STM6600, STM6601
Smart push-button on/off controller with Smart Reset™ and
power-on lockout
Datasheet - production data
• Debounced PB and SR inputs
• PB and SR ESD inputs withstand voltage up to
±15 kV (air discharge) ±8 kV (contact
discharge)
• Active high or active low enable output option
(EN or EN) provides control of MOSFET,
DC-DC converter, regulator, etc.
• Secure startup, interrupt, Smart Reset™ or
power-down driven by push-button
• Precise 1.5 V voltage reference with 1%
accuracy
7')1
• Industrial operating temperature –40 to +85 °C
• Available in TDFN12 2 x 3 mm package
Features
Applications
• Operating voltage 1.6 V to 5.5 V
• Low standby current of 0.6 µA
• Portable devices
• Adjustable Smart Reset™ assertion delay time
driven by external CSRD
• Terminals
• Power-up duration determined primarily by
push-button press (STM6600) or by fixed time
period, tON_BLANK (STM6601)
• Cell phones and smart phones
• Audio and video players
• PDAs, palmtops, organizers
Table 1. Device summary
Device
RST
CSRD
PB / SR
EN or EN
INT
Startup process
STM6600
open drain(1)
✓
✓
Push-pull
Open drain(1)
PB must be held low until the
PSHOLD(2) confirmation
STM6601
open drain(1)
✓
✓
Push-pull
Open drain(1)
PB can be released before the
PSHOLD(2) confirmation
1. External pull-up resistor needs to be connected to open drain outputs.
2. For a successful startup, the PSHOLD (power supply hold) needs to be pulled high within specific time, tON_BLANK.
October 2014
This is information on a product in full production.
DocID15453 Rev 12
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www.st.com
Contents
STM6600, STM6601
Contents
1
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
2
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3
Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
4
Waveforms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
5
Typical operating characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
6
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
7
DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
8
Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
9
Part numbering . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
10
Product selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
11
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
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STM6600, STM6601
List of tables
List of tables
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Pin descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38
Operating and AC measurement conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
DC and AC characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
TDFN12 (2 x 3 mm) package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
Carrier tape dimensions for TDFN12 (2 x 3 mm) package . . . . . . . . . . . . . . . . . . . . . . . . . 45
STM6600 ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
STM6601 ordering information scheme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
STM6600 product selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
STM6601 product selector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
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List of figures
STM6600, STM6601
List of figures
Figure 1.
Figure 2.
Figure 3.
Figure 4.
Figure 5.
Figure 6.
Figure 7.
Figure 8.
Figure 9.
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24.
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29.
Figure 30.
Figure 31.
Figure 32.
Figure 33.
Figure 34.
Figure 35.
Figure 36.
Figure 37.
Figure 38.
Figure 39.
Figure 40.
Figure 41.
Figure 42.
Figure 43.
4/52
Application hookup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Basic functionality (option with enable deassertion after long push) . . . . . . . . . . . . . . . . . . 6
Basic functionality (option with RST assertion after long push) . . . . . . . . . . . . . . . . . . . . . . 6
Logic diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
TDFN12 pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Successful power-up on STM6600 (PB released prior to tON_BLANK expiration) . . . . . . . . 14
Successful power-up on STM6600 (tON_BLANK expires prior to PB release) . . . . . . . . . . . 15
Unsuccessful power-up on STM6600 (PB released prior to tON_BLANK) . . . . . . . . . . . . . . 16
Unsuccessful power-up on STM6600 (tON_BLANK expires prior to PB release) . . . . . . . . . 17
Successful power-up on STM6601 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Unsuccessful power-up on STM6601 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Power-up on STM660x with voltage dropout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
PB interrupt . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Long push, PB pressed first . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Long push, SR pressed first . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Invalid long push . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Long push (option with RST assertion). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Long push (option with enable deassertion) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Undervoltage detected for tSRD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
PBOUT output waveform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
