MICROSEMI SG29085P

SG29085/85A
LOW DROPOUT DUAL REGULATOR
DESCRIPTION
FEATURES
• 2% Internally Trimmed Output
• Two regulated outputs
• Output current in excess of
1000mA
• Low quiescent current standby
regulator
• Input-output differential less than
0.6V at 0.5A
• Reverse battery protection
• 60V load dump protection
• -50V reverse transient protection
• Short circuit protection
• Internal thermal overload protection
• Available in plastic TO-220
The SG29085 is the 8.2 volt, ±5% version of a family of dual regulators with a standby • ON/OFF switch for high current
output
output voltage of 5V. Other high current outputs of 5 and 12 volts are available. Also
available is the SG28085A which offers an improved output voltage tolerance of ±2%.
They are available in the plastic TO-220 power package and are designed to function
over the automotive ambient temperature range of -40°C to 85°C.
The SG29085/85A is a dual 8.2V/5V positive voltage regulator. One output is a high
current (up to 1000 mA) regulator that can be turned on or off by a high impedance low
current TTL compatible switch. The second or standby output remains on regardless.
The on/off switch not only shuts off the high current output but actually puts the IC in a
micropower mode making possible a low quiescent current. This unique characteristic
coupled with an extremely low dropout, (.55V for output current of 10mA) makes the
SG29085/85A well suited for power systems that require standby memory. The
SG29085/85A includes other features which were originally designed for automotive
applications. These include protection from reverse battery installations and double
battery jumps. The high current regulator has overvoltage shutdown to protect both the
internal circuitry and the load during line transients, such as load dump (60V). In addition,
the high current regulator design also has built-in protection for short circuit and thermal
overload. During these fault conditions of the primary regulator the standby regulator will
continue to power its load.
* Required if regulator is located far from power
supply filter.
** Required for stability. May be increased without
bound. Capacitor must be rated to operate at the
minimum temperature expected for the regulator
system.
TYPICAL APPLICATION CIRCUIT
INPUT VOLTAGE
1
C1*
0.1µF
SG29085/85A
2
C2 **
10µF
OVERVOLTAGE
THERMAL
SHUTDOWN
ON/OFF SWITCH
(for output voltage only)
4
OUTPUT VOLTAGE
(8.2V, 1000mA)
REGULATOR
BIAS
1.23V
REFERENCE
5
5V STANDBY
REGULATOR
STANDBY OUTPUT
(5V, 50mA)
5.6V
3
C3 **
10µF
GROUND
LINFINITY
12/90 Rev 1.1 2/94
Copyright  1994
1
Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
(714) 898-8121 ∞ FAX: (714) 893-2570
SG29085/85A
ABSOLUTE MAXIMUM RATINGS
Note 1. Exceeding these values may destroy this part.
Input Voltage (VIN) Operating .............................................. 26V
Input Voltage (VIN) Overvoltage Transient .............. -15V to 60V
ON/OFF Switch ...................................................... -0.3V to V IN
Storage Temperature Range (TSTG) .................. -65°C to 150°C
Operating Junction Temperature (TJ ) ...............................150°C
THERMAL DATA
P Package:
Thermal Resistance-Junction to Case, θ JT ................ 4.0°C/W*
Thermal Resistance-Junction to Ambient, θ JA .............. 55°C/W
*
Note A. Junction Temperature Calculation: TJ = TA + (PD x θ JA).
Note B. The above numbers for θJC are maximums for the limiting
thermal resistance of the package in a standard mounting configuration. The θJA numbers are meant to be
guidelines for the thermal performance of the device/pcboard system. All of the above assume no ambient
airflow.
= θ JT (Junction to Tab)
RECOMMENDED OPERATING CONDITIONS
(Notes 2 & 3)
Input Voltage (VIN ) ...................................................... 9V to 26V
ON/OFF Threshold Voltage
Low Level, VIL (VOUT is OFF) .................................. 0.8V max.
High Level, VIH (VOUT is ON) .................................... 2.0V min.
Load Current VOUT (with adequate heatsinking) .... 5 to 1000mA
Maximum Line Transient (Load Dump) VSB ≤ 6V ....... 60V max.
Input Capacitor (VIN to GND) ................................... 0.1 µF min.
Reverse Polarity D.C. Input Voltage (VIN)
(VO ≥ -0.6V, 16Ω load) ........................................... -15V max.
Reverse Polarity Transient Input Voltage (VIN )
(1% duty cycle, T ≤ 100ms, VO ≥ -9V, 16Ω load) ... -50V max.
Output Capacitor with ESR of 10Ω max.
(VOUT to GND & VSBto GND) ................................... 10µF min.
Operating Ambient Temperature Range - (TA)
SG29085/85A ................................................. -40°C to 85°C
Note 2. Range over which the device is functional.
