TrilithIC
Data Sheet
1
Overview
BTS 7811K
1.1
Features
• Quad D-MOS switch
• Free configurable as bridge or quad-switch
• Optimized for DC motor management applications
• Low
R
DS ON
: 26 mΩ high-side switch, 14 mΩ low-side
switch (typical values @ 25
°C)
P-TO263-15-1
• Maximum peak current: typ. 42 A @ 25
°C
• Very low quiescent current: typ. 4
µA
@ 25
°C
• Small outline, thermal optimized PowerPak
• Load and GND-short-circuit-protection
• Operates up to 40 V
• Status flag for over temperature
• Open load detection in Off-mode
• Overtemperature shut down with hysteresis
• Internal clamp diodes
• PWM capability up to 25kHz
• Cross current free operation up to 13A load current (typ. value @ 12V/150°C)
• Under-voltage detection with hysteresis
Type
BTS 7811K
1.2
Description
Package
P-TO263-15-1
The
BTS 7811K
is part of the
TrilithIC
family containing three dies in one package:
One double high-side switch and two low-side switches. The drains of these three
vertical DMOS chips are mounted on separated leadframes. The sources are connected
to individual pins, so the
BTS 7811K
can be used in H-bridge- as well as in any other
configuration. The double high-side is manufactured in
SMART SIPMOS
®
technology
which combines low
R
DS ON
vertical DMOS power stages with CMOS control circuit. The
protected high-side switch contains the control and diagnosis circuit. To achieve low
R
DS ON
and fast switching performance, the low-side switches are manufactured in
S-
FET 2
logic level technology.
Data Sheet
1
Rev. 2.0, 2006-07-18
BTS 7811K
1.3
Pin Configuration
(top view)
Molding
Compound
NC
SL1
IL1
NC
IH1
ST1
SH1
DHVS
GND
IH2
ST2
SH2
IL2
SL2
NC
1
Heat-Slug 1
2
18
3
4
5
Heat-Slug 2
6
7
8
9
10
11
12
Heat-Slug 3
13
16
14
15
DL2
17
DHVS
DL1
Figure 1: Pin Assignment
Data Sheet
2
Rev. 2.0, 2006-07-18
BTS 7811K
1.4
Pin No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
Pin Definitions and Functions
Symbol
NC
SL1
IL1
NC
IH1
ST1
SH1
DHVS
GND
IH2
ST2
SH2
IL2
SL2
NC
DL2
DHVS
DL1
Function
Not connected
Source of low-side switch 1
Analog input of low-side switch 1
Not connected
Digital input of high-side switch 1
Status of high-side switch 1; open Drain output
Source of high-side switch 1
Drain of high-side switches and power supply voltage
Ground of high-side switches
Digital input of high-side switch 2
Status of high-side switch 2; open Drain output
Source of high-side switch 2
Analog input of low-side switch 2
Source of low-side switch 2
Not connected
Drain of low-side switch 2
Heat-Slug 3
Drain of high-side switches and power supply voltage
Heat-Slug 2
Drain of low-side switch 1
Heat-Slug 1
Pins written in
bold type
need power wiring.
Data Sheet
3
Rev. 2.0, 2006-07-18
BTS 7811K
1.5
Functional Block Diagram
DHVS
6
8, 17
ST1
ST2
11
Diagnosis
Biasing and Protection
IH1
5
IH2
GND
10
Driver
IN OUT
0 0 L L
0 1 L H
1 0 H L
1 1 H H
R
O1
R
O2
16
12
SH2
DL2
9
7
18
SH1
DL1
3
IL1
13
IL2
2
14
SL1
SL2
Figure 2: Block Diagram
Data Sheet
4
Rev. 2.0, 2006-07-18
BTS 7811K
1.6
Circuit Description
Input Circuit
The control inputs IH1,2 consist of TTL/CMOS compatible Schmitt-Triggers with
hysteresis. Buffer amplifiers are driven by these stages and convert the logic signal into
the necessary form for driving the power output stages. The inputs are protected by ESD
clamp-diodes. The inputs IL1 and IL2 are connected to the gates of the standard N-
channel vertical power-MOS-FETs.
Output Stages
The output stages consist of a low
R
DS ON
Power-MOS H-bridge. In H-bridge
configuration, the D-MOS body diodes can be used for freewheeling when commutating
inductive loads. If the high-side switches are used as single switches, positive and
negative voltage spikes which occur when driving inductive loads are limited by
integrated power clamp diodes.
Short Circuit Protection
The outputs are protected against
– output short circuit to ground
– overload (load short circuit).
An internal OP-amp controls the Drain-Source-voltage by comparing the DS-voltage-
drop with an internal reference voltage. Above this trippoint the OP-Amp reduces the
output current depending on the junction temperature and the drop voltage.
Overtemperature Protection
The high-side switches incorporate an overtemperature protection circuit with hysteresis
which switches off the output transistors and sets the status output to low.
Undervoltage-Lockout (UVLO)
When
V
S
reaches the switch-on voltage
V
UVON
the IC becomes active with a hysteresis.
The high-side output transistors are switched off if the supply voltage
V
S
drops below the
switch off value
V
UVOFF.
Open Load Detection
The open load detection of the BTS 7811K works in OFF condition and is based on a
voltage measurement at the source of the high side switch. In order to use the open load
detection a pull up resistor to 5V has to be connected to source of one of the high side
switches. Because in ON condition this pull up resistor would connect the bridge output
to the µC supply it needs to be disconnected by a transistor when the high side switch is
Data Sheet
5
Rev. 2.0, 2006-07-18
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