November 2011 Doc ID 1107 Rev 10 1/16
16
L6234
Three phase motor driver
Features
■Supply voltage from 7 to 52 V
■5 A peak current
■RDSon 0.3 Ω typ. value at 25 °C
■Cross conduction protection
■TTL compatible driver
■Operating frequency up to 150 kHz
■Thermal shutdown
■Intrinsic fast free wheeling diodes
■Input and enable function for each half bridge
■10 V external reference available
Description
The L6234 is a triple half bridge to drive a
brushless DC motor.
It is realized in BCDmultipower technology which
combines isolated DMOS power transistors with
CMOS and Bipolar circuits on the same chip.
By using mixed technology it has been possible to
optimize the logic circuitry and the power stage to
achieve the best possible performance.
The output DMOS transistors can sustain a very
high current due to the fact that the DMOS
structure is not affected by the second breakdown
effect, the RMS maximum current is practically
limited by the dissipation capability of the
package.
All the logic inputs are TTL, CMOS and µP
compatible. Each channel is controlled by two
separate logic input.
L6234 is available in 20 pin PowerDIP package
(16+2+2) and in PowerSO20.
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Table 1. Device summary
Order code Package Packing
L6234 PowerDIP20 Tube
L6234PD PowerSO20 Tube
L6234PD013TR PowerSO20 Tape and reel
www.st.com
Contents L6234
2/16 Doc ID 1107 Rev 10
Contents
1 Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Thermal data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.1 Recommended operating conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
6 Circuit description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
7 Typical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
8 Mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
9 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
L6234 Block diagram
Doc ID 1107 Rev 10 3/16
1 Block diagram
Figure 1. Block diagram
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Pin connections L6234
4/16 Doc ID 1107 Rev 10
2 Pin connections
Figure 2. Pin connections
Table 2. Pin functions
PowerDIP PowerSO20 Name Function
1
20
10
6
5
15
OUT 1
OUT 2
OUT 3
Output of the channels 1/2/3.
2
19
9
7
4
14
IN 1
IN 2
IN 3
Logic input of channels 1/2/3. A logic HIGH level (when the
corresponding EN pin is HIGH) switches ON the upper DMOS
Power Transistor, while a logic LOW switches ON the
corresponding low side DMOS Power.
3
18
8
8
3
13
EN 1
EN 2
EN 3
Enable of the channels 1/2/3. A logic LOW level on this pin
switches off both power DMOS of the related channel.
4,7 9, 12 Vs Power supply voltage.
14 19 SENSE2
A sense resistor connected to this pin provides feedback for
motor current control for the bridge 3.
17 2 SENSE1
A sense resistor connected to this pin provides feedback for
motor current control for the bridges 1 and 2.
11 16 VREF
Internal voltage reference. A capacitor connected from this pin
to GND increases the stability of the Power DMOS drive
circuit.
12 17 VCP
Bootstrap oscillator. Oscillator output for the external charge
pump.
13 18 VBOOT Overvoltage input to drive the upper DMOS
5,6
15,16
1,10
11,20 GND Common ground terminal. In PowerDIP and SO packages
these pins are used to dissipate the heat forward the PCB.
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L6234 Thermal data
Doc ID 1107 Rev 10 5/16
3 Thermal data
Figure 3. Printed Heatsink
Table 3. Thermal data
Symbol Parameter DIP16+2+2 PowerSO20 Unit
Rth j-pin Thermal resistance, junction to pin 12 (1)
1. The thermal resistance is referred to the thermal path from the dissipating region on the top surface of the
silicon chip, to the points along the four central pins of the package, at a distance of 1.5 mm away from the
stand-offs.
– °C/W
Rth j-amb1 Thermal resistance, junction to ambient 40 (2)
2. If a dissipating surface, thick at least 35 mm, and with a surface similar or bigger than the one shown in
Figure 3, is created making use of the printed circuit. Such heatsinking surface is considered on the bottom
side of an horizontal PCB (worst case).
– °C/W
Rth j-amb2
Thermal resistance, junction characteristics) to
ambient 50 (3)
3. If the power dissipating pins (the four central ones), as well as the others, have a minimum thermal
connection with the external world (very thin strips only) so that the dissipation takes place through still air
and through the PCB itself. It is the same situation of note 2, without any heatsinking surface created on
purpose on the board.
