GM7230 of regulators provides all the active functions for a
step-down (buck) switching regulator, and drives 3A load
with excellent line and load regulation. GM7230's is avail-
able in fixed output voltages of 3.3V, 5V, 12V, and a versa-
tile
Adjustable output version.
These regulators are simple to use and require a minimum
number of external components. Features include internal
frequency compensation and a fixed-frequency oscillator.
The GM7230 is high-efficiency replacements for popular
three-terminal linear regulators, and is requiring a smaller
heatsink or even no heatsink.
GM7230 performs well with standard inductors from sev-
eral manufacturers, and simplifying the design of switch-
mode power supplies. GM7230 guarantees ±4% tolerance
on output voltage within specified input voltages and out-
put load conditions, and ±15% on the oscillator frequency.
External shutdown is included with 80 µA (typical) standby
current. The output switch has cycle-by-cycle current limit-
ing as well as thermal shutdown for full protection under
fault conditions.
GM7230 operates at a switching frequency of 150 kHz thus al-
lowing smaller sized filter components than what would be
needed with lower frequency switching regulators. Available in a
standard 5-lead TO-220 package with several different
lead bend options, and a 5-lead TO-263 surface mount
package.
Features
3.3V, 5V, 12V and Adjustable output versions
Adjustable version output voltage range 1.23V
to 37V
4% max over line and load conditions
3A output current
Input voltage range up to 40V
Requires only 4 external components
High efficiency
TTL shutdown capability, low power standby
mode
Low power standby mode, IQ typically 80 UA
Thermal shutdown, current limit protection
Uses standard inductors
150 kHz fixed frequency internal oscillator
Application
Pre-regulator for linear regulators
High-efficiency step-down buck regulator
On-card/board switching regulators
Positive to negative converter (buck-boost)
TYPICAL APPLICATIONS
12V
Unregulated
DC Input
+V
IN
1
+ C
IN
GM7230
5.0
L1
68 µH
+
C
OUT
220 µF
5
680 µF
ON / OFF
3
GND
5.0V
Regulated
Output
3A Load
D1
1N5824
www.gammamicro.com
GM7230
V0.11
1
Feedback
4
Output
2
MICROELECTRONICS
A
A
Power Management
GM7230
3A STEP-DOWN VOLTAGE REGULATOR
MARKING INFORMATION & PIN CONFIGURATIONS
TO-220- 5
TO-220- 5B
TO-263-5(D PAK)
2
.
GM7230
VVAYWW
.
GM7230
VVAYWW
.
GM7230
VVAYWW
V
IN
Output
Ground
ON/OFF
Feedback
V
IN
Output
Ground
ON/OFF
Feedback
V
IN
Output
Ground
ON/OFF
Feedback
1 2 3 4 5
V V / VVV= Output Voltage
(33=3.3V , 12=12V, A=Adj)
