ETC UC2904Q

UC1904
UC2904
UC3904
Precision Quad Supply and Line Monitor
FEATURES
DESCRIPTION
•
Inputs for Monitoring Up to Four
Supply Voltages
•
Two Inputs Preset for -5V and -12V
Monitoring, or Programmable
Positive Levels
•
The UC1904 Quad Supply Monitor will respond to under- and over-voltage conditions on up to four continuously monitored voltage levels. Four
independent positive voltages can be monitored or, alternatively, two of
the sense inputs are preset to monitor -5V and -12V supplies. The device also monitors Over-Current and Line Sense inputs, both with precision input thresholds.
Precision 2.5V Reference
•
Separate Inputs for Over-Current and
Line Fault Sensing
•
Adjustable Under- to Over-Voltage
Fault Windows
•
Latched Over-Voltage and
Over-Current Output
•
Power Good and Power Warning
Outputs
•
Auto Restart Function with ON/OFF
Control, and Programmable Delay
•
Programmable Pwr On Reset Delay
BLOCK DIAGRAM
Four open collector outputs on the UC1904 give the following responses: 1. The OV/OC output is a latched over-voltage, or over-current
response. 2. A Power Good signal responds low with any fault detection
– on power-up a programmable delay is used to hold this output low for
a system Power On Reset signal. 3. The PWRW output responds only to
a Line Sense input, for early warning of power failures. 4. The last open
collector, the ON/OFF output, generates a delayed supply OFF control
signal in response to an OFF input command, under-voltage condition,
or line fault detection.
The OV-UV fault window is adjustable with a programming input. The
thresholds are centered around the precision 2.5V reference, with a
scaled hysteresis for precise, glitch free operation. In the positive mode
of operation, the fault windows at each of the sense inputs can be independently scaled using external resistors and the 2.5V reference output.
An Auto Restart function couples with the under-voltage and line sensing circuits to allow controlled power supply start-up and shutdown.
This device will operate over a supply range of 4.75V to 18V. The device
is available in a DIP, SOIC, or PLCC outline. This device is ESD protected on all pins.
Note: Pin Numbers refer to J, N, and DW Packages.
4/97
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UC1904
UC2904
UC3904
ABSOLUTE MAXIMUM RATINGS (Note 1)
Input Supply Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
Sense Inputs, S1 And S2, Other Analog And Logic Inputs
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -0.3V to 10V
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . ±10mA
Sense Input S3, (-12V Sense Input)
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -18V to 10V
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . ±10mA
Sense Input S4, (-5V Sense Input)
Maximum Forced Voltage . . . . . . . . . . . . . . . . . . -10V to 10V
Maximum Forced Current . . . . . . . . . . . . . . . . . . . . . . ±10mA
Open Collector Outputs
Maximum Voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20V
Maximum Current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50mA
Reference Output Current . . . . . . . . . . . . . . . Internally Limited
Operating Junction Temperature . . . . . . . . . . . -55°C to +150°C
Storage Temperature . . . . . . . . . . . . . . . . . . . . -65°C to +150°C
Note 1: Unless otherwise indicated, voltages are reference to
ground and currents are positive into, negative out of, the specified terminals.
CONNECTION DIAGRAMS
PLCC-20 (TOP VIEW)
Q PACKAGE
PACKAGE PIN FUNCTION
FUNCTION
PIN
2.5V
POR DLY
N.C.
S1
S2
S3
S4
N.C.
