Control circuit for power MOS bridge driver in automotive applications with ISO 9141bus interface.
R
Reference
BIAS
VCC
Charge
pump
=
V
S1TH
Control Logic
=
V
S2TH
CP
11
CP
13
CB1
12
GH1
14
S1
R
S1
19
GL1
R
GL1
18
GL2
R
GL2
17
S2
R
S2
15
GH2
16
CB2
October 2005
7
RX
R
RX
VCC
R
TX
8
TX
ISO-Interface
=
0.5 • V
VS
I
KH
9
K
20
GND
REV. 4
1/17
L9904
Table 2. Pin Function
N°PinDescription
1 STOpen Drain Switch for Stepup converter
2DGOpen drain diagnostic output
3PWMPWM input for H-bridge control
4ENEnable input
5DIRDirection select input for H-bridge control
6PRProgrammable cross conduction protection time
7RXISO 9141 interface, receiver output
8TXISO 9141 interface, transmitter input
9KISO 9141 Interface, bidirectional communication K-line
10VSSupply voltage
11CPCharge pump for driving a power MOS as reverse battery protection
12GH1Gate driver for power MOS highside switch in halfbridge 1
13CB1External bootstrap capacitor
14S1Source/drain of halfbridge 1
15GH2Gate driver for power MOS highside switch in halfbridge 2
16CB2External bootstrap capacitor
17S2Source/drain of halfbridge 2
18GL2Gate driver for power MOS lowside switch in halfbridge 2
19GL1Gate driver for power MOS lowside switch in halfbridge 1
20GNDGround
Figure 3. Pin Connection (Top view)
ST
DG
PWM
EN
DIR
PR
RX
TX
KGH1
VSCP
2
3
4
5
6
7
8
9
10
SO20
20
19
18
17
16
15
14
13
12
11
GND1
GL1
GL2
S2
CB2
GH2
S1
CB1
2/17
L9904
Table 3. Absolute Maximum Ratings
SymbolParameterValueUnit
V
, V
CB1
, I
I
CB1
V
CP
I
CP
,V
V
DIR
,V
PWM ,VTX
,I
I
DIR
,I
PWM ,ITX
,V
V
DG
,IRX Logic output current-1mA
I
DG
, V
V
GH1
, I
I
GH1
, V
V
GL1
, I
I
GL1
V
V
PR
I
PR
, V
V
S1
, I
I
S1
V
ST
I
ST
V
VSDC
V
VSP
I
VS
For externally applied voltages or currents exceeding these limits damage of the device may occur!
All pins of the IC are protected against ESD. The verification is performed according to MIL883C, human body
model with R=1.5k
0.2mJ.
Bootstrap voltage -0.3 to 40V
CB2
Bootstrap current-100mA
CB2
Charge pump voltage-0.3 to 40V
Charge pump current-1mA
Logic input voltage-0.3 to 7 V
EN
Logic input current±1mA
EN
Logic output voltage -0.3 to 7V
RX
Gate driver voltage -0.3 to VSX + 10V
GH2
Gate driver current-1mA
GH2
Gate driver voltage-0.3 to 10V
GL2
Gate driver current-10mA
GL2
K-line voltage-20 to V
K
S
Programming input voltage -0.3 to 7V
Programming input current-1mA
Source/drain voltage-2 to VVS + 2V
S2
Source/drain current-10mA
S2
Output voltage-0.3 to 40V
Step up output current-1mA
DC supply voltage-0.3 to 28V
Pulse supply voltage (T < 500ms)40V
DC supply current-100mA
Ω
, C=100pF and discharge voltage ±2kV, corresponding to a maximum discharge energy of
V
Table 4. Thermal Data
SymbolParameterValueUnit
T
T
JSD
T
JSDH
R
th j-amb
1. see application note 110 for SO packages.
Operating junction temperature-40 to 150°C
J
Junction temperature thermal shutdown thresholdmin 150°C
Junction thermal shutdown hysteresistyp 15°C
Thermal resistance junction to ambient
1)
85°C/W
.
