GTM G5ULM2596

ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
G5ULM2596
Simple Switcher Power converter 150kHz 3A Step-Down Voltage Regulator
Description
The G5ULM2596 series of regulators are monolithic integrated circuits that provide all active functions for a step-down (buck) switching
regulator, capable of driving 3A load with excellent line and load regulation. These devices are available in fixed output voltage of 3.3v, 5v,
12v and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and
include internal frequency compensation and a fixed-frequency oscillator.
The G5ULM2596 series operates at a switching frequency of 150 kHz thus allowing smaller sized filter components than what would be
needed with lower frequency switching regulators. Available in a standard 5-lead TO-263 package with several different lead bend options.
A standard series if inductors are available from several different manufactures optimized for use with the G5ULM2596 series. This feature
greatly simplifies the design of switch-mode power supplies. Other feature include a guaranteed ±4% to tolerance on output voltage under
specified input voltages and output load conditions, and ±15% on the oscillator frequency. External shutdown is included, featuring 80uA
standby current. Self protection features include a two stage frequency reducing current limit for the output switch and an over temperature
shutdown for complete protection under fault conditions.
Features
3.3V, 5.0V, 12V and adjustable output versions
Adjustable version output voltage range , 1.2V to 37V ±4% max over line and load conditions
Guaranteed 3A output current
Input voltage range up to 40V
Efficient pre-regulator for linear regulators
Requires only 4 external components
150kHz fixed frequency internal oscillator
TTL shutdown capability, low power standby mode
High efficiency
Uses readily available standard inductors
Thermal shutdown and current limit protection
Applications
Simple high-efficiency step-down (buck) regulator
On-card switching regulators
Positive to negative converter
Package Dimensions
REF.
A
b
L4
c
L1
E
Millimeter
Min.
Max.
4.40
4.80
0.66
0.91
0.00
0.30 B
0.36
0.5
2.29
2.79
9.80
10.4
REF.
c2
L2
D
e
L
Millimeter
Min.
Max.
1.25
1.45
1.27 REF.
8.6
9.0
1.70 REF.
14.6
15.8
0˚
8˚
Typical Application (Fixed Output Voltage Version)
12V
Unregulated
DC Input
G5ULM2596-5.0
33
680
G5ULM2596
1N5824
680
220
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ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
Block Diagram
FEEDBACK
Pin Function
Pin Name
Pin#
Function
This is the positive input supply for the IC switching regulator. A suitable input bypass capacitor
must be present at this pin to minimize voltage transients and to supply the switching current
needed by regulator.
Internal switch. The voltage at this pin switches between (+V IN – V SAT) and approximately -0.5V,
with a duty cycle of approximately V OUT/V IN. To minimize coupling to sensitive circuit, the PC board
copper area connected to this pin should be keep to a minimum.
+VIN
1
Output
2
Ground
Feedback
3
Circuit ground
4
Senses the regulated output voltage to complete the feedback loop
5
Allows the switching regulator circuit to be shutdown using logic level signals thus dropping the
total input supply current to approximately 80 A. Pulling this pin below a threshold voltage of
approximately 1.3V turns the regulator on, and pulling this pin above 1.3V (up to a maximum of
25V) shuts the regulator down. If this shutdown feature is not needed, ON/OFF pin can be wired to
the ground pin or it can be left open, in either case the regulator will be in the ON condition.
