SUPERTEX PS10

PS10/PS11
PS10 - Active High
PS11 - Active Low
Initial Release
Quad Power Sequencing Controller
Features
Description
Sequencing of Four or More* Supplies, ICs, or Subsystems
Independently Programmable Delays Between Open
Drain PWRGD Flags (5ms to 200ms)
±10V to ±90V Operation
Tracking in Combination with Schottky Diodes
Input Supervisors Including:
o UV/OV Lock Out/Enable
o Power-On-Reset (POR)
Low Power Consumption, 0.4mA Supply Current
Small SO-14 Package
Many of today’s high performance FPGA’s, Microprocessors, DSP and industrial/embedded subsystems require
sequencing of the input power. Historically this has been
accomplished: i) discretely using comparators, references
& RC circuits; ii) using expensive programmable controllers; or iii) with low voltage sequencers requiring resistor
drop downs and several high voltage optocoupler or level
shift components.
The PS10/11 saves board space, improves accuracy,
eliminates optocouplers or level shifts and reduces overall
component count by combining four timers, programmable
input UV/OV supervisors, a programmable POR and four
90V open drain outputs. A high reliability, high voltage,
junction isolated process allows the PS10/11 to be connected directly across the high voltage input rails.
*By Daisy-Chaining PS10/11’s
Applications
The power-on-reset interval (POR) may be programmed
by a capacitor on Cramp. To sequence additional systems, PS10/11 may be daisy chained together. If at any
time the input supply falls outside the UV/OV detector
range the PWRGD outputs will immediately become INACTIVE. Down sequencing may be accomplished with
additional components (see page 11).
Power Supply Sequencing
-48V Telecom and Networking Distributed Systems
-24V Cellular and Fixed Wireless Systems
-24V PBX Systems
+48V Storage Systems
FPGA, Microprocessor Tracking
Industrial/Embedded System Timing/Sequencing
High Voltage MEMs Driver’s Supply Sequencing
High Voltage Display Driver’s Supply Sequencing
The PS10/PS11 is available in a space saving SO-14
package.
Typical Application Circuit
Waveform
(49.9k pull-up on PS11 PWRGD pins)
GND or +48V
14
487K
/EN
VIN
6
PWRGD-D / PWRGD-D
UV
PWRGD-C / PWRGD-C
6.81K
PWRGD-B / PWRGD-B
5
9.76K
7
PS10/PS11
OV
VEE
TB
RTB
TD
TC
11
12
RTC
13
RTD
PWRGD-A / PWRGD-A
Ramp
1
+12V
DC/DC
CONVERTER
COM
2
3
4
/EN
+5V
DC/DC
CONVERTER
COM
/EN
10
+3.3V
DC/DC
CONVERTER
COM
10nF
/EN
+2.5V
DC/DC
CONVERTER
-48V or GND
COM
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
Relative to Negative Rail
A051204
Supertex, Inc.
• 1235 Bordeaux Drive, Sunnyvale, CA 94089 • Tel: (408) 222-8888 • FAX: (408) 222-4895 • www.supertex.com
1
PS10/PS11
Absolute Maximum Ratings*
VEE referenced to VIN pin
+0.3V to -100V
VPWRGD referenced to VEE voltage
-0.3V to +100V
VUV and VOV referenced to VEE Voltage
-0.3V to 12V
Operating Ambient Temperature
-40°C to +85°C
Operating Junction Temperature
-40°C to +125°C
Storage Temperature Range
Ordering Information
Active State of Power
Good Flags
Package Options
High
PS10NG
Low
PS11NG
-65° to +150°C
Power Dissipation @ 25°C, 14-Pin SOIC
14 Pin SOIC
750mW
*Absolute Maximum Ratings are those values beyond which damage to the device may
occur. Functional operation under these conditions is not implied. Continuous operation of
the device at the absolute rating level may affect device reliability. All voltages are referenced to device ground.
