MMBZ27VCL,215 - NXP - Product.Network

1. Product proﬁle

1.1 General description

Unidirectional double ElectroStatic Discharge (ESD) protection diodes in a common

cathode conﬁguration, encapsulated in a SOT23 (TO-236AB) small Surface-Mounted

Device (SMD) plastic package. The devices are designed for ESD and transient

overvoltage protection of up to two signal lines.

[1] All types available as /DG halogen-free version.

1.2 Features

1.3 Applications

MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage

suppression

Rev. 01 — 3 September 2008 Product data sheet

Table 1. Product overview

Type number[1] Package Conﬁguration

NXP JEDEC

MMBZ12VDL SOT23 TO-236AB dual common cathode

MMBZ15VDL

MMBZ18VCL

MMBZ20VCL

MMBZ27VCL

MMBZ33VCL

nUnidirectional ESD protection of

two lines

nESD protection up to 30 kV (contact

discharge)

nBidirectional ESD protection of one line nIEC 61000-4-2; level 4 (ESD)

nLow diode capacitance: Cd≤140 pF nIEC 61643-321

nRated peak pulse power: PPPM ≤40 W nAEC-Q101 qualiﬁed

nUltra low leakage current: IRM ≤5nA

nComputers and peripherals nAutomotive electronic control units

nAudio and video equipment nPortable electronics

nCellular handsets and accessories

Product data sheet Rev. 01 — 3 September 2008 2 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

1.4 Quick reference data

2. Pinning information

Table 2. Quick reference data

amb

=25

C unless otherwise speciﬁed.

Symbol Parameter Conditions Min Typ Max Unit

Per diode

VRWM reverse standoff voltage

MMBZ12VDL

MMBZ12VDL/DG - - 8.5 V

MMBZ15VDL

MMBZ15VDL/DG - - 12.8 V

MMBZ18VCL

MMBZ18VCL/DG - - 14.5 V

MMBZ20VCL

MMBZ20VCL/DG --17V

MMBZ27VCL

MMBZ27VCL/DG --22V

MMBZ33VCL

MMBZ33VCL/DG --26V

Cddiode capacitance f = 1 MHz; VR=0V

MMBZ12VDL

MMBZ12VDL/DG - 110 140 pF

MMBZ15VDL

MMBZ15VDL/DG - 85 105 pF

MMBZ18VCL

MMBZ18VCL/DG - 7090pF

MMBZ20VCL

MMBZ20VCL/DG - 6580pF

MMBZ27VCL

MMBZ27VCL/DG - 4860pF

MMBZ33VCL

MMBZ33VCL/DG - 4555pF

Table 3. Pinning

Pin Description Simpliﬁed outline Graphic symbol

1 anode (diode 1)

2 anode (diode 2)

3 common cathode

006aaa150

Product data sheet Rev. 01 — 3 September 2008 3 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

3. Ordering information

4. Marking

[1] * = -: made in Hong Kong

* = p: made in Hong Kong

* = t: made in Malaysia

* = W: made in China

Table 4. Ordering information

Type number Package

Name Description Version

MMBZ12VDL - plastic surface-mounted package; 3 leads SOT23

MMBZ15VDL

MMBZ18VCL

MMBZ20VCL

MMBZ27VCL

MMBZ33VCL

MMBZ12VDL/DG - plastic surface-mounted package; 3 leads SOT23

MMBZ15VDL/DG

MMBZ18VCL/DG

MMBZ20VCL/DG

MMBZ27VCL/DG

MMBZ33VCL/DG

Table 5. Marking codes

Type number Marking code[1] Type number Marking code[1]

MMBZ12VDL *MA MMBZ12VDL/DG TJ*

MMBZ15VDL *MB MMBZ15VDL/DG TL*

MMBZ18VCL *MC MMBZ18VCL/DG TN*

MMBZ20VCL *MD MMBZ20VCL/DG TQ*

MMBZ27VCL *ME MMBZ27VCL/DG TS*

MMBZ33VCL *MF MMBZ33VCL/DG TU*

Product data sheet Rev. 01 — 3 September 2008 4 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

5. Limiting values

[1] In accordance with IEC 61643-321 (10/1000 µs current waveform).