3/17
L9904
Table 5.
Electrical Characteristcs
(8V < VVS < 20V, VEN = HIGH, -40°C ≤ TJ ≤ 150°C, unless otherwise specified. The voltages are refered to
GND and currents are assumed positive, when current flows into the pin
SymbolParameterTest ConditionMin. Typ.Max.Unit
Supply (VS)
V
VS OVH
V
VS OVh
V
VS UVH
V
VS UVh
I
VSL
I
VSH
I
VSD
Enable input (EN)
V
V
V
R
H-bridge control inputs (DIR, PWM)
V
DIRL
V
PWML
V
DIRH
V
PWMH
V
DIRh
V
PWMh
R
R
PWM
DIAGNOSTIC output (DG)
V
R
Programmable cross conduction protection
N
I
ISO interface, transmission input (TX)
V
Overvoltage disable HIGH
283336V
threshold
Overvoltage threshold hysteresis
Undervoltage disable HIGH
2)
67V
1.6V
threshold
Undervoltage threshold
hysteresis
2)
0.66V
Supply currentVEN = 0 ; VVS = 13.5V; TJ< 85°C50µA
Supply current, pwm-modeVVS= 13.5V; VEN= HIGH;
= LOW; S1 = S2 = GND
V
DIR
f
PWM
C
GLX
R
PR
= 20kHz; C
= 4.7nF; C
= 10kΩ; C
CBX
GHX
= 150pF
PR
= 0.1µF;
= 4.7nF;
Supply current, dc-modeVVS= 13.5V; VEN= HIGH;
V
= LOW; S1 = S2 = GND
DIR
= LOW; C
V
PWM
= 10kΩ; C
R
PR
Low level1.5V
ENL
High level3.5V
ENH
ENh
Hysteresis threshold
Input pull down resistanceVEN = 5V1650100kΩ
EN
2)
GHX
= 150pF
PR
= 4.7nF
8.113mA
5.810mA
1V
Input low level1.5V
Input high level3.5V
Input threshold hysteresis
Internal pull up resistance
DIR
to internal VCC
Output dropIDG = 1mA0.6V
DG
Internal pull up resistance
DG
to internal VCC
Threshold voltage ratio V
PR
V
PRL
Current capability
PR
Input low level1.5V
TXL
3)
3)
2)
PRH
1V
V
DIR
= 0; V
= 01650100kΩ
PWM
VDG = 0V102040kΩ
4)
R
V
PR
PR
= 10kΩ
= 2V
/
1.822.2
-0.5mA
4/17
L9904
Table 5.
(8V < V
Electrical Characteristcs
< 20V, VEN = HIGH, -40°C ≤ TJ ≤ 150°C, unless otherwise specified. The voltages are refered to
VS
(continued)
GND and currents are assumed positive, when current flows into the pin
SymbolParameterTest ConditionMin. Typ.Max.Unit
V
V
R
ISO interface, receiver output (RX)
V
R
R
RXON
t
RXH
t
RXL
ISO interface, K-line (K)
V
V
V
I
R
I
KSC
t
t
t
t
t
Charge pump
V
Input high level3.5V
TXH
Input hysteresis voltage 2)1V
TXh
Internal pull up resistance to
TX
VTX = 0102040kΩ
internal VCC 3)
Output voltage high stage
RXL
Internal pull up resistance
RX
to internal VCC
3)
ON resistance to ground TX = LOW;
TX = HIGH; I
TX = HIGH;
= 0V
V
RX
= 1mA
I
RX
RX
= 0; V
= V
K
VS
4.55.5V
51020kΩ
4090Ω
Output high delay time Fig. 10.5µs
Output low delay time0.5µs
Input low level-20V0.45 ·
KL
Input high level
KH
Input hysteresis voltage 2)0.025·
Kh
Input currentVTX = HIGH-525µA
KH
ON resistance to groundVTX = LOW; IK=10mA1030Ω
KON
0.55 ·
V
VS
V
VS
Short circuit currentVTX = LOW40130mA
Transmission frequency60100kHz
f
K
2. not tested in production: guaranteed by design and verified in characterization
3. Internal V
4. see page 18 for calculation of programmable cross conduction protection time
Rise timeVVS = 13.5V; Fig. 1
Kr
is 4.5V ... 5.5V
VCC
26µs
External loads at K-line:
= 510Ω pull up
R
K
to V
VS
C
= 2.2nF to GND
K
Fall time26µs
Kf
Switch high delay time417µs
KH
Switch low delay time417µs
KL
Short circuit detection timeVVS = 13.5V;
SH
1040µs
TX = LOW
> 0.55 · V
V
Charge pump voltageVVS = 8V
CP
K
VS
V
+
VS
7V
V
VS
= 13.5V
+
V
VS
10V
V
= 20V
VS
+
V
VS
10V
V
VS
V
VS
0.8V
VVS+
14V
V
VS
14V
V
VS
+14V
+
5/17
L9904
Table 5.