Supply current vs. temperature, normal state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Supply current vs. temperature, standby state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Supply current vs. supply voltage, normal state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Supply current vs. supply voltage, standby state . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Threshold vs. temperature, VTH+ = 3.4 V (typ.) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Threshold hysteresis vs. temperature, VHYST = 200 mV (typ.) . . . . . . . . . . . . . . . . . . . . . . 30
Debounce period vs. supply voltage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
CSRD charging current vs. temperature, VCC = 3.6 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Output low voltage vs. output low current, TA = 25 °C . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Output high voltage vs. output high current, TA = 25 °C. . . . . . . . . . . . . . . . . . . . . . . . . . . 32
Output voltage vs. supply voltage, IOUT = 1 mA, TA = 25 °C . . . . . . . . . . . . . . . . . . . . . . . 33
Input voltage vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Reference output voltage vs. temperature, VCC = 2.0 V. . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Reference output voltage vs. load current, VCC = 2.0 V, TA = 25 °C . . . . . . . . . . . . . . . . . 34
Reference output voltage vs. supply voltage, TA = 25 °C. . . . . . . . . . . . . . . . . . . . . . . . . . 35
Reference startup, IREF = 15 µF, TA = 25 °C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
Reference response to steps on supply voltage, IREF = 15 µA, TA = 25 °C . . . . . . . . . . . . 36
Reference response to steps in load current, VCC = 3.6 V, TA = 25 °C . . . . . . . . . . . . . . . 37
TDFN12 (2 x 3 mm) package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
TDFN12 (2 x 3 mm) recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44
Carrier tape for TDFN12 (2 x 3 mm) package . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
DocID15453 Rev 12
STM6600, STM6601
1
Description
Description
The STM6600-01 devices monitor the state of connected push-button(s) as well as
sufficient supply voltage. An enable output controls power for the application through the
MOSFET transistor, DC-DC converter, regulator, etc. If the supply voltage is above a
precise voltage threshold, the enable output can be asserted by a simple press of the
button. Factory-selectable supply voltage thresholds are determined by highly accurate and
temperature-compensated references. An interrupt is asserted by pressing the push-button
during normal operation and can be used to request a system power-down. The interrupt is
also asserted if undervoltage is detected. By a long push of one button (PB) or two buttons
(PB and SR) either a reset is asserted or power for the application is disabled depending on
the option used.
The device also offers additional features such as precise 1.5 V voltage reference with very
tight accuracy of 1%, separate output indicating undervoltage detection and separate output
for distinguishing between interrupt by push-button or undervoltage.
The device consumes very low current of 6 µA during normal operation and only 0.6 µA
current during standby.
The STM6600-01 is available in the TDFN12 package and is offered in several options
among features such as selectable threshold, hysteresis, timeouts, output types, etc.
Figure 1. Application hookup
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1. A resistor is required for open drain output type only. A 10 kΩ pull-up is sufficient in most applications.
2. Capacitor CREF is mandatory on VREF output (even if VREF is not used). Capacitor value of 1 µF is recommended.
3. For the STM6601 the processor has to confirm the proper power-on during the fixed time period, tON_BLANK. This failsafe
feature prevents the user from turning on the system when there is a faulty power switch or an unresponsive
microprocessor.
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51
Description
STM6600, STM6601
Figure 2. Basic functionality (option with enable deassertion after long push)
POWER-UP(1)
INTERRUPT
(short push)
POWER-DOWN
(long push)
PB
SR
EN
INT
interrupt
interrupt
AM00243v1
1. For power-up the battery voltage has to be above VTH+ threshold.
Figure 3. Basic functionality (option with RST assertion after long push)
INTERRUPT
(short push)
POWER-UP(1)
POWER-DOWN
(long push)
PB
SR
RST
INT
interrupt
interrupt
AM00243bv1
1. For power-up the battery voltage has to be above VTH+ threshold.
Figure 4. Logic diagram
VCC
EN (EN)
RST
PB
SR
PSHOLD
STM6600
STM6601
INT
PBOUT
VCC LO
CSRD
VREF
GND
AM00236v1
6/52
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STM6600, STM6601
Description
Table 2. Pin descriptions
Pin number
Symbol
Function
1
VCC
Power supply input
2
SR
Smart Reset™ button input
3
VREF
4
PSHOLD
5
CSRD
6
PB
7
VCCLO
Output for high threshold comparator output (VTH+)
8
PBOUT
Status of PB push-button input
9
EN or EN
Enable output
10
RST
Reset output
11
INT
Interrupt output
12
GND
Ground
Precise 1.5 V voltage reference
PSHOLD input
Adjustable Smart Reset™ delay time input
Push-button input
Figure 5. TDFN12 pin connections
VCC
1
12
GND
SR
2
11
INT
VREF
3
10
RST
PSHOLD
4
9
EN (EN)
CSRD 5
8
PBOUT
7
VCC LO
PB
6
AM00245v1
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Description
STM6600, STM6601
Figure 6. Block diagram
VCC LO
VCC VCC
(1)
RPB
PB
(2)
RSR
EN (EN)
VCC
+
+
–
–
VTH+
RST
tREC
generator
PSHOLD
VTH–
Smart
logic
Glitch immunity
Edge detector debounce
(3)
