TB9000F
2003-10-16
1
TOSHIBA BiCMOS Integrated Circuit Silicon Monolithic
TB9000F
5 V Voltage Regulator with Watchdog Timer
The TB9000F is an IC specially designed for microcomputer
systems in automobile. It features low standby current and
various system reset functions.
With external pass Tr., TB9000F can supply high output
current. As a protective function, current limiter function is
incorporated.
The system reset includes low voltage reset/power on
reset/watchdog timer.
Features
Accurate output: 5.0 V 0.15 V
Low current consumption: 120 A (V
IN
= 12V ,Ta = 25C) at 5 V Output + Reset timer
Reset functions: Low voltage reset/Power on reset/Watchdog timer
Current limiter: Adjustable with external resistor
Operating temperature : -40 to 125C
Small SMD package: SSOP-16pin
Weight: 0.14 g (typ.)
TB9000F
2003-10-16
2
Block Diagram & Pin Layout
Note:
Some of the functional blocks, circuits, or constants in the block diagram are omitted or simplified to clarify
the descriptions of the relevant features.
Comp
0.3 V
16
15
14
13
12
11
10
9
1
2
3
4
5
6
7
8
Watchdog timer
Power on reset
Vref
1
00 k
5 V Reg
Amp
70 k
Current
limiter
NC NC WS CK NC
TC
NC
RESET
V
IN
NC V
S
OUT
COMP
Vcc
NC
GND
TB9000F
2003-10-16
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Pin Description
Pin No.
Symbol
Description
1 V
IN
Power supply input pin. It contains current limiter and startup circuit.
3 V
S
Detection pin for the V
CC
current limiter.
A voltage drop occurring in the external resistor R
S
between pins V
IN
and V
S
is monitored.
The current limiter is actuated when the voltage drop exceeds 0.3 V.
Ex.) When the current limiter need to be actuated at a load current of 600 mA
R
S
= 0.3 V/600 mA = 0.5
4 OUT
This pin is used to connect the base of an external PNP transistor.
The output voltage is controlled by an internal op-amp to maintain it stably at 5 V.
Since the recommended current of I
OUT
is 8 mA, an output current of 600 mA can be flowed if
H
FE
of the external transistor is 80 or more.
5 COMP
Phase compensating pin for V
CC
.
Connect a phase compensating capacitor between pin V
CC
and this pin.
6 V
CC
Voltage detection pin for the 5 V constant-voltage power supply, V
CC
.
It also supplies power to the reset timer circuit.
8 GND
Grounded
9
RESET
Reset output pin for power on reset and watchdog timer.
Generates a reset signal which is determined by CT at the TC pin.
If no clock is fed to the CK input, this pin generates a reset pulse intermittently.
This is an N-MOS drain output with a 100 k
pull-up resistor to V
CC
.
11 TC
Time setup pin for the reset and watchdog timers. Connect capacitor CT to GND.
The time is set up by internal constant current.
13 CK
Clock input pin for the watchdog timer.
This pin detects rising edge of the input signal and does not require external coupling
capacitor.
14 WS
Watchdog timer function ON/OFF control pin.
Set to "Low" for active mode and "High" for inactive mode.
2, 7, 10,
12, 15, 16
NC
Not connected. (Electrically, this pin is completely open.)
TB9000F
2003-10-16
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Functional Description
The TB9000F incorporates a constant-voltage 5 V power supply function to feed stable power to the CPU and
the system reset and CPU monitor functions to ensure stable operation of the CPU, etc. These functions are
explained below.
(1) Constant-voltage 5V power supply function
This constant-voltage function has the reference voltage V
ref
in the IC that is insusceptible to temperature
changes and input voltage fluctuations. The power supply circuit is designed in such a way that this
voltage is stepped up to 5 V by using an OP amp and a voltage-dividing resistor. These OP amp and
dividing resistor and an output transistor connected to the OP amp output together configure a closed
loop.
An overcurrent protection function is incorporated as a protective measure in case a fault such as shorting
to GND occurs in the 5 V output. A current detecting resistor is inserted between the V
IN
and the V
S
pins,
and a voltage drop across this resistor is detected by a comparator, thereby suppressing the operation of
the OP amp to ensure that the voltage drop will not exceed 0.3 V. In this way, a current limiter function is
actuated to prevent no more current from flowing.
