CM1234-08DE_技术文档

PicoGuard XS® ESD Clamp Array For High

Speed Data Line Protectio

n

CM1234

Features

Product Description

•

ESD protection for 4 pairs of differential

channels

The PicoGuard XS (Xtreme Speed) protection family

is specifically designed for next generation deep

sub-micron high speed data line protection.

•

ESD protection to IEC61000-4-2 Level 4

15kV contact discharge

20kV air discharge

•

The CM1234 is ideal for protecting systems with

high data and clock rates or for circuits requiring low

capacitive loading and tightly controlled signal

skews (with channel-to-channel matching at 2% max

deviation).

•

Pass-through impedance matched clamp

architecture

Flow-through routing for high-speed signal integ-

rity

Minimal line capacitance change with

temperature and voltage

The device is particularly well-suited for protecting

systems using high-speed ports such as DVI or

HDMI, along with corresponding ports in removable

storage, digital camcorders, DVD-RW drives and

other applications where extremely low loading

capacitance with ESD protection are required.

100Ω matched impedance for each paired

differential channel

Each I/O pin can withstand over 1000 ESD

strikes*

RoHS compliant (lead-free) TDFN-16 package

The CM1234 also features easily routed "pass-

through" pinouts in a RoHS compliant (lead-free),16-

lead TDFN, small footprint package.

Applications

•

DVI ports, HDMI ports in notebooks, set top

boxes, digital TVs, LCD displays

General purpose high-speed data line ESD

protection

•

April 2010 – Rev. 3

Publication Order Number:

CM1234/D

CM1234

Block Diagram

*Standard test condition is IEC61000-4-2 level 4 test circuit with each pin subjected to 8kV contact discharge for 1000 pulses. Discharges are timed at 1 second intervals and all 1000 strikes are completed in one continuous

test run. The part is then subjected to standard production test to verify that all of the tested parameters are within spec after the 1000 strikes.

PicoGuard XS ESD Protection Architecture

Conceptually, an ESD protection device performs the following actions upon an ESD strike discharge into a

protected ASIC (see Figure 1):

1. When an ESD potential is applied to the system under test (contact or air-discharge), Kirchoff’s Current Law

(KCL) dictates that the Electrical Overstress (EOS) currents will immediately divide throughout the circuit,

based on the dynamic impedance of each path.

2. Ideally, the classic shunt ESD clamp will switch within 1ns to a low-impedance path and return the majority of

the EOS current to the chassis shield/reference ground. In actuality, if the ESD component's response time

(t_CLAMP) is slower than the ASIC it is protecting, or if the Dynamic Clamping Resistance (RDYN) is not signifi-

cantly lower than the ASIC's I/O cell circuitry, then the ASIC will have to absorb a large amount of the EOS

energy, and be more likely to fail.

3. Subsequent to the ESD/EOS event, both devices must immediately return to their original specifications, and

be ready for an additional strike. Any deterioration in parasitics or clamping capability should be considered a

failure, since it can then affect signal integrity or subsequent protection capability. (This is known as "multi-

strike" capability.)

Rev. 3 | Page 2 of 13 | www.onsemi.com

CM1234

In the CM1234 PicoGuard XS architecture, the signal line leading the connector to the ASIC routes through the

CM1234 chip which provides 100Ω matched differential channel characteristic impedance that helps optimize

100Ω load impedance applications such as the HDMI high speed data lines.

Note:When each of the channels are used individually for single-ended signal lines protection, the individual

channel provides 50Ω characteristic impedance matching.

The load impedance matching feature of the CM1234 helps to simplify system designer’s PCB layout

considerations in impedance matching and also eliminates associated passive components.

The route through the PicoGuard XS architecture enables the CM1234 to provide matched impedance for the

signal path between the connector and the ASIC. Besides this function, this circuit arrangement also changes the

way the parasitic inductance interacts with the ESD protection circuit and helps reduce the I_RESIDUALcurrent to the

ASIC.

