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OM1575 Series OMH1575 Series

STEP-DOWN SWITCHING VOLTAGE REGULATOR IN HERMETIC ISOLATED PACKAGE

OM1575 Series OMH1575 Series
STEP-DOWN SWITCHING VOLTAGE REGULATOR IN HERMETIC ISOLATED PACKAGE
1.0 Amp, 5V, 12V, 15V And Adjustable Output Voltage Versions In MO-078 Metal Package
FEATURES
· · · · · · · Similar To Industry Standard LM1575 Available in 5V, 12V, 15V, And Adjustable Versions 1.0 Amp Output Wide Input Voltage Range, 4V to 60V 53 kHz Fixed Frequency Internal Oscillator High Efficiency Hermetic Metal Packages
DESCRIPTION
This series of regulators are monolithic integrated circuits designed for the active functions of a step down, buck or buck / boost regulator. It requires only four readily available standard components to complete the DC to DC converter design at 1 Amp. Current limiting and thermal shutdown features fully protect the device against overstress. The hermetic package is ideally suited for those critical environments requiring high reliability over a wide operating temperature range.
BLOCK DIAGRAM
INPUT Feedback Internal Resistors For Fixed Options Only + E / A REF REG ON / OFF ON / OFF
+ PWM OSC RESET
DRV PROTECTION Output GND
OM1575 OMH1575 Series
ELECTRICAL CHARACTERISTICS
ISTBY
OM1575 OMH1575 Series
OPERATIONAL DATA
Dropout Voltage
Minimum Operating Voltage
2.5 VIN - VOUT (V) 2.0 1.5 1.0 0.5
Junction Temperature (°C)
Normalized Feedback Voltage (mV)
Line Regulation (Adjustable Version Only)
Feedback Pin Current
Input Voltage (V)
Junction Temperature (°C)
25 Normalized Feedback Voltage (mV) 15 5 0 -5 -15 -25 -75 -50 -25 0 25 50 75 100 125 150
Normalized Feedback Voltage (Adjustable Version Only)
15 10 Feedback Voltage Change (mV) 5 0
Feedback Voltage vs Duty Cycle (Adjustable Version Only)
Junction Temperature (°C)
OM1575 OMH1575 Series
OPERATIONAL DATA
Supply Current vs. Duty Cycle
Supply Current
Supply Current (mA)
Current Limit
3.0 Saturation Voltage (V) 1.2 1.0 0.8
Switch Saturation Voltage
Output Current (A)
Junction Temperature (°C)
Switch Current (A)
Efficiency
Standby Quiescent Current (µA) 200
Standby Quiescent Current
Input Voltage (V)
OM1575 OMH1575 Series
BUCK MODE FIXED VOLTAGE
1 + CIN 68µF ON / OFF REC + E / A REF 5 3 + PWM OSC RESET 330µH L1 2 D1 3A + COUT 330µF 4
DRV PROTECTION
BUCK MODE ADJUSTABLE VOLTAGE
1 + CIN 68µF ON / OFF REC + E / A REF 5 3 + PWM OSC RESET 330µH L1 2 D1 3A + 330µF COUT 2K R2 R1
4 DRV PROTECTION
The above fixed and adjustable voltage selections will be adequate for most applications for output currents from 150mA to 1.0A. Applications of VOUT below 5V or above 24V may require component adjustment for maximum performance please contact factory for application assistance.
OM1575 OMH1575 Series
Switching Spikes Switching spikes will also occur due to distributive capacitance across turns of the inductor when combined with output capacitor series inductance (ESL). Reduction to a level at or below the switching ripple can be achieved by using a post filter, as shown in the Switching Spike Reduction Schematic.
SWITCHING SPIKE REDUCTION
L1 +VIN DC INPUT CIN OUTPUT 1µH+ VOUT 10µF+ TANT
TYPICAL APPLICATION
TURN-ON DELAY WITH SPIKE FILTER
4 FEEDBACK 2 OUTPUT CIN 0.47µF 1 to 3.0µF 5 10k 2.2k 1N914 + Regulated Output
3 COUT
Spike filter reduces input noise, causing false triggering of delay.
