UPC1933 [NEC]
DC-DC CONVERTER CONTROL IC; 的DC-DC转换器控制IC
| 型号： | UPC1933 |
| 厂家： | 
NEC |
| 描述： | DC-DC CONVERTER CONTROL IC |
| 文件： | 总20页 (文件大小：119K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
DATA SHEET
BiCMOS INTEGRATED CIRCUIT
µ PC1933
DC-DC CONVERTER CONTROL IC
DESCRIPTION
The µ PC1933 is an IC that controls a low-voltage input DC-DC converter. This IC is suitable for an operation with3-V,
3.3-V input or a lithium ion secondary battery input, because the minimum operating supply voltage is 2.5 V.
Because of its wide operating voltage range, it can also be used to control DC-DC converters that use an AC adapter for
input.
FEATURES
• Low supply voltage: 2.5 V (MIN.)
• Operating voltage range: 2.5 to 20 V (breakdown voltage: 30 V)
• Timer latch circuit for short-circuit protection.
• Ceramic capacitor with low capacitance (0.1 µ F) can be used for short-circuit protection.
• Open drain output (1 cannel: This output can be used to control a step-down converter, a step-up converter.)
• Dead time is internally fixed to 85 %.
• Soft start function (with a circuit to convert the timer latch circuit.)
ORDERING INFORMATION
Part Number
Package
µ PC1933GR
8-pin plastic SOP (5.72 mm (225))
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. G13690EJ3V0DS00 (3rd edition)
Date Published April 2000 NS CP (K)
The mark ★ shows major revised points.
1998
Printed in Japan
µ PC1933
BLOCK DIAGRAM
FB
8
R
T
GND
6
OUT
5
7
Oscillation
section
MOS input
E/A
PWM
–
+
–
+
+
MOS output
Soft start
select switch
Internal
fixed
voltage
Timer latch for
short-circuit
protection section
Reference
voltage
section
DTC
(Internal fixed)
1
2
3
4
I
I
DLY
V
CC
V
REF
2
Data Sheet G13690EJ3V0DS00
µ PC1933
PIN CONFIGURATION (Top View)
8-pin plastic SOP (5.72 mm (225))
• µ PC1933GR
I
I
1
2
3
4
8
7
6
5
FB
DLY
RT
V
CC
GND
OUT
V
REF
PIN FUNCTIONS
Pin No.
Symbol
II
Function
Error amplifier inverted input
Short-circuit protection
Power supply
Pin No.
Symbol
OUT
GND
RT
Function
Open-drain output
Ground
1
2
3
4
5
6
7
8
DLY
VCC
Frequency setting resistor connection
Error amplifier output
VREF
Reference voltage output
FB
3
Data Sheet G13690EJ3V0DS00
µ PC1933
CONTENTS
1. ELECTRICAL SPECIFICATIONS................................................................................................................ 5
2. CONFIGURATION AND OPERATION OF EACH BLOCK.................................................................... 11
2.1 Reference Voltage Generator ...........................................................................................................................11
2.2 Oscillator ...........................................................................................................................................................11
2.3 Under Voltage Lock-out Circuit........................................................................................................................11
2.4 Error Amplifier...................................................................................................................................................11
2.5 PWM Comparator..............................................................................................................................................12
2.6 Timer Latch-Method Short Circuit Protection Circuit ....................................................................................12
2.7 Output Circuit....................................................................................................................................................12
3. NOTES ON USE........................................................................................................................................ 13
3.1 Setting the Output Voltage ...............................................................................................................................13
3.2 Setting the Oscillation Frequency...................................................................................................................13
3.3 Preventing Malfunction of theTimer Latch-Method Short Circuit Protection Circuit..................................13
3.4 ON/OFF Control.................................................................................................................................................14
3.5 Maximum Duty Limit.........................................................................................................................................15
3.6 Notes on Actual Pattern Wiring........................................................................................................................15
4. APPLICATION EXAMPLE ......................................................................................................................... 16
4.1 Application Example.........................................................................................................................................16
4.2 List of External Parts........................................................................................................................................16
5. PACKAGE DRAWING................................................................................................................................ 17
6. RECOMMENDED SOLDERING CONDITIONS ....................................................................................... 18
4
Data Sheet G13690EJ3V0DS00
µ PC1933
1. ELECTRICAL SPECIFICATIONS
Absolute Maximum Ratings (unless otherwise specified, TA = 25 °C)
Parameter
Symbol
VCC
VO
Ratings
Unit
V
Supply voltage
Output voltage
30
30
V
Output current (open drain output)
Total power dissipation
IO
21
mA
mW
°C
°C
PT
480
Operating ambient temperature
Storage temperature
TA
−20 to + 85
−55 to + 150
Tstg
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
Symbol
VCC
VO
Ratings
Unit
V
Supply voltage
Output voltage
Output current
2.5
0
20
20
V
IO
20
mA
°C
Operating temperature
Oscillation frequency
TA
−20
+85
800
fOSC
20
kHz
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.