Figure 1. Standard ESD Protection Device Block Diagram

Rev. 3 | Page 3 of 13 | www.onsemi.com

CM1234

The PicoGuard XS Architecture Advantages

Figure 2 illustrates a standard ESD protection device. The inductor element represents the parasitic inductance

arising from the bond wire and the PCB trace leading to the ESD protection diodes.

Figure 2. Standard ESD Protection Model

Figure 3 illustrates a standard ESD protection device. The inductor element represents the parasitic inductance

arising from the bond wire and the PCB trace leading to the ESD protection diodes.

Figure 3. CM1234 PicoGuard XS ESD Protection Model

Rev. 3 | Page 4 of 13 | www.onsemi.com

CM1234

CM1234 Inductor Elements

In the CM1234 PicoGuard XS architecture, the inductor elements and ESD protection diodes interact differently

compared to the standard ESD model.

In the standard ESD protection device model, the inductive element presents high impedance against high slew

rate strike voltage, i.e. during an ESD strike. The impedance increases the resistance of the conduction path

leading to the ESD protection element. This limits the speed that the ESD pulse can discharge through the ESD

protection element.

In the PicoGuard XS architecture, the inductive elements are in series to the conduction path leading to the

protected device. The elements actually help to limit the current and voltage striking the protected device.

First the reactance of the inductive element, L1, on the connector side when an ESD strike occurs, acts in the

opposite direction of the ESD striking current. This helps limit the peak striking voltage. Then the reactance of the

inductive element, L2, on the ASIC side forces this limited ESD strike current to be shunted through the ESD

protection diodes. At the same time, the voltage drop across both series element acts to lower the clamping

voltage at the protected device terminal.

Through this arrangement, the inductive elements also tune the impedance of the ESD protection element by

cancelling the capacitive load presented by the ESD diodes to the signal line. This improves the signal integrity

and makes the overall ESD protection device more transparent to the high bandwidth data signals passing

through the channel.

The innovative PicoGuard XS architecture turns the disadvantages of the parasitic inductive elements into useful

components that help to limit the ESD current strike to the protected device and also improves the signal integrity

of the system by balancing the capacitive loading effects of the ESD diodes. At the same time, this architecture

provides an impedance matched signal path for 50Ω loading applications.

Board designs can take advantage of precision internal component matching for improved signal integrity, which

is not otherwise possible with discrete components at the system level. This helps to simplify the PCB layout

considerations by the system designer and eliminates the associated passive components for load matching that

is normally required with standard ESD protection circuits.

Each ESD channel consists of a pair of diodes in series which steer the positive or negative ESD current pulse to

either the Zener diode or to ground. This embedded Zener diode also serves to eliminate the need for a separate

bypass capacitor to absorb positive ESD strikes to ground. The CM1234 protects against ESD pulses up to

18kv contact per the IEC 61000-4-2 standard.

Rev. 3 | Page 5 of 13 | www.onsemi.com

CM1234

PIN DESCRIPTIONS

1

Name

In_1+

In_1-

Description

Bidrectional Clamp to ASIC (inside system)

Bidrectional Clamp to Connector (outside system)

Ground return to shield

2

3

In_2+

In_2-

4

5

In_3+

In_3-

6

7

In_4+

In_4-

8

9

Out_4-

Out_4+

Out_3-

Out_3+

Out_2-

Out_2+

Out_1-

Out_1+

GND

10

11

12

13

14

15

16

PAD

Ordering Information

PART NUMBERING INFORMATION

ORDERING PART NUMBER

(LEAD-FREE FINISH)

PACKAGE

TDFN-16

PART MARKING

16

CM1234-08

CM1234-08DE

Note 1: Parts are shipped in Tape & Reel form unless otherwise specified.

Rev. 3 | Page 6 of 13 | www.onsemi.com

CM1234

Specifications

ABSOLUTE MAXIMUM RATINGS*

PARAMETER

RATING

-40 to +85

-65 to +150

6

UNITS

°C

Operating Temperature Range

Storage Temperature Range

°C

Breakdown Voltage

(Positive)

V

*Exposure to absolute maximum rating conditions for extended periods may affect device reliability.