(8V < V
Electrical Characteristcs
< 20V, VEN = HIGH, -40°C ≤ TJ ≤ 150°C, unless otherwise specified. The voltages are refered to
VS
(continued)
GND and currents are assumed positive, when current flows into the pin
SymbolParameterTest ConditionMin. Typ.Max.Unit
I
t
CP
CP
Charging current
= VVS + 8V
V
CP
Charging time
2)
VCP= VVS + 8V
f
Charge pump frequencyVVS = 13.5V250500750kHz
CP
Drivers for external highside power MOS
V
V
R
R
R
R
V
V
R
R
R
R
GH1L
GH2L
GH1H
GH2H
GH1H
GH2H
Bootstrap voltageVVS = 8V; I
CB1
CB2
ON-resistance of SINK stage
ON-resistance of SOURCE stage I
Gate ON voltage (SOURCE)VVS= VSX = 8V; I
Gate discharge resistanceEN = LOW10100kΩ
GH1
GH2
Sink resistance10100kΩ
S1
S2
Drivers for external lowside power MOS
R
GL1L
R
GL2L
R
GL1H,
R
GL2H
V
GL1H,
V
GL2H
R
R
2. not tested in production: guaranteed by design and verified in characterization
ON-resistance of SINK stageI
ON-resistance of SOURCE stage I
Gate ON voltage (SOURCE)VVS = 8V; I
Gate discharge resistanceEN = LOW10100kΩ
GL1
GL2
Timing of the drivers
t
GH1LH
t
GH2LH
Propagation delay timeFig. 2
V
= 13.5V-50-75µA
VS
V
= 13.5V
VS
C
= 10nF
CP
VVS =13.5V; I
V
= 20V; I
VS
V
CBX
I
GHX
V
CBX
I
GHX
GHX
I
GHX
C
CBX
= VSX = 13.5V; I
V
VS
C
CBX
= VSX = 20V; I
V
VS
C
CBX
GLX
I
GLX
GLX
I
GLX
V
= 13.5V; I
VS
= 20V; I
V
VS
CBX
CBX
CBX
= 8V; VSX = 0
= 50mA; T
= 8V; VSX = 0
= 50mA; T
= -50mA; TJ = 25°C
= -50mA; TJ = 125°C
= 0.1µF
= 0.1µF
= 0.1µF
= 50mA; TJ = 25°C
= 50mA; TJ = 125°C
= -50mA; TJ = 25°C
= -50mA; TJ = 125°C
= 0
GLX
GLX
GLX
= 0; VSX = 0
= 0; VSX = 0
= 0; VSX = 0
= 25°C
J
= 125°C
J
= 0;
GHX
= 0;
GHX
= 0;
GHX
= 0
= 0
7.5
10
10
V
VS
+6.5V
V
VS
10V
V
VS
+10V
7V
10V
10V
1.24ms
+
14
14
14
10Ω
20Ω
10
20
V
VS
+14V
V
VS
+14V
V
VS
+14V
10
20
10
20
V
VS
V
VS
14V
500ns
= 13.5V
V
VS
VS1 = VS2 =0
C
= 0.1µF
CBX
V
V
V
Ω
Ω
Ω
Ω
Ω
Ω
6/17
RPR= 10kW
L9904
Table 5.