(2) System reset function (
See Timing Chart
)
Voltage monitoring function
When powered on, the power-on reset timer starts counting the moment the voltage V
CC
applied to the
CPU exceeds 4.7 V. When powered off, this voltage monitoring function outputs a reset signal
immediately when V
CC
drops below 4.7 V. A reset signal also is output immediately when V
CC
drops
for some reason during normal operation. Then, when V
CC
is restored to the normal voltage and
exceeds 4.7 V, the power-on reset timer starts counting.
The reset signal is output from the RESET pin.
Power-on reset timer function
To allow the 5 V constant voltage to stabilize at power-on, as well as provide a sufficient time for the
clock oscillation in the CPU to stabilize, the device remains reset for a predetermined time before being
released from the reset state. The duration of this time can be set as desired by choosing appropriate
values for the external capacitor connected to the TC pin.
The system starts charging the capacitor when the V
CC
voltage exceeds 4.7 V. When this charge voltage
exceeds 4 V, the capacitor is discharged by the IC's internal transistor. When the capacitor is
discharged down to 2 V, the reset signal is inverted to deactivate the reset.
Watchdog
timer
function
Program your system to output a clock each time one program routine is finished in the CPU system
software, and input this clock to the CK pin of the IC. The IC's TC pin is repeatedly charged and
discharged between 2 V and 4 V. However, when a clock is input, it switches over and starts
discharging in the middle of charging and then starts charging from 2 V again. Since the clock is
generated at predetermined intervals when the CPU system is operating normally, the TC pin switches
over and starts discharging before the charge voltage reaches 4 V. However, if no clock is input while
being charged from 2 V to 4 V, the clock is assumed to have stopped, i.e., the CPU system has gone wild,
so that a reset signal is output to reset the CPU system.
Watchdog timer stop function
The watchdog timer can be switched ON or OFF by WS pin. If WS pin is fixed to low, the watchdog
timer will be active. (TIMING CHART 1) If WS pin is fixed to high, the watchdog timer will be inactive.
(TIMING CHART 2) When the WS pin is fixed to high, no reset signal is output, in which case only the
power-on reset timer is useful.
Note:
The overcurrent protection feature is only intended to protect the IC from a temporary short circuit. A short
circuit over an extended period of time may place excessive stress on the IC, possibly causing it to be
damaged. The system must be configured so that any overcurrent condition will be eliminated as soon as
possible.
TB9000F
2003-10-16
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Timing Chart 1
WS =
=
=
= Low
Timing Chart 2
WS =
=
=
= High
Note:
Timing charts may be simplified to clarify the descriptions of features and operations.
0 V
0 V
0 V
0 V
V
CC
TC
CK
RESET
5 V
V
TH
T
POR
T
WD
T
POR
T
RST
0 V
V
CC
5 V
V
TH
T
POR
T
POR
0 V
TC
0 V
RESET
V
TH
TB9000F
2003-10-16
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Maximum Rating
(Ta
=
=
=
= 25C)
Characteristics Symbol
Rating
Unit
V
IN
45 (1 s)
V
Input voltage
COMP,Vcc,
RESET
------------------
,CK,
WS,TC
6.0 V
Output current
I
OUT
10
mA
Operating temperature
T
opr
-40 to 125
C
Storage temperature
T
stg
-55 to 150
C
Lead temperature-time
T
sol
240 (10 s)
C
SSOP16-P-225 Thermal Resistance Data
(Ta
=
=
=
= 25C)
Characteristics Rating Unit
Test
Condition
R
j-a
200
C/W
Without radiation board
PD1
0.6
W
Without radiation board
PD2 0.78
W
50
50 1.6 mm 30% Cu board mounted
Note:
The absolute maximum ratings of a semiconductor device are a set of specified parameter values which
must not be exceeded during operation, even for an instant.
If any of these levels is exceeded during operation, the device's electrical characteristics may be irreparably
altered and the reliability and lifetime of the device can no longer be guaranteed, possibly causing damage
to any other equipment with which it is used. Applications using the device should be designed such that the
maximum ratings will never be exceeded in any operating conditions.
Ensuring that the parameter values remain within these specified ranges during device operation will help to
ensure that the integrity of the device is not compromised.
TB9000F
2003-10-16
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Electrical Characteristics
(V
IN
=
=
=
= 6 to 16 V, ILOAD ==== 10 mA, Ta ==== ----40 to 125C)
Characteristics Symbol
Pin
Test
Circuit
Test Condition
Min
Typ.