OM1575 OMH1575 Series
TYPICAL APPLICATIONS
TYPICAL BUCK SHUTDOWN
FEEDBACK + Unregulated DC Input + CIN 5 ON / OFF 3 +5V 0 ON OFF Shutdown Input TTL, CMOS, etc. GND +VIN 1 4 OUTPUT L1 2 D1 + COUT + Regulated Output
FEEDBACK + Unregulated DC Input + CIN +VIN 1 100k 5 +5V 0 ON OFF Shutdown 100k Input 100k 3 GND ON / OFF 4 OUTPUT L1 2 D1 + COUT + Regulated Output
TURN-ON DELAY
2 OUTPUT CIN 0.47µF to 3.0µF 10k 1 5 1N914 3 COUT + Regulated Output
Circuit allows for CIN to be fully charged before start-up, provides CIN to supply hi-peak current instead of input supply.
OM1575 OMH1575 Series
TYPICAL APPLICATIONS
INVERTING BUCK / BOOST SHUTDOWN
FEEDBACK + Unregulated DC Input 220k 470k ON OFF Shutdown Input 470k 470k 330k - Regulated Output + +VIN 1 CIN 5 ON / OFF 3 GND 4 OUTPUT L1 2 D1 + COUT
FEEDBACK + Unregulated DC Input +VIN + CIN 5 ON / OFF 3 GND +5V +5V 0 ON OFF 220V Shutdown Input 100k 470k D1 + COUT 1 4 OUTPUT L1 2
- Regulated Output
UNDER VOLTAGE LOCKOUT
Unregulated DC Input
4 FEEDBACK +VIN + 1 5 ON / OFF 3 GND OUTPUT 2
+ Regulated Output
R1 20K Z1
Q1 R2 10k COUT
Regulator will be off until a VIN set point is reached.
VO(ON) VZ + 3VBE Q1
OM1575 OMH1575 Series
TYPICAL APPLICATIONS
INVERTING BUCK / BOOST
+5V 1 + CIN 47µF ON / OFF REC + E / A REF 5 3 + PWM OSC RESET 4
DRV PROTECTION
100µH L1 2 D1 + 3A
COUT 330µF -5V @ 250mA
+5V TO -5V @ 250mA
+12V 1 + REC CIN 47µF ON / OFF + E / A REF 5 3 + PWM OSC RESET 4
DRV PROTECTION
COUT 200µF
COMMON
+12V TO -5V @ 100mA
-5V @ 100mA
Inverting buck / boost operation is a different topology of operation than buck. This difference reduces the output current capability of the device, in that the inductor must supply all of the load current during the time the power switch is off: Maximum output current is approximately: IOUT @ 1.3 / 2 (1 + oeVOoe / VIN) Component requirement stress is very similar to the buck with a few exceptions: · Catch diode breakdown VBR must be greater than VIN + oeVOUToe · Input capacitor is larger due to the increased peak current during switch turn on. Power dissipation of the OM1575 is approximately: PD @ oeVOoe (oeVOoe+ VIN) IO (1 + oeVOoe / VIN) / Please contact factory for additional assistance when using the buck / boost topology.
OM1575 OMH1575 Series
MECHANICAL OUTLINE
PIN CONNECTION
MO-078 PACKAGE
.550 .530 .092 MAX.
.100 TYP.
.140 TYP.
Pin 1: VIN Pin 2: OUT Pin 3: GND Pin 4: Feedback Pin 5: ON / OFF
Z-TAB PACKAGE
.250 TYP . . 25 1 2 PLCS
.695 .685 .550 .285 .530 .750 .500 .100 TYP .
.250 TYP . 125 TYP . .
.270 MAX.
Pin 1: VIN Pin 2: OUT Pin 3: GND Pin 4: Feedback Pin 5: ON / OFF
ORDERING INFORMATION
205 Crawford Street, Leominster, MA 01453 USA (508) 534-5776 FAX (508) 537-4246