LS Input
OC Input
PWRW Out
PG Out
OV/OC Out
VIN
ON/OFF Out
OFF DLY
ON/OFF Input
ARST Input
WADJ
Gnd
DIL-18, SOIC-18 (TOP VIEW)
J or N PACKAGE, DW PACKAGE
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
ELECTRICAL CHARACTERISTICS: Unless otherwise stated, these specifications hold for TA = 0 to 70°C for the
UC3904, -40 to +85°C for the UC2904, and -55 to +125°C for the UC1904, +VIN =
15V, WADJ = 0.5V, Sense Inputs 1-4, OC and LS Inputs = 2.5V. The ON/OFF Input
and the ARST Input = 0V.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
mA
Input Supply
VIN Supply Current
VIN = 15V
3.2
4.5
VIN UVLO Threshold
Low to High
4.5
4.75
V
UVLO Threshold Hysteresis
50
mV
Minimum VIN to Enable PG Out
0.8
1.5
V
2.5
Reference
Output Voltage(VREF)
TJ = 25°C
2.475
2.525
V
Over Temperature, UC3904
2.47
2.53
V
Over Temperature, UC2904 & UC1904
2.465
2.535
V
6
mV
5
mV
Load Regulation
IOUT = 0 to 4mA
Line Regulation
VIN = 4.75 to 18V
Short Circuit Current
VREF = 0V
17
mA
OV UV Window, LS Input, OC Input, ARST Input, and ON/OFF Input Thresholds
Over-Voltage Thresholds
WADJ = 0.25V, Offset from VREF, Input L to H
110
125
140
mV
S1, S2
WADJ = 0.5V, Offset from VREF, Input L to H
230
250
270
mV
WADJ = 1V, Offset from VREF, Input L to H
460
500
540
mV
WADJ = 0.25V, Offset from VREF, Input L to H
110
125
145
mV
WADJ = 0.5V, Offset from VREF, Input L to H
230
250
280
mV
WADJ = 1V, Offset from VREF, Input L to H
460
500
550
mV
Over-Voltage Thresholds
S3, S4 Positive Mode
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2
UC1904
UC2904
UC3904
Unless otherwise stated, these specifications hold for TA = 0 to 70°C for the UC3904, -40 to
ELECTRICAL
CHARACTERISTICS (cont): +85°C for the UC2904, and -55 to +125°C for the UC1904, +VIN = 15V, WADJ = 0.5V, Sense
Inputs 1-4, OC and LS Inputs = 2.5V. The ON/OFF Input and the ARST Input = 0V.
PARAMETER
TEST CONDITIONS
MIN
TYP
MAX
UNITS
OV UV Window, LS Input, OC Input, ARST Input, and ON/OFF Input Thresholds (cont.)
Under-Voltage Thresholds
WADJ = 0.25V, Offset from VREF, Input H to L
-140
-125
-110
mV
S1, S2
WADJ = 0.5V, Offset from VREF, Input H to L
-270
-250
-230
mV
WADJ = 1V, Offset from VREF, Input H to L
-540
-500
-460
mV
WADJ = 0.25V, Offset from VREF, Input H to L
-150
-125
-110
mV
WADJ = 0.5V, Offset from VREF, Input H to L
-285
-250
-230
mV
WADJ = 1V, Offset from VREF, Input H to L
-555
-500
-460
mV
Under-Voltage Thresholds
S3, S4 Positive Mode
30
50
70
mV/V
Over-Voltage, WADJ = 0.5V, Input H to L
-13.52
-13.2
-12.88
V
Under-Voltage, WADJ = 0.5V, Input L to H
-11.06
-10.8
-10.54
V
80
120
160
mV
OV and UV Threshold Hysteresis As a Function of WADJ
S3 Negative Mode Thresholds
Hysteresis, WADJ = 0.5V
S4 Negative Mode Thresholds
Over-Voltage, WADJ = 0.5V, Input H to L
-5.63
-5.5
-5.37
V
Under-Voltage, WADJ = 0.5V, Input L to H
-4.61
-4.5
-4.39
V
50
70
mV
5
µA/V
Hysteresis, WADJ = 0.5V
30
WADJ Input Bias Current
0.25V < WADJ <1.0V
-5
LS Threshold
Input = H to L
OC Threshold
1.96
2
2.04
V
Threshold hysteresis
65
100
125
mV
Input = H to L
1.9
2
2.1
V
Threshold hysteresis
ARST Input Threshold
ON/OFF Input Threshold
50
100
150
mV
Input = L to H
2.25
2.5
2.75
V
Input = H to L
0.56
0.625
0.69
V
1.74
2.4
V
Input high level
Input low level
0.6
1.35
Input = 2.2V
-1000
-250
Input = -12V
-700
-500
-700
V
Sense and Logic Input Bias Currents
Sense 1-4, Positive Mode
Sense 3 Negative Mode
Input = 2.8V
Sense 4 Negative Mode
Input = -5V
Line, and OC Inputs
Input = 2.2V
ON/OFF Input
Input = 2.5V
ARST Input
Input = 0.5
250
-2000
800
nA
-300
µA
-500
-300
µA
300
1000
nA
150
600
nA
nA
-700
nA
Open Collector Outputs (OV/OC Out, PG Out, PWRW Out, ON/OFF Out)
Saturation Voltage
IOUT = 10mA
Leakage current
VOUT = 20V
0.2
0.4
V
5
µA
350
ms/µF
POR Delay
Delay
160
250
Internal Pullup Current
9
µA
Threshold Low to High
2.25
V
OFF Delay
Delay
120
185
250
ms/µF
Internal Pullup current
12
µA
Threshold Low to High
2.25
V
OV Fault Delay
Delay
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10
3
20
50
µs
UC1904
UC2904
UC3904
PIN FUNCTIONAL DESCRIPTION
the fault latch is reset by the ON/OFF Input, or a UVLO
condition on the device.
