ETC BTS737-S2

BTS737S2
Smart High-Side Power Switch
Four Channels: 4 x 35mΩ
Ω
Advanced Current Sense
with ReverSave
Product Summary
Package
Operating Voltage
Vbb(on)
Active channels
On-state Resistance
RON
Nominal load current
IL(NOM)
Current limitation
IL(SCr)
one
35mΩ
5.4A
21A
4.5 ...40V
four parallel
9mΩ
11.1A
21A
P-DSO-28
General Description
•
•
N channel vertical power MOSFET with charge pump, ground referenced CMOS compatible input and
diagnostic feedback, monolithically integrated in Smart SIPMOS technology.
Fully protected by embedded protection functions
Applications
•
•
•
•
µC compatible high-side power switch with diagnostic feedback for 12V and 24V grounded loads
All types of resistive and capacitve loads
Most suitable for loads with high inrush currents, so as lamps
Replaces electromechanical relays, fuses and discrete circuits
Basic Functions
•
•
•
•
•
Very low standby current
Improved electromagnetic compatibility (EMC)
CMOS compatible input
Stable behaviour at undervoltage
Wide operating voltage range
Protection Functions
•
•
•
•
•
•
•
•
Reverse battery protection without external components
(ReverSave
)
Short circuit protection
Overload protection
Current limitation
Thermal shutdown
Overvoltage protection (not load dump) without external
resistor
Loss of ground protection
Electrostatic discharge protection (ESD)
Diagnostic Function
• Proportional load current sense (with defined fault signal
during thermal shutdown)
Infineon technologies
Page 1 of 1
Block Diagram
Vbb
IN1
IS1
IS2
Logic
Channel 1
Channel 2
Load 1
IN2
Load 2
IN3
IS3
IS4
IN4
Logic
Channel 3
Channel 4
GND
Load 3
Load 4
2001-07-13
BTS737S2
Functional diagram
overvoltage
protection
internal
voltage supply
logic
gate
control
+
charge
pump
current limit
VBB
clamp for
inductive load
OUT1
IN1
ESD
temperature
sensor
reverse
battery
protection
Proportional sense
current
IS1
R0
LOAD
only active
in off-state
.
IN2
IS2
channel 1
control and protection circuit
of
channel 2
GND1/2
IN3
IS3
OUT2
control and protection circuit
of
channel 3
OUT3
IN4
IS4
control and protection circuit
of
channel 4
GND3/4
Infineon technologies
OUT4
Page 2
2001-07-13
BTS737S2
Pin Definitions and Functions
Pin configuration
Pin
Symbol Function
1, 7, 8, Vbb
Positive power supply voltage. Design the
14,
wiring for the simultaneous max. short circuit
15, 28
currents from channel 1 to 4 and also for low
thermal resistance
4
IN1
Input 1,2, 3,4 activates channel 1,2,3,4 in case
of logic high signal
3
IN2
11
IN3
10
IN4
25,26,27 OUT1
Output 1,2,3,4 protected high-side power output
22,23,24 OUT2
of channel 1,23,4. Design the wiring for the
19,20,21 OUT3
max. short circuit current
16,17,18 OUT4
5
IS1
Diagnostic feedback 1 .. 4 of channel 1 to 4
Providing a sense current, proportional to the
6
IS2
load current
12
IS3
13
IS4
2
GND1/2 Ground of chip 1 (channel 1,2)
9
GND3/4 Ground of chip 2 (channel 3,4)
(top view)
Infineon technologies
Page 3
Vbb
GND1/2
IN2
IN1
IS1
IS2
Vbb
Vbb
GND3/4
IN4
IN3
IS3
IS4
Vbb
1
2
3
4
5
6
7
8
9
10
11
12
13
14
•
28
27
26
25
24
23
22
21
20
19
18
17
16
15
Vbb
OUT1
OUT1
OUT1
OUT2
OUT2
OUT2
OUT3
OUT3
OUT3
OUT4
OUT4
OUT4
Vbb
2001-07-13
BTS737S2
Maximum Ratings at Tj = 25°C unless otherwise specified