Electrical Characteristics (-10V ≤ V
IN
Symbol
Parameter
≤ -90V, TA = 25°C unless otherwise specified)
Min
Typ
Max
Units
Conditions
-10
V
400
450
µA
VEE = -48V
1.16
1.22
1.28
V
Low to High Transition
1.06
1.12
1.18
V
High to Low Transition
Supply (Referenced to VIN pin)
VEE
Supply Voltage
IEE
Supply Current
-90
OV and UV Control (Referenced to VEE pin)
VUVH
VUVL
VUVHY
IUV
UV High Threshold#
#
UV Low Threshold
#
UV Hysteresis
100
UV Input Current
#
mV
1.0
nA
VUV = VEE + 1.9V
VOVH
OV High Threshold
1.16
1.22
1.28
V
Low to High Transition
VOVL
#
1.06
1.12
1.18
V
High to Low Transition
VOVHY
IOV
OV Low Threshold
OV Hysteresis
#
100
OV Input Current
mV
1.0
nA
VUV = VEE + 1.9V
#
Specifications apply over 0°C ≤ TA ≤ 70°C
Power Good Timing (Test Conditions: CRAMP = 10nF, VUV = VEE + 1.9V, VOV = VEE + 0.5V)
Ramp Pin Output Current
10
µA
tPWRGD-A
Time from UV High to PWRGD-A
8.8
ms
VEE = -48V, CRAMP = 10nF,
see Typical Application Circuit
tPWRGD-B
Maximum time from PWRGD-A to PWRGD-B
150
200*
250
ms
RTB = 120kΩ
tPWRGD-B
Minimum time from PWRGD-A to PWRGD-B
3.0
5.0*
8.0
ms
RTB = 3kΩ
tPWRGD-C
Maximum time from PWRGD-B to PWRGD-C
150
200*
250
ms
RTC = 120kΩ
tPWRGD-C
Minimum time from PWRGD-B to PWRGD-C
3.0
5.0*
8.0
ms
RTC = 3kΩ
tPWRGD-D
Maximum time from PWRGD-C to PWRGD-D
150
200*
250
ms
RTD = 120kΩ
tPWRGD-D
Minimum time from PWRGD-C to PWRGD-D
3.0
5.0*
8.0
ms
RTD = 3kΩ
IRAMP
*Note: Variations will track. For example if tPWRGD-A is 250ms then so will be tPWRGD-B/C/D. Contact factory for tighter tolerance version.
Power Good Outputs (Test Conditions: VUV = VEE + 1.9V, VOV = VEE + 0.5V)
VPWRGD-x(hi)
Power Good Pin Breakdown Voltage
90
VPWRGD-x(lo)
Power Good Pin Output Low Voltage
0.4
IPWRGD-x(lk)
Maximum Leakage Current
<1.0
2
V
PWRGD-x = HI Z
0.5
V
IPWRGD = 1mA, PWRGD-x = LOW
10
µA
VPWRGD = 90V, PWRGD-x = HI Z
A051204
PS10/PS11
PWRGD Logic
Model
Condition
PS10
INACTIVE (not ready)
0
VEE
ACTIVE (Ready)
1
HI Z
INACTIVE (not ready)
1
HI Z
ACTIVE (Ready)
0
VEE
PS11
PWRGD-A/B/C/D
Pinout
PWRGD-D (PS10)
PWRGD-D (PS11)
1
14
V IN
PWRGD-C (PS10)
PWRGD-C (PS11)
2
13
TD
PWRGD-B (PS10)
PWRGD-B (PS11)
3
12
TC
PWRGD-A (PS10)
PWRGD-A (PS11)
4
11
TB
OV
5
10
RAMP
UV
6
9
NC
V EE
7
8
NC
Top View
Pin Description
PWRGD-D – This open drain Power Good Output Pin is
held inactive on initial power application and goes active a
programmed time delay after PWRGD-C goes active.
PWRGD-C – This open drain Power Good Output Pin is
held inactive on initial power application and goes active a
programmed time delay after PWRGD-B goes active.
PWRGD-B – This open drain Power Good Output Pin is
held inactive on initial power application and goes active a
programmed time delay after PWRGD-A goes active.
PWRGD-A – This open drain Power Good Output Pin is
held inactive on initial power application and goes active one
POR delay after the UV pin goes above its High threshold
(provided VIN stays within the UV/OV window during this
period).