A
= Assembly Location
Y
= Year
WW
= Weekly
ORDERING INFORMATION
Ordering Number
GM7230-ATB5T
GM7230-ATB5BT
GM7230-ATA5R
GM7230-ATA5T
GM7230-3.3TB5T
GM7230-3.3TB5BT
GM7230-3.3TA5R
GM7230-3.3TA5T
GM7230-5.0TB5T
GM7230-5.0TB5BT
GM7230-5.0TA5R
GM7230-5.0TA5T
GM7230-12TB5T
GM7230-12TB5BT
GM7230-12TA5R
GM7230-12TA5T
GM7230-15TB5T
GM7230-15TB5BT
Output Voltage
Adj
Adj
Adj
Adj
3.3
3.3
3.3
3.3
5.0
5.0
5.0
5.0
12
12
12
12
15
15
15
15
Package
TO-220-5
TO-220-5B
TO-263-5
TO-263-5
TO-220-5
TO-220-5B
TO-263-5
TO-263-5
TO-220-5
TO-220-5B
TO-263-5
TO-263-5
TO-220-5
TO-220-5B
TO-263-5
TO-263-5
TO-220-5
TO-220-5B
TO-263-5
TO-263-5
Shipping
50 Units / Tube
50 Units / Tube
800 Units/ Tape & Reel
50 Units / Tube
50 Units / Tube
50 Units / Tube
800 Units/ Tape & Reel
50 Units / Tube
50 Units / Tube
50 Units / Tube
800 Units/ Tape & Reel
50 Units / Tube
50 Units / Tube
50 Units / Tube
800 Units/ Tape & Reel
50 Units / Tube
50 Units / Tube
50 Units / Tube
800 Units/ Tape & Reel
50 Units / Tube
GM7230
GM7230-15TA5R
GM7230-15TA5T
* TB5B: Bent and Staggered Leads of TO-220 package
** For detail Ordering Number identification, please see last page.
2
MICROELECTRONICS
A
A
Power Management
GM7230
3A STEP-DOWN VOLTAGE REGULATOR
Value
45
-0.3
V
-1.0
Internally Limited
-65 to + 150
+150
-40
T
J
2
+260
125
+25
ABSOLUTE MAXIMUM RATINGS
Rating
Maximum Supply Voltage
ON/OFF Pin Input Voltage/ Feed back pin voltage
Output Voltage to Ground (Steady State)
Power Dissipation
Storage Temperature Range
Maximum Junction Temperature
Operating Temperature Range
Minimum ESD Rating (C=100pF, R=1.5kW)
Lead Temperature (Soldering, 10 sec.)
Lead Temperature
S Package
Vapor Phase (60 secretary.)
Infrared (10 secretary.)
T Package (Soldering, 10 secretary.)
Maximum Junction Temperature
Unit
V
V
V
-
°C
°C
°C
kV
°C
+215
+245
+260
+150
°C
OPERATING CONDITIONS
Rating
Temperature Range
Supply Voltage
45
Value
T
J
+125
Unit
°C
V
4.5 to 40
BLOCK DIAGRAM
ON/ OFF
Current
Source
Bias
1.235V
Reference
2.5V
Regulator
+
+
COMP
-
Current
Limit
-
COMP
+
+
220 220
mV mV
V
IN
Start Up
2.5V
FEEDBACK
R2
R1=
2.5K
Latch
Reset
Driver
Capacitor
3.3V,R2=4.2K
5V,R2=7.6K
12V,R2=21.8K
ADJ,R2=0W
R1=OPEN
+
OP AMP
-
FREQ SHIFT
150kHz
OSC
Thermal
Limit
OUTPUT
GND
GM7230
3
+
AMP
-
Active
GM
-
COMP
+
3A
Switch
MICROELECTRONICS
A
A
Power Management
GM7230
3A STEP-DOWN VOLTAGE REGULATOR
ELECTRICAL CHARACTERISTICS: GM7230-3.3
(Specifications with standard type face are for T
J
= 25°C, and those with
boldface type
apply over full Operating Temperature Range)
Parameter
Output Voltage
Efficiency
4.75
Conditions
V
IN
40V, 0.2A I
LOAD
3A
V
IN
= 12V, I
LOAD
= 3.0A
Symbol
V
OUT
h
Min
3.168/3.135
-
Typ
3.3
73
Max
3.432/3.465
-
Unit
V
%
ELECTRICAL CHARACTERISTICS: GM7230-5.0
(Specifications with standard type face are for T
J
= 25°C, and those with
boldface type
apply over full Operating Temperature Range)
Parameter
Output Voltage
Efficiency
7V
V
IN
Conditions
40V, 0.2A I
LOAD
3A
Symbol
V
OUT
h
Min
4.800/4.750
-
Typ
5.0
80
Max
5.200/5.250
-
Unit
V
%
V
IN
= 12V, I
LOAD
= 3.0A
ELECTRICAL CHARACTERISTICS: GM7230-12
(Specifications with standard type face are for T
J
= 25°C, and those with
boldface type
apply over full Operating Temperature Range)
Parameter
Output Voltage
Efficiency
15V
V
IN
Conditions
40V, 0.2A I
LOAD
3A
Symbol
V
OUT
h
Min
11.52/11.40
-
Typ
12.0
90
Max
12.48/12.60
-
Unit
V
%
V
IN
= 25V, I
LOAD
= 3.0A
ELECTRICAL CHARACTERISTICS: GM7230-ADJ
(Specifications with standard type face are for T
J
= 25°C, and those with
boldface type
apply over full Operating Temperature Range)
Parameter
Feedback Voltage
Efficiency
4.5V
Conditions
V
IN
40V, 0.2A I
LOAD
3A
V
OUT
= 3V
Symbol
V
OUT
h
Min
1.193/1.180
-
Typ
1.230
73
Max
1.267/1.280
-
Unit
V
%
V
IN
= 12V, I
LOAD
= 3A, V
OUT
=3V
GM7230
4
MICROELECTRONICS
A
A
Power Management
GM7230
3A STEP-DOWN VOLTAGE REGULATOR
ELECTRICAL CHARACTERISTICS: All Output Voltage Versions
(Specifications with standard type face are for T
J
= 25 C, and those with
boldface type
apply over full Operating Temperature Range.
