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D1067
DESCRIPTION
The DMS1067 is a monolithic step-down switch
mode converter with a built in internal power
MOSFET. It achieves 2A continuous output cur-
rent over a wide input supply range with excel-
lent load and line regulation.
The DMS1067 requires a minimum number of
readily available standard external components.
Current mode operation provides fast transient
response and eases loop stabilization.
Fault condition protection includes cycle-by-
cycle current limiting and thermal shutdown. In
shutdown mode the regulator draws 25µA of
supply current.
FEATURES
2A Output Current
0.22Internal Power MOSFET Switch
Stable with Low ESR Output Ceramic Ca-
pacitors
Up to 95% Efficiency
25µA Shutdown Mode
Fixed 420KHz Frequency
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Wide 4.75 to 25V Operating Input Range
Output Adjustable from 1.22V to 21V
Programmable Under Voltage Lockout
APPLICATIONS
Distributed Power Systems
Battery Chargers
Pre-Regulator for Linear Regulators
PC Monitors
4.75 to 25
DMS1067
PACKAGE REFERENCE
Part number
DMS1067S
DMS1067P
Package
SOIC8
PDIP8
Temperature
–40°C to +125°C
–40°C to +125°C
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ABSOLUTE MAXIMUM RATINGS (1)
Supply Voltage (VIN)..................................... 27V
Switch Voltage (VSW)................ –1V to VIN + 1V
Bootstrap Voltage (VBS) ...Vsw-0.3V to VSW + 6V
Enable/UVLO Voltage (VEN)...........–0.3V to +6V
Comp Voltage (VCOMP) ...................–0.3V to +6V
Feedback Voltage (VFB) ................–0.3V to +6V
Junction Temperature ........................... +150°C
Lead Temperature ................................. +260°C
Storage Temperature.............. –65°C to +150°C
D1067
Recommended Operating Conditions(2)
Input Voltage (VIN) ......................... 4.75V to 25V
Operating Temperature...............–40°C to +125°C
Thermal Resistance(3) θJA θJC
SOIC8 .................................... 105..... 50... °C/W
PDIP8 ...................................... 95…...55.. °C/W
Notes:
1) Exceeding these ratings may damage the device.
2) The device is not guaranteed to function outside of its
operating conditions.
3) Measured on approximately 1” square of 1 oz copper.
ELECTRICAL CHARACTERISTICS
VIN = 12V, VEN = 5V,TA = +25°C, unless otherwise noted.
Parameter
Condition
Feedback Voltage
Upper Switch-On Resistance
4.75V VIN 25V
Lower Switch-On Resistance
Upper Switch Leakage
Current Limit
VEN = 0V, VSW = 0V
Oscillator Frequency
Short Circuit Frequency
Maximum Duty Cycle
Minimum Duty Cycle
EN Shutdown Threshold Voltage
EN UVLO Threshold Rising
EN UVLO Threshold Hysteresis
Enable Pull-Up Current
Supply Current (Shutdown)
Supply Current (Quiescent)
Thermal Shutdown
VFB = 0V
VFB = 1.0V
VFB = 1.5V
ICC > 100µA
VEN Rising
VEN = 0V
VEN 0.4V
VEN 2.6V, VFB = 1.4V
Min
1.184
2.4
370
2.0
2.0
Typ
1.222
0.22
10
3.1
420
42
90
2.3
2.5
200
2
25
1.0
160
Max
1.258
10
470
0
2.5
3.0
50
1.5
Units
V
µA
A
KHz
KHz
%
%
V
V
mV
µA
µA
mA
°C
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D1067
PIN FUNCTIONS
Pin # Name Description
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-channel
1 BS MOSFET switch. Connect a 10nF or greater capacitor from SW to BS to power the
switch.
Power Input. IN supplies the power to the IC, as well as the step-down converter switch.
2 IN Drive In with a 4.75 to 25V power source. Bypass IN to GND with a suitably large capaci-
tor to eliminate noise on the input to the IC. See Input Capacitor.
3 SW Power Switching Output. SW is the switching node that supplies power to the output.
Connect the output LC filter from SW to the output load. Note that a capacitor is required
from SW to BS to power the high-side switch.
4 GND Ground.
5 FB Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a
resistive voltage divider from the output voltage. The feedback threshold is 1.222V. See
Setting the Output Voltage.
6 COMP Compensation Node. COMP is used to compensate the regulation control loop. Connect
a series RC network from COMP to GND to compensate the regulation control loop. See
Compensation.
7 EN Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn
on the regulator, low to turn it off. For automatic startup, leave EN unconnected.
8 NC No Connect.
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