[2] Measured from pin 1 or 2 to pin 3.

[3] Device mounted on an FR4 Printed-Circuit Board (PCB), single-sided copper, tin-plated and standard

footprint.

[4] Device mounted on an FR4 PCB, single-sided copper, tin-plated, mounting pad for cathode 1 cm2.

[1] Device stressed with ten non-repetitive ESD pulses.

[2] Measured from pin 1 or 2 to pin 3.

Table 6. Limiting values

In accordance with the Absolute Maximum Rating System (IEC 60134).

Symbol Parameter Conditions Min Max Unit

Per diode

PPPM rated peak pulse power tp= 10/1000 µs[1][2] -40W

IPPM rated peak pulse current tp= 10/1000 µs[1][2]

MMBZ12VDL

MMBZ12VDL/DG - 2.35 A

MMBZ15VDL

MMBZ15VDL/DG - 1.9 A

MMBZ18VCL

MMBZ18VCL/DG - 1.6 A

MMBZ20VCL

MMBZ20VCL/DG - 1.4 A

MMBZ27VCL

MMBZ27VCL/DG -1A

MMBZ33VCL

MMBZ33VCL/DG - 0.87 A

Per device

Ptot total power dissipation Tamb ≤25 °C[3] - 350 mW

[4] - 440 mW

Tjjunction temperature - 150 °C

Tamb ambient temperature −55 +150 °C

Tstg storage temperature −65 +150 °C

Table 7. ESD maximum ratings

amb

=25

C unless otherwise speciﬁed.

Symbol Parameter Conditions Min Max Unit

Per diode

VESD electrostatic discharge voltage [1][2]

IEC 61000-4-2

(contact discharge) -30kV

machine model - 2 kV

Product data sheet Rev. 01 — 3 September 2008 5 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

6. Thermal characteristics

[1] Device mounted on an FR4 PCB, single-sided copper, tin-plated and standard footprint.

[2] Device mounted on an FR4 PCB, single-sided copper, tin-plated, mounting pad for cathode 1 cm2.

[3] Soldering point at pin 3.

Table 8. ESD standards compliance

Standard Conditions

Per diode

IEC 61000-4-2; level 4 (ESD) > 15 kV (air); > 8 kV (contact)

MIL-STD-883; class 3 (human body model) > 8 kV

Fig 1. 10/1000 µs pulse waveform according to

IEC 61643-321 Fig 2. ESD pulse waveform according to

IEC 61000-4-2

tp (ms)

0 4.03.01.0 2.0

006aab319

100

150

IPP

(%)

50 % IPP; 1000 µs

100 % IPP; 10 µs

001aaa631

IPP

100 %

90 %

30 ns 60 ns

10 %

tr = 0.7 ns to 1 ns

Table 9. Thermal characteristics

Symbol Parameter Conditions Min Typ Max Unit

Per device

Rth(j-a) thermal resistance from junction

to ambient in free air [1] - - 350 K/W

[2] - - 280 K/W

Rth(j-sp) thermal resistance from junction

to solder point [3] --60K/W

Product data sheet Rev. 01 — 3 September 2008 6 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

7. Characteristics

Table 10. Characteristics

amb

=25

C unless otherwise speciﬁed.