Parameter
Symbol
Supply voltage (overvoltage protection see page 6)
Supply voltage for full short circuit protection
Tj,start = -40 ...+150°C
Load current (Short-circuit current, see page 6)
Load dump protection1) VLoadDump = VA + Vs, VA = 13.5 V
RI2) = 2 Ω, td = 400 ms; IN = low or high,
each channel loaded with RL = 4.7 Ω,
Operating temperature range
Storage temperature range
Power dissipation (DC)4)
Ta = 25°C:
(all channels active)
Ta = 85°C:
Maximal switchable inductance, single pulse
Vbb = 12V, Tj,start = 150°C4),
IL = 4.0 A, EAS = 0.8J, 0 Ω
one channel:
IL = 6.0 A, EAS = 1.0J, 0 Ω
two parallel channels:
four parallel channels:
IL = 9.5 A, EAS = 1.5J, 0 Ω
Vbb
Vbb
Values
Unit
43
36
V
V
IL
VLoad dump3)
self-limited
60
A
V
Tj
Tstg
Ptot
-40 ...+150
-55 ...+150
3.7
1.9
°C
ZL
33
37
64
mH
VESD
1.0
4.0
8.0
kV
-10 ... +16
±0.3
±0.3
V
mA
W
see diagrams on page 11
Electrostatic discharge capability (ESD)
IN:
(Human Body Model)
IS:
out to all other pins shorted:
acc. MIL-STD883D, method 3015.7 and ESD assn. std. S5.1-1993
R=1.5kΩ; C=100pF
Input voltage (DC)
Current through input pin (DC)
Current through sense pin (DC)
VIN
IIN
IIS
see internal circuit diagram page 10
1)
2)
3)
4)
Supply voltages higher than Vbb(AZ) require an external current limit for the GND and status pins (a 75Ω
resistor for the GND connection is recommended.
RI = internal resistance of the load dump test pulse generator
VLoad dump is setup without the DUT connected to the generator per ISO 7637-1 and DIN 40839
Device on 50mm*50mm*1.5mm epoxy PCB FR4 with 6cm2 (one layer, 70µm thick) copper area for Vbb
connection. PCB is vertical without blown air. See page 16
Infineon technologies
Page 4
2001-07-13
BTS737S2
Thermal Characteristics
Parameter and Conditions
Symbol
min
Thermal resistance
junction - soldering point5)6),
each channel: Rthjs
6)
Rthja
junction – ambient
2
@ 6 cm cooling area
one channel active:
all channels active:
Values
typ
Max
--
--
11
---
40
33
---
Unit
K/W
Electrical Characteristics
Parameter and Conditions, each of the four channels
Symbol
at Tj = -40...+150°C, Vbb = 12 V unless otherwise specified
Load Switching Capabilities and Characteristics
On-state resistance (Vbb to OUT); IL = 5 A, Vbb ≥ 7V
each channel,
Tj = 25°C: RON
Tj = 150°C:
two parallel channels, Tj = 25°C:
four parallel channels, Tj = 25°C:
Values
min
typ
Max
Unit
-----
30
55
15
8
35
64
18
9
mΩ
5.0
6.7
10.5
5.4
7.4
11.1
----
A
--
--
1
mA
---
50
120
150
220
µs
dV/dton
0.3
--
1
V/µs
-dV/dtoff
0.15
--
1
V/µs
see diagram, page 12
Nominal load current
one channel active: IL(NOM)
two parallel channels active:
four parallel channels active:
Device on PCB6), Ta = 85°C, Tj ≤ 150°C
Output current while GND disconnected, VIN = 0,
IL(GNDhigh)
see diagram page 11; (not tested specified by design)
Turn-on time7)
IN
Turn-off time
IN
RL = 12 Ω
Slew rate on 7)
10 to 30% VOUT, RL = 12 Ω:
Slew rate off 7)
70 to 40% VOUT, RL = 12 Ω:
5)
6)
7)
to 90% VOUT: ton
to 10% VOUT: toff
Soldering point: upper side of solder edge of device pin 7,8. See page 16.
Device on 50mm*50mm*1.5mm epoxy PCB FR4 with 6cm2 (one layer, 70µm thick) copper area for Vbb
connection. PCB is vertical without blown air. See page 16
See timing diagram on page 13.
