–1.8
–2.0
0 0.5
VCC = 3.3V
1.5 2.5
1.0 2.0 3.0 VA/VB (V)
TPC 10. Charge Injection vs. Source Voltage
0
TA = 25C
–10
= 3.3V/2.5V
V
CC
= 0dBm
V
IN
–20
N/W ANALYZER
= RS = 50
R
L
–30
–40
–50
–60
ATTENUATION (dB)
–70
–80
–90
–100
0.1 1000110
:
FREQUENCY (MHz)
100
TPC 13. Off Isolation vs. Frequency
0
TA = 25C
–2
= 3.3V/2.5V
V
CC
= 0dBm
V
IN
–4
N/W ANALYZER
= RS = 50
R
L
–6
–8
ATTENUATION (dB)
–10
–12
–14
0.03 0.1 1000
:
110100
FREQUENCY (MHz)
TPC 11. Bandwidth vs. Frequency
4.0
VCC = 3.3V
3.5
3.0
2.5
ENABLE
2.0
TIME (ns)
1.5
1.0
0.5
0
–40 –20 0
TEMPERATURE (C)
ENABLE
DISABLE
VCC = 2.5V
DISABLE
20 806040
TPC 14. Enable/Disable Time vs. Temperature
0
TA = 25C
–10
V
= 3.3V/2.5V
CC
V
= 0dBm
–20
IN
N/W ANALYZER
–30
R
= RS = 50
L
–40
–50
–60
–70
ATTENUATION (dB)
–80
–90
–100
0.03 0.1 1.0
10 1000100
FREQUENCY (MHz)
TPC 12. Crosstalk vs. Frequency
100
VCC = 3.3V
90
= 1.5V p-p
V
IN
20dB ATTENUATION
80
70
60
50
40
JITTER (ps p-p)
30
20
10
0
0.5
0.7 0.9 1.1 1.3 1.5 1.7 1.9 DATA RATE (Gbps)
TPC 15. Jitter vs. Data Rate; PRBS 31
100
95
VCC = 3.3V
90
V
= 1.5V p-p
IN
20dB ATTENUATION
85
80
75
70
EYE WIDTH (%)
65
60
% EYE WIDTH = ((CLOCK PERIOD –
55
JITTER p-p)/CLOCK PERIOD) 100%
50
0.5 DATA RATE (Gbps)
1.51.31.10.90.7 1.7 1.9
TPC 16. Eye Width vs. Data Rate; PRBS 31
50mV/DIV 200ps/DIV
VCC = 3.3V
= 1.5V p-p
V
IN
20dB ATTENUATION T
= 25C
A
TPC 17. Eye Pattern; 1.5 Gbps,
= 3.3 V, PRBS 31
V
CC
20mV/DIV 200ps/DIV
V
= 2.5V
CC
V
= 1.5V p-p
IN
20dB ATTENUATION T
= 25C
A
TPC 18. Eye Pattern; 1.244 Gbps,
= 2.5 V, PRBS 31
V
CC
REV. 0–6–
Page 7
ADG3243

TIMING MEASUREMENT INFORMATION

For the following load circuit and waveforms, the notation that is used is V
VVand V V or V V and V V
GENERATOR
NOTE S PULSE GENERATOR FOR ALL PULSES: FREQUENCY 10MHz.
INCLUDES BOARD, STRAY, AND LOAD CAPACITANCES.
C
L
RT IS THE TERMINATION RESISTOR, SHOULD BE EQUAL TO Z OF THE PULSE GENERATOR .
and V
IN
====
IN A OUT B IN B OUT A
PULSE
where
OUT
V
CC
R
OUT
L
R
L
DUT
t
2.5ns,
R
V
OUT
C
L
t
2.5ns,
F
V
IN
R
T
SW1
2 V
GND
CC
Figure 1. Load Circuit
V
CONTROL INPUT BEx
V
OUT
t
PLH
t
PLH
IH
V
T
0V
V
H
V
T
V
L
Figure 2. Propagation Delay

Test Conditions

Symbol VCC = 3.3 V 0.3 V VCC = 2.5 V 0.2 V Unit
R
L
V
C
L
V
T
500 500 300 150 mV 50 30 pF
1.5 0.9 V
Table II. Switch Position
Test S1
CONTROL INPUT BEx
V
SW1 @ 2V
CC
SW1 @ GND
OUT
V
OUT
= 0V
V
IN
= V
V
IN
t t
CC
PLZ
PHZ
, t
PZL
, t
PZH
ENABLE
t
PZL
t
PZH
2 × V
CC
GND
DISABLE
t
PLZ
V
CC
V
T
t
PHZ
V
T
0V
V
INH
V
T
0V
V
CC
VL + V V
L
V
H
VH –V
0V
Figure 3. Enable and Disable Times
REV. 0
–7–
Page 8
ADG3243
V
IN
1.8V
V
OUT
0V
2.5V
SWITCH
INPU T
SWITCH
OUTPUT
2.5V SUPPLY
BUS SWITCH APPLICATIONS Mixed Voltage Operation, Level Translation
Bus switches can provide an ideal solution for interfacing between mixed voltage systems. The ADG3243 is suitable for applica­tions where voltage translation from 3.3 V technology to a lower voltage technology is needed. This device can translate from
2.5 V to 1.8 V or bidirectionally from 3.3 V directly to 2.5 V.
Figure 4 shows a block diagram of a typical application in which a user needs to interface between a 3.3 V ADC and a 2.5 V micro­processor. The microprocessor may not have 3.3 V tolerant inputs, therefore placing the ADG3243 between the two devices allows the devices to communicate easily. The bus switch directly connects the two blocks, thus introducing minimal propagation delay, timing skew, or noise.
3.3V
3.3V ADC
3.3V
ADG3243
2.5V
2.5V
MICROPROCESSOR
Figure 4. Level Translation between a 3.3 V ADC and a 2.5 V Microprocessor