Symbol Parameter Conditions Min Typ Max Unit

Per diode

VFforward voltage

MMBZ12VDL

MMBZ12VDL/DG IF= 10 mA - - 0.9 V

MMBZ15VDL

MMBZ15VDL/DG IF= 10 mA - - 0.9 V

MMBZ18VCL

MMBZ18VCL/DG IF= 10 mA - - 0.9 V

MMBZ20VCL

MMBZ20VCL/DG IF= 10 mA - - 0.9 V

MMBZ27VCL

MMBZ27VCL/DG IF= 200 mA - - 1.1 V

MMBZ33VCL

MMBZ33VCL/DG IF= 10 mA - - 0.9 V

VRWM reverse standoff

voltage

MMBZ12VDL

MMBZ12VDL/DG - - 8.5 V

MMBZ15VDL

MMBZ15VDL/DG - - 12.8 V

MMBZ18VCL

MMBZ18VCL/DG - - 14.5 V

MMBZ20VCL

MMBZ20VCL/DG --17V

MMBZ27VCL

MMBZ27VCL/DG --22V

MMBZ33VCL

MMBZ33VCL/DG --26V

IRM reverse leakage current

MMBZ12VDL

MMBZ12VDL/DG VRWM = 8.5 V - 0.1 5 nA

MMBZ15VDL

MMBZ15VDL/DG VRWM = 12.8 V - 0.1 5 nA

MMBZ18VCL

MMBZ18VCL/DG VRWM = 14.5 V - 0.1 5 nA

MMBZ20VCL

MMBZ20VCL/DG VRWM =17V - 0.1 5 nA

MMBZ27VCL

MMBZ27VCL/DG VRWM =22V - 0.1 5 nA

MMBZ33VCL

MMBZ33VCL/DG VRWM =26V - 0.1 5 nA

Product data sheet Rev. 01 — 3 September 2008 7 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

VBR breakdown voltage IR=1mA

MMBZ12VDL

MMBZ12VDL/DG 11.4 12 12.6 V

MMBZ15VDL

MMBZ15VDL/DG 14.3 15 15.8 V

MMBZ18VCL

MMBZ18VCL/DG 17.1 18 18.9 V

MMBZ20VCL

MMBZ20VCL/DG 19 20 21 V

MMBZ27VCL

MMBZ27VCL/DG 25.65 27 28.35 V

MMBZ33VCL

MMBZ33VCL/DG 31.35 33 34.65 V

Cddiode capacitance f = 1 MHz; VR=0V

MMBZ12VDL

MMBZ12VDL/DG - 110 140 pF

MMBZ15VDL

MMBZ15VDL/DG - 85 105 pF

MMBZ18VCL

MMBZ18VCL/DG - 7090pF

MMBZ20VCL

MMBZ20VCL/DG - 6580pF

MMBZ27VCL

MMBZ27VCL/DG - 4860pF

MMBZ33VCL

MMBZ33VCL/DG - 4555pF

VCL clamping voltage [1][2]

MMBZ12VDL

MMBZ12VDL/DG IPPM = 2.35 A - - 17 V

MMBZ15VDL

MMBZ15VDL/DG IPPM = 1.9 A - - 21.2 V

MMBZ18VCL

MMBZ18VCL/DG IPPM = 1.6 A - - 25 V

MMBZ20VCL

MMBZ20VCL/DG IPPM = 1.4 A - - 28 V

MMBZ27VCL

MMBZ27VCL/DG IPPM =1A --38V

MMBZ33VCL

MMBZ33VCL/DG IPPM = 0.87 A - - 46 V

Table 10. Characteristics

…continued

amb

=25

C unless otherwise speciﬁed.

Symbol Parameter Conditions Min Typ Max Unit

Product data sheet Rev. 01 — 3 September 2008 8 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

[1] In accordance with IEC 61643-321 (10/1000 µs current waveform).

[2] Measured from pin 1 or 2 to pin 3.

SZtemperature coefﬁcient IZ=1mA

MMBZ12VDL

MMBZ12VDL/DG - 8.1 - mV/K

MMBZ15VDL

MMBZ15VDL/DG - 11 - mV/K

MMBZ18VCL

MMBZ18VCL/DG - 14 - mV/K

MMBZ20VCL

MMBZ20VCL/DG - 15.8 - mV/K

MMBZ27VCL

MMBZ27VCL/DG - 23 - mV/K

MMBZ33VCL

MMBZ33VCL/DG - 29.4 - mV/K

Table 10. Characteristics

…continued

amb

=25

C unless otherwise speciﬁed.