Note 3. During 60V load dump, VSB shall not be less than 4.75V at IOUT = 10mA.
ELECTRICAL CHARACTERISTICS (Unless otherwise specified, these specifications apply for the operating ambient temperature of TA =
25°C. VIN = 14V, IO = 500mA for VOUT and 10mA for VSB and are for DC characteristics only. Low duty cycle pulse testing techniques are used which
maintains junction and case temperatures equal to the ambient temperature.)
Parameter
Voltage Output (VOUT) Section
Output Voltage (Note 4)
Line Regulation
Load Regulation
Output Impedance
Quiescent Current
Output Noise Voltage
Long Term Stability
Ripple Rejection
Dropout Voltage
Current Limit
Maximum Operational Input Voltage
Maximum Line Transient
ON/OFF Switch (IIH)
ON/OFF Switch (IIL)
Test Conditions
9V ≤ VIN ≤ 26V, IO ≤ 1000mA, -40°C ≤ TA ≤ 85°C
SG29085
SG29085A
9V ≤ VIN ≤ 16V, IO = 5mA
9V ≤ VIN ≤ 26V, IO = 5mA
5mA ≤ IO ≤ 1000mA
500mADC and 10mARMS , 100Hz - 10kHz
IO ≤ 10mA, No Load on Standby
IO = 500mA, No Load on Standby
IO = 750mA, No Load on Standby
IO = 220mA, ISB = 10mA, VIN = VOUT - 200mV
10Hz - 100kHz
FO = 120Hz
IO = 500mA
IO = 1000mA
Double Battery
VO ≤ 9V
IO = 10mA, Pin 4 = 2.4V
IO = 10mA, Pin 4 = 0.4V
7.8
8.0
8.2 8.6
8.2 8.4
4
25
10
50
10
50
200
2
40 100
90
15
25
100
20
66
0.45 0.6
0.7
1.2
1.0 1.8 2.5
26.5 31
60
70
10
-10
LINFINITY
12/90 Rev 1.1 2/94
Copyright  1994
SG29085/85A
Min. Typ. Max.
2
Units
V
V
mV
mV
mV
mΩ
mA
mA
mA
mA
µVRMS
mV/1000hr
dB
V
V
A
V
V
µA
µA
Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
(714) 898-8121 ∞ FAX: (714) 893-2570
SG29085/85A
ELECTRICAL CHARACTERISTICS
(continued)
Parameter
SG29085/85A
Min. Typ. Max.
Test Conditions
Standby Output (VSB ) Section
Output Voltage (Note 4)
Line Regulation
Load Regulation
6V ≤ VIN ≤ 26V, IO ≤ 50mA, -40°C ≤ TA ≤ 85°C
6V ≤ VIN ≤ 26V
1mA ≤ IO ≤ 35mA
1mA ≤ IO ≤ 50mA
1mADC and 1mARMS, 100Hz - 10kHz
IO ≤ 10mA, VOUTOFF
10Hz - 100kHz
Output Impedance
Quiescent Current
Output Noise Voltage
Long Term Stability
Ripple Rejection
Dropout Voltage
Current Limit
Maximum Operational Input Voltage
4.75
FO = 120Hz
IO ≤ 50mA
50
60
4.75V ≤ VO ≤ 6V
Units
5.0 5.25
V
50
4
mV
10
25
mV
25
50
mV
1
Ω
1.2
3
mA
300
µVRMS
20
mV/1000hr
66
dB
0.55 0.7
V
100
mA
70
V
Note 4. The temperature extremes are guaranteed but not 100% production tested.
TYPICAL CIRCUIT WAVEFORM
60V
33V
INPUT
VOLTAGE
PIN 1 (V)
26V
14V
14V
4V
0V
ON/OFF
SWITCH
2V
0.8V
0.8V
OUTPUT
VOLTAGE
PIN 2 (V)
8.2V
5V
8.2V
8.2V
8.2V
8.2V
3.5V
0V
0V
STANDBY
VOLTAGE
PIN 5 (V)
SYSTEM
CONDITION
5.0V
5V
3.7V
TURN
ON
LOAD
DUMP
LINE NOISE,
ETC.
LOW VIN
VOUT
SHORT
CIRCUIT
THERMAL
SHUTDOWN
TURN
OFF
APPLICATION NOTES
The advantages of using a low-dropout regulator such as the
SG29085/85A are the need for less “headroom” for full regulation, and the inherent reverse polarity protection provided by the
PNP output device. A typical NPN regulator design requires an
input to output differential of approximately two volts minimum.
