LITTELFUSE PGB

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PulseGuard ® Suppressors
Polymeric ESD Suppressors
PGB Series SOT23 Surface Mount ESD Suppressor
Product Overview
PulseGuard ESD Suppressors help protect sensitive electronic
equipment against electrostatic discharge (ESD). They supplement the
on-chip protection of integrated circuitry and are best suited for lowvoltage, high-speed applications where low capacitance is important.
Data ports utilizing such high-speed protocols as USB 2.0, IEEE1394
and InfiniBandSM can benefit from this new technology. PulseGuard
suppressors use polymer composite materials to suppress fast-rising
ESD transients (as specified in IEC 61000-4-2 and MIL-STD-883E).
Features
• Ultra-low capacitance
• Low leakage current
• Fast response time
• 2-lines of protection
• Bi-directional
• Withstands multiple ESD strikes
• Standard JEDEC SOT23 outline
• Compatible with pick-and-place processes
• Available in 3,000 piece reels
Physical Specifications
Typical Applications
•
•
•
•
•
•
PULSEGUARD®
SUPPRESSORS
4
Materials:
Servers
Laptop/Desktop Computers
Network Hardware
Computer Peripherals
Digital Cameras
External Storage
Body: Glass Epoxy
Terminations: Tin-Lead
Soldering Parameters:
Wave solder -- 260°C, 10 seconds maximum
Reflow solder -- 260°C, 30 seconds maximum
Operating Temperature Range:
-65°C to 125°C
Electrical Characteristics
Trigger Voltage1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1,000V typical
Ordering Information
Clamping Voltage1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150V typical
CATALOG NUMBER
PIECES PER REEL
Rated Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24VDC max
PGB002ST23WR
3,000
Capacitance2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.055pF
Response Time1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <1ns
Design Consideration
Leakage Current3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . <1nA
Because of the fast rise-time of the ESD transient, placement of
PulseGuard suppressors is a key design consideration. To achieve
optimal ESD suppression, the devices should be placed on the circuit
board as close to the source of the ESD transient as possible. Install
PulseGuard suppressors directly behind the connector so that they are
the first board-level circuit component encountered by the ESD transient.
They are connected from signal/data line to ground.
ESD Pulse Withstand . . . . . . . . . . . . . . . . . . . . . 1,000 pulses minimum
1
Notes:
1. 8 kV direct discharge method, per IEC 61000-4-2.
2. Measured at 1 MHz.
3. Measured at 6 VDC. Testing at fast ESD pulse rates (1-20Hz) may
cause a change in leakage current performance (6µA, max).
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PulseGuard ® Suppressors
Polymeric ESD Suppressors
PGB Series SOT23 Surface Mount ESD Suppressor
Generalized PulseGuard Suppressor Response to ESD
Generalized I-V Curve
(Positive and Negative Polarity ESD Pulses)
(Positive and Negative Polarity ESD Pulses)
Trigger
Voltage
Current (A)
Voltage (V)
Trigger Voltage
Clamping Voltage
Clamping
Voltage
Voltage (V)
Time (ns)
Definitions
Capacitance vs. Frequency
Trigger Voltage: The measured peak voltage across the ESD
suppressor before it transitions from high to low resistance. It is
manifested as a “spike” before the clamping voltage is achieved.
This voltage is typically well below the damage threshold of on-chip
IC protection.
ESD Impulse Voltage: Also known as the ESD Threat Voltage. This is
the voltage that is “zapped” into the circuit. Voltages generated by people
can exceed 15 kV. The IEC 61000-4-2 defines four levels of impulse
voltage for testing purposes:
AIR DISCHARGE
DIRECT
DISCHARGE
1
2 kV
2 kV
2
4 kV
4 kV
3
8 kV
6 kV
4
15 kV
8 kV
Capacitance (fF)
Clamping Voltage: The voltage level to which the ESD impulse voltage
is reduced. This is the voltage that the suppressor holds at, until the ESD
transient energy is dissipated.
SEVERITY LEVEL
** Note: 1,000 fF = 1 pF
70
60
50
40
0.5
DESCRIPTION
Carrier Tape Specifications
Parts are delivered on 7” (178mm) reel, plastic carrier tape
Tt
Ds
Dd
+
+
+
+
Tw
+
Pd
Ph
+
Ps
Pw
1.5
2.0
MEASUREMENT (MM)
Ct - Cover tape thickness
0.06
Dd - Drive hole diameter
1.50
Ds - Drive hole spacing
4.00
Pd - Pocket depth
1.02
Ph - Pocket height
3.23
Ps - Pocket spacing
4.00
Pw - Pocket width
2.46
Tt - Carrier tape thickness
0.30
Tw - Carrier tape width
8.00
Ct
178
1.0
Frequency (GHz)
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PulseGuard ® Suppressors
Polymeric ESD Suppressors
PGB Series SOT23 Surface Mount ESD Suppressor
Test Set-up for IEC 61000-4-2 Waveform, 2kV-15kV
Device under test
Tek P6156 Probe (Voltage measurement)
Faraday cage
Brown tip (x100)
KeyTek pulser
2,000- 15,000 V
x10
Ground return
x10
4
Tektronic TDS 684B
PULSEGUARD®
SUPPRESSORS
Blue tip (x10)
.5 ohm shunt (10-5 ohms in parallel)
Tek P6156 Probe (Current measurement)
Reference Schematics:
Equivalent Circuit:
Device Dimensions:
Recommended Pad Layout:
2.24
(0.088")
a
+
1
d
2.997
(0.118")
2.032
(0.080")
b
3
+
c
2
e
a
b
* Dimension "a" is: 0.066 (.026")
* Dimension "b" is: 0.076 (.030")
A
B
C
D
E
SOLDER METHOD
INCH
MM
INCH
MM
INCH
MM
INCH
MM
INCH
MM
Wave Solder
0.050
1.27
0.040
1.016
0.050
1.27
0.090
2.29
0.150
3.81
Reflow Solder
0.050
1.27
0.040
1.016
0.040
1.01
0.080
2.032
0.140
3.56
Note: Pin 3 (common) is typically connected to chassis ground.
However, since PulseGuard suppressors are bi-directional, thex system
voltage bus can also be used as the ESD “dump”.
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