(8V < V
Electrical Characteristcs
< 20V, VEN = HIGH, -40°C ≤ TJ ≤ 150°C, unless otherwise specified. The voltages are refered to
VS
(continued)
GND and currents are assumed positive, when current flows into the pin
SymbolParameterTest ConditionMin. Typ.Max.Unit
t
GH1LH
t
GH2LH
t
GH1HL
t
GH2HL
Propagation delay time including
cross conduction protection time
t
CCP
Propagation delay time500ns
Fig. 2
V
VS
V
S1
C
CBX
C
PR
= 13.5V
= VS2 =0
= 0.1µF
= 150pF;
RPR= 10kΩ;
5)
t
GL1LH
t
GL2LH
Propagation delay timeFig. 2
V
VS
= 13.5V
VS1 = VS2 =0
C
= 0.1µF
CBX
= 10kΩ
R
PR
t
GL1LH
t
GL2LH
t
GL1HL
t
GL2HL
Propagation delay time including
cross conduction protection time
t
CCP
Propagation delay time500ns
Fig. 2
V
VS
V
S1
C
CBX
C
PR
= 13.5V
= VS2 =0
= 0.1µF
= 150pF;
RPR= 10kΩ;
5)
t
GH1r
t
GH2r
t
GH1f
t
GH2f
t
GL1r
t
GL2r
t
GL1f
t
GL2f
Rise timeFig. 2
= 13.5V
V
VS
V
= VS2 =0
Fall time1µs
Rise time1µs
Fall time1µs
C
C
C
R
S1
CBX
GHX
GLX
PR
= 0.1µF
= 4.7nF
= 4.7nF
= 10kΩ;
Short Circuit Detection
V
S1TH
V
S2TH
t
SCd
Step up converter (ST) (5.2V ≤ V
V
V
R
DSON
f
Threshold voltage 4V
Detection time51015µs
< 10V)
VS
ST disable HIGH threshold10V
STH
ST disable threshold hysteresis
STh
voltage
Open drain ON resistance
Clock frequency50100149kHz
ST
2. not tested in production: guaranteed by design and verified in characterization
5. tested with differed values in production but guaranteed by design and verified in characterization
2)
= 5.2V;
V
VS
= 50mA
I
ST
0.711.3µs
500ns
0.711.3µs
1µs
12V
20Ω
7/17
L9904
Figure 4. Timing of the ISO-interface
V
TX
0.3 • V
VCC
t
V
K
KL
t
Kf
0.7 • V
t
KH
t
Kr
VCC
0.3 • V
VCC
t
0.55 • V
0.45 • V
V
RX
open drain
transistor at
K-pin
ON
OFF
VS
VS
t
RXL
0.3 • V
VCC
20%
80%
t
RXH
0.7 • V
VCC
IK> I
t
SH
KSC
Figure 5. Timing of the drivers for the external MOS regarding the inputs DIR and PWM
PWM
or
DIR
50%
t
t
8/17
GHX
GLX
80%
20%
80%
20%
t
GHXLHtGHXr
t
GLXHLtGLXf
t
GHXHL
t
GLXLH
t
GHXf
t
GLXr
t
t
t
Figure 6. I(V) characteristics of the K-Line for TX = HIGH and VVS=13.5V
IK [mA]
0.2
L9904
Figure 7. Driving sequence
0.1
0.0
-0.1
-0.2
-0.3
-0.4
-0.5
-20-1001020
Ω
~50k
VK [V]
EN
DIR
Ω
~50k
≈
≈
Note:
Before standby mode
(EN=low) a braking phase
is mandatory to discharge
the stored energy of the
motor.