5
Data Sheet G13690EJ3V0DS00
µ PC1933
Electrical Characteristics (unless otherwise specified, TA = 25 °C, VCC = 3 V, fOSC = 100 kHz)
Block
Under
Parameter
Start-up voltage
Symbol
VCC (L-H)
VCC (H-L)
VH
Conditions
IREF = 0.1 mA
MIN.
TYP.
1.57
1.5
70
MAX.
Unit
V
voltage
Lock-out
section
Operation stop voltage
Hysteresis voltage
Reset voltage (timer latch)
Reference voltage
Line regulation
IREF = 0.1 mA
V
IREF = 0.1 mA
30
mV
V
VCCR
IREF = 0.1 mA
1.0
2.1
2
Reference
Voltage
section
VREF
IREF = 1 mA
2.0
2.2
12.5
7.5
V
REGIN
REGL
∆VREF/∆T
∆fOSC
2.5 V≤VCC≤20 V
0.1 mA≤IREF≤1 mA
−20 °C≤TA≤+85 °C, IREF = 0 A
RT = 18 kΩ
mV
mV
%
Load regulation
2
Temperature coefficient
fOSC setting accuracy
fOSC total stability
0.5
Oscillation
section
−20
−20
+30
+50
%
∆fOSC
−20 °C≤TA≤+85 °C,
2.5 V≤VCC≤20 V
%
PWM
Maximum duty
Soft start time
DMAX.
tSS
85
50
%
comparator
CDLY = 0.1 µF
ms
section
Error
Input threshold voltage
Input bias current
Open loop gain
VITH
IB
0.285
−100
70
0.3
0.315
V
nA
dB
MHz
V
Amplifier
section
+100
Av
VO = 0.3 V
VO = 0.3 V
IO = −45 µA
IO = 45 µA
VFB = 0.5 V
VFB = 1.6 V
VO = 30 V
80
1.5
2
Unity gain
funity
+
VOM
Maximum output voltage (+)
Maximum output voltage (−)
Output sink current
Output source current
Drain cutoff current
Output ON voltage
Rise time
1.6
0.8
−
VOM
0.02
1.4
−70
0.5
V
IOsink
IOsource
ILEAK
VOL
tr
m A
µA
µA
V
−45
100
0.6
Output
section
RL = 150 Ω
RL = 150 Ω
RL = 150 Ω
0.2
50
ns
Fall time
tf
60
ns
Short-circuit
Protection
section
Input sense voltage
UV sense voltage
VTH
VUV
1.75
1.0
1.92
0.8
1.6
50
2.05
0.85
2.7
V
V
Source current on short-circuiting IOUV
µA
ms
mA
Delay time
tDLY
ICC
CDLY = 0.1 µF
Overall
Circuit operation current
VCC = 3 V
1.4
2.6
3.9
Caution Connect a capacitor of 0.01 to 10 µ F to the VREF pin.