To function as an indicator a pullup resistor must be connected from this pin to a voltage rail no more than 90V from
VEE.
OV – This Over Voltage (OV) sense pin, when raised above
its high threshold will immediately cause the Power Good
Outputs to be pulled low. These outputs will remain low until
the voltage on this pin falls below the low threshold limit,
initiating a new start-up cycle.
VEE - This pin is the negative terminal of the power supply
input to the circuit.
VIN – This pin is the positive terminal of the power supply
input to the circuit and can withstand 90V with respect to
VEE.
TD – The resistor connected from this pin to VEE pin sets the
time delay from PWRGD-C going active to PWRGD-D going
active.
TC – The resistor connected from this pin to VEE pin sets the
time delay from PWRGD-B going active to PWRGD-C going
active.
TB – The resistor connected from this pin to VEE pin sets the
time delay from PWRGD-A going active to PWRGD-B going
active.
RAMP – This pin provides a current output so that a timing
ramp is generated when a capacitor is connected. This timing Ramp is used to program POR and the time from satisfaction of the UV/OV supervisors to PWRGD-A.
NC– No Connect. This pin can be grounded or left floating.
UV – This Under Voltage (UV) sense pin, when lowered
below its low threshold will immediately cause the Power
Good Outputs to be pulled low. These outputs will remain
low until the voltage on this pin rises above the low threshold limit, initiating a new start-up cycle.
3
A051204
PS10/PS11
Functional Block Diagram
Band Gap
Reference
UV
Vint
Regulator
& POR
-
V IN
+
Vbg
Logic
UVLO
PWRGD-A
-
OV
+
PWRGD-B
VEE
PWRGD-C
Vint
-
+
PWRGD-D
Programmable
Timer
10uA
Vint - 1.2V
TB
RAMP
Functional Description
The PS10/PS11 are designed to sequence up to 4 power
supply modules, ICs or subsystems when the backplane
voltage is within the programmed Under-voltage and Overvoltage limits. The power good open drain outputs are
sequentially enabled starting from PWRGD-A to PWRGDD. The time delay between power goods is programmable
up to 200ms simply by changing the value(s) of RTB,
RTC, and RTD. The initial time between satisfaction of the
UV/OV supervisors & PWRGD-A can be programmed with
Cramp.
TC
TD
tive transition. PWRGD-D will change into an active state
after a programmed time delay from PWRGD-C inactive to
active transition.
The controller continuously monitors the UV and OV pins
as long as the internal UVLO and POR circuits are satisfied. At any time during the start up cycle or thereafter,
crossing the UV low and OV high limits will cause an immediate discharge on Cramp and reset on the power good
pins. When the input voltage returns to a value within the
programmed UV and OV limits, a new start up sequence
will initiate immediately.
Description of Operation
Programming the Under and Over Voltage Limits
During the initial power application, the Power Good pins
are held low (rising with VIN) for PS10 and high for the
PS11. Once the internal under voltage lock out has been
satisfied, the circuit checks the input supply under voltage
(UV) and over voltage (OV) sense circuits to ensure that
the input voltage is within programmed limits. These limits
are determined by the selected values for R1, R2, and R3,
which form a voltage divider.
The UV and OV pins are connected to comparators with
nominal 1.17V thresholds and 100mV of hysteresis (1.17V
± 50mV). They are used to detect under voltage and over
voltage conditions at the input to the circuit. Whenever the
OV pin rises above its high threshold (1.22V) or the UV pin
falls below its low threshold (1.12V), the PWRGD outputs
immediately deactivate.
At the same time, a 10µA current source is enabled,
charging the external capacitor connected to the ramp pin.
The rise time of the ramp pin is determined by the value of
the capacitor (10µA/Cramp). When the ramp voltage
reaches 8.8V, the PWRGD-A pin will change into an active
state. PWRGD-B will change into an active state after a
programmed time delay from PWRGD-A inactive to active
transition. PWRGD-C will change into an active state after
a programmed time delay from PWRGD-B inactive to ac-
Calculations can be based on either the desired input voltage operating limits or the input voltage shutdown limits. In
the following equations the shutdown limits are assumed.