Symbol Parameter Conditions Min Typ Max Unit

MMBZ27VCL: unidirectional and bidirectional

Tamb =25°C

Fig 3. Rated peak pulse power as a function of

exponential pulse duration (rectangular

waveform); typical values

Fig 4. Relative variation of rated peak pulse power as

a function of junction temperature; typical

values

006aab327

102

103

PPPM

(W)

tp (ms)

10−2103

102

10−1101 Tj (°C)

0 20015050 100

006aab321

0.4

0.8

1.2

PPPM

PPPM(25°C)

Product data sheet Rev. 01 — 3 September 2008 9 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

f = 1 MHz; Tamb =25°C

(1) MMBZ15VDL: unidirectional

(2) MMBZ15VDL: bidirectional

(3) MMBZ27VCL: unidirectional

(4) MMBZ27VCL: bidirectional

MMBZ27VCL: VRWM =22V

Fig 5. Diode capacitance as a function of reverse

voltage; typical values Fig 6. Reverse leakage current as a function of

junction temperature; typical values

Fig 7. V-I characteristics for a unidirectional

ESD protection diode Fig 8. V-I characteristics for a bidirectional

ESD protection diode

VR (V)

0252010 155

006aab328

100

(pF)

(1)

(2) (3)

(4)

006aab329

10−1

10−2

102

IRM

(nA)

10−3

Tamb (°C)

−75 17512525 75−25

006aab324

−VCL −VBR −VRWM −IRM

−IR

−IPP

P-N

−+

−IPPM

006aab325

−VCL −VBR −VRWM VCL

VBR

VRWM

−IRM

IRM

−IR

−IPP

IPP

−+

IPPM

−IPPM

Product data sheet Rev. 01 — 3 September 2008 10 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

8. Application information

The MMBZxVCL series and the MMBZxVDL series are designed for the protection of up

to two unidirectional data or signal lines from the damage caused by ESD and surge

pulses. The devices may be used on lines where the signal polarities are either positive or

negative with respect to ground. The devices provide a surge capability of 40 W per line

for a 10/1000 µs waveform.

Circuit board layout and protection device placement

Circuit board layout is critical for the suppression of ESD, Electrical Fast Transient (EFT)

and surge transients. The following guidelines are recommended:

1. Place the devices as close to the input terminal or connector as possible.

2. The path length between the device and the protected line should be minimized.

3. Keep parallel signal paths to a minimum.

4. Avoid running protected conductors in parallel with unprotected conductors.

5. Minimize all Printed-Circuit Board (PCB) conductive loops including power and

ground loops.

6. Minimize the length of the transient return path to ground.

7. Avoid using shared transient return paths to a common ground point.

8. Ground planes should be used whenever possible. For multilayer PCBs, use ground

vias.

9. Test information

9.1 Quality information

This product has been qualiﬁed in accordance with the Automotive Electronics Council

(AEC) standard

Q101 - Stress test qualiﬁcation for discrete semiconductors

, and is

suitable for use in automotive applications.

Fig 9. Typical application: ESD and transient voltage protection of data lines

006aab330

MMBZxVCL/VDL

line 1 to be protected

unidirectional protection

of two lines bidirectional protection

of one line

line 2 to be protected

GND

MMBZxVCL/VDL

line 1 to be protected

GND

Product data sheet Rev. 01 — 3 September 2008 11 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

10. Package outline

11. Packing information

[1] For further information and the availability of packing methods, see Section 15.

Fig 10. Package outline SOT23 (TO-236AB)

04-11-04Dimensions in mm

0.45

0.15

1.9

1.1

0.9

3.0

2.8

2.5

2.1 1.4

1.2

0.48

0.38 0.15

0.09

Table 11. Packing methods

The indicated -xxx are the last three digits of the 12NC ordering code.

