BUS IC
DC/DC CONVERTER
Wide range SMPS with watchdog
Wide range SMPS with reset
ÿ
PFM controller family
Step down converter, fully integrated
Step down converter, for external FET
PWM controller for LED
MOTOR DRIVER IC
RIPPLE COUNTER
DRIVER IC
I/O IC
SENSOR IC
SENSOR INTERFACE IC
ÿ
Adjustable, wide input range PFM controller family
FEATURES
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
ÿ
Supply voltage range VS
3V
to
60V
Up to
90%
efficiency
40µA
standby current
180µA
circuit operating current
1.5V
to
24V
or more adjustable output voltage
Up to
300kHz
switching frequency
Improved current-limited PFM control scheme
High current driver for external MOSFET
Under-voltage lockout and thermal shutdown
–
40°C
to +
125°C
operating temperature
SO8n package
910.26
basis version
910.24
additive with peak current halving for
medium loads and extended max. switch-on-time
910.25
additive with peak current halving for
medium loads and extended max. switch-on-time
and fault protection
APPLICATION
ÿ
ÿ
ÿ
ÿ
Minimum component DC-DC converters
14V, 28V
or
42V
automotive systems
Power conditioning for portable equipment
High efficiency on-card switching regulators
7
BLOCK DIAGRAM
VSM
Operating from
3V
to
60V
supply and in temperature ranges from
–
40°C
to +
125°C
the device is well suited for automotive appli-
cations. Requiring a minimum number of external components,
these regulators are simple to use and cost-saving.
Self-protection features include an overload detection circuit, an
overtemperature shutdown under fault conditions and an under-
voltage lockout.
6
VS
5
ON
4
VFB
The switching circuits are suitable for topologies requiring low
side FET, such as boost, flyback, Sepic, etc. Depending on the uti-
lized topology the controllers are capable of producing regulated
positive or negative output voltage.
3
ISEN
An advanced PFM control scheme gives these devices the benefits
of PWM converters with high efficiency for heavy loads, while us-
ing very low operating current for light loads to maintain excel-
lent behaviour with output load variation.
2
AGND
1
PGND
DESCRIPTION
The family of highly flexible, easy to use PFM controllers is ideal
for the use in wide input range switching regulator applications.
PINNING
Pin
Name
Description
Driver power ground pin. Connect pin to the current
sense resistor, the (-) terminal of the input capacitor
and the (-) terminal of the output capacitor. Due to
high currents, and high frequency operation of the
IC, a low impedance circuit ground plane is highly
recommended
Analog ground pin. This pin provides a clean ground
for the controller circuitry: The output voltage sensing
resistors should be connected to this ground pin. This
pin is connected to the IC substrate. Connect to the (-)
terminal of the output capacitor
Current sense input pin. Voltage generated across
an external sense resistor is fed into this pin. Filters
extensive high-frequency noise
Positive feedback pin. Connect to SMPS output via
external resistor divider to set output voltage and is
referenced to
1.22V.
For best stability, keep VFB lead as
short as possible and VFB stray capacitance as small
as possible
Switch ON input. Tie this pin to ground to force the IC
into idle mode. A voltage of VSM or higher switches
the controller in operating mode
Main supply input. Filters out high-frequency noise
with a
100nF
ceramic capacitor placed close to the pin
to PGND
Internal
5V
regulator output. The driver and all control
circuits are powered from this voltage. Decouple this
pin to PGND with a minimum of
4.7µF
tantalum and
100nF
ceramic capacitors
Drive output. Drives the gate of the external MOSFET
between PGND and VSM. Connect the external
MOSFET via a damping resistor to this pin
E910.24 | 25 | 26
PACKAGE
PGND
AGND
ISEN
VFB
1
2
3
4
8
7
6
5
MDRV
VSM
VS
ON
VBAT
8
VS
MDRV
VSM
VSM
int. supply &
references
VOut
ON
on/off
logic
MDRV
DRV
gain
control
PFM
circuit
Instr.
Ampl.
+
-
ISEN
AGND
overload
protection
VFB
PGND
Note
ELMOS Semiconductor AG (below ELMOS) reserves the right to make changes to the product contained in this publication without notice. ELMOS assumes no responsibility for the use of any
circuits described herein, conveys no licence under any patent or other right, and makes no representation that the circuits are free of patent infringement. While the information in this publication
has been checked, no responsibility, however, is assumed for inaccuracies. ELMOS does not recommend the use of any of its products in life support applications where the failure or malfunction of
the product can reasonably be expected to cause failure of a life-support system or to significantly affect its safety or effectiveness. Products are not authorized for use in such applications.
Copyright ©
2005
ELMOS
Reproduction, in part or whole, without the prior written consent of ELMOS, is prohibited.
www.elmos.de | sales@elmos.de
28
elmos product catalog june
2005
29
ELMOS [ ELMOS SEMICONDUCTOR AG ]