4
µPC1933
6
CREF = 0.01 to 10 µF
6
Data Sheet G13690EJ3V0DS00
Timing Chart
Soft start by CDLY Detected
finishing of soft- start, Switch
Short-load
Soft start by CDLY
Voltage of FB pin
DTC (internal fixed)
Pin voltage
Voltage of DLY pin
Voltage of DLY pin
OUT
OFF ON
Output oscillation
is stopped
µ
µ
µ PC1933
Typical Characteristic Curves (unless otherwise specified,VCC = 3 V, fOSC = 100 kHz,TA = 25 °C) (Nominal)
P
T
vs T
A
VREF vs VCC
0.5
0.4
0.3
0.2
0.1
2.5
2.0
1.5
1.0
0.5
I
REF = 0 A
260.4 ° C/W
0
25
50
75
100 125 150
(°C)
0
1
2
3
4
5
100
20
Operating ambient temperature T
A
A
A
Supply voltage VCC (V)
V
REF vs T
A
f
OSC vs R
T
2.13
2.12
1000
100
I
REF = 0 A
2.11
2.10
2.09
2.08
2.07
10
–25
0
25
50
75
100
1
10
Operating ambient temperature T
(°C)
Timing resistance R (kΩ)
T
∆fOSC vs T
A
V
OL vs I
O
6
4
2
0
0.5
0.4
0.3
0.2
0.1
R
T
= 18 kΩ
–2
–4
–6
–25
0
25
50
75
100
0
5
10
15
Operating ambient temperature T
(°C)
Output current I
O
(mA)
8
Data Sheet G13690EJ3V0DS00
µ PC1933
D
MAX. vs R
T
V
OL vs T
A
0.4
0.3
0.2
0.1
0
100
90
IO = 20 mA
80
70
60
50
–25
0
25
50
75
100
1
10
100
Operating ambient temperature T
A
(°C)
Timing resistance R (kΩ)
T
tSS vs CDLY
tDLY vs CDLY
600
500
400
300
200
100
600
500
400
300
200
100
0
0.2
0.4
0.6
0.8
1.0
0
0.2
0.4
0.3
0.4
1.0
F)
DLY pin capacitor capacitance CDLY
(µF)
DLY pin capacitor capacitance CDLY
(
µ
tDLY vs T
A
Av, φ vs f
60
50
100
80
60
40
20
0
180
135
90
φ
40
30
20
10
0
φ
45
Av
0
–45
CDLY = 0.1 µF
–90
–20
100
1 k
10 k 100 k 1 M 10 M
Frequency f (Hz)
–25
0
25
50
75
100
(°C)
Operating ambient temperature T
A
9
Data Sheet G13690EJ3V0DS00
µ PC1933
I
CC vs VCC
I
CC vs T
A
3
2
1
4
3
2
1
0
0
5
10
15
20
25
30
–25
0
25
50
75
100
Supply voltage VCC (V)
Operating ambient temperature T
A
(°C)
10
Data Sheet G13690EJ3V0DS00
µ PC1933
2. CONFIGURATION AND OPERATION OF EACH BLOCK
Figure 2-1 Block Diagram
Oscillation
section
7
5
R
T
8
1
FB
OUT
I
I
Error amplifier
0.3 V
Output
section
PWM
comparator
4
3
V
REF
Under voltage
lock-out
section
Reference
voltage
V
CC
section
SCP
comparator
Dead time setting: 85 %
(internally fixed)
S
Q
Q
Q
1
Q
2
6
GND
1.92 V
Soft start
select switch
DLY
Timer latch for
short-circuit
protection section
2
CDLY
2.1
Reference Voltage Generator
The reference voltage generator is comprised of a band-gap reference circuit, and outputs a temperature-compensated
reference voltage (2.1 V). The reference voltage can be used as the power supply for internal circuits, or as a reference
voltage, and can also be accessed externally via the VREF pin (pin 4).
2.2
Oscillator
The oscillator self-oscillates if a timing resistor is attached to the RT pin (pin 7). This oscillator waveform is input to the
inverted input pin of the PWM comparator to determine the oscillation frequency.
2.3
Under Voltage Lock-out Circuit
The under voltage lock-out circuit prevents malfunctioning of the internal circuits when the supply voltage is low, such as
when the supply voltage is first applied, or when the power supply is interrupted. When the voltage is low, the output
transistor is cut off at the same time.
2.4
Error Amplifier
The non-inverted input pin of the error amplifier is connected internally to 0.3 V (the input threshold voltage is 0.3 V
(TYP.)). The first stage of the error amplifier is a P-channel MOS transistor input.
11
Data Sheet G13690EJ3V0DS00
µ PC1933
2.5
PWM Comparator
The output ON duty is controlled according to the outputs of the error amplifier.
A triangular waveform is input to the inverted pin, and the error amplifier output and Dead Time Control pin voltage (fixed
internally) are input to the non-inverted pins of the PWM comparator. Therefore, the output transistor ON period is the
period when the triangular waveform is lower than the error amplifier output and Dead Time Control pin voltage (fixed
internally) (refer to Timing Chart).