ELECTRICAL OPERATING CHARACTERISTICS ^{(SEE NOTE 1)}

SYMBOL PARAMETER

CONDITIONS

MIN

TYP

MAX UNITS

V_IN

I_IN

I/O Voltage Relative to GND

-0.5

5.5

V

Continuous Current through signal pins

(IN to OUT) 1000 Hr

100

0.1

mA

I_F

Channel Leakage Current

T_A= 25°C; V_N= 0V, V_TEST= 5V

1.0

µA

V_ESD

ESD Protection - Peak Discharge Voltage

at any channel input, in system:

a) Contact discharge per IEC 61000-4-2

Standard

T_A= 25°C

15

20

kV

and

b) Air discharge per IEC 61000-4-2 Stan- T_A= 25°C

dard

I_RES

Residual ESD Peak Current on RDUP

(Resistance of Device Under Protection)

IEC 61000-4-2 8kV;

RDUP = 5Ω T_A= 25°C;

2.5

A

V_CL

Channel Clamp Voltage

(Channel clamp voltage per IEC 61000-4-

5 Standard)

I_PP= 1A, T_A= 25°C,

t_P= 8/20µS

Positive Transients

Negative Transients

+9

–1.5

V

R_DYN

Dynamic Resistance

Positive Transients

Negative Transients

I_PP= 1A, T_A= 25ºC;

t_P= 8/20

0.44

0.38

Ω

µ

S

Zo

Differential Channels pair characteristic

impedance

T_R= 200ps

100

Ω

Rev. 3 | Page 7 of 13 | www.onsemi.com

CM1234

SYMBOL PARAMETER

∆Zo

Channel-to-Channel Impedance Match

(Differential)

CONDITIONS

MIN

TYP

MAX UNITS

T_R= 200ps

2

%

Z

Individual Channel Characteristic Imped-

ance in Single-ended Connection

T_R= 200ps

T_R= 200ps;

50

2

Ω

CHANNEL

∆

Z

Channel-to-Channel Impedance Match

(Individual)

%

CHANNEL

Note 1: All parameters specified at T_A= –40°C to +85°C unless otherwise noted.

Performance Information

Graphical Comparison and Test Setup

Figure 4 shows that the CM1234(PicoGuard XS ESD protector) lowers the peak voltage and clamping voltage by

45% across a wide range of loading conditions in comparison to a standard ESD protection device. Figure 5 also

indicates that the DUP/ASIC protected by the CM1235 dissipates less energy than a standard ESD protection

device. This data was derived using the test setups shown in Figure 6.

Figure 4. Normalized VPeak (8KV IEC-61000 4-2 ESD Contact Strike) vs. Loading (RDUP)*

Rev. 3 | Page 8 of 13 | www.onsemi.com

CM1234

Figure 5. Normalized Residual Current into DUP vs RDUP*

* RDUP is the emulated Dynamic Resistance (load) of the Device Under Protection (DUP).

Figure 6. Test Setups: Standard Device (Left) and CM1234 (Right)

Rev. 3 | Page 9 of 13 | www.onsemi.com

CM1234

CM1234 Application and Guidelines

As a general rule, the CM1234 ESD protection array should be located as close as possible to the point of entry

of expected electrostatic discharges with minimum PCB trace lengths to the ground planes and between the sig-

nal input and the ESD device to minimize stray series inductance.

Figure 8. Application of Positive ESD Pulse Between Input Channel and Ground

Figure 9. Typical PCB Layout

Additional Information

See also California Micro Devices Application Note AP209, “Design Considerations for ESD Protection,” in the

Applications section at www.calmicro.com.

Rev. 3 | Page 10 of 13 | www.onsemi.com

CM1234

Mechanical Details

TDFN-16 Mechanical Specifications, 0.75mm

The 16-lead, 6.0x4.0mm, 0.75mm pitch TDFN package dimensions are presented below.

PACKAGE DIMENSIONS

TDFN

Package

MO-229C^*

JEDEC

No.

16

Leads

Dim.