Max
Unit
Ta
= -40 to 105C
4.85
5.0
5.15
Output voltage
VREG
V
CC
Ta
= -40 to 125C
4.82
5.0
5.15
V
Line regulation
VLINE
V
CC
VIN
= 6 to 40 V
0.1 0.5 %
Load regulation
VLOAD
V
CC
ILOAD
= 1 to 300 mA
0.2 1.0 %
Temperature coefficient
V
CC
0.01 %/C
Output voltage
VOL
RESET
IOL
= 2 mA
0.3 V
Output leakage current
ILEAK
RESET
VIN(
RESET
)
= V
CC
5 A
Input current
IIN
TC
VIN(TC)
= GND
-10
A
Input current
IIN
CK
VIN(CK)
= 0 to V
CC
-5
5 A
Input current
IIN
WS
VIN(WS)
= 0 to V
CC
-5
5 A
VIH
0.8
V
CC
Input voltage
VIL
CK
0.2
V
CC
V
VIH
0.8
V
CC
Input voltage
VIL
WS
0.2
V
CC
V
Current limiter detection
VLIMIT
V
CC
0.225 0.3 0.375 V
Ta
= 25C, V
IN
= 12 V
120 170
Current consumption
I
CC
Ta
= -40 to 125C
V
IN
= 12 V
120 190
A
VTH
4.5 4.7 4.9
Reset detection voltage
VTH
V
CC
V
CC
- VTH
0.25
0.30
0.35
V
Power on reset
TPOR
RESET
280
CT
400
CT
520
CT
Watchdog timer
TWD
RESET
140
CT
200
CT
260
CT
Reset timer
TRST
RESET
4.0
CT
8.0
CT
12.0
CT
ms
Clock pulse width
Tw
CK
3
s
Note1: CT is measured in unit of
F.
Note2: The specification values of power-on reset, watchdog timer and reset timer above are intended
to guarantee the IC itself. Note that the fluctuations of CT value should be taken into consideration
for practical use of the IC.
Note3:The specification of "Current consumption" is specified that ILOAD=0mA.
Recommended Conditions
Part Name
Min
Typ.
Max
Unit
CT 0.01
0.25
10
F
TB9000F
2003-10-16
8
Reference Characteristics
Input Output characteristics
VIN (V)
VCC (V)
V
CC
(
V
)
0
0
2
4
6
2
4
6
V
R
E
SET
(
V
)
VLIMIT (V)
Current Limiter Characteristics
V
CC
(V
)
7
0
0
6
5
4
3
2
1
0.1 0.2 0.3 0.4
RESET output characteristics
0
2
4
6
0
2
4
6
TB9000F
2003-10-16
9
Example of Application Circuit
Caution for Wiring
Note 1: C1 and C2 are for absorbing disturbances, noise, etc. C3 is for phase compensation.
Note 2: Connect each capacitor as close to the IC as possible.
Note 3: Ensure that the IC is mounted correctly. Failing to do so may result in the IC or target equipment being
damaged.
Note 4: The application circuit shown above is not intended to guarantee mass production. A thorough evaluation is
required when designing an application circuit for mass production.
VB
C1
Current limiter
Constant voltage
5 V monitor
V
IN
V
S
OUT
COMP
V
CC
470 pF
Reset timer
C2
V
DD
CPU
RESET
Po1
RESET
C3
C
T
TC
TB9000F
5.0 V
R
S
CK
WS
TB9000F
2003-10-16
10
Package Dimensions
Weight: 0.14 g (typ.)
TB9000F
2003-10-16
11
The information contained herein is subject to change without notice.
The information contained herein is presented only as a guide for the applications of our products. No
responsibility is assumed by TOSHIBA for any infringements of patents or other rights of the third parties which
may result from its use. No license is granted by implication or otherwise under any patent or patent rights of
TOSHIBA or others.
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devices in general can malfunction or fail due to their inherent electrical sensitivity and vulnerability to physical
stress. It is the responsibility of the buyer, when utilizing TOSHIBA products, to comply with the standards of
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such TOSHIBA products could cause loss of human life, bodily injury or damage to property.
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set forth in the most recent TOSHIBA products specifications. Also, please keep in mind the precautions and
conditions set forth in the "Handling Guide for Semiconductor Devices," or "TOSHIBA Semiconductor Reliability
Handbook" etc..
The TOSHIBA products listed in this document are intended for usage in general electronics applications
(computer, personal equipment, office equipment, measuring equipment, industrial robotics, domestic appliances,
etc.). These TOSHIBA products are neither intended nor warranted for usage in equipment that requires
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030619EBA
RESTRICTIONS ON PRODUCT USE
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