Infineon technologies
Page 5
2001-07-13
BTS737S2
Parameter and Conditions, each of the four channels
Symbol
Values
min
typ
Max
Vbb(on)
Vbb(AZ)
4.5
41
-47
40
52
V
V
Ibb(off)
-----
25
80
25
4
15
µA
IL(off)
10
40
-1
--
IGND
---
1.6
6.0
---
mA
IL(lim)
36
45
58
A
---
40
40
--
A
ms
at Tj = -40...+150°C, Vbb = 12 V unless otherwise specified
Operating Parameters
Operating voltage
Overvoltage protection8)
I bb = 40 mA
Standby current9)
Tj =-40...25°C:
VIN = 0; see diagram page 12
Tj =150°C:
not tested, specified by design: Tj =125°C:
Off-State output current
Tj =-40...25°C:
(included in Ibb(off))VIN = 0; each channel;Tj=150°C:
Operating current, VIN = 5V,
IGND = IGND1/2 + IGND3/4,
one channel on:
four channels on:
Unit
µA
Protection Functions10)
Current limit, (see timing diagrams, page 14)
Repetitive short circuit current limit,
Tj = Tjt
each channel IL(SCr)
two,three or four parallel channels
(see timing diagrams, page 14)
Initial short circuit shutdown time
Tj,start =25°C: toff(SC)
--
4
---
18
14
150
--
21
17
-10
30
20
---
(see timing diagrams on page 14)
Output clamp (inductive load switch off)11)
at VON(CL) = Vbb - VOUT, IL= 40 mA Tj =-40°C..25°C: VON(CL)
Tj =150°C:
Thermal overload trip temperature
Tjt
Thermal hysteresis
∆Tjt
V
°C
K
Supply voltages higher than Vbb(AZ) require an external current limit for the GND and status pins (a 150Ω
resistor for the GND connection is recommended). See also VON(CL) in table of protection functions and
circuit diagram on page 10.
9) Measured with load; for the whole device; all channels off
10) Integrated protection functions are designed to prevent IC destruction under fault conditions described in the
data sheet. Fault conditions are considered as "outside" normal operating range. Protection functions are not
designed for continuous repetitive operation.
11) If channels are connected in parallel, output clamp is usually accomplished by the channel with the lowest
VON(CL)
8)
Infineon technologies
Page 6
2001-07-13
BTS737S2
Parameter and Conditions, each of the four channels
Symbol
at Tj = -40...+150°C, Vbb = 12 V unless otherwise specified
Reverse Battery
Reverse battery voltage 12)
On-state resistance with reverse battery
IL = 2A; Vbb = 12V
Tj =25°C:
Tj =150°C:
Input13)
Input resistance
Values
min
typ
Max
Unit
-Vbb
--
--
28
V
Ron
---
45
80
60
120
mΩ
2.5
3.5
6.0
kΩ
1.7
1.5
-1
20
--0.3
-50
3.2
--35
90
V
V
V
µA
µA
RI
(see circuit page 10)
Input turn-on threshold voltage
Input turn-off threshold voltage
Input threshold hysteresis
Off state input current
On state input current
VIN(T+)
VIN(T-)
∆ VIN(T)
VIN = 0.4 V: IIN(off)
VIN = 5 V: IIN(on)
12)
Power dissipation is higher compared to normal operating conditions due to the elevated on-state reistance.
The temperature protection and sense functionality is not active during reverse current operation! Input and
Status currents have to be limited (see max. ratings page 4 and circuit page 10).
13) If ground resistors R
GND are used, add the voltage drop across these resistors.
