LMS4684 0.5Ω Low-Voltage, Dual SPDT Analog Switch
June 2004
LMS4684 0.5Ω Low-Voltage, Dual SPDT Analog Switch
General Description
The LMS4684 is a low on-resistance, low voltage dual SPDT (Single-Pole/Double-Throw) analog switch that operates from a 1.8V to 5.5V supply. The LMS4684 features a 0.5Ω RON for its NC switch and 0.8Ω RON for its NO switch at a 2.7V supply. The digital logic inputs are 1.8V logiccompatible with a 2.7V to 3.3V supply. The LMS4684 is available in the 12 bump micro SMD and the 10 lead LLP miniature packages. These PCB real estate saving packages offer extreme performance while saving money with small footprints.
Features
n n n n n n n n NC switch RON 0.5Ω max @ 2.7V NO switch RON 0.8Ω max @ 2.7V 50nA (max) supply current TA = 25˚C 1.8 to 5.5V single supply operation 12-Bump micro SMD package LLP-10 package, 3x4mm See AN-1112 for micro SMD package considerations See AN-1187 for LLP package considerations
Applications
n n n n n Power routing Battery-operated equipment Communications circuits Modems Cell phones
Connection Diagrams
10-LLP Package 12-Bump micro SMD Package
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Center Bumps B2 and C2 are Not Electrically Connected
DAP needs to be connected to pin 6 on the board
Top View
Top View (Bumped Side Down)
IN 0 1
NO Off On
NC On Off
Switches shown for Logic "0" input
© 2004 National Semiconductor Corporation
DS200775
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LMS4684
Absolute Maximum Ratings (Note 1)
If Military/Aerospace specified devices are required, please contact the National Semiconductor Sales Office/ Distributors for availability and specifications. V+, IN COM, NO, NC Continuous Current NO, NC, COM ESD Tolerance (Note 2) Human Body Model Machine Model 2000V 200V −0.3V to 6.0V −0.3V to (V+ + 0.3V)
Storage Temperature Range Junction Temperature (Note 3)
−65˚C to 150˚C 150˚C Max
Operating Ratings
Nominal Supply Voltage Temperature Range Thermal Resistance θJA LLP-10 micro SMD-12 TBD TBD 1.8V to 5.5V −40˚C to 85˚C
± 400mA
Electrical Characteristics
Unless otherwise specified, V+ = 2.7 to 3.3V, VIH = 1.4V, VIL = 0.5V. Typical values are measured at 3V, and TJ = 25˚C. Boldface limits apply at temperature extremes. Symbol VNO, VNC, VCOM RON (NC) RON (NO) ∆RON Parameter Analog Signal Range Conditions Min 0 Typ Max V
+
Units V
NC-On-Resistance (Note 4) NO-On-Resistance (Note 4) On-Resistance Match Between Channels (Note 4), (Note 5)
V+ =2.7, ICOM =100ma, VNC =0 to V+ V+ =2.7, ICOM =100ma, VNO =0 to V+ V+ =2.7, ICOM =100ma, VNC or VNO =1.5V V+ =2.7V, ICOM =100mA, VNC =0 to V+ LLP TJ =0˚C to 85˚C micro SMD TJ =0˚C to 85˚C LLP TJ = −40˚C to +85˚C micro SMD TJ = −40˚C to +85˚C
0.3 0.45
0.5 0.8 0.06 0.15
Ω Ω Ω
RFLAT(NC) NC-On-Resistance Flatness (Note 6)
0.17 0.18 0.20 0.35 −1 −10 −2 −20 35 25 2 15 200 1.4 0.5 1 10 2 20 55 65 30 40 nA Ω Ω
RFLAT(NO) NO-On Resistance Flatness (Note 6) INO(OFF) or INC(OFF) ICOM (ON) tON tOFF tBBM Q Digital I/O VIH VIL IIN Input Logic High Input Logic Low IN Input Leakage Current NO or NC Off-Leakage Current
V+ =2.7V, ICOM =100mA, VNO = 0 to V+ V+ =3.3V, VNO or VNC =3V, 0.3V; VCOM =0.3V, 3V V+ =3.3V, VNO or VNC =3V, 0.3V, or floating; VCOM =3V, or floating V+ =2.7V, VNO or VNC =1.5V; RL =50Ω; CL =35pF; V+ =2.7V, VNO or VNC =1.5V; RL = 50Ω; CL =35pF; V+ =2.7V, VNO or VNC =1.5V; RL =50Ω; CL =35pF; COM =0; RS =0; CL = 1nF;
COM On-Leakage Current
nA
Dynamic Characteristics Turn-On Time Turn-Off Time Break-Before-Make-Delay Charge Injection ns ns ns pC V V µA 1
VIN =0 or V+
−1
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LMS4684
Electrical Characteristics
Symbol Power Supply V+ I+ Power-Supply Range Supply Current (Note 4) Parameter
(Continued) Unless otherwise specified, V+ = 2.7 to 3.3V, VIH = 1.4V, VIL = 0.5V. Typical values are measured at 3V, and TJ = 25˚C. Boldface limits apply at temperature extremes. Conditions Min 1.8 −50 −200 0.04 Typ Max 5.5 50 200 Units V nA
Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is intended to be functional, but specific performance is not guaranteed. Note 2: Human body model: 1.5kΩ in series with 100pF. Machine model, 0Ω in series with 200pF. Note 3: The maximum power dissipation is a function of TJ(max) θJA and TA. Note 4: Guaranteed by design. Note 5: ∆RON is equal to the difference between NC1/NC2 RON or NO1/NO2 RON at a specified voltage. Note 6: Flatness is defined as the difference between the maximum and minimum value of on-resistance as measured over the specified analog signal ranges.