2.6
Timer Latch-Method Short Circuit Protection Circuit
When the output of the converter drops, the non-inverted input pin (1 pin) voltage of the error amplifier drops, and the
FB output of the error amplifier of the output goes high. If the FB output exceeds the timer latch input detection voltage
(VTH = 1.92 V), then the output of the SCP comparator goes low, and Q1 goes off.
When Q1 turns OFF, the constant-current supply charges CDLY via the DLY pin. The DLY pin is internally connected to a
flip-flop. When the DLY pin voltage reaches the UV detection voltage (VUV = 0.7 V (TYP.)), the output Q of the flip-flop goes
low, and the output stage is latched to OFF (refer to Figure 2-1 Block Diagram).
Make the power supply voltage briefly less than the reset voltage (VCCR, 1.0 V TYP.) to reset the latch circuit when the
short-circuit protection circuit has operated.
2.7
Output Circuit
The output circuit has an N-channel open-drain output providing an output withstand voltage of 30 V (absolute maximum
rating), and an output current of 21 mA (absolute maximum rating).
12
Data Sheet G13690EJ3V0DS00
µ PC1933
3. NOTES ON USE
3.1
Setting the Output Voltage
Figure 3-1 illustrates the method of setting the output voltage. The output voltage is obtained using the formula shown in
the figure.
The input threshold value of the error amplifier is 0.3 V (TYP.) for the error amplifier. Therefore, select a resistor value
that gives this voltage.
Figure 3-1 Setting the Output Voltage
R
R
1
2
VOUT (positive voltage)
V
OUT
=
1 +
• 0.3
R
1
2
1
8
E/A
C
NF
NF
R
R
0.3 V
3.2
Setting the Oscillation Frequency
Choose RT according to the oscillation frequency (fOSC) vs timing resistor (RT) characteristics (refer to Typical
Characteristics Curves fOSC vs RT.) The formula below (3-1) gives an approximation of fOSC. However, the result of
formula 3-1 is only an approximation, and the value must be confirmed in actual operation, especially for high-frequency
operation.
fOSC[Hz] 1.856 x 109/RT[Ω]
(3-1)
3.3
Preventing Malfunction of the Timer Latch-Method Short Circuit Protection Circuit
The timer latch short-circuit protection circuit operates when the error amplifier output (pin 8) exceed approximately 1.92
V, and cuts off the output. However, if the rise of the power supply voltage is fast, or if there is noise on the DLY pin (pin 2),
the latch circuit may malfunction and cut the output off.
To prevent this, lower the wiring impedance between the DLY pin and the GND pin (pin 6), and avoid applying noise to
the DLY pin.
13
Data Sheet G13690EJ3V0DS00
µ PC1933
3.4
ON/OFF Control
The ON/OFF control method of the output oscillation is to input the ON/OFF signal from ON as shown in Figure 3-2.
Soft start or timer latch (SCP) is internally selected. Soft start is executed when the first start signal is input. When the
end of soft start is detected, the soft start select switch is turned OFF and the timer latch circuit operates.
Figure 3-2 ON/OFF Control
VO
(Converter
output
voltage)
FB
R
1
2
SCP comparator
I
I
–
+
+
–
Error amplifier
Q
R
0.3 V
0.63 V
VREF
D1
R
To output stage
Dead time
setting: 85 %
(internally fixed)
+
+
–
PWM comparator
Oscillation section
(common to each channel)
ON
Q1
SW
CDLY
DLY
(1) When ON is high: OFF status
Q1: ON → DLY pin: Low level → Output duty of PWM comparator: 0 %
D1: ON → II pin: High level → FB output: Low level
(2) When ON is low: ON status (start up)
Q1
: OFF → CDLY is charged in the sequence of [VREF → R
1
→ SW → DLY pin → CDLY] → Soft start
D1
: OFF → I pin: Low level → FB output: High level
I
(3) When ON goes high again after start up (SW: OFF): OFF status
Q1: ON → DLY pin: Low level (Nothing happens because SW is OFF.)
D1: ON → II pin: High level → FB output: Low level → PWM comparator output duty: 0 %
→ Converter output voltage (VO) drops.
Caution Even if start up is executed by making ON low again after (3), soft start is not executed because the
soft start select switch (SW) remains OFF. To execute soft start again, drop VCC to 0 V once.