Infineon technologies
Page 7
2001-07-13
BTS737S2
Parameter and Conditions, each of the four channels
Symbol
at Tj = -40...+150°C, Vbb = 12 V unless otherwise specified
Diagnostic Characteristics
Current sense ratio, static on-condition,
kILIS
kILIS =IL:IIS
-40°C
+25°C
+150°C
IL = 10 A:
IL = 2 A:
IL = 1 A:
IL = 0.5 A:
IL = 10 A:
IL = 2 A:
IL = 1 A:
IL = 0.5 A:
IL = 10 A:
IL = 2 A:
IL = 1 A:
IL = 0.5 A:
Sense signal in case of fault-conditions14)
Vfault
Sense signal delay after thermal shutdown15)
tdelay(fault)
Sense current saturation
IIS,lim
Current sense output voltage limitation
IIS = 0, IL = 5 A: VIS(lim)
Current sense leakage/offset current
VIN=0, VIS = 0, IL = 0: IIS(LL)
VIN=5 V, VIS = 0, IL = 0: IIS(LH)
Current sense settling time to IIS static±10% after
tson(IS)
positive input slope, IL = 0
5 A,
Values
min
typ
Max
Unit
--
5 000
--
4575
4100
4200
3580
4600
4250
4310
3820
4675
4475
4350
4200
5000
5000
5200
5800
4900
4900
5100
5600
4900
4900
5000
5200
5425
5900
6200
8080
5200
5550
6010
7320
5125
5325
5650
6200
5.8
6.3
6.9
V
--
--
1
ms
4
--
--
mA
5.8
6.3
6.9
V
---
-2.5
1
--
µA
--
--
300
µs
--
7
--
kΩ
(not tested, specified by design)
Internal output pull down
R0
only active in off-state
14)
In the case of current limitation or thermal shutdown the sense signal is no longer a current proportional to
the load current, but a fixed voltage of typ. 5 V.
15) In the case of thermal shutdown the V
signal remains for tdelay(fault) longer than the restart of the switch (see
fault
diagram on page 15).
Infineon technologies
Page 8
2001-07-13
BTS737S2
Truth Table
Input
level
Output
level
L
H
L
H
Current
Sense
IIS
0
nominal
H
H
Vfault
L
H
L
H
L
H
L
H
L
L
L
L
H
H
Z
H
0
Vfault
0
Vfault
0
<nominal17)
0
0
L
L
0
Normal
Operation
CurrentLimitation16)
Short circuit to GND
Overtemperature
Short circuit to Vbb
Open load
Negative output
Voltage clamp
L = "Low" Level
X = don't care
Z = high impedance, potential depends on external circuit
H = "High" Level
Vfault = 5V typ, constant voltage independent of external used sense resistor.
Parallel switching of channels is possible by connecting the inputs and outputs in parallel. The current sense
outputs have to be connected with a single sense resistor.
Terms
Ibb
IIN1
V bb
IIN2
IIS1
V IN1
V IN2
IIS2
V IS1
V IS2
Leadfram e
3
5
2
6
IN 1
V bb
OUT1
IN 2
IS 1
IS 2
PROFE T
Chip 1
OUT2
GND1/2
V O N1
25
26
27
22
23
24
V O N2
V bb
IL1
V IN3
V O UT1
IIN4
IIS3
IL2
V IN4
IIS4
V IS3
4
IIG ND1/2
IIN3
V O UT2
V IS4
Leadfram e
10
12
9
13
IN 3
V bb
OUT3
IN 4
IS3
PROFET
Chip 2
IS4
GND3/4
OUT4
V O N4
VON3
19
20
21
16
17
18
IL3
IL4
11
IIG ND3/4
V O UT4
V O UT3
Leadframe (Vbb) is connected to pin 1, 7, 8, 14, 15, 28
.
16)
17)
Current limitation is only possible while the device is switched on.
Low ohmic short to Vbb may reduce the output current IL and therefore also the sense current IIS.
Infineon technologies
Page 9
2001-07-13
BTS737S2
Input circuit (ESD protection), IN1 to IN4
R
IN
Overvoltage output clamp, OUT1 or OUT2
+Vbb
I
VZ
ESD-ZD I
I
V
I
ON
GND
OUT
The use of ESD zener diodes as voltage clamp at DC
conditions is not recommended.
Power GND
VON clamped to VON(CL) = 21 V typ.
Sense output
Normal operation: IS = IL / kILIS
VIS = IS * RIS; RIS = 1 kΩ nominal
RIS > 500Ω
I
IS
Overvoltage protection of logic part
GND1/2 or GND3/4
Sense output
logic
IS
V
+ V bb
IS
Vf
R
ESD-ZD
V
RI
IN
Logic
IS
IS
GND
V
ESD-Zener diode: VESD = 6.1 V typ., max 14 mA;
Integrated
GND resistor
RGND
Z1
R IS
GND
Operation under fault condition
so as thermal shut down or current limitation
Sense output
logic
Vfault
Vfault
Vf
ESD-ZD
R
Z2
Signal GND
VZ1 = 6.1 V typ., VZ2 = 47 V typ., RI = 3.5 kΩ typ.,
RGND = 75 Ω
Reverse battery protection
IS
- Vbb
GND
Logic
Vfault = 6V typ
Vfault < VESD under all conditions
IN
RI
Logic
MOSFET
IS
OUT
Power
MOSFET
Integrated
GND resistor
RGND
R IS
RL
Signal GND
Power GND
RGND = 75 Ω, RI = 3.5 kΩ typ,
In case of reverse battery the channel of the MOSFET is
turned on.