Millimeters

Inches

Min

Nom Max

Min

Nom Max

0.70

0.75

0.02

0.80 0.028 0.030 0.031

0.05 0.000 0.001 0.002

A

A1

A3

b

0.00

0.175 0.200 0.225 0.007 0.008 0.009

0.20

5.90

5.05

3.90

1.75

0.25

6.00

0.30 0.008 0.010 0.012

6.10 0.232 0.236 0.240

5.15 0.199 0.201 0.203

4.10 0.153 0.157 0.161

1.85 0.012 0.016 0.020

0.029 BSC

D

5.10

D2

E

4.00

1.80

E2

e

0.75 BSC

0.70 REF

0.40

0.028 REF

K

0.35

0.45 0.014 0.016 0.018

3000 pieces

L

# per

tape and

reel

Controlling dimension: millimeters

This package is compliant with JEDEC standard MO-229C with

Dimensions for 16-Lead, 0.75mm pitch

TDFN package

*

the exception of the D, D2, E, E2, K and L dimensions as called

out in the table above.

Rev. 3 | Page 11 of 13 | www.onsemi.com

CM1234

Tape and Reel Specifications

PACKAGE SIZE

(mm)

POCKET SIZE (mm) TAPE WIDTH

W

REEL

DIAMETER

QTY PER

REEL

PART NUMBER

B₀X A₀X K₀

P₀

P₁

CM1234

6.00 X 4.00 X 0.75

6.30 X 4.30 X 1.10

12mm

330mm (13")

3000

4mm 8mm

Rev. 3 | Page 12 of 13 | www.onsemi.com

CM1234

ON Semiconductor and

are registered trademarks of Semiconductor Components Industries, LLC (SCILLC). SCILLC reserves the right to make changes without further

notice to any products herein. SCILLC makes no warranty, representation or guarantee regarding the suitability of its products for any particular purpose, nor does SCILLC

assume any liability arising out of the application or use of any product or circuit, and specifically disclaims any and all liability, including without limitation special, conse-

quential or incidental damages. “Typical” parameters which may be provided in SCILLC data sheets and/or specifications can and do vary in different applications and actual

performance may vary over time. All operating parameters, including “Typicals” must be validated for each customer application by customer's technical experts. SCILLC

does not convey any license under its patent rights nor the rights of others. SCILLC products are not designed, intended, or authorized for use as components in systems

intended for surgical implant into the body, or other applications intended to support or sustain life, or for any other application in which the failure of the SCILLC product

could create a situation where personal injury or death may occur. Should Buyer purchase or use SCILLC products for any such unintended or unauthorized application,

Buyer shall indemnify and hold SCILLC and its officers, employees, subsidiaries, affiliates, and distributors harmless against all claims, costs, damages, and expenses, and

reasonable attorney fees arising out of, directly or indirectly, any claim of personal injury or death associated with such unintended or unauthorized use, even if such claim

alleges that SCILLC was negligent regarding the design or manufacture of the part. SCILLC is an Equal Opportunity/Affirmative Action Employer. This literature is subject to

all applicable copyright laws and is not for resale in any manner.

PUBLICATION ORDERING INFORMATION

LITERATURE FULFILLMENT:

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Toll Free USA/Canada

ON Semiconductor Website: www.onsemi.com

Order Literature: http://www.onsemi.com/orderlit

Literature Distribution Center for ON Semiconductor

P.O. Box 5163, Denver, Colorado 80217 USA

Phone: 303-675-2175 or 800-344-3860 Toll Free USA/Canada

Fax: 303-675-2176 or 800-344-3867 Toll Free USA/Canada

Email: orderlit@onsemi.com

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Phone: 421 33 790 2910

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Phone: 81-3-5773-3850

For additional information, please contact your local

Sales Representative

Rev. 3 | Page 13 of 13 | www.onsemi.com


型号：	CM1234-08DE
厂家：	ONSEMI
描述：	PicoGuard XS? ESD Clamp Array For High Speed Data Line Protection 的PicoGuard XS® ESD钳位阵列高速数据线路保护瞬态抑制器二极管光电二极管局域网
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CM1234-08DE [ONSEMI]

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