14
Data Sheet G13690EJ3V0DS00
µ PC1933
3.5
Maximum Duty Limit
µ PC1933 is switched internally between Soft Start and Timer Latch. For this reason, the DTC voltage is fixed internally,
and the maximum duty is limited to 85%.
3.6
Notes on Actual Pattern Wiring
When actually carrying out the pattern wiring, it is necessary to separate control-related grounds and power-related
grounds, and make sure that they do not share impedances as far as possible. In addition, make sure the high-frequency
impedance is lowered using capacitors and other components to prevent noise input to the VREF pin.
15
Data Sheet G13690EJ3V0DS00
µ PC1933
4. APPLICATION EXAMPLE
4.1
Application Example
Figure 4-1 shows an example circuit for obtaining +5 V/50 mA from a +3 V power supply.
Figure 4-1 Application Example
COM
VIN = 3 V
V
I
O
O
= + 5 V
= 50 mA
C
5
1
µ F
L 47 µ H
1
D1
R
2
47 kΩ
150 Ω
R6 470 Ω
R9
68 Ω
R
5
R
T
3.9 kΩ
Q
1
C
100
pF
2
R
7
C
68
4
Q
3
C
3
100 pF
8
7
6
5
20 kΩ
µ F
R
3
Q
2
FB
RT
GND OUT
2.4 kΩ
R
10
C
3300
pF
1
VR
4
R
8
20 kΩ
µ PC1933
1 kΩ
7.5 kΩ
COM
I
I
DLY
2
V
CC
V
REF
R
30 kΩ
1
1
3
4
C
0.D1LYµ
C
0
F
0.1
µ F
4.2
List of External Parts
The list below shows the external parts.
Table 4-1 List of External Parts
Symbol
C4
Parameter
Function
Part number
20SA68M
Maker
SANYO
Remark
68 µ F
Output capacitor
Schottkey diode
Choke inductor
Switching transistor
Buffer transistor
Buffer transistor
OS-CON, SA series
D1
L1
D1FS4
SHINDENGEN
TOKO
47 µ H
636FY-470M
2SD2403
2SC1623
2SA812
D73F series
Q3
Q1
Q2
NEC
NEC
NEC
Remarks 1. The capacitors that are not specified in the above list are multilayer ceramic capacitors.
2. The resistors that are not specified in the above list are 1/4W resistors.
16
Data Sheet G13690EJ3V0DS00
µ PC1933
5. PACKAGE DRAWING
8-PIN PLASTIC SOP (5.72 mm (225))
8
5
detail of lead end
P
1
4
A
H
I
F
J
G
S
B
L
N
S
C
K
M
D
M
E
NOTE
ITEM MILLIMETERS
Each lead centerline is located within 0.12 mm of
its true position (T.P.) at maximum material condition.
+0.17
A
5.2
−0.20
B
C
0.78 MAX.
1.27 (T.P.)
+0.08
0.42
D
−0.07
E
F
G
H
I
0.1±0.1
1.59±0.21
1.49
6.5±0.3
4.4±0.15
1.1±0.2
J
+0.08
0.17
K
−0.07
L
M
N
0.6±0.2
0.12
0.10
+7°
3°
P
−3°
S8GM-50-225B-6
17
Data Sheet G13690EJ3V0DS00
µ PC1933
6. RECOMMENDED SOLDERING CONDITIONS
Recommended solder conditions for this product are described below.
For details on recommended soldering conditions, refer to Information Document “Semiconductor Device Mounting
Technology Manual” (C10535E).
For soldering methods and conditions other than those recommended, consult NEC.
Surface Mount Type
µ PC1933GR: 8-pin plastic SOP (5.72 mm (225))
Soldering Method
Infrared reflow
VPS
Soldering Conditions
Symbol of Recommended
Conditions
Package peak temperature: 235 °C, Time: 30 seconds MAX. (210 °C MIN.),
Number of times: 3 MAX.
IR35-00-3
VP15-00-3
WS60-00-1
Package peak temperature: 215 °C, Time: 40 seconds MAX. (200 °C MIN.),
Number of times: 3 MAX.
Wave soldering
Soldering bath temperature: 260 °C MAX., Time: 10 seconds MAX.,
Number of times: 1,
Preheating temperature: 120 °C MAX. (package surface temperature)
Caution Do not use two or more soldering methods in combination.
