LINFINITY SG7900A, SG7900 Service Manual
SG7900A/SG7900 SERIES
NEGATIVE FIXED VOLTAGE REGULATOR
SG7900A/SG7900
DESCRIPTION
The SG7900A/SG7900 series of negative regulators offer self-contained,
fixed-voltage capability with up to 1.5A of load current. With a variety of
output voltages and four package options this regulator series is an
optimum complement to the SG7800A/SG7800, SG140 line of three
terminal regulators.
These units feature a unique band gap reference which allows the
SG7900A series to be specified with an output voltage tolerance of ±1.5%.
The SG7900A versions also offer much improved line regulation characteristics.
All protective features of thermal shutdown, current limiting, and safe-area
control have been designed into these units and since these regulators
require only a single output capacitor (SG7900 series) or a capacitor and
5mA minimum load (SG120 series) for satisfactory performance, ease of
application is assured.
Although designed as fixed-voltage regulators, the output voltage can be
increased through the use of a simple voltage divider. The low quiescent
drain current of the device insures good regulation when this method is
used, especially for the SG120 series.
These devices are available in hermetically sealed TO-257, TO-3, TO-39
and LCC package.
FEATURES
••
•
Output voltage set internally to
••
••
• Output current to 1.5A
••
••
• Excellent line and load regulation
••
••
• Foldback current limiting
••
••
• Thermal overload protection
••
••
• Voltages available: -5V, -12V, -15V
••
••
• Contact factory for other voltage options
••
••
• Available in surface mount package
••
±±
±1.5% on SG7900A
±±
HIGH RELIABILITY FEATURES
- SG7900A/SG7900
♦♦
♦ Available to MIL-STD - 883
♦♦
♦♦
♦ MIL-M38510/11501BXA - JAN7905T
♦♦
♦♦
♦ MIL-M38510/11505BYA - JAN7905K
♦♦
♦♦
♦ MIL-M38510/11502BXA - JAN7912T
♦♦
♦♦
♦ MIL-M38510/11506BYA - JAN7912K
♦♦
♦♦
♦ MIL-M38510/11503BXA - JAN7915T
♦♦
♦♦
♦ MIL-M38510/11507BYA - JAN7915K
♦♦
♦♦
♦ LMI level "S" processing available
♦♦
SCHEMATIC DIAGRAM
**
**
For normal
operation the (VOS)
Sense Pin must be
externally
connected to the
load.
12/91 Rev 1.4 12/99 LINFINITY Microelectronics Inc.
Copyright 1999 11861 Western Avenue
1 (714) 898-8121
∞ ∞
∞ Garden Grove, CA 92841
∞ ∞
∞∞
∞FAX: (714) 893-2570
∞∞
SG7900A/SG7900 SERIES
ABSOLUTE MAXIMUM RATINGS (Note 1)
Device Input Voltage Differential
Output Voltage Input Voltage (Output shorted to ground)
-5V -35V 35V
-12V -35V 35V
-15V -40V 35V
NEGATIVE REGULATOR
Operating Junction Temperature
Hermetic (K, T, IG & L - Packages) ........................
Note 1. Values beyond which damage may occur.
150°C
THERMAL DATA
K Package:
Thermal ResistanceThermal Resistance-
T Package:
Junction to Case, θ
Junction to Ambient, θ
................. 3.0°C/W
JC
............... 35°C/W
JA
Thermal Resistance-Junction to Case, θJC.................. 15°C/W
Thermal Resistance-Junction to Ambient, θJA............ 120°C/W
IG Package:
Thermal Resistance-Junction to Case, θJC................. 3.5°C/W
Thermal Resistance-Junction to Ambient, θJA.............. 42°C/W
L Package:
Thermal Resistance-Junction to Case, θJC.................. 35°C/W
Thermal Resistance-Junction to Ambient, θJA............ 120°C/W
RECOMMENDED OPERATING CONDITIONS (Note 2)
Operating Junction Temperature Range:
SG7900A/7900 .............................................
Note 2. Range over which the device is functional.
-55°C to 150°C
CHARACTERISTIC CURVES
Storage Temperature Range ..........................
-65°C to 150°C
Lead Temperature (Soldering, 10 Seconds) .................
Note A. Junction Temperature Calculation: TJ = TA + (PD x θJA).
Note B. The above numbers for θ
resistance of the package in a standard mounting configuration.
The θJA numbers are meant to be guidelines for the thermal
performance of the device/pc-board system. All of the above
assume no ambient airflow.
are maximums for the limiting thermal
JC
300°C
FIGURE 1.
MAXIMUM AVERAGE POWER DISSIPATION
12/91 Rev 1.4 12/99 LINFINITY Microelectronics Inc.
Copyright 1999 11861 Western Avenue
FIGURE 2.
QUIESCENT CURRENT VS. LOAD
2 (714) 898-8121
FIGURE 3.
TEMPERATURE COEFFICIENT
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SG7900A/SG7900 SERIES
CHARACTERISTIC CURVES (continued)
NEGATIVE REGULATOR
FIGURE 4.
SHORTCIRCUIT CURRENT VS. V
APPLICATIONS
IN
FIGURE 7.
DROPOUT CHARACTERISTICS
FIGURE 5.
QUIESCENT CURRENT VS. V
FIGURE 6.
IN
FIGURE 8.
RIPPLE REJECTION VS. FREQUENCY
SHORT CIRCUIT CURRENT VS. V
IN
FIGURE 9 - FIXED OUTPUT REGULATOR
NOTE: 1. C1 is required only if regulator is separated from rectifier filter.
NOTE: C3 optional for improved transient response and ripple rejec
FIGURE 10 - CIRCUIT FOR INCREASING OUTPUT VOLTAGE
2. Both C1 and C2 should be low E.S.R. types such as solid
tantalum. If aluminum electrolytics are used, at least 10 times
values shown should be selected.
3. If large output capacities are used, the regulators must be
V
= V (REGULATOR)
OUT
R1 + R
R
1
R2 =
V(REG)
15mA
2
protected from momentary input shorts. A high current diode
12/91 Rev 1.4 12/99 LINFINITY Microelectronics Inc.
Copyright 1999 11861 Western Avenue
3 (714) 898-8121
∞ ∞
∞ Garden Grove, CA 92841
∞ ∞
∞∞
∞FAX: (714) 893-2570
∞∞
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