– °C/W
Rth j-case Thermal resistance junction-case – 1.5 °C/W
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Maximum ratings L6234
6/16 Doc ID 1107 Rev 10
4 Maximum ratings
4.1 Recommended operating conditions
Table 4. Absolute maximum ratings
Symbol Parameter Value Unit
VS Power supply voltage 52 V
VIN, VEN Input enable voltage – 0.3 to 7 V
Ipeak Pulsed output current (1)
1. Pulse width limited only by junction temperature and the transient thermal impedance
5 A
VSENSE Sensing voltage (DC voltage) -1 to 4 V
Vboot Bootstrap peak voltage 62 V
VOD Differential output voltage (between any of the 3 OUT pins) 60 V
fC Commutation frequency 150 kHz
VREF Reference voltage 12 V
Ptot Total power dissipation L6234PD, TA = 70°C 2.3 W
Ptot Total power dissipation L6234, TA = 70°C 1.6 (2)
2. Mounted on board with minimized copper area
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Tstg, Tj Storage and junction temperature range -40 to 150 °C
Table 5. Recommended operating conditions
Symbol Parameter Value Unit
VS Supply voltage 7 to 42 V
VOD Peak to peak differential voltage (between any of the 3 out pins) 52 V
Iout
DC output current powerSO20 (TA = 25°C) 4 A
DC output current powerDIP (TA = 25°C) with infinite heatsink 2.8 A
VSENSE Sensing voltage (pulsed tw < 300 nsec) -4 to 4 V
Sensing voltage (DC) -1 to 1 V
Tj Junction temperature range -40 to 125 °C
L6234 Electrical characteristics
Doc ID 1107 Rev 10 7/16
5 Electrical characteristics
VS = 42 V; Tj = 25 °C unless otherwise specified.
Table 6. Electrical characteristics
Symbol Parameter Test condition Min. Typ. Max. Unit
VS Supply voltage 7 52 V
Vref Reference voltage 10 V
IS Quiescent supply current 6.5 mA
TS Thermal shutdown 150 °C
TD Dead time protection 300 ns
Output dmos transistor
IDSS Leakage current 1 mA
RDSon ON resistance 0.3 Ω
Source drain diode
VSD Forward ON voltage ISD = 4A; EN =
LOW 1.2 V
TRR Reverse recovery time IF = 4A 900 ns
Tpr Forward recovery time 200 ns
Logic levels
VINL, VENL Input LOW voltage -0.3 0.8 V
VINH, VENH Input HIGH voltage 2 7 V
IINL, IENL Input LOW current VIN,VEN = L -10 µA
IINH, IENH Input HIGH current VIN,VEN = H 30 µA
Circuit description L6234
8/16 Doc ID 1107 Rev 10
6 Circuit description
L6234 is a triple half bridge designed to drive brushless DC motors. Each half bridge has 2
power DMOS transistors with RDSon = 0.3 Ω.
The 3 half bridges can be controlled independently by means of the 3 inputs IN1, IN2, IN3
and the 3 inputs EN1, EN2, and EN3. An external connection to the 3 common low side
DMOS sources is provided to connect a sensing resistor for constant current chopping
application.
The driving stage and the logic stage are designed to work from 7 V to 52 V.
L6234 Typical characteristics
Doc ID 1107 Rev 10 9/16
7 Typical characteristics
Figure 4. Quiescent current vs. supply
voltage
Figure 5. Normalized quiescent current vs.
switching frequency
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Figure 6. Typical RDSon vs. supply voltage Figure 7. Source drain forward on voltage vs.
junction temperature
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Typical characteristics L6234
10/16 Doc ID 1107 Rev 10
Figure 8. Typical diode forward ON
characteristics
Figure 9. Reference voltage vs. supply
voltage
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Figure 10. Reference voltage vs. junction
temperature
Figure 11. PowerSO-20 transient thermal
resistance
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L6234 Typical characteristics
Doc ID 1107 Rev 10 11/16
Figure 12. PowerSO-20 thermal resistance
(mounted on Aluminium substrate)
Figure 13. PowerSO-20 thermal resistance
(mounted on FR4 monolayer
substrate)
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Figure 14. PowerSO-20: with external heatsink Figure 15. Thermal impedance of PowerSO-20
and standard SO20
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Mechanical data L6234
12/16 Doc ID 1107 Rev 10
8 Mechanical data
In order to meet environmental requirements, ST offers these devices in different grades of
ECOPACK® packages, depending on their level of environmental compliance. ECOPACK®
specifications, grade definitions and product status are available at: www.st.com.
ECOPACK® is an ST trademark.
Table 7. PowerSO20 mechanical data
Dim.
mm
Min. Typ. Max.
A 3.6
a1 0.1 0.3
a2 3.3
a3 0 0.1
b 0.4 0.53
c 0.23 0.32
D (1) 15.8 16
D1 9.4 9.8
E 13.9 14.5
e 1.27
e3 11.43
E1 (1) 10.9 11.1
E2 2.9
E3 5.8 6.2
G 0 0.1
H 15.5 15.9
h 1.1
L 0.8 1.1
N 8° (typ.)
S 8° (max.)
T 10
L6234 Mechanical data
Doc ID 1107 Rev 10 13/16
Figure 16. PowerSO20 mechanical drawing
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Mechanical data L6234
14/16 Doc ID 1107 Rev 10
Figure 17. PowerDIP20 mechanical drawing
Table 8. PowerDIP20 mechanical data
Dim.
mm
Min. Typ. Max.
a1 0.51
B 0.85 1.40
b 0.50
b1 0.38 0.50
D 24.80
E 8.80
e 2.54
e3 22.86
F 7.10
I 5.10
L 3.30
Z 1.27
L6234
16/16 Doc ID 1107 Rev 10
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