[1]

Type number Package Description Packing quantity

3000 10000

MMBZ12VDL SOT23 4 mm pitch, 8 mm tape and reel -215 -235

MMBZ15VDL

MMBZ18VCL

MMBZ20VCL

MMBZ27VCL

MMBZ33VCL

MMBZ12VDL/DG SOT23 4 mm pitch, 8 mm tape and reel -215 -235

MMBZ15VDL/DG

MMBZ18VCL/DG

MMBZ20VCL/DG

MMBZ27VCL/DG

MMBZ33VCL/DG

Product data sheet Rev. 01 — 3 September 2008 12 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

12. Soldering

Fig 11. Reﬂow soldering footprint SOT23 (TO-236AB)

Fig 12. Wave soldering footprint SOT23 (TO-236AB)

solder lands

solder resist

occupied area

solder paste

sot023_fr

0.5

(3×)

0.6

(3×)

0.6

(3×)

0.7

(3×)

3.3

2.9

1.7

1.9

Dimensions in mm

solder lands

solder resist

occupied area

preferred transport direction during soldering

sot023_fw

2.8

4.5

1.4

4.6

1.4

(2×)

1.2

(2×)

2.2

2.6

Dimensions in mm

Product data sheet Rev. 01 — 3 September 2008 13 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

13. Revision history

Table 12. Revision history

Document ID Release date Data sheet status Change notice Supersedes

MMBZXVCL_MMBZXVDL_SER_1 20080903 Product data sheet - -

Product data sheet Rev. 01 — 3 September 2008 14 of 15

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

14. Legal information

14.1 Data sheet status

[1] Please consult the most recently issued document before initiating or completing a design.

[2] The term ‘short data sheet’ is explained in section “Deﬁnitions”.

[3] The product status of device(s) described in this document may have changed since this document was published and may differ in case of multiple devices. The latest product status

information is available on the Internet at URL http://www.nxp.com.

14.2 Deﬁnitions

Draft — The document is a draft version only. The content is still under

internal review and subject to formal approval, which may result in

modiﬁcations or additions. NXP Semiconductors does not give any

representations or warranties as to the accuracy or completeness of

information included herein and shall have no liability for the consequences of

use of such information.

Short data sheet — A short data sheet is an extract from a full data sheet

with the same product type number(s) and title. A short data sheet is intended

for quick reference only and should not be relied upon to contain detailed and

full information. For detailed and full information see the relevant full data

sheet, which is available on request via the local NXP Semiconductors sales

ofﬁce. In case of any inconsistency or conﬂict with the short data sheet, the

full data sheet shall prevail.

14.3 Disclaimers

General — Information in this document is believed to be accurate and

reliable. However, NXP Semiconductors does not give any representations or

warranties, expressed or implied, as to the accuracy or completeness of such

information and shall have no liability for the consequences of use of such

information.

Right to make changes — NXP Semiconductors reserves the right to make

changes to information published in this document, including without

limitation speciﬁcations and product descriptions, at any time and without

notice. This document supersedes and replaces all information supplied prior

to the publication hereof.

Suitability for use — NXP Semiconductors products are not designed,

authorized or warranted to be suitable for use in medical, military, aircraft,

space or life support equipment, nor in applications where failure or

malfunction of an NXP Semiconductors product can reasonably be expected

to result in personal injury, death or severe property or environmental

damage. NXP Semiconductors accepts no liability for inclusion and/or use of

NXP Semiconductors products in such equipment or applications and

therefore such inclusion and/or use is at the customer’s own risk.

Applications — Applications that are described herein for any of these

products are for illustrative purposes only. NXP Semiconductors makes no

representation or warranty that such applications will be suitable for the

speciﬁed use without further testing or modiﬁcation.