Temperature protection and sense functionality is not active
during inverse current operation.
Infineon technologies
Page 10
2001-07-13
BTS737S2
GND disconnect
Inductive load switch-off energy
dissipation
E bb
IN
E AS
Vbb
PROFET
IN
OUT
IS
bb
V
IN
V
OUT
PROFET
GND
V
ELoad
Vbb
=
V
GND
ST
L
IS
GND
ZL
{
EL
ER
R
L
Any kind of load. In case of IN = high is VOUT ≈ VIN - VIN(T+).
Due to VGND > 0, no VST = low signal available.
Energy stored in load inductance:
Vbb disconnect with energized inductive
load
high
IN
2
EL = 1/2·L·I L
While demagnetizing load inductance, the energy
dissipated in PROFET is
EAS= Ebb + EL - ER= VON(CL)·iL(t) dt,
Vbb
PROFET
with an approximate solution for RL > 0 Ω:
OUT
EAS=
IS
GND
V
IL· L
(V + |VOUT(CL)|)
2·RL bb
ln (1+ |V
IL·RL
OUT(CL)|
)
Maximum allowable load inductance for
a single switch off (one channel)4)
bb
L = f (IL ); Tj,start = 150°C, Vbb = 12 V, RL = 0 Ω
For inductive load currents up to the limits defined by ZL
(max. ratings and diagram on page 11) each switch is
protected against loss of Vbb.
ZL [mH]
1000
Consider at your PCB layout that in the case of Vbb disconnection with energized inductive load all the load current
flows through the GND connection.
100
10
1
0.1
0
1
2
3
4
5
6
7
IL [A]
Infineon technologies
Page 11
2001-07-13
BTS737S2
Typ. on-state resistance
RON = f (Vbb,Tj ); IL = 2 A, IN = high
RON [mOhm]
60
Tj = 150°C
50
180
25°C
30
-40°C
20
0
3
5
7
9
30
40
Vbb [V]
Typ. standby current
Ibb(off) = f (Tj ); Vbb = 9...34 V, IN1,2,3,4 = low
Ibb(off) [µA]
45
40
35
30
25
20
15
10
5
0
-50
0
50
100
150
200
Tj [°C]
Infineon technologies
Page 12
2001-07-13
BTS737S2
Functionality diagrams
All diagrams are shown for chip 1 (channel 1/2). For chip 2 (channel 3/4) the diagrams are valid too. The
channels 1 and 2, respectively 3 and 4, are symmetric and consequently the diagrams are valid for each
channel as well as for permuted channels
Figure 1a: Switching a resistive load,
change of load current in on-condition:
IN
Figure 1c: Behaviour of sense output:
Sense current (IS) and sense voltage (VS) as
function of load current dependent on the sense
resistor
Shown is VS and IS for three different sense
resistors. Curve 1 refers to a low resistor, curve 2 to
a medium-sized resistor and curve 3 to a big resistor.
Note, that the sense resistor may not fall short of a
minimum value of 500Ω.
VOUT
t on
IL
t off
t slc(IS)
t slc(IS)
VS
Load 1
VESD
Vfault
Load 2
3
IS,VS
t son(IS)
2
t soff(IS)
t
1
The sense signal is not valid during settling time after turn on or
change of load current.
IL
IS
1
Figure 1b: Vbb turn on:
IN
2
3
Vbb
IL(lim)
IL
IL
IS = IL / kILIS
VIS = IS * RIS; RIS = 1 kΩ nominal
RIS > 500Ω
IS,VS
proper turn on under all conditions
Infineon technologies
Page 13
2001-07-13
BTS737S2
Figure 2a: Switching a lamp:
Figure 3a: Short circuit:
shut down by overtempertature, reset by cooling
IN
IN
IL
IL(lim)
ST
V
OUT
VS
I
I L(SCr)
Vfault
L
t
The initial peak current should be limited by the lamp and not by the
current limit of the device.