ON/OFF
Absolute Maximum Ratings (Note1)
Parameter
Maximum Supply Voltage
ON/OFF pin input Voltage
Feedback pin Voltage
Output Voltage to ground (steady state)
Power dissipation
Storage Temperature
Maximum junction temperature
Minimum ESD rating (C=100pF, R=1.5k )
Lead temperature (soldering, 10seconds)
Operating Ratings
Temperature range
Supply Voltage
G5ULM2596
Parameter
Ratings
45
-0.3 V +25
-0.3 V +25
-1
Internally Limited
-65 ~ +150
+150
2k
+260
Ratings
-40 TJ +125
4.5 ~ 40
Unit
V
V
V
V
V
Unit
V
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ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
G5ULM2596-3.3 Electrical Characteristics
Specifications with standard type face are for TJ=25
Parameter
Symbol
, and those with boldface type apply over full operating temperature range
Conditions
System Parameters (Note5) Test Circuit Figure 2
4.75V VIN 40V
Output Voltage
VOUT
0.2A ILOAD 3A
Efficiency
VIN=12V, ILOAD=3A
(Note4)
Min
(Note3)
Typ
(Note4)
Max
Unit
3.168/3.135
3.3
3.432/3.465
V
73
%
G5ULM2596-5.0 Electrical Characteristics
Specifications with standard type face are for TJ=25
Parameter
Symbol
, and those with boldface type apply over full operating temperature range
Conditions
System Parameters (Note5) Test Circuit Figure 2
7V VIN 40V
Output Voltage
VOUT
0.2A ILOAD 3A
Efficiency
VIN=12V, ILOAD=3A
(Note4)
Min
(Note3)
Typ
(Note4)
Max
Unit
4.80/4.75
5.0
5.20/5.25
V
80
%
G5ULM2596-12 Electrical Characteristics
Specifications with standard type face are for TJ=25
Parameter
Symbol
, and those with boldface type apply over full operating temperature range
Conditions
System Parameters (Note5) Test Circuit Figure 2
15V VIN 40V
Output Voltage
VOUT
0.2A ILOAD 3A
Efficiency
VIN=15V, ILOAD=3A
(Note4)
Min
(Note3)
Typ
(Note4)
Max
Unit
11.52/11.40
12
12.48/12.60
V
90
%
G5ULM2596 Electrical Characteristics
Specifications with standard type face are for TJ=25
Parameter
Symbol
, and those with boldface type apply over full operating temperature range
Conditions
System Parameters (Note5) Test Circuit Figure 2
4.5 VIN 40V, 0.2A ILOAD 3A
Output Voltage
VOUT
VOUT=3V, Circuit of Figure 2
Efficiency
VIN=12V, ILOAD=3A, VOUT=3V
(Note4)
Min
(Note3)
Typ
(Note4)
Max
Unit
1.180/1.168
1.230
1.280/1.292
V
77
%
All Output Voltage Version Electrical Characteristics
Specifications with standard type face are for TJ=25
, and those with boldface type apply over full operating temperature range.
Unless otherwise specified, V IN=12V for the 3.3V, 5.0V and Adjustable versions, V IN=24V for 12V version. ILOAD=0.5A
Parameter
Symbol
Feedback bias current
Oscillator frequency
Saturation voltage
Ib
Conditions
VFB=1.3V (adjustable version only)
(Note4)
Min
(Note3)
Typ
(Note4)
Max
Unit
127/110
10
50/00
nA
150
173/173
1.4/1.5
kHz
V
fO
VSAT
(Note 6)
ILOAD=3A (Note 7, 8)
-
1.16
Maximum duty cycle (ON)
DC
(Note 8)
(Note 9)
-
100
0
-
%
Current limit
ICL
Output leakage current
IL
Peak Current (Note 7, 8)
Output=0V(Note 7, 9)
Output=-1V (Note 10)
Quiescent current
Standby quiescent
current
IQ
3.6/3.4
-
4.5
2
5
6.9/7.5
50
30
10
A
uA
mA
mA
-
80
200/250
uA
(OFF)
Thermal Resistance
G5ULM2596
(Note 9)
ISTBY ON/OFF pin=5V (OFF)(Note 10)
JC
Junction to Case
-
2
-
JA
Junction to Ambient (Note 11)
Junction to Ambient (Note 12)
Junction to Ambient (Note 13)
-
50
30
20
-
/W
Page: 3/8
ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
ON/OFF Control Test Circuit Figure 2
-
1.3
-
2.0
-
-
0.6
ON/OFF pin logic input
Threshold Voltage
VIH
VIL
High (Regulator OFF)
Low (Regulator ON)
ON/OFF pin input
IH
VLOGIC=2.5V ( Regulator OFF)
-
5
15
current
IL
VLOGIC=0.5V ( Regulator ON)
-
0.02
5
V
uA
Note 1: Absolute Maximum Rating indicate limits beyond which damage to the device may occur. Operating Rating indicate conditions for
which the device is intended to be functional, but do not guaranteed specific performance limits. For guaranteed specifications and
test conditions, see the Electrical Characteristics.
Note 2: The human body mode is a 100pF capacitor discharged through a 1.5k
Note 3: Typical number are at 25
and represent the most likely norm.
resistor into each pin.