This is due to the 2Vbe + Vcesat of the NPN Darlington used in
the output, coupled with the voltage drop across the current limit
resistor. In contrast, the “PNP Regulator” uses a single series
pass transistor with its single Vcesat, thus the lower input to
output voltage differential or dropout voltage.
regulator enters a micropower mode. Here all but the most
essential circuitry to power the standby output is deactivated.
This allows the lowest possible quiescent current (typical around
1.2mA), a vital factor when used in a battery powered system.
In some applications the regulator output voltage is used not only
as a power supply but also as a voltage reference for control
systems. In such cases not just the temperature stability of the
output is important but also the initial accuracy. The SG29085/
85A fills this need as the internal bandgap reference is trimmed
allowing a typical output voltage tolerance of ±1%.
In addition to a low dropout voltage, an important advantage of
the SG29085/85A series is low quiescent current in the standby
mode. When the high current or primary regulator is shut off, the
LINFINITY
12/90 Rev 1.1 2/94
Copyright  1994
3
Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
(714) 898-8121 ∞ FAX: (714) 893-2570
SG29085/85A
APPLICATION HINTS
EXTERNAL CAPACITORS
To stabilize the outputs and prevent oscillation (perhaps by many
volts) external capacitors are required. The minimum recommended value for the output capacitors is 10µF, although the
actual size and type will likely vary according to the particular
application, e.g., operating temperature range and load. Another
consideration is the effective series resistance (ESR) of the
capacitor. Capacitor ESR will vary by manufacturer. Consequently, some evaluation may be required to determine the
minimum value of the output capacitors. Generally worst case
occurs at the maximum load and minimum ambient temperature.
the current through the external resistor should be sufficient to
bias internal resistors up to this point. Approximately 60µA will
suffice, resulting in a 10k external resistor for most applications
(Figure 1).
HIGH CURRENT OUTPUT
VIN
RD
10K
STANDBY
OUTPUT
SG29085/85A
The size of the output capacitor can be increased to any value
above the minimum. One possible advantage of this would be to
maintain the output voltage during brief periods of negative input
transients
C3
The output capacitors chosen should be rated for the full range
of ambient temperature over which the circuit will be exposed and
expected to operate. For example, many aluminum type electrolytic capacitors will freeze at -30°C. The effective capacitance is
reduced to zero in such a situation. Capacitors rated for -40°C
operation must be used in order to maintain regulator stability at
that temperature. Tantalum capacitors satisfy this requirement.
FIGURE 1. Disabling Standby Output to Eliminate C3
The high current regulated output features fault protection
against overvoltage as well as a thermal shutdown feature. If the
input voltage rises above 33V (load dump), the high current
output shuts down automatically. The internal circuitry is thus
protected and the IC is able to survive higher voltage transients
than might otherwise be expected. The thermal shutdown of the
high current output effectively guards against overheating of the
die since this section of the IC is the principle source of power
dissipation on the chip.
STANDBY OUTPUT
The SG29085/85A differs from most fixed voltage regulators in
that it is equipped with two regulator outputs instead of one. The
additional output is intended for use in systems requiring standby
memory circuits. While the high current regulator output can be
controlled with the ON/OFF pin described below, the standby
remains on under all conditions as long as sufficient input voltage
is applied to the IC. Thus, memory and other circuits powered by
this output remain unaffected by positive line transients, thermal
shutdown, etc.
ON/OFF SWITCH
The ON/OFF pin is a high impedance low current switch that
controls the main output voltage (pin 2). This is directly compatible with all 5 volt logic families. For use with open collector logic
outputs, a 100Kresistor from this pin to a 5V supply, such as Pin
5, is required.
The standby regulator circuit is designed so that the quiescent
current to the IC is very low (<1.5mA) when the other regulator
output is off.
If the standby output is not required it can be disabled. This is
accomplished by connecting a resistor from the standby output to
the supply voltage, thereby also eliminating the requirement for
a more expensive output capacitor to prevent unwanted oscillations. The resistor value depends upon the minimum input
voltage expected for a given system.
Since the standby output is shunted with an internal 5.6V zener,
CONNECTION DIAGRAM & ORDERING INFORMATION
Package
5-PIN TO-220 PLASTIC
P - PACKAGE
Part No.
SG29085P
SG29085AP
(See Note Below)
Ambient
Temperature Range
Connection Diagram
-40°C to 85°C
-40°C to 85°C
GND
5
4
3
2
1
STANBY OUTPUT
ON/OFF SWITCH
GROUND
OUTPUT VOLTAGE (VOUT)
INPUT VOLTAGE (VIN)
Note: 1. All packages are viewed from the top.
LINFINITY
12/90 Rev 1.1 2/94
Copyright  1994
4
Microelectronics Inc.
11861 Western Avenue ∞ Garden Grove, CA 92841
(714) 898-8121 ∞ FAX: (714) 893-2570