PWM
GL2
GH2
GL1
GH1
braking
≈≈
≈
9/17
L9904
Figure 8. Charging time of an external capacitor of 10nF connected to CP pin at VVS=8V and
=13.5V
V
VS
voltage [V]
30
25
20
15
10
5
0
01234
Figure 9. Application Circuit Diagram
V
BAT
D1
VS
10
C
C
S2
Voltage
Regulator
µC
V
GND
CC
S1
ST
1
VCC
Overvoltage
Undervoltage
R
DG
DG
EN
DIR
PWM
PR
C
R
PR
PR
RX
TX
Thermal shut down
2
4
R
EN
5
R
DIR
VCC
R
PWM
3
6
Timer
7
R
RX
VCC
R
TX
8
Charging time of a 10nF load at CP
CP for VS=13.5V
CP for VS=8V
EN
time [ms]
R
Refer ence
+
V
=
STH
f
ST
VCC
BIAS
Charge
pump
V
=
S1TH
Control Logic
V
=
S2TH
ISO-Interface
0.5•V
=
VS
I
KH
CP
11
CP
13
CB1
12
GH1
14
S1
R
S1
GL1
19
R
GL1
GL2
18
R
GL2
S2
17
R
S2
GH2
15
CB2
16
K
9
GND
20
R
C
B1
C1
M
R
R
C
B2
R
K-Line
10/17
L9904
3FUNCTIONAL DESCRIPTION
3.1 General
The L9904 integrated circuit (IC) is designed to control four external N-channel MOS transistors in H-Bridge configuration for DC-motor driving in automotive applications. It includes an ISO9141 compatible interface. A typical
application is shown in fig.9.
3.2 Voltage supply
The IC is supplied via an external reverse battery protection diode to the VVS pin. The typical operating voltage
range is down to 8V.
The supply current consumption of the IC composes of static and a dynamic part. The static current is typically
5.8mA. The dynamical current I
of the external power mos transistor. The current can be estimated by the expression:
An external power transistor with a gate charge of Q
quires a dynamical supply current of I
The total supply current consumption is I
3.3 Extended supply voltage range (ST)
The operating battery voltage range can be extended down to 6V using the additional components shown in
fig.7. A small inductor of L~150
with the switching open drain output ST. The switching frequency is typical 100kHz with a fixed duty cycle of
50%. The step up converter starts below V
at V
> 10V to avoid EME at nominal battery voltage. The diode D2 in series with the ST pin is necessary only
VS
for systems with negative battery voltage. No additional load can be driven by the step up converter.
is depending of the PWM frequency f
dyn
I
µ
H (I
= 2 · f
dyn
= 6.4mA.
dyn
= 5.8mA + 6.4mA = 12.2mA.
VS
~500mA) in series to the battery supply builts up a step up converter
peak
< 8V, increases the supply voltage at the VS pin and switches off
VS
· Q
PWM
Gate
Gate
= 160nC and a PWM frequency of f
and the required gate charge Q
PWM
PWM
Gate
= 20kHz re-
Figure 10.
V
BAT
L1D1
D2
C1C2
VS
ST
L9904
-
+
V
=
STH
f
ST
11/17
L9904
3.4 Control inputs (EN, DIR, PWM)
The cmos level inputs drive the device as shown in fig.7 and described in the truth table.
The device is activated with enable input HIGH signal. For enable input floating (not connected) or VEN=0V the
device is in standby mode. When activating the device a wake-up time of 50µs is recommended to stabilize the
internal supplies.
The DIR and PWM inputs control the driver of the external H-Bridge transistors. The motor direction can be
choosen with the DIR input, the duty cycle and frequency with the PWM input. Unconnected inputs are defined
by internal pull up resistors. During wake-up and braking and before disactivating the IC via enable both inputs
should be driven HIGH.