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) method. All limits are used to calculate Average Outgoing Quality Level (AOQL).
Note 5: External component such as the catch diode, inductor, input and output capacitors, and voltage programming resistor can affect
switching regulator system performance. When the G5ULM2596 is used as shutdown 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. The amount of reduction is determined by the
severity of current over-load.
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 Adjustable, 3.3V and 5V versions, and 15V for the 12V version,
to force the output transistor switch OFF.
Note 10: V IN=40V.
2
Note 11: Junction to ambient thermal resistance with the TO -263 package tab soldered to a single sided printed circuit board with 0.5 in
of (1 oz.) copper area.
2
Note 12: Junction to ambient thermal resistance with the TO -263 package tab soldered to a single sided printed circuit board with 2.5 in
of (1 oz.) copper area.
Note 13: Junction to ambient thermal resistance with the TO -263 package tab soldered to a double sided printed circuit board with 3.0 in
2
of (1 oz.) copper area on the G5ULM2596 side of the board, and approximately 16in of copper on the other side of the p-c board.
Typical Performance Characteristics (circuit of Figure 2)
Normalized Output Voltage
G5ULM2596
Line Regulator
Page: 4/8
2
ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
Efficiency
Switch Saturation Voltage
Switch Current Limit
Dropout Voltage
Operating Quiescent Current
G5ULM2596
Shutdown Quiescent Current
Page: 5/8
ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
Minimum Operating Supply Voltage
ON/OFF Threshold Voltage
ON/OFF Pin Current (Sinking)
Switching Frequency
Feedback Pin Bias Current
G5ULM2596
Page: 6/8
ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
Horizontal Time Base: 2 s/div
Continuous Mode Switching Waveforms
G5ULM2596
Horizontal Time Base: 2 s/div
Discontinuous Mode Switching Waveforms
Horizontal Time Base: 100 s/div
Horizontal Time Base: 200 s/div
Load Transient Response
for Continuous Mode
Load Transient Response
for Discontinuous Mode
Page: 7/8
ISSUED DATE :2005/04/15
REVISED DATE :2006/06/26B
Test Circuit and layout Guidelines
As in any switching regulator, layout is very important. Rapidly switching currents associated with wiring inductance generate voltage
transients which can cause problems. For minimal inductance and ground loops, the wires indicated by heavy lines should be wide
printed circuit traces and should be kept as short as possible. For best results, external components should be located as close to the
switcher IC as possible using ground plane construction or single point grounding.
If open core inductors are used, special care must be taken as to the location and positioning of this type of inductor. Allowing the
inductor flux to intersect sensitive feedback, IC groundpath and C OUT wiring can cause problems. When using the Adjustable version,
special care must be taken as to the location of the feedback resistors and the associated wiring. Physically locate both resistors near the
IC, and route the wiring away from the inductor, especially an open core type of inductor.
Cin-- 470uF, 50V, Aluminum Electrolytic
Cout-- 220uF, 25V Aluminum Electrolytic
D1-- 5A, 40V Schottky Rectifer, 1N5825
L1-- 68uH
Vout=VREF*(1+R2/R1)
Where VREF=1.23V
R2=R1*(Vout/VREF-1)
Select R1 to be approximately 1k , use a 1% resistor for best stability.
Cin-- 470uF, 50V, Aluminum Electrolytic
Cout-- 220uF, 35V Aluminum Electrolytic
D1-- 5A, 40V Schottky Rectifer, 1N5825
L1-- 68uH
Figure 2 Standard
Test Circuits and Layout
Guides
Important Notice:
All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of GTM.
GTM reserves the right to make changes to its products without notice.
GTM semiconductor products are not warranted to be suitable for use in life-support Applications, or systems.
GTM assumes no liability for any consequence of customer product design, infringement of patents, or application assistance.
Head Office And Factory:
Taiwan: No. 17-1 Tatung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, Taiwan, R. O. C.
TEL : 886-3-597-7061 FAX : 886-3-597-9220, 597-0785
China: (201203) No.255, Jang-Jiang Tsai-Lueng RD. , Pu-Dung-Hsin District, Shang-Hai City, China
TEL : 86-21-5895-7671 ~ 4 FAX : 86-21-38950165
G5ULM2596
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