Unless otherwise specified, V
IN
= 12V for the 3.3V, 5.0V and ADJ version and V
IN
= 24V for 12V version. I
LOAD
= 500 mA)
Parameter
Feedback Bias Current
Oscillator Frequency
Saturation Voltage
Max Duty Cycle (ON)
Min Duty Cycle (OFF)
Current Limit
Output Leakage Current
Conditions
V
FB
= 1.3V (Adjustable Version Only)
(Note 6)
I
OUT
= 3A (Notes 7, 8)
(Note 8)
(Note 9)
Peak Current (Notes 7, 8)
(Notes 7, 9, 10)
(Notes 10)
Output = 0 V
Output = -0.9V
(Note 9)
ON/OFF Pin = 5V (OFF) (Note 10)
TO-220 or TO-263 Package, Junction to Case
TO-220 Package, Junction to Ambient (Note 11)
Symbol
I
b
f
o
V
SAT
DC
DC
I
CL
I
L
I
Q
I
STBY
q
JC
q
JA
q
JA
q
JA
q
JA
V
IH
V
IL
I
H
I
L
Min
-
127/110
-
Typ
10
150
1.16
100
0
Max
50 /
100
173 /
173
1.4 /
1.5
-
-
6.9 /
7.5
50
30
10
200 /
250
-
-
-
-
-
0.6
-
15
5
Unit
nA
kHz
V
%
%
A
µA
mA
mA
µA
3.6 /
3.4
-
-
-
-
-
-
-
-
-
-
2.0
-
-
4.5
-
2
5
80
2
50
50
30
20
1.3
1.3
5
0.02
Quiescent Current
Standby Quiescent Current
Thermal Resistance
TO-263 Package, Junction to Ambient (Note 12)
TO-263 Package, Junction to Ambient (Note 13)
TO-263 Package, Junction to Ambient (Note 14)
°C/W
ON/OFF Pin
Logic Input Level
Low (ON)
High (OFF)
V
LOGIC
= 2.5V (OFF)
V
V
µA
µA
ON/OFF Pin Input Current
V
LOGIC
= 0.5V (ON)
Note 1:
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for which the device is
intended to be functional, but do not guarantee specific performance limits. For guaranteed specifications and test conditions, see the Electrical
Characteristics.
Note 2:
The human body model is a 100 pF capacitor discharged through a 1.5k resistor into each pin.
Note 3:
Typical numbers are at 25°C and represent the most likely norm.
Note 4:
All limits guaranteed at room temperature (standard type face) and at temperature extremes (bold type face). All room temperature limits are
100% production tested. All limits at temperature extremes are guaranteed via correlation using standard Statistical Quality Control (SQC) methods.
All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 5:
External components such as the catch diode, inductor, input and output capacitors, and voltage programming resistors can affect switching regulator
system performance. When the GM7230 is used as shown in the Figure 1 test circuit, system performance will be as shown in system parameters section
of Electrical Characteristics.
Note 6:
The switching frequency is reduced when the second stage current limit is activated.
Note 7:
No diode, inductor or capacitor connected to output pin.
Note 8:
Feedback pin removed from output and connected to 0V to force the output transistor switch ON.
Note 9:
Feedback pin removed from output and connected to 12V for the 3.3V, 5V, and the ADJ. version, and 15V for the 12V version, to force the output transistor
switch OFF.
Note 10:
V
IN
= 40V.
Note 11:
Junction to ambient thermal resistance (no external heat sink) for the TO-220 package mounted vertically, with the leads soldered to a printed circuit board
with (1 oz.) copper area of approximately 1 in .
Note 12:
Junction to ambient thermal resistance with the TO-263 package tab soldered to a single printed circuit board with 0.5 in
2
of (1 oz.) copper area.
Note 13:
Junction to ambient thermal resistance with the TO-263 package tab soldered to a single sided printed circuit board with 2.5 in
2
of (1 oz.) copper area.
Note 14:
Junction to ambient thermal resistance with the TO-263 package tab soldered to a double sided printed circuit board with 3 in
2
of (1 oz.) copper area on
Gm7230 side of the board, and approximately 16 in of copper on the other side of the p-c board.