DATA SHEET
BIPOLAR ANALOG INTEGRATED CIRCUIT
µ
PC1945
ADJUSTABLE PRECISION SHUNT REGULATORS
DESCRIPTION
The
µ
PC1945 is an adjustable-shunt regulator featuring a high-precision internal reference voltage. The separate
power supply pin (V
CC
pin) allows the cathode voltage to be dropped to as low as 0.4V, making this product ideal for
error amplifiers that use a low voltage (minimum 1.8 V) output switching regulator.
Support for high-density mounting is also provided through the use of a 5-pin plastic mini-mold package.
FEATURES
• Separate cathode and power supply pins
• Suitable for low voltage (minimum 1.8 V) output switching regulator
Cathode voltage range: 0.4 V to 5 V
Power supply voltage range: V
REF
to 5 V
Reference voltage: 1.26 V
• 5-pin plastic mini-mold package
Mold dimensions: 2.9 mm(L)×1.5 mm(W)×1.1 mm(H)
ORDERING INFORMATION
Part Number
Package
5-pin plastic mini-mold
(SC-74A)
Marking
K95
Form of Shipment
–
µ
PC1945TA
µ
PC1945TA-E1
5-pin plastic mini-mold
(SC-74A)
K95
• Embossed taping
• Pin 1 in wind-in direction
• 3000 units/reel
µ
PC1945TA-E2
5-pin plastic mini-mold
(SC-74A)
K95
• Embossed taping
• Pin 1 in pull-out direction
• 3000 units/reel
The information in this document is subject to change without notice. Before using this document, please
confirm that this is the latest version.
Not all devices/types available in every country. Please check with local NEC representative for
availability and additional information.
Document No. G14875EJ2V0DS00 (2nd edition)
Date Published September 2001 NS CP (K)
Printed in Japan
2001
µ
PC1945
PIN CONNECTION (Top View)
5-pin plastic mini-mold (SC-74A)
µ
PC1945TA
V
CC
5
A
4
1
REF
2
A
3
K
Pin No
1
2
3
4
5
Pin Symbol
REF
A
K
A
V
CC
Reference
Anode
Cathode
Anode
Pin Name
Supply Voltage
Caution It is recommended to connect pins 2 and 4 externally. If this is not possible, leave pin 2 open.
BLOCK DIAGRAM
V
CC
K
REF
A
2
Data Sheet G14875EJ2V0DS
µ
PC1945
STANDARD CONNECTION
R
0
V
IN
R
1
V
CC
REF
R
2
GND
A
K
C
KA
Note
V
OUT
V
OUT
1
+
R
1
R
2
×
V
REF
Note
C
KA
= 100 pF minimum. Connect to prevent oscillation.
Caution Supply K (Cathode) and V
CC
from the same power supply.
Remark
The
µPC1945
is represented by the following symbol in this data sheet.
V
CC
REF
K
A
APPLICATION CIRCUIT EXAMPLE
V
O
+
photocoupler
Input to control IC
V
CC
REF
A
V
O
−
K
C
KA
Data Sheet G14875EJ2V0DS
3
µ
PC1945
ABSOLUTE MAXIMUM RATINGS
(Unless otherwise specified, T
A
= 25°C)
Parameter
Supply Voltage
Cathode Voltage
Cathode Current
Cathode/Anode Reverse Current
Reference Current
Reference/Anode Reverse Current
Circuit Current
Total Power Dissipation
Operating Ambient Temperature
Operating Junction Temperature
Symbol
V
CC
V
K
I
K
–I
K
I
REF
–I
REF
I
CC
P
T
T
A
T
J
Ratings
6
V
CC
15
–5
50
–5
2
90
–20 to+85
–20 to+125
Unit
V
V
mA
mA
µ
A
mA
mA
mW
°C
°C
Caution Product quality may suffer if the absolute maximum rating is exceeded even momentarily for any
parameter. That is, the absolute maximum ratings are rated values at which the product is on the
verge of suffering physical damage, and therefore the product must be used under conditions
that ensure that the absolute maximum ratings are not exceeded.
RECOMMENDED OPERATING CONDITIONS
Parameter
Supply Voltage
Cathode Voltage
Cathode Current
Total Power Dissipation
Operating Ambient Temperature
Operating Junction Temperature
V
CC
V
K
I
K
P
T
T
A
T
J
–20
–20
Symbol
MIN.
V
REF
0.4
TYP.
MAX.
5
V
CC
Note
12
20
+85
+100
Unit
V
V
mA
mW
°C
°C
Note V
K
≤
V
CC
Caution The recommended operating range may be exceeded without causing any problems provided that
the absolute maximum ratings are not exceeded. However, if the device is operated in a way that
exceeds the recommended operating conditions, the margin between the actual conditions of use
and the absolute maximum ratings is small, and therefore thorough evaluation is necessary. The
recommended operating conditions do not imply that the device can be used with all values at
their maximum values.
4
Data Sheet G14875EJ2V0DS
µ
PC1945
ELECTRICAL SPECIFICATIONS
(Unless otherwise specified, T
A
= 25°C, I
K
= 2 mA ( including I
CC
), V
REF
= V
CC
= V
K
, C
KA
= 100 pF)
Parameter
Reference Voltage
Reference Voltage Deviation
Over Temperature
Reference Voltage Deviation
Over Supply Voltage
Reference Input Current
Reference Input Current
Deviation Over Temperature
Minimum Circuit Current
Minimum Cathode Voltage
Off-state Cathode Current
Dynamic Impedance
Unity Gain Bandwidth
I
CC MIN.
V
K MIN.
I
K OFF
|
Z
KA
|
f
unity
I
REF
|
∆
I
REF
|
|
∆
V
REF
/
∆
V
CC
|
V
REF
|
∆
V
REF
|
0°C
≤
T
A
≤
+70°C
V
REF
≤
V
K
≤
5 V
R
1
= 10 kΩ, R
2
=
∞
0°C
≤
T
A
≤
+70°C
2
0.3
110
60
0.01
0.3
500
Symbol
Conditions
MIN.
1.235
TYP.
1.26
5
MAX.
1.285
30
Unit
V
mV
1.5
4
1.2
400
400
1
0.7
mV/V
µ
A
µ
A
µ
A
mV
∆
V
REF
= –2%
I
K
: I
CC
= 10 : 1
V
CC
= V
K
= 6 V, V
REF
= 0 V
f = 1 kHz, 2 mA
≤
I
K
≤
12 mA
R
1
= R
2
= 10 kΩ
µ
A
Ω
kHz
Data Sheet G14875EJ2V0DS
5
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