18
Data Sheet G13690EJ3V0DS00
µ PC1933
NOTES FOR BiCMOS DEVICES
1
PRECAUTION AGAINST ESD FOR SEMICONDUCTORS
Note:
Strong electric field, when exposed to a device, can cause destruction of the gate oxide and
ultimately degrade the device operation. Steps must be taken to stop generation of static electricity
as much as possible, and quickly dissipate it once, when it has occurred. Environmental control
must be adequate. When it is dry, humidifier should be used. It is recommended to avoid using
insulators that easily build static electricity. Semiconductor devices must be stored and transported
in an anti-static container, static shielding bag or conductive material. All test and measurement
tools including work bench and floor should be grounded. The operator should be grounded using
wrist strap. Semiconductor devices must not be touched with bare hands. Similar precautions need
to be taken for PW boards with semiconductor devices on it.
2
HANDLING OF UNUSED INPUT PINS
Note:
No connection for device inputs can be cause of malfunction. If no connection is provided to the
input pins, it is possible that an internal input level may be generated due to noise, etc., hence
causing malfunction. Input levels of devices must be fixed high or low by using a pull-up or pull-
down circuitry. Each unused pin should be connected to VDD or GND with a resistor, if it is
considered to have a possibility of being an output pin. All handling related to the unused pins must
be judged device by device and related specifications governing the devices.
3
STATUS BEFORE INITIALIZATION OF BiCMOS DEVICES
Note:
Power-on does not necessarily define initial status of device. Production process of BiCMOS does
not define the initial operation status of the device. Immediately after the power source is turned
ON, the devices with reset function have not yet been initialized. Hence, power-on does not
guarantee out-pin levels, I/O settings or contents of registers. Device is not initialized until the reset
signal is received. Reset operation must be executed immediately after power-on for devices
having reset function.
19
Data Sheet G13690EJ3V0DS00
µ PC1933
[MEMO]
• The information in this document is subject to change without notice. Before using this document, please
confirm that this is the latest version.
• No part of this document may be copied or reproduced in any form or by any means without the prior written
consent of NEC Corporation. NEC Corporation assumes no responsibility for any errors which may appear in
this document.
• NEC Corporation does not assume any liability for infringement of patents, copyrights or other intellectual property
rights of third parties by or arising from use of a device described herein or any other liability arising from use
of such device. No license, either express, implied or otherwise, is granted under any patents, copyrights or other
intellectual property rights of NEC Corporation or others.
• Descriptions of circuits, software, and other related information in this document are provided for illustrative
purposes in semiconductor product operation and application examples. The incorporation of these circuits,
software, and information in the design of the customer's equipment shall be done under the full responsibility
of the customer. NEC Corporation assumes no responsibility for any losses incurred by the customer or third
parties arising from the use of these circuits, software, and information.
• While NEC Corporation has been making continuous effort to enhance the reliability of its semiconductor devices,
the possibility of defects cannot be eliminated entirely. To minimize risks of damage or injury to persons or
property arising from a defect in an NEC semiconductor device, customers must incorporate sufficient safety
measures in its design, such as redundancy, fire-containment, and anti-failure features.
• NEC devices are classified into the following three quality grades:
"Standard", "Special", and "Specific". The Specific quality grade applies only to devices developed based on a
customer designated "quality assurance program" for a specific application. The recommended applications of
a device depend on its quality grade, as indicated below. Customers must check the quality grade of each device
before using it in a particular application.
Standard: Computers, office equipment, communications equipment, test and measurement equipment,
audio and visual equipment, home electronic appliances, machine tools, personal electronic
equipment and industrial robots
Special: Transportation equipment (automobiles, trains, ships, etc.), traffic control systems, anti-disaster
systems, anti-crime systems, safety equipment and medical equipment (not specifically designed
for life support)
Specific: Aircraft, aerospace equipment, submersible repeaters, nuclear reactor control systems, life
support systems or medical equipment for life support, etc.
The quality grade of NEC devices is "Standard" unless otherwise specified in NEC's Data Sheets or Data Books.
If customers intend to use NEC devices for applications other than those specified for Standard quality grade,
they should contact an NEC sales representative in advance.
M7 98. 8
相关型号：
UPC1943T-AZ
Two Terminal Voltage Reference, 1 Output, 1.26V, Trim/Adjustable, BIPolar, PSSO3, MINI, POWER, PLASTIC, SOT-89, 3 PIN
NEC
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