3.3 V to 2.5 V Translation

When VCC is 3.3 V and the input signal range is 0 V to VCC, the maximum output signal will be clamped to within a voltage threshold below the V
3.3V
2.5V
supply.
CC
3.3V
2.5V
ADG3243
2.5V

2.5 V to 1.8 V Translation

When VCC is 2.5 V and the input signal range is 0 V to VCC, the maximum output signal will, as before, be clamped to within a voltage threshold below the V
supply. In this case, the output
CC
will be limited to approximately 1.8 V, as shown in Figure 8.
2.5V
2.5V
ADG3243
1.8V
Figure 7. 2.5 V to 1.8 V Voltage Translation
Figure 8. 2.5 V to 1.8 V Voltage Translation

Bus Isolation

A common requirement of bus architectures is low capacitance loading of the bus. Such systems require bus bridge devices that extend the number of loads on the bus without exceeding the specifications. Because the ADG3243 is designed specifically for applications that do not need drive yet require simple logic functions, it solves this requirement. The device isolates access to the bus, thus minimizing capacitance loading.
Figure 5. 3.3 V to 2.5 V Voltage Translation
In this case, the output will be limited to 2.5 V, as shown in Figure 6. This device can be used for translation from 2.5 V to
3.3 V devices and also between two 3.3 V devices.
V
OUT
SWITCH
INPU T
3.3V SUPPLY
3.3V
V
IN
2.5V
SWITCH
OUTPUT
0V
Figure 6. 3.3 V to 2.5 V Voltage Translation
BUS SWITCH
LOCATION
LOAD A
LOAD B
LOAD C
LOAD D
BUS/
BACKPLANE
Figure 9. Location of Bus Switched in a Bus Isolation Application

Hot Plug and Hot Swap Isolation

The ADG3243 is suitable for hot swap and hot plug applications. The output signal of the ADG3243 is limited to a voltage that is below the V
supply, as shown in Figures 6 and 8. Therefore
CC
the switch acts like a buffer to take the impact from hot insertion, protecting vital and expensive chipsets from damage.
In hot plug applications, the system cannot be shut down when new hardware is being added. To overcome this, a bus switch can be positioned on the backplane between the bus devices and the hot plug connectors. The bus switch is turned off during hot plug. Figure 10 shows a typical example of this type of application.
REV. 0–8–
Page 9
CPU
RAM
BUS
ADG3243 ADG3243
PLUG-IN CARD (1)
PLUG-IN CARD (2)
CARD I/O
CARD I/O
Figure 10. ADG3243 in a Hot Plug Application
There are many systems, such as docking stations, PCI boards for servers, and line cards for telecommunications switches, that require the ability to handle hot swapping. If the bus can be isolated prior to insertion or removal, there is more control over the hot swap event. This isolation can be achieved using bus
ADG3243
switches. The bus switches are positioned on the hot swap card between the connector and the devices. During hot swap, the ground pin of the hot swap card must connect to the ground pin of the backplane before any other signal or power pins.

Analog Switching

Bus switches can be used in many analog switching applications, for example, video graphics. Bus switches can have lower on resistance, smaller ON and OFF channel capacitance, and thus improved frequency performance than their analog counterparts. The bus switch channel itself, consisting solely of an NMOS switch, limits the operating voltage (see TPC 1 for a typical plot), but in many cases, this does not present an issue.

High Impedance during Power-Up/Power-Down

To ensure the high impedance state during power-up or power­down, BEx should be tied to V minimum value of the resistor is determined by the current­sinking capability of the driver.
through a pull-up resistor; the
CC
REV. 0
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Page 10
ADG3243

OUTLINE DIMENSIONS

8-Lead Small Outline Transistor Package [SOT-23]
(RJ-8)
Dimensions shown in millimeters
2.90 BSC
1.60 BSC
PIN 1
1.30
1.15
0.90
0.15 MAX
7
2
1.95
BSC
5 6
4
2.80 BSC
0.65 BSC
1.45 MAX
SEATING PLANE
0.22
0.08
8
1 3
0.38
0.22
COMPLIANT TO JEDEC STANDARDS MO-178BA
8 4 0
0.60
0.45
0.30
REV. 0–10–
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