IP1842 SERIES
IP1843 SERIES
TOP VIEW
COMP
1
V
FB
2
I
SENSE
3
R
T
/C
T
4
8
7
6
5
V
REF
V
CC
OUTPUT
GROUND
CURRENT MODE
REGULATING
PULSE WIDTH
MODULATORS
FEATURES
•
•
•
•
•
Guaranteed ±1% reference voltage tolerance
Guaranteed ±10% frequency tolerance
Low start–up current (<500
m
A)
Under voltage lockout with hysteresis
Output state completely defined for all supply
and input conditions
J Package – 8 Pin Ceramic DIP
N Package – 8 Pin Plastic DIP
D-8 Package – 8 Pin Plastic (150) SOIC
TOP VIEW
COMP
1
N/C
2
14
13
12
11
10
9
8
V
REF
N/C
V
CC
V
C
OUTPUT
GROUND
POWER
GROUND
V
FB
3
N/C
4
I
SENSE
5
N/C
6
• Interchangeable with UC1842 and UC1843
series for improved operation
• 500kHz operation
R
T
/C
T
7
D-14 Package – 14 Pin Plastic (150) SOIC
Order Information
Part
Number
IP1842
IP2842
IP3842
IP1843
IP2843
IP3843
J–Pack
8 Pin
✔
✔
✔
✔
✔
✔
N–Pack
8 Pin
✔
✔
✔
✔
D–8
8 Pin
✔
✔
✔
✔
D–14
14 Pin
✔
✔
✔
✔
Temp.
Range
-55 to +125°C
-25 to +85°C
0 to +70°C
-55 to +125°C
-25 to +85°C
0 to +70°C
Note:
To order, add the package identifier to the
part number.
eg.
IP1842J
IP3843D-14
ABSOLUTE MAXIMUM RATINGS
(T
case
= 25°C unless otherwise stated)
V
CC
I
O
Supply Voltage
Output Current
Output Energy
Analog Inputs
Error Amp Output Sink Current
Power Dissipation
Derate @ T
amb
> 50°C
Power Dissipation
Derate @ T
case
> 25°C
Storage Temperature Range
Lead Temperature
(low impedance source)
(I
CC
< 30mA)
(capacitive load)
(pins 2 and 3)
T
amb
= 25°C
T
case
= 25°C
+30V
Self limiting
±1A
5
m
J
–0.3V to +V
CC
10mA
1W
10mW/°C
2W
24mW/°C
–65 to 150°C
+300°C
Prelim.3/00
P
D
P
D
T
STG
T
L
(soldering, 10 seconds)
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
IP1842 SERIES
IP1843 SERIES
DESCRIPTION
The IP1842 and IP1843 series of switching regulator control circuits contain all the functions necessary to
implement off–line, current mode switching regulators, using a minimum number of external parts. Functions
included are voltage reference, error amplifier, current sense comparator, oscillator, totem pole output driver and
under-voltage lockout circuitry.
Although pin compatible with the UC1842 and 1843 series, SEMELAB has incorporated several improvements in
the IP1842 and IP1843 series allowing tighter and more complete specification of electrical performance.
BLOCK DIAGRAM
V
CC
7/12
34V
G
ND
5/9
UNDER–VOLTAGE
LOCKOUT
ENABLE
REFERENCE 5V
REGULATOR
INTERNAL
BIAS
2.5V
REG
8/14
V
REF
16V
(8.4V)
6V
(0.5V)
S
R
3.6V
R
T
/C
T
4/7
V
REF
STATUS
LATCH
7/11
V
C
6/10
OSCILLATOR
ERROR
AMP
OUTPUT
2R
R
1V
S
R
CURRENT
SENSE
COMPARATOR
PWM
LATCH
5/8
V
FB
C
OMP
I
SENSE
2/3
POW ER
GROUND
1/1
3/5
Values in brackets are for IP1843 series.
PIN NUMBERS
1st Number – N, J and 8 Pin D Packages
2nd Num ber – 14 Pin D Package.