RPSHOLD
INT
SR
Glitch immunity
Edge detector debounce
VREF
GND
SRD logic
PBOUT
1.5 V
CSRD
AM00237v3
1. Internal pull-up resistor connected to PB input (see Table 5 for precise specifications).
2. Optional internal pull-up resistor connected to SR input (see Table 5 for precise specifications and Table 10 for detailed
device options).
3. Internal pull-down resistor is connected to PSHOLD input only during startup (see Figure 7, 8, 9, 10, 11, 12, 13, and 18).
8/52
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STM6600, STM6601
2
Pin descriptions
Pin descriptions
VCC - power supply input
VCC is monitored during startup and normal operation for sufficient voltage level. Decouple
the VCC pin from ground by placing a 0.1 µF capacitor as close to the device as possible.
SR - Smart Reset™ button input
This input is equipped with voltage detector with a factory-trimmed threshold and has ±8 kV
HBM ESD protection.
Both PB and SR buttons have to be pressed and held for tSRD period so the long push is
recognized and the reset is asserted (or the enable output is deasserted depending on the
option) - see Figure 15, 16, and 17.
Active low SR input is usually connected to GND through the momentary push-button (see
Figure 1) and it has an optional 100 kΩ pull-up resistor. It is also possible to drive this input
using an external device with either open drain (recommended) or push-pull output. Open
drain output can be connected in parallel with push-button or other open drain outputs,
which is not possible with push-pull output. SR input is monitored for falling edge after
power-up and must not be grounded permanently.
VREF - external precise 1.5 V voltage reference
This 1.5 V voltage reference is specified with very tight accuracy of 1% (see Table 5). It has
proper output voltage as soon as the reset output is deasserted (i.e. after tREC expires) and
it is disabled when the device enters standby mode. A mandatory capacitor needs to be
connected to VREF output (even if VREF is not used). Capacitor value of 1 µF is
recommended.
PSHOLD input
This input is equipped with a voltage detector with a factory-trimmed threshold. It is used to
confirm correct power-up of the device (if EN or EN is not asserted) or to initiate a shutdown
(if EN or EN is asserted).
Forcing PSHOLD high during power-up confirms the proper start of the application and keeps
enable output asserted. Because most processors have outputs in high-Z state before
initialization, an internal pull-down resistor is connected to PSHOLD input during startup (see
Figure 7, 8, 9, 10, 11, 12, 13, and 18).
Forcing the PSHOLD signal low during normal operation deasserts the enable output (see
Figure 14). Input voltage on this pin is compared to an accurate voltage reference.
CSRD - Smart Reset™ delay time input
A capacitor to ground determines the additional time (tSRD) that PB with SR must be
pressed and held before a long push is recognized. The connected CSRD capacitor is
charged with ISRD current. Additional Smart Reset™ delay time tSRD ends when voltage on
the CSRD capacitor reaches the VSRD voltage threshold. It is recommended to use a low
ESR capacitor (e.g. ceramic). If the capacitor is not used, leave the CSRD pin open. If no
capacitor is connected, there is no tSRD and a long push is recognized right after tINT_Min
expires (see Figure 18 and 19).
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Pin descriptions
STM6600, STM6601
PB - power ON switch
This input is equipped with a voltage detector with a factory-trimmed threshold and has
± 8 kV HBM ESD protection.
When the PB button is pressed and held, the battery voltage is detected and EN (or EN) is
asserted if the battery voltage is above the threshold VTH+ during the whole tDEBOUNCE
period (see Figure 13).
A short push of the push-button during normal operation can initiate an interrupt through
debounced INT output (see Figure 14) and a long push of PB and SR simultaneously can
either assert reset output RST (see Figure 18) or deassert the EN or EN output (see
Figure 19) based on the option used.
Note:
A switch to GND must be connected to this input (e.g. mechanical push-button, open drain
output of external circuitry, etc.), see Figure 1. This ensures a proper startup signal on PB
(i.e. a transition from full VCC below specified VIL). PB input has an internal 100 kΩ pull-up
resistor connected.