2.5V: This is the output of the precision 2.5V reference.
ARST Input: This input, with a 4:1 hysteretic threshold,
is used to sequence a power system through the Auto
ReStarT cycle. A delayed representation of a supply output voltage is used at this pin to provide adequate startup
time for the power system, and a minimum power-off period.
POR DLY: This pin is used, with an external capacitor, to
program a Power-On-Reset delay. This delay is reset
whenever there is a UV condition at one of the S1-S4 inputs, and then triggered upon the clearing of the UV condition. When reset, the voltage across the capacitor is
quickly discharged to near zero volts, and the PG Out pin
goes active low. Once triggered the capacitor is charged
by a 9µA current source. The PG Out pin remains active
low until the delay capacitor voltage reaches a 2.1V
threshold.
Gnd: Reference point for the internal reference and all
thresholds, as well as the return for the remainder of the
device.
LS Input: The Line Sense input is used to monitor a voltage that varies with the input line voltage to a system.
The input is compared to a precision 2.0V level and is
used to activate the PWRW and PG outputs, as well as
triggering the Auto Restart sequence.
PG Out: During any fault, under-voltage, or UVLO condition this output is low. A Power Good indication (output
off) is given when all supply conditions are within defined
operating limits. During power-up the PG signal is delayed by a programmable Power On Reset delay. During
UVLO the output is active low as long as the input supply, VIN, is above approximately 1.0V.
OC Input: The Over-Current input can be used to respond to an inverted over-current signal. A low level signal at this input latches in a fault indication at the OV/OC
output.
PWRW Out: When a low line condition is sensed by the
LS Input this output goes low. This output is disabled
(off) during a UVLO condition.
OFF DLY: This pin functions similarly to the POR DLY
pin to delay the turn-on of the ON/OFF output transistor.
The charging current and upper threshold are 12µA and
2.1V.
S1-S4: These are the sense inputs for OV and UV monitoring of external voltages. All four inputs can be used to
sense positive voltages with a simple divider to scale the
voltage level to the 2.5V centered window. The S3 and
S4 inputs can also be used to sense -12V and -5V supplies respectively with no external components. This is
done with internal precision resistor dividers and two
source only op-amps that are disabled when the pins are
used in the positive mode.
ON/OFF Input: With a high level at this input the
ON/OFF Out pin is activated after a user-programmable
delay. A high level also activates the PG Out pin, and resets the OV/OC fault latch.
On/Off Out: This output is an open collector output that
is activated by the ON/OFF Input, or the Auto Restart circuitry. Saturation voltage on this and all the open collector outputs is rated at 10mA of current.
VIN: Input supply for the UC1904. The device is operational with 4.75V to 18V on this pin.
OV/OC Out: In response to either an Over-Voltage or
Over-Current situation this output is latched active low.
There is nominal 20µs delay in the OV path to the fault
latch, providing rejection to transient overshooting on the
monitored voltages. The low condition is cleared when
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WADJ: The WADJ input is used to program the OV and
UV window thresholds. The OV-UV window is centered
around the 2.5V reference and is nominally ±20% per
volt on the WADJ input pin.
4
UC1904
UC2904
UC3904
Note: Pin Numbers refer to J, N, and DW Packages.
UNITRODE CORPORATION
7 CONTINENTAL BLVD. • MERRIMACK, NH 03054
TEL. (603) 424-2410 • FAX (603) 424-3460
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