Limiting values — Stress above one or more limiting values (as deﬁned in

the Absolute Maximum Ratings System of IEC 60134) may cause permanent

damage to the device. Limiting values are stress ratings only and operation of

the device at these or any other conditions above those given in the

Characteristics sections of this document is not implied. Exposure to limiting

values for extended periods may affect device reliability.

Terms and conditions of sale — NXP Semiconductors products are sold

subject to the general terms and conditions of commercial sale, as published

at http://www.nxp.com/proﬁle/terms, including those pertaining to warranty,

intellectual property rights infringement and limitation of liability, unless

explicitly otherwise agreed to in writing by NXP Semiconductors. In case of

any inconsistency or conﬂict between information in this document and such

terms and conditions, the latter will prevail.

No offer to sell or license — Nothing in this document may be interpreted

or construed as an offer to sell products that is open for acceptance or the

grant, conveyance or implication of any license under any copyrights, patents

or other industrial or intellectual property rights.

Quick reference data — The Quick reference data is an extract of the

product data given in the Limiting values and Characteristics sections of this

document, and as such is not complete, exhaustive or legally binding.

ESD protection devices — These products are only intended for protection

against ElectroStatic Discharge (ESD) pulses and are not intended for any

other usage including, without limitation, voltage regulation applications. NXP

Semiconductors accepts no liability for use in such applications and therefore

such use is at the customer’s own risk.

14.4 Trademarks

Notice: All referenced brands, product names, service names and trademarks

are the property of their respective owners.

15. Contact information

For more information, please visit: http://www.nxp.com

For sales ofﬁce addresses, please send an email to: salesaddresses@nxp.com

Document status[1][2] Product status[3] Deﬁnition

Objective [short] data sheet Development This document contains data from the objective speciﬁcation for product development.

Preliminary [short] data sheet Qualiﬁcation This document contains data from the preliminary speciﬁcation.

Product [short] data sheet Production This document contains the product speciﬁcation.

NXP Semiconductors MMBZxVCL; MMBZxVDL series

Double ESD protection diodes for transient overvoltage suppression

For more information, please visit: http://www.nxp.com

For sales office addresses, please send an email to: salesaddresses@nxp.com

Date of release: 3 September 2008

Document identifier: MMBZXVCL_MMBZXVDL_SER_1

Please be aware that important notices concerning this document and the product(s)

described herein, have been included in section ‘Legal information’.

16. Contents

1 Product proﬁle . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 General description. . . . . . . . . . . . . . . . . . . . . . 1

1.2 Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.4 Quick reference data. . . . . . . . . . . . . . . . . . . . . 2

2 Pinning information. . . . . . . . . . . . . . . . . . . . . . 2

3 Ordering information. . . . . . . . . . . . . . . . . . . . . 3

4 Marking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

5 Limiting values. . . . . . . . . . . . . . . . . . . . . . . . . . 4

6 Thermal characteristics. . . . . . . . . . . . . . . . . . . 5

7 Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . 6

8 Application information. . . . . . . . . . . . . . . . . . 10

9 Test information. . . . . . . . . . . . . . . . . . . . . . . . 10

9.1 Quality information . . . . . . . . . . . . . . . . . . . . . 10

10 Package outline . . . . . . . . . . . . . . . . . . . . . . . . 11

11 Packing information. . . . . . . . . . . . . . . . . . . . . 11

12 Soldering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

13 Revision history. . . . . . . . . . . . . . . . . . . . . . . . 13

14 Legal information. . . . . . . . . . . . . . . . . . . . . . . 14

14.1 Data sheet status . . . . . . . . . . . . . . . . . . . . . . 14

14.2 Deﬁnitions. . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

14.3 Disclaimers. . . . . . . . . . . . . . . . . . . . . . . . . . . 14

14.4 Trademarks. . . . . . . . . . . . . . . . . . . . . . . . . . . 14

15 Contact information. . . . . . . . . . . . . . . . . . . . . 14

16 Contents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15