VCCLO - high threshold detection output
During power-up, VCCLO is low when VCC supply voltage is below the VTH+ threshold. After
successful power-up (i.e. during normal operation) VCCLO is low anytime undervoltage is
detected (see Figure 13).
Output type is active low and open drain by default. Open drain output type requires a pullup resistor. A 10 kΩ is sufficient in most applications.
VCCLO is floating when STM660x is in standby mode.
PBOUT - PB input state
If the push-button PB is pressed, the pin stays low during the tDEBOUNCE time period.
If PB is asserted for the entire tDEBOUNCE period, PBOUT will then stay low for at least
tINT_Min. If PB is asserted after tINT_Min expires, PBOUT will return high as soon as PB is
deasserted (see Figure 22). PBOUT ignores PB assertion during an undervoltage condition.
At startup on the STM6601 PBOUT will respond only to the first PB assertion and any other
assertion will be ignored until tON_BLANK expires. This output is active low and open drain by
default. Open drain output type requires a pull-up resistor. A 10 kΩ is sufficient in most
applications.
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STM6600, STM6601
Pin descriptions
EN or EN - enable output
This output is intended to enable system power (see Figure 1). EN is asserted high after
a valid turn-on event has been detected and confirmed (i.e. push-button has been pressed
and held for tDEBOUNCE or more and VCC > VTH+ voltage level has been detected - see
Figure 13). EN is released low if any of the conditions below occur:
a)
the push-button is released before PSHOLD is driven high (valid for STM6600, see
Figure 9) or tON_BLANK expires before PSHOLD is driven high during startup (valid
for both STM6600 and STM6601, see Figure 10 and 12).
b)
PSHOLD is driven low during normal operation (see Figure 14).
c)
an undervoltage condition is detected for more than tSRD + tINT_Min + tDEBOUNCE
(see Figure 21).
d)
a long push of the buttons is detected (only for the device with option “EN
deasserted by long push” - see Figure 19) or PSHOLD is not driven high during
tON_BLANK after a long push of the buttons (only for the device with option “RST
asserted by long push” - see Figure 18).
Described logic levels are inverted in case of EN output. Output type is push-pull by default.
RST - reset output
This output pulls low for tREC:
a)
during startup. PB has been pressed (falling edge on the PB detected) and held
for at least tDEBOUNCE and VCC > VTH+ (see Figure 7, 8, 9, 10, 11, 12 and 13 for
more details).
b)
after long push detection (valid only for the device with option “RST asserted by
long push”). PB has been pressed (falling edge on the PB detected) and held for
more than tDEBOUNCE + tSRD (additional Smart Reset™ delay time can be adjusted
by the external capacitor CSRD) - see Figure 18.
Output type is active low and open drain by default. Open drain output type requires a pullup resistor. A 10 kΩ is sufficient in most applications.
INT - interrupt output
While the system is under normal operation (PSHOLD is driven high, power for application is
asserted), the INT is driven low if:
a)
VCC falls below VTH- threshold (i.e. undervoltage is detected - see Figure 20 and
21).
b)
the falling edge on the PB is detected and the push-button is held for tDEBOUNCE
or more. INT is driven low after tDEBOUNCE and stays low as long as PB is held.
The INT signal is held high during power-up.
The state of the PBOUT output can be used to determine if the interrupt was caused by
either the assertion of the PB input, or was due to the detection of an undervoltage condition
on VCC.
INT output is asserted low for at least tINT_Min.
Output type is active low and open drain by default. Open drain output type requires a pullup resistor. A 10 kΩ is sufficient in most applications.
GND - ground
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Operation
3
STM6600, STM6601
Operation
The STM6600-STM6601 simplified smart push-button on/off controller with Smart Reset™
and power-on lockout enables and disables power for the application depending on pushbutton states, signals from the processor, and battery voltage.
Power-on
Because most of the processors have outputs in high-Z state before initialization, an internal
pull-down resistor is connected to PSHOLD input during startup (see Figure 7, 8, 9, 10, 11,
12, 13, and 18).
To power up the device the push-button PB has to be pressed for at least tDEBOUNCE and
VCC has to be above VTH+ for the whole tDEBOUNCE period. If the battery voltage drops
below VTH+ during the tDEBOUNCE, the counter is reset and starts to count again when VCC >
VTH+ (see Figure 13). After tDEBOUNCE the enable signal is asserted (EN goes high, EN
goes low), reset output RST is asserted for tREC and then the startup routine is performed by
the processor. During initialization, the processor sets the PSHOLD signal high.