Figure 2b: Switching a lamp with current limit:
The behaviour of IS and VS is shown for a resistor,
which refers to curve 1 in figure 1c
IN
Heating up may require several milliseconds, depending on
external conditions
ILL(lim’) = 50 A typ. increases with decreasing temperature.
Figure 3b: Turn on into short circuit:
shut down by overtemperature, restart by cooling
(two parallel switched channels 1 and 2)
IN1/2
IL1 + IL2
IL(SCp)
VOUT
I L(SCr)
IL
t
IS
off(SC)
VS1, VS2
VS
Vfault
Vfault
t
Infineon technologies
Page 14
2001-07-13
BTS737S2
Figure 4a: Overtemperature:
Reset if Tj <Tjt
The behaviour of IS and VS is shown for a resistor,
which refers to curve 1 in figure 1c
Figure 6b: Current sense ratio18):
10000
kILIS
IN
5000
IL
IS
0
[A] IL
0 1 2 3 4 5 6 7 8 9 10 11 12 13
VS
Vfault
tdelay(fault)
TJ
t
Figure 6a: Current sense versus load current:
1.3
[mA]
1.2
I IS
1.1
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
IL
0
0
1
2
3
4
5 [A] 6
18)
Infineon technologies
Page 15
This range for the current sense ratio refers to all
devices. The accuracy of the kILIS can be raised at
least by a factor of two by calibrating the value of
kILIS for every single device.
2001-07-13
BTS737S2
Package and Ordering Code
Standard: P-DSO-28-16
Q67060-S7017
+0.09
0.23
8˚ ma
x
0.35 x 45˚
7.6 -0.2 1)
0.4 +0.8
1.27
0.35
2.65 max
Ordering Code
0.2 -0.1
BTS 737 S2
2.45 -0.2
Sales Code
+0.15 2)
0.1
0.2 28x
28
1
10.3 ±0.3
15
18.1 -0.4 1)
14
Index Marking
1) Does not include plastic or metal protrusions of 0.15 max rer side
2) Does not include dambar protrusion of 0.05 max per side
GPS05123
All dimensions in millimetres
Definition of soldering point with temperature Ts:
upper side of solder edge of device pin 15.
Published by Infineon technologies AG, Bereich Bauelemente,
Vertrieb, Produkt-Information, Balanstraße 73, D-81541
München
Infineon technologies AG 2001. All Rights Reserved
As far as patents or other rights of third parties are concerned,
liability is only assumed for components per se, not for applications,
processes and circuits implemented within components or assemblies. The information describes a type of component and shall not
be considered as warranted characteristics. The characteristics for
which SIEMENS grants a warranty will only be specified in the
purchase contract. Terms of delivery and rights to change design
reserved. For questions on technology, delivery and prices please
contact the Offices of Semiconductor Group in Germany or the
Siemens Companies and Representatives woldwide (see address
list). Due to technical requirements components may contain dangerous substances. For information on the type in question please
contact your nearest Infineon technologies AG Office,
Semiconductor Group. Siemens AG is an approved CECC
manufacturer.
Packing: Please use the recycling operators known to you. We can
also help you - get in touch with your nearest sales office. By
agreement we will take packing material back, if it is sorted. You
must bear the costs of transport. For packing material that is returned to us unsorted or which we are not obliged to accept we shall
have to invoice you for any costs incurred.
Components used in life-support devices or systems must be
expressly authorised for such purpose! Critical components19) of
the Semiconductor Group of Infineon technologies AG, may only be
used in life supporting devices or systems20) with the express
written approval of the Semiconductor Group of Infineon
technologies AG.
Pin 7,8
Printed circuit board (FR4, 1.5mm thick, one layer
70µm, 6cm2 active heatsink area) as a reference for
max. power dissipation Ptot, nominal load current
IL(NOM) and thermal resistance Rthja
19) A critical component is a component used in a life-support
device or system whose failure can reasonably be expected to
cause the failure of that life-support device or system, or to
affect its safety or effectiveness of that device or system.
20) Life support devices or systems are intended (a) to be
implanted in the human body or (b) support and/or maintain
and sustain and/or protect human life. If they fail, it is
reasonably to assume that the health of the user or other
persons may be endangered.
Infineon technologies
Page 16
2001-07-13