SITI PS121

PS121
Version
: A.017
Issue Date : 2008/11/04
File Name : SP-PS121-A.017.DOC
Total Pages: 9
Voltage Detecting IC
新竹市科學園區展業一路 9 號 7 樓之 1
SILICON TOUCH TECHNOLOGY INC.
9-7F-1, Prosperity Road I, Science Based Industrial Park,
Hsin-Chu, Taiwan 300, R.O.C.
Tel：886-3-5645656
Fax：886-3-5645626
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
PS121
Voltage Detecting IC
General Description
PS121 is specially designed for +5V power good signal generating. Power good
signal notifies microprocessor whether the +5V supply voltage is ready, therefore it can
provide a stable and reliable power supply and computing environment.
Delay circuit is also built-in to provide delay time by adding an external capacitor.
Features
1. Power Good Logic to Check +5V
2. Adjustable delay time
3. 4-pin SIP package
Block Diagram
+5V INPUT
2
Id
23.6K
10K
1
PG
OUTPUT
10K
1.25 V
Vth_cd
4
GND
Voltage Detecting IC
3
DELAY
CAPACITOR
-1 -
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Function Diagram
+5V INPUT
VOLTAGE
4.3
4.3-Vhy
t
PG
OUTPUT
td
td
t
Pin Descriptions
TO-93
Pin No
PIN NAME
1
PG
2
+5V(VDD)
3
Cd
4
VSS
Descriptions
Power good output signal pin
+5V(VDD) input pin
External capacitor for PG delay
Ground
SOT-26
Pin No
PIN NAME
1
NC
NO connect
2
VSS
Ground
3
PG
Power good output signal pin
4
+5V(VDD)
5
Cd
External capacitor for PG delay
6
NC
NO connect
Voltage Detecting IC
Descriptions
+5V(VDD) input pin
-2 -
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Absolute Maximum Ratings
Parameter
Supply Voltage
Symbol
VDD
Output Sink Current
Isink
Output Voltage
VPG
Power Dissipation
Pd
Storage Temperature
Tstg
Operating Temperature
Topr
Junction Temperature
Package Thermal Resistance
Rating
-0.5
~
Unit
+7.5
V
30
-0.5
~
mA
+7.5
300
-40
-30
~
~
Tj
150
θ JA
160
V
mW
+125
o
+90
o
C
C
o
C
o
C/W
Electrical characteristics, Vcc=5V, Ta = 25 oC. (unless otherwise specified)
Parameter
Test Condition
MIN
TYP
MAX
Unit
Vth
Detecting Threshold Voltage
4.05
4.30
4.55
V
Vhy
Vth Hysteresis Voltage
0.1
0.2
0.3
V
IDD
Circuit Current
VCC=5V
0.97
2.5
mA
Td
Delay Time
Cd=0.1μF
21.4
Id
Constant Current at Cd Pin
Vsat
PG Output Saturation Voltage
Vthcd
Threshold Voltage in Pin Cd
ΔT
Temperature coefficient
Voltage Detecting IC
8.0
V+5=4.0V,
Isink=10mA
8.7
ms
9.4
μA
0.128
0.192
V
VDD = 0Æ 5
1.79
1.87
1.95
VDD = 5Æ 0
1.72
1.77
1.82
+1
-3 -
+2
V
mV/°C
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Typical Application
(1) For Forward Type
S.P.S
Secondary Side
+5V
OUTPUT
Vz=6V
Rx
X1
=
X2
or
X1
or
+5V INPUT
I2
Vpgi
2
Id
Cd
D1
3
N-PG
4
R1
Cx
=
C>0.01uF
1
PG
GND
X2
(2) For Flyback Type
S.P.S
Secondary Side
+5V
OUTPUT
Vz=6V
Rx
X1
=
X2
or
X1
2
Id
Cd
D1
Voltage Detecting IC
or
+5V INPUT
I2
Vpgi
Cx
=
C>0.01uF
3
N-PG
4
R1
-4 -
1
GND
PG
X2
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Note1: Once AC power is turned on, Vpgi will be pulled high before +5V input. At this time,
diode D1 will be turn off. The PG delay time is dependent on Cd as follows,
⎛
C × Vthcd Cd × 1.85
=
Td −ON = 0.216 × Cd ( pF ) μ sec, ⎜⎜ T = d
8 .7 μ
I d −ON
⎝
⎞
⎟⎟
⎠
Note2: Diode D1 is connected to Vpgi to control the PG delay time when AC is off. The AC
off delay time can be controlled as follows,
Td −OFF ≒
Cd × Vthcd Cd × Vthcd
C d × Vthcd
C d × 1.85
=
=
=
1
1
I2 − Id
I d −OFF
× (VCd + Vthcd )
× (VCd + 1.85)
2
2
R1
R1
1
Among Td −OFF equation, the × (VCd + Vthcd ) is discharged average current.