Table 6.
StatusControl inputsDevice status
Truth table:
Driver stage for external
power MOS
ENDIR
1 0xxxxxx
2 1xx1000LLLLLthermal
3 1xx0100LLLLLovervoltage
4 1xx0010LLLLL undervoltage
5 1xx0001
6 1000000LHHLH
7 1x10000LHLHH braking mode
8 1100000HLLHH
PWM
TSOVUVSCGH1GL1GH2GL2DG
7)
R
X
R
6)
X
7)
R
6)
6)
X
DiagnosticComment
RTstandby mode
shutdown
6
X
L
short circuit
Symbols: x Don't careR:Resistive outputTS:Thermal shutdown
0: Logic LOW or not activeL: Output in sink conditionOV:Overvoltage
1: Logic HIGH or activeH: Output in source conditionUV:Undervoltage
T: TristateSC:Short Circuit
6. Only those external MOS transistors of the H-Bridge which are in short circuit condition are switched off. All others remain driven
by DIR and PWM.
7. See Application Note AN2229
6)
3.5 Thermal shutdown
When the junction temperature exceeds T
the diagnostic DG is LOW until the junction temperature drops below T
all driver are switched in sink condition (L), the K- output is off and
JSD
JSD
- T
JHYST
.
3.6 Overvoltage Shutdown
When the supply voltage VVS exceeds the overvoltage threshold V
all driver are switched in sink condi-
VSOVH
tion (L), the K- output is off and the diagnostic DG is LOW.
3.7 Undervoltage Shutdown
For supply voltages below the undervoltage disable threshold the gate driver remains in sink condition (L) and
the diagnostic DG is low.
12/17
L9904
3.8 Short Circuit Detection
The output voltage at the S1 and S2 pin of the H-Bridge is monitored by comparators to detect shorts to ground
or battery. The activated external highside MOS transistor will be switched off if the voltage drop remains below
the comparator threshold voltage V
transistor remains in off condition, the diagnostic output goes LOW until the DIR or PWM input status will be
changed. The status doesn't change for the other MOS transistors. The external lowside MOS transistor will be
switched off if the voltage drop passes over the comparator threshold voltage V
the short current detection time t
SCd
until the DIR or PWM input status will be changed. The status doesn't change for the other MOS transistors.
3.9 Diagnostic Output (DG)
The diagnostic output provides a real time error detection, if monitors the following error stacks: Thermal shutdown, overvoltage shutdown , undervoltage shutdown and short circuit shutdown. The open drain output with
internal pull up resistor is LOW if an error is occuring.
3.10 Bootstrap capacitor (CB1,CB2)
To ensure, that the external power MOS transistors reach the required R
of 5V for logic level and 10V for standard power MOS transistors has to be guaranteed. The highside transistors
require a gate voltage higher than the supply voltage. This is achieved with the internal chargepump circuit in
combination with the bootstrap capacitor. The bootstrap capacitor is charged, when the highside MOS transistor
is OFF and the lowside is ON. When the lowside is switched OFF, the charged bootstrap capacitor is able to
supply the gate driver of the highside power MOS transistor. For effective charging the values of the bootstrap
capacitors should be larger than the gate-source capacitance of the power MOS and respect the required PWM
ratio.
S1TH
and V
for longer than the short current detection time t
S2TH
and V
S1TH
for longer than
S2TH
SCd
. The
. The transistor remains in off condition, the diagnostic output goes LOW
, a minimum gate source voltage
DSON
3.11 Chargepump circuit (CP)
The reverse battery protection can be obtained with an external N-channel MOS transistor as shown in fig.6. In
this case its drain-bulk diode provides the protection. The output CP is intended to drive the gate of this transistor above the battery voltage to switch on the MOS and to bypass the drain-bulk diode with the R
CP has a connection to VS through an internal diode and a 20k
Ω
resistor.