Symbolic Diagram
20077503
Ordering Information
Package 12-Bump micro SMD 10-Pin LLP Part Number LMS4684ITL LMS4684ITLX LMS4684LD LMS4684LDX Package Marking F09A L4684 Transport Media 250 Units Tape and Reel 3k Units Tape and Reel 1k Units Tape and Reel 4.5k Units Tape and Reel LDA10B NSC Drawing TLA12DPA
Pin Descriptions
Name LLP NC IN COM NO V+ GND 5, 7 4, 8 3, 9 2, 10 1 6, GND Pin ID micro SMD D3, D1 C3, C1 B3, B1 A3, A1 A2 D2 B2, C2 Analog switch normally closed terminal Digital control input Analog switch common terminal Analog switch normally open terminal Positive supply voltage Ground Not electrically connected. Can be used to help dissipate heat by connecting to GND pin. Description
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LMS4684
Typical Performance Characteristics
Supply Current vs. Supply Voltage NO ON Resistance vs. COM Voltage
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NC ON Resistance vs. COM Voltage
Logic Threshold Voltage vs. Supply Voltage
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20077507
Turn-on / Turn-off Times vs. Temperature
Charge Injection vs. COM Voltage
20077508
20077509
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LMS4684
Typical Performance Characteristics
NC On-Resistance vs. COM Voltage
(Continued) NC On-Resistance vs. COM Voltage
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NO On-Resistance vs. COM Voltage
NO On-Resistance vs. COM Voltage
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LMS4684
Application Notes
PRODUCT DESCRIPTION The LMS4684 is a low voltage dual analog switch with extremely low On-Resistance operating with a supply voltage range of 1.8V to 5.5V. National has fully characterized the LMS4684 to operate in applications with 3V nominal supply voltage. The LMS4684 also features fast switching times for Turn-Off (40ns max over temp) and Turn-On (65ns max over temp). The switch operates asymmetrically, one terminal is normally closed (NC) and the other terminal normally open (NO). Both NC and NO terminals are connected to a common terminal (COM). This configuration is ideal for applications with asymmetric loads such as speaker handsets and internal speakers. ANALOG SIGNAL LEVELS The Analog signal ranges from GND to V+ and are passed through the switch with very little change. Each switch is bidirectional so any pin can be an input or output. DIGITAL CONTROL INPUTS The IN pin can be driven to 5.5V regardless of the voltage level of the supply pin V+. For example if you wanted to have a supply of 2V you could still drive the IN digital control input to 5V. Minimum power is lost when the IN pin, is driven rail-to-rail. SUPPLY VOLTAGE SEQUENCING It is good general practice to first apply the supply voltage to a CMOS device before any other supply on other pins.This is also true for the LMS4684 analog switch which is a CMOS device. However if it is necessary to have an analog signal applied before the supply voltage is applied and the analog signal supply is not limited to 20mA max, a diode connected between the supply voltage and the V+ pin as shown in the figure below will supply adequate input protection. This will limit the max analog voltage to a diode drop below V+. This diode D1 will also provide protection against some overvoltage situations.
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FIGURE 1. Overvoltage Protection Circuitry PCB LAYOUT Both the LLP and micro SMD packages offer enhanced board real estate savings because of their tiny footprints. These tiny packages are capable of supporting up to an absolute maximum of 400mA of continuous current because of the advanced thermal handling capabilities. The LLP package has the exposed die attach pad internally connected to the internal circuit GND. When this pad is soldered to copper on the PCB board according to Application Note AN-1187 the full thermal capability of the LLP package can be achieved without additional bulky heat sinks to dissipate the heat generated. The micro SMD package has a similar capability to help dissipate heat generated through Bumps B2 and C2 which are not electrically connected. To enhance heat dissipation of the micro SMD package B2 and C2 could be connected to the GND pin and through copper traces on the board. Please see Application Note AN-1112 for micro SMD package considerations.
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LMS4684
Parameter Measuring Information
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FIGURE 2. tON / tOFF Time
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FIGURE 3. Break-Before Make Delay
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FIGURE 4. Charge Injection
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LMS4684
Parameter Measuring Information
(Continued)
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FIGURE 5. Channel Capacitance
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LMS4684
Physical Dimensions
inches (millimeters) unless otherwise noted
10-Lead LLP NS Package Number LDA10B
X1 = 1590 ± 30 µm; X2 = 2327 ± 30 µm; X3 = 600 ± 75 µm
12-Bump micro SMD NS Package Number TLA12DPA
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LMS4684 0.5Ω Low-Voltage, Dual SPDT Analog Switch
Notes
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