The undervoltage and overvoltage shut down thresholds
can be programmed by means of the three resistor divider
formed by R1, R2 and R3. Since the input currents on the
UV and OV pins are negligible the resistor values may be
calculated as follows:
4
A051204
PS10/PS11
From the calculated resistor values the OV and UV start
up threshold voltages can be calculated as follows:
UVOFF = VUVL = 1.12 = (VEEUV(off)) x (R2+R3)/(R1+R2+R3)
UVON = VUVH = 1.22 = (VEEUV(on)) x (R2+R3)/(R1+R2+R3)
OVOFF = VOVL = 1.22 = (VEEOV(off)) x R3/(R1+R2+R3)
OVON = VOVL = 1.12 = (VEEOV(on)) x R3/(R1+R2+R3)
Where (VEEUV(off)) and (VEEOV(off)) relative to VEE are Under
and Over Voltage Shut Down Threshold points.
Where (VEEUV(on)) and (VEEOV(on)) are Under and Over Voltage Start Up Threshold points relative to VEE.
If we select a divider current of 100 µA at a nominal operating input voltage of 50 Volts, then
Then
(VEEUV(on)) = 1.22 x (R1+R2+R3)/(R2+R3)
R1+R2+R3 = 50V/100µA = 500kΩ
(VEEUV(on)) = 1.22 x (487k+6.65k+9.31k)/(6.65k+9.31k )
= 38.45V
From the second equation, for an OV shut down threshold
of 65V, the value of R3 may be calculated.
And
(VEEOV(on)) = 1.12 x (R1+R2+R3)/R3
OVOFF = 1.22 = (65xR3)/500k
(VEEOV(on) ) = 1.12 x (487k +6.65k +9.31k)/9.31k = 60.51V
R3 = (1.22x 500k)/65 = 9.38k
Therefore, the circuit will start when the input supply voltage is in the range of 38.45V to 60.51V.
The closest 1% value is 9.31kΩ.
From the first equation, for a UV shut down threshold of
35V, the value of R2 can be calculated.
UVOFF = 1.12 = 35 x (R2+R3)/ 500k
R2 = ((1.12 x 500k)/35) – 9.76k = 6.69k
6.65kΩ is a standard 1% value
Then
R1 = 500k – R2 – R3 = 484.04kΩ.
487kΩ, is a standard 1% value.
5
A051204
PS10/PS11
Undervoltage/Overvoltage Operation
PWRGD Flags Delay Programming
GND
When the ramp voltage hits Vint – 1.17V, PWRGD-A becomes active indicating that the input supply voltage is
within the programmed limits. PWRGD-B goes active after
a programmed time delay after PWRGD-A went active.
PWRGD-C goes active after a programmed time delay
after PWRGD-B went active. PWRGD-D goes active after
a programmed time delay after PWRGD-C went active.
UVOFF
UVON
Vin
OVON
OVOFF
PWRGD
The resistors connected from TB, TC, and TD to VEE pin
determines the delay times between the PWRGD flags.
SET RESET
Start-up Timing (PS11 PWRGD-A Active Low)
The value of the resistors determines the capacitor charging and discharging current of a triangular wave oscillator.
The oscillator output is fed into an 8-bit counter to generate the desired time delay.
The respective time delay is defined by the following equation:
tTX = (255 x 2 x COSC x VPP)/ICD
and
ICD = Vbg / (4 x RTX)
Where
tTX = Time delay between respective PWRGD flags
COSC = 120pF (internal oscillator capacitor)
VPP = 8.2V (peak-to-peak voltage swing of oscillator)
ICD = Charge and discharge current of oscillator
Vbg = 1.17V (internal band gap reference)
RTX = Programming resistor at TB, TC, or TD
Combining the two equations and solving for RTX yields:
RTX
= (Vbg x tTX) / (2040 x COSC x VPP)
6
= 0.585 x 10 x tTX
tPWRGD-A is the time delay from VEEUV(on) to PWRGD-A going
active. It can be approximated by
For a time delay of 200ms
RTX
tPWRGD-A = CRAMP x (VINT-1.17)/IRAMP
where
= 0.585 x 106 x 0.2 = 117k
For a time delay of 5ms
RTX
= 0.585 x 106 x 0.005 = 2.925k
CRAMP = capacitor connected from RAMP pin to VEE pin
VINT = internal regulated power supply voltage (10V typ)
IRAMP = 10µA charge current
6
A051204
PS10/PS11
The following waveforms demonstrate the sequencing of
the PWRGD flags:
PWRGD Timing (Maximum Delays)
Test conditions: VIN = 48V, CRAMP = 10nF, RTB = 118k,
RTC = 118k, RTD = 118k, RPULL-UP = 47k.