On the STM6600 the PSHOLD signal has to be set high prior to push-button release and
tON_BLANK expiration, otherwise the enable signal is deasserted (EN goes low, EN goes
high) - see Figure 7, 8, 9, and 10. The time up to push-button release represents the
maximum time allowed for the system to power up and initialize the circuits driving the
PSHOLD input. If the PSHOLD signal is low at push-button release, the enable output is
deasserted immediately, thus turning off the system power. If tON_BLANK expires prior to
push-button release, the PSHOLD state is checked at its expiration. This safety feature
disables the power and prevents discharging the battery if the push-button is stuck or it is
held for an unreasonable period of time and the application is not responding (see Figure 8
and 10). PB status, INT status and VCC undervoltage detection are not monitored until
power-up is completed.
On the STM6601 the PSHOLD signal has to be set high before tON_BLANK expires, otherwise
the enable signal is deasserted - see Figure 11 and 12. In this case the tON_BLANK period is
the maximum time allowed for the power switch and processor to perform the proper poweron. If the PSHOLD signal is low at the end of the blanking period, the enable output is
released immediately, thus turning off the system power. PB status, INT status and VCC
undervoltage detection are not monitored during the entire tON_BLANK period. This failsafe
feature prevents the user from turning on the system when there is a faulty power switch or
an unresponsive microprocessor.
Push-button interrupt
If the device works under normal operation (i.e. PSHOLD is high) and the push-button PB is
pressed for more than tDEBOUNCE, a negative pulse with minimum tINT_Min width is
generated on the INT output. By connecting INT to the processor interrupt input (INT or
NMI) a safeguard routine can be performed and the power can be shut down by setting
PSHOLD low - see Figure 14.
Forced power-down mode
The PSHOLD output can be forced low anytime during normal operation by the processor
and can deassert the enable signal - see Figure 14.
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STM6600, STM6601
Operation
Undervoltage detection
If VCC voltage drops below VTH- voltage threshold during normal operation, the INT output is
driven low (see Figure 20 and Figure 21).
If an undervoltage condition is detected for tDEBOUNCE + tINT_Min + tSRD, the enable output is
deasserted (see Figure 21).
Hardware reset or power-down while system not responding
If the system is not responding and the system hangs, the PB and SR push-buttons can be
pressed simultaneously longer than tDEBOUNCE + tINT_Min + tSRD, and then
a)
either the reset output RST is asserted for tREC and the processor is reset (valid
only for the device with option “RST asserted by long push”) – see Figure 18
b)
or the power is disabled by EN or EN signal (valid only for the device with option
“EN deasserted by long push”) – see Figure 19
The tSRD is set by the external capacitor connected to the CSRD pin. SR input is monitored
for falling edge after power-up and must not be grounded permanently.
Standby
If the enable output is deasserted (i.e. EN is low or EN is high), the STM660x device enters
standby mode with low current consumption (see Table 5). In standby mode PB input is only
monitored for the falling edge. The external 1.5 V voltage reference is also disabled in
standby mode.
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Waveforms
4
STM6600, STM6601
Waveforms
Figure 7. Successful power-up on STM6600 (PB released prior to tON_BLANK expiration)
Push-button pressed and
PB connected to GND
processor
sets PSHOLD
PB released prior to t ON_BLANK
expiration
PSHOLD state detected as high
EN remains asserted
VCC undervoltage detection
ignored
PSHOLD
ignored
internal pull-down resistor
connected to PSHOLD input
PB(1)
PSHOLD(2)
EN(3)
RST
tDEBOUNCE
tREC
tON_BLANK
Note: INT signal is held high during power-up (i.e. until PB release in this case).
VCC is considered VCC > VTH+.
AM00247v3
1. PB detection on falling and rising edges.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. EN signal is high even after PB release, because processor sets PSHOLD signal high before PB is released.
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STM6600, STM6601
Waveforms
Figure 8. Successful power-up on STM6600 (tON_BLANK expires prior to PB release)
Push-button pressed and
PB connected to GND
processor
sets PSHOLD
tON_BLANK expired prior to PB
release
PSHOLD state detected as high
EN remains asserted
PB released
VCC undervoltage detection
ignored
PSHOLD
ignored
internal pull-down resistor
connected to PSHOLD input
PB(1)
PSHOLD(2)
EN(3)
RST
tDEBOUNCE
tREC
tON_BLANK
Note: INT signal is held high during power-up (i.e. until tON_BLANK expires in this case).