RECOMMENDED OPERATING CONDITIONS
V
CC
I
O
Supply Voltage
1
Output Current
Analog Inputs
(pins 2 and 3)
IP1842 , IP1843
IP2842 , IP2843
IP3842 , IP3843
Error Amp Output Sink Current
Operating Ambient Temperature Range
£
30V
0 to ±200mA
–0.3V to 3V
0 to 2mA
–55 to 125°C
–25 to 85°C
0 to 70°C
Notes:
1.
Lower limit set by under voltage lockout specification.
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
Prelim.3/00
IP1842 SERIES
IP1843 SERIES
ELECTRICAL CHARACTERISTICS
(Over Full Operating Temperature Range unless otherwise stated)
IP1842/IP1843
IP2842/IP2843
Min.
Typ.
Max.
T
J
= 25°C
Parameter
Output Voltage
Input Regulation
Output Regulation
Temperature Stability
Total Output Variation
Output Noise Voltage
Long Term Stability
Output Short Circuit
Current
Frequency
Voltage stability
Temperature Stability
Amplitude
Discharge Current
Test Conditions
REFERENCE SECTION
I
O
= 1mA
V
CC
= 12V to 25V
I
O
= 1mA to 20mA
Min.
4.90
IP3842
IP3843
Typ.
5.00
6
6
0.2
Max. Units
5.10
20
25
0.4
5.18
V
mV
mV
°C
V
m
4.95
5.00
6
6
0.2
5.05
20
25
0.4
5.10
Line, Load, Temp
f = 10Hz to 10kHz
T
J
= 25°C
T
J
= 125°C @ 1000Hrs
V
REF
= 0
4.90
50
5
30
80
4.82
50
5
30
80
V
25
160
25
160
mV
mA
OSCILLATOR SECTION
T
J
= 25°C
V
CC
= 12V to 25V
D
47
52
0.2
5
1.7
8.3
8
57
1
47
52
0.2
5
1.7
8.3
8
57
1
kHz
%
%
V
mA
%
T
A
= Min to Max
V
PIN4
Peak to Peak
T
J
= 25°C
D
T
A
= Min to Max
ERROR AMP SECTION
Input Voltage
Input Bias Current
Open Loop Voltage
Gain
Unity Gain Bandwidth
Supply Voltage
Rejection
Output Sink Current
Output Source Current
V
OUT
High
V
OUT
Low
V
CC
= 12V to 25V
V
PIN2
= 2.7V
V
PIN2
= 2.3V
V
PIN2
= 2.3V
V
PIN2
= 2.7V
V
PIN1
= 1.1V
V
PIN1
= 4.6V
R
L
= 15k
W
R
L
= 15k
W
V
O
= 2V to 4V
V
PIN1
= 2.5V
2.45
2.50
–0.3
2.55
–1
2.42
2.50
–0.3
2.58
–2
V
m
A
65
0.7
60
2
–0.5
4.6
90
1
70
6
–0.8
4.8
0.7
1.1
65
0.7
60
2
–0.5
4.6
90
1
70
6
–0.8
4.8
0.7
1.1
dB
MHz
dB
mA
V
NOTES
1. Test Conditions unless otherwise stated:
V
CC
= 15V* , R
T
= 10k
W
, C
T
= 3.3nF , f = 52kHz.
*Adjust V
CC
above start threshold before setting at required level.
All specifications apply over the full operating temperature range
unless otherwise stated. (See Ordering Information for further details).
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
Prelim.3/00
IP1842 SERIES
IP1843 SERIES
ELECTRICAL CHARACTERISTICS
(Over Full Operating Temperature Range unless otherwise stated)
IP1842/IP1843
IP2842/IP2843
Min.
Typ.
Max.
2.85
(Note 2)
Parameter
Gain
Maximum Input Signal
Supply Voltage
Rejection
Input Bias Current
Delay to Output
Test Conditions
CURRENT SENSE SECTION
See Notes 2,3
V
PIN1
= 4.6V
V
C
= 12V to 25V
Min.