2
Note3: Since the maximum threshold voltage at Pin 3(Cd) is 1.95V, the voltage across R1
has to be higher than 2V at normal operation.
Note4: In PCB layout condition, when the input-pin(VDD) smaller than detecting threshold
voltage(Vth), the power good signal of PS121 will connect to LOW, so the
ground-pin(VSS) must connect to the most clean ground of the power supply
system to avoid noise appear.
Note5: Suggested using RC filter circuit (Rx and Cx) to decrease ripples.
Note6: Suggested using component X1 and R1 to cut down Vpgi voltage.
Note7: Suggested using component X2 to avoid overshoot voltage damages IC.
Voltage Detecting IC
-5 -
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Package Specification (SOT-26)
Symbol
A
A1
A2
b
c
D
e
e1
E1
L
L1
L2
R
R1
θ
θ1
E
NOTE
Dimension in mm
± 0.225
1.225
± 0.075
0.075
1.000
± 0.3
0.4
± 0.1
0.165 ± 0.085
2.9
± 0.2
0.95 BSC
1.90 BSC
1.600
± 0.2
0.450
± 0.15
0.6 REF
0.25 BSC
0.1
(TYP)
0.1
(TYP)
5 °
(TYP)
10 °
(TYP)
± 0.2
2.8
Voltage Detecting IC
-6 -
Pin No
PIN NAME
1
NC
2
VSS
3
PG
4
+5V(VDD)
5
Cd
6
NC
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
Package Specification (TO-93)
(TO-93 4-pin)
s
D
I
θ2
N-PG
1
2
3
E
θ1
A
L1
4
L2
θ3
L3
b1
e1
e1
e1
e
NOTE
Symbol
A
b1
D
e
e1
E
I
L1
L2
L3
s
θ1
θ2
θ3
Dimension in mm Dimension in inch
± 0.1
± 0.004
0.144
3.65
± 0.1
0.015
± 0.004
0.38
± 0.1
0.20
5.22
± 0.004
± 1.0
0.27
6.9
± 0.02
± 0.75
0.09
2.3
± 0.03
0.06
± 0.1
1.55
± 0.004
± 0.14
4.20
0.16
± 0.006
± 0.5
1.75
0.07
± 0.02
2.10
± 0.5
0.08
± 0.02
2.70
± 0.5
0.11
± 0.02
1.50
± 0.5
0.06
± 0.02
(TYP)
5.0°
5.0°
(TYP)
3.0°
(TYP)
3.0°
(TYP)
46.0°
(TYP)
46.0°
(TYP)
Voltage Detecting IC
PINOUT:
Pin1 PG
Pin2 +5V / Vcc
Pin3 Cd
Pin4 Vss
-7 -
Version：A.017
點晶科技股份有限公司
SILICON TOUCH TECHNOLOGY INC.
PS121
The products listed herein are designed for ordinary electronic applications, such as electrical
appliances, audio-visual equipment, communications devices and so on. Hence, it is advisable
that the devices should not be used in medical instruments, surgical implants, aerospace
machinery, nuclear power control systems, disaster/crime-prevention equipment and the like.
Misusing those products may directly or indirectly endanger human life, or cause injury and
property loss.
Silicon Touch Technology, Inc. will not take any responsibilities regarding the misusage of
the products mentioned above. Anyone who purchases any products described herein with the
above-mentioned intention or with such misused applications should accept full responsibility
and indemnify. Silicon Touch Technology, Inc. and its distributors and all their officers and
employees shall defend jointly and severally against any and all claims and litigation and all
damages, cost and expenses associated with such intention and manipulation.
Voltage Detecting IC
-8 -
Version：A.017