VCC is considered VCC > VTH+.
AM00247bv2
1. PB detection on falling and rising edges.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. tON_BLANK expires prior to PB release so PSHOLD is checked at its expiration.
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Waveforms
STM6600, STM6601
Figure 9. Unsuccessful power-up on STM6600 (PB released prior to tON_BLANK)
PB released
PSHOLD state detected as low
EN deasserted
Push-button pressed and
PB connected to GND
VCC undervoltage detection
ignored
PSHOLD
ignored
internal pull-down resistor
connected to PSHOLD input
PB(1)
PSHOLD(2)
PB status
ignored
EN(3)
RST
tDEBOUNCE
tEN_OFF
tREC
tON_BLANK
Note: INT signal is held high during power-up (i.e. until PB release in this case).
VCC is considered VCC > VTH+.
AM00248v3
1. PB detection on falling and rising edges.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. EN signal goes low with PB release, because processor did not force PSHOLD signal high.
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STM6600, STM6601
Waveforms
Figure 10. Unsuccessful power-up on STM6600 (tON_BLANK expires prior to PB release)
tON_BLANK expired prior to PB release
PSHOLD state detected as low
EN is deasserted
Push-button pressed and
PB connected to GND
PB (1)
PB released
VCC undervoltage detection ignored
PB status
ignored
PSHOLD
ignored
internal pull-down resistor connected to
PSHOLD input
PSHOLD(2)
EN(3)
RST
tDEBOUNCE
tEN_OFF
tREC
tON_BLANK
Note: INT signal is held high during power-up (i.e. until tON_BLANK expires in this case).
VCC is considered VCC > VTH+.
AM00248bv2
1. PB detection on falling and rising edges.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. tON_BLANK expires prior to PB release so PSHOLD is checked at its expiration.
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Waveforms
STM6600, STM6601
Figure 11. Successful power-up on STM6601
tON_BLANK expires
processor
PSHOLD state detected as high
sets PSHOLD EN remains asserted
Push-button pressed and
PB connected to GND
PB
PB status and V CC undervoltage
detection ignored
(1)
PSHOLD ignored
(2)
PSHOLD
EN
internal pull-down resistor
connected to PSHOLD input
(3)
RST
t DEBOUNCE
t REC
t ON_BLANK
Note: INT signal is held high during power-up (i.e. until tON_BLANK expires in the case of the STM6601).
VCC is considered VCC > VTH+.
AM00250v2
1. PB detection on falling edge.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. PSHOLD signal is ignored during tON_BLANK. When tON_BLANK expires, the level of the PSHOLD signal is high therefore the
EN signal remains asserted.
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STM6600, STM6601
Waveforms
Figure 12. Unsuccessful power-up on STM6601
tON_BLANK expires
PSHOLD state detected as low Push-button pressed and
PB connected to GND
EN deasserted
Push-button pressed and
PB connected to GND
(1)
PB
PSHOLD ignored
(2)
PSHOLD
intenal pull-down resistor
connected to PSHOLD input
(3)
EN
RST
t
DEBOUNCE
t REC
Note: INT signal is held high during power-up (i.e. until tON_BLANK expires in the case of the STM6601).
VCC is considered VCC > VTH+.
AM00238v2
1. PB detection on falling edge.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. PSHOLD signal is ignored during tON_BLANK. When tON_BLANK expires, the level of the PSHOLD signal is not high therefore
the EN signal goes low. Even releasing the PB button after the tON_BLANK will not prevent this.
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Waveforms
STM6600, STM6601
Figure 13. Power-up on STM660x with voltage dropout
Push-button pressed and
PB connected to GND
VCC goes above VTH+ and
tDEBOUNCE is counted again
VTH+
VTH–
VCC
VCC LO
VCC–Min
VCC
undervoltage
detected
VCC
drop
(1)
PB
(2)
PSHOLD
INT
internal pull-down resistor
connected to PSHOLD input
(3)
INT signal is held high during power-up
EN
RST
< t DEBOUNCE
t DEBOUNCE
tREC
< t ON_BLANK
AM00249v2
1. PB detection on falling and rising edges.
2. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during power-up.