2.85
0.9
60
IP3842
IP3843
Typ.
3
1
70
–2
200
0.1
1.5
Max. Units
3.15
1.1
V/V
V
dB
–10
400
0.4
2.2
m
3
1
70
–2
200
3.15
1.1
0.9
60
–10
400
0.4
2.2
13
12
150
150
1.1
17
9
11
8.2
0.5
15
17
40
30
14.5
7.8
8.5
7
A
ns
OUTPUT SECTION
Output Low Level
Output High Level
Rise Time
Fall Time
UVLO Saturation
Upper Threshold
(V
CC
)
Lower Threshold
(V
CC
)
Start–up Current
Operating Supply
Current
V
CC
Zener Voltage
V
PIN2
= 0V
V
PIN3
= 0V
I
CC
= 25mA
1842 Series
1843 Series
I
SINK
= 20mA
I
SINK
= 200mA
I
SOURCE
= 20mA
I
SOURCE
= 200mA
C
L
= 1nF
C
L
= 1nF
V
CC
= 6V
1842 Series
1843 Series
1842 Series
1843 Series
T
J
= 25°C
T
J
= 25°C
I
L
= 1mA
0.1
1.5
13
12
13.5
13.5
50
50
0.7
15
7.8
9
7
16
8.4
10
7.6
0.3
11
14
30
34
V
V
13.5
13.5
50
50
0.7
16
8.4
10
7.6
0.3
11
14
34
150
150
1.1
17.5
9
11.5
8.2
0.5
15
17
40
ns
V
UNDER–VOLTAGE LOCKOUT SECTION
V
V
TOTAL STANDBY CURRENT
mA
mA
V
NOTES
1. Test Conditions unless otherwise stated:
V
CC
= 15V* , R
T
= 10k
W
, C
T
= 3.3nF , f = 52kHz.
*Adjust V
CC
above start threshold before setting at
required level.
All specifications apply over the full operating temperature
range unless otherwise stated.
(See Ordering Information for further details).
2. Parameter measured at trip point of latch with
V
PIN2
= 0V
3. Gain defined as:
V
PIN1
D
V
PIN3
0
£
V
PIN3
£
0.8
A=
D
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
Prelim.3/00
IP1842 SERIES
IP1843 SERIES
APPLICATIONS INFORMATION
Oscillator Waveforms and Maximum Duty Cycle
COMP
1
V
FB
2
I
SENSE
3
R
T
/C
T
4
8
7
6
5
V
REF
V
CC
OUTPUT
GROUND
Oscillator timing capacitor C
T
is charged by V
REF
t
c
»
0.55 R
T
C
T
through R
T
and discharged by an internal current source.
.0063 R
T
– 2.3
During the discharge time, the internal clock signal
t
d
»
R
T
C
T
R
n
.0063 – 4
blanks the output to the low state. Selection of R
T
and
1
C
T
therefore determines both oscillator frequency and
Resultant frequency f =
(t
c
+ t
d
)
maximum duty cycle. Charge and discharge times are
determined by the formulae:
For R
T
> 5k
W
,
Resultant frequency f
»
1.8
(R
T
C
T
)
(
)
Open–Loop Laboratory Test Fixture
COMP
1
N/C
2
14
13
12
11
10
9
8
V
REF
N/C
V
CC
V
C
OUTPUT
GROUND
POWER
GROUND
V
FB
3
N/C
4
I
SENSE
5
N/C
6
R
T
/C
T
7
High peak current associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should
be connected close to pin 5 in a single point ground. The transistor and 5K potentiometer are used to sample the oscillator wave
form and apply an adjustable ramp to pin 3.
Semelab plc.
Telephone +44(0)1455 556565. Fax +44(0)1455 552612.
E-mail:
sales@semelab.co.uk
Website:
http://www.semelab.co.uk
Prelim.3/00
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