PWRGD Timing (PS11)
Test conditions: VIN = 48V, CRAMP = 10nF,
RTB = 118k, RTC = 59k, and RTD = 46.4k.
Relative to Negative Rail
PS11 Power Down Sequence after UVOFF
Relative to Negative Rail
Test conditions: CRAMP = 10nF, RTB = 3.24k, RTC = 3.24k,
RTD = 3.24k, RPULL-UP = 47k, CPWRGD_B = 0.47µF, CPWRGD_C
= 0.94µF, CPWRGD_D = 1.41µF, VUVOFF = 33.4V, the assumed brick turn-off threshold is 2.7V min TTL logic high.
See power down sequencing on Page 11.
PWRGD Timing (Minimum Delays)
Test conditions: VIN = 48V, CRAMP = 10nF, RTB = 3.24k,
RTC = 3.24k, RTD = 3.24k, RPULL-UP = 47k.
Relative to Negative Rail
Relative to Negative Rail
7
A051204
PS10/PS11
PS11 Power Down Sequence after OVOFF
Test conditions: CRAMP = 10nF, RTB = 3.24k, RTC = 3.24k,
RTD = 3.24k, RPULL-UP= 47k, CPWRGD_B = 0.47µF, CPWRGD_C
= 0.94µF, CPWRGD_D = 1.41µF, VOVOFF = 61.6V, the assumed brick turn-off threshold is 2.7V min TTL logic high.
See power down sequencing on Page 11.
Relative to Negative Rail
PWRGD Output Configuration
The PS10 and PS11 open drain power good outputs can be connected directly to the Enable pins of the DC/DC converter.
The internal pull-up and clamp of the DC/DC converter sets the logic High Enable/Disable voltage.
GND
487K
V IN
V+
PWRGD-D
UV
DC/DC
Converter
PWRGD-C
6.81K
9.76K
EN
PWRGD-A
OV
VEE
+3.3V
PWRGD-B
PS10
COM
TB
RTB
TC
RTC
TD
RTD
V-
Ramp
10nF
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Other power good outputs will have the same
configuration as PWGRGD-A for Active High Enabled
Converters.
8
A051204
PS10/PS11
PWRGD Output Configuration, continued
GND
487K
V IN
V+
PWRGD-D
UV
DC/DC
Converter
PWRGD-C
6.81K
V EE
/EN
PWRGD-A
OV
9.76K
+3.3V
PWRGD-B
PS11
COM
TB
TC
RTB
RTC
TD
V-
Ramp
10nF
RTD
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Other power good outputs will have the same
configuration as PWGRGD-A for Active Low Enabled
Converters.
Opto-isolated Enable
Some applications require opto-isolator interface to the Enable pin of the DC/DC converter. Make sure that the current transfer
ratio of the opto-coupler selected is at least 100% to ensure proper pull-down current on the Enable pin.
GND
487K
VIN
V+
PWRGD-D
UV
49.9k
DC/DC
Converter
PWRGD-C
6.81K
PWRGD-B
PS10
Opto-coupler
PWRGD-A
+3.3V
EN
OV
9.76K
V EE
COM
TC
TB
RTB
RTC
TD
RTD
V-
Ramp
10nF
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Other power good outputs will have the same
configuration as PWGRGD-A for Active High Enabled
Converters.
9
A051204
PS10/PS11
Opto-isolated Enable, continued
GND
487K
VIN
PWRGD-D
UV
49.9k
V+
DC