3. INT signal is held high during power-up.
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STM6600, STM6601
Waveforms
Figure 14. PB interrupt
processor interrupt starts power-down sequence
processor sets PSHOLD low
Push-button pressed and
PB connected to GND
PB
and EN is deasserted
accordingly
PB status
ignored
(1)
PSHOLD
PB status
ignored
VCC undervoltage
detection ignored
t DEBOUNCE
t INT_Min
Note: VCC is considered VCC > VTH+.
tEN_OFF
AM00251v2
1. PB detection on falling edge.
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Waveforms
STM6600, STM6601
Figure 15. Long push, PB pressed first
Push-button tSRD starts to
SR is pressed be counted
Push-button
PB is pressed
PB
tSRD
tDEBOUNCE
set by CSRD
tDEBOUNCE
SR
INT
PB status
ignored
tINT_Min
AM00257v1
Figure 16. Long push, SR pressed first
Push-button
SR is pressed
PB
Push-button
PB is pressed
tSRD starts to
be counted
tDEBOUNCE
tSRD
SR
set by CSRD
INT
PB status
ignored
tINT_Min
AM00258v1
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STM6600, STM6601
Waveforms
Figure 17. Invalid long push
Push-button
PB is pressed
Push-button
SR is pressed
PB
tSRD starts to
be counted
Any rising edge will stop
tSRD to count regardless
of glitch immunity
tDEBOUNCE
< tSRD
SR
set by CSRD
INT
PB status
ignored
tINT_Min
AM00259v1
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Waveforms
STM6600, STM6601
Figure 18. Long push (option with RST assertion)
Push-button pressed
and PB connected to
GND
tON_BLANK expires
PSHOLD state detected as high
therefore EN remains high
Push-button held even
after tSRD expires
therefore RST is asserted
tSRD(1)
set by CSRD
PB
After tON_BLANK
PB is monitored
for falling edge
tON_BLANK
(valid for STM6600 and STM6601)
SR
PB status
ignored
INT (2)
RST
INT can go high, if PB goes high,
but system freezes and processor
won’t respond
VCC undervoltage detection status ignored
PSHOLD ignored
if system freezes, processor won’t
respond to any INT status change
(3, 4)
PSHOLD
tDEBOUNCE
t INT_Min
internal pull-down resistor
connected to PSHOLD input
tREC
tDEBOUNCE
Note: EN is high.
AM00252v2
1. tSRD period is set by external capacitor CSRD.
2. PB ignored during tINT_Min.
3. PSHOLD signal is ignored during tON_BLANK. Its level is checked after tON_BLANK expires and if it is high the EN signal
remains asserted, otherwise EN goes low.
4. Internal pull-down resistor 300 kΩ is connected to PSHOLD input during startup when device is reset.
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STM6600, STM6601
Waveforms
Figure 19. Long push (option with enable deassertion)
Push-button
pressed and PB
connected to GND
Push-button held even
after tSRD expires and
EN is deasserted
tSRD(1)
set by CSRD
PB
After tEN_OFF expires
PB is monitored for
falling edge
PB status
ignored
SR
INT can go high, if PB goes high,
PB status
but system freezes and processor
ignored
won’t respond
INT (2)
EN(3)
VCC undervoltage detection status ignored
if system freezes, processor won’t
respond to any INT status change
PSHOLD
tDEBOUNCE
t INT_Min
tEN_OFF
tDEBOUNCE
AM00253v2
1. tSRD period is set by external capacitor CSRD.
2. PB ignored during tINT_Min.
3. After tSRD expires EN is forced low.
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Waveforms
STM6600, STM6601
Figure 20. Undervoltage detected for tSRD
VCC
undervoltage
detected
VCC is below VTH+ even after tSRD expires
thus power is disabled (EN goes low) and
PB is monitored for regular startup
VTH+
(1)
VCC
tSRD(2)
VTH–
set by CSRD
VCC-Min
VCCLO
PSHOLD
VCC
undervoltage
detection
ignored
INT
PB status ignored
PB status
ignored
EN
tDEBOUNCE
tINT_Min
tEN_OFF
AM00255v1
1. After tSRD expires VCC is still insufficient (below VTH+) thus power is disabled (EN goes low or EN goes high).
2. tSRD period is set by external capacitor CSRD.
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STM6600, STM6601
Waveforms
Figure 22. PBOUT output waveform