DSON
. The
3.12 Gate drivers for the external N-channel power MOS transistors (GH1, GH2, GL1, GL2)
High level at EN activates the driver of the external MOS under control of the DIR and PWM inputs (see truth
table and driving sequence fig.4). The external power MOS gates are connected via series resistors to the device to reduce electro magnetic emission (EME) of the system. The resistors influence the switching behaviour.
They have to be choosen carefully. Too large resistors enlarge the charging and discharging time of the power
MOS gate and can generate cross current in the halfbridges. The driver assures a longer switching delay time
from source to sink stage in order to prevent the cross conduction.
The gate source voltage is limited to 14V. The charge/discharge current is limited by the R
of the driver.
DSON
The drivers are not protected against shorts.
3.13 Programmable cross conduction protection
The external power MOS transistors in H-Bridge ( two half bridges) configuration are switched on with an additional delay time t
t
is determined by the external capacitor CPR and resistor RPR at the PR pin. The capacitor CPR is charged
CCP
up to the voltage limit V
ternal MOS transistor and the charging source at the PR pin. The resistor R
to prevent cross conduction in the halfbridge. The cross conduction protection time
CCP
. A level change on the control inputs DIR and PWM switches off the concerned ex-
PRH
discharges the capacitor CPR.
PR
The concerned external power MOS transistor will be switched on again when the voltage at PR reaches the
value of V
and 1nF. The resistor R
. After that the CPR will be charged again. The capacitor CPR should be choosen between 100pF
PRL
should be higher than 7kW. The delay time can be expressed as follows:
PR
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L9904
K
t
= RPR · CPR · ln NPR with NPR= V
CCP
t
= 0.69 · RPR · CPR
CCP
3.14 ISO-Interface
The ISO-Interface provides the communication between the micro controller and a serial bus with a baud rate
up to 60kbit/s via a single wire which is V
and GND compatible. The logic level transmission input TX drives
BAT
the open drain K-output. The K output can be connected to a serial bus with a pull up resistor to V
pin is protected against overvoltage, short to GND and VS and can be driven beyond V
or GND the output shows high impedance characteristic. The open drain output RX with an internal pull
of V
VS
up resistor monitors the status at the K-pin to read the received data and control the transmitted data. Short
circuit condition at K-pin is recognized if the internal open drain transistor isn't able to pull the voltage potential
at K-pin below the threshold of 0.45·V
. Then the RX stays in high condition. A timer starts and switches the
VS
open drain transistor after typ. 20µs off. A next low at the TX input resets the timer and the open drain transistor
switches on again.
Figure 11. Functional schematic of the ISO-interface
RX
PRH
/ V
PRL
= 2
. The K-
and GND. During lack
VS
BAT
TX
R
RX
0.5 •V
R
=
delay
T
SH
V
CC
R
TX
R
Q
S
VS
I
KH
14/17
Figure 12. SO20 Mechanical Data & Package Dimensions
L9904
DIM.
A2.352.650.0930.104
A10.100.300.0040.012
B0.330.510.0130.200
C0.230.320.0090.013
(1)
D
E7.407.600.2910.299
e1.270.050
H10.010.65 0.3940.419
h0.250.75 0.0100.030
L0.401.27 0.0160.050
k0˚ (min.), 8˚ (max.)
ddd0.100.004
(1) “D” dimension does not include mold flash, pro tusions or gate
burrs. Mold flash, protusions or g ate burrs shall not exceed
0.15mm per side.
mminch
MIN.TYP. MAX. MIN.TYP. MAX.
12.6013.00 0.4960.512
OUTLINE AND
MECHANICAL DATA
SO20
0016022 D
15/17
L9904
Table 7. Revision History
DateRevisionDescription of Changes
October 20021First Issue on ST-Press DMS
January 20042Migration from ST-Press to EDOCS DMS
May 20043Change Maturity from Product Preview to Final.
October 20054Inserted on pag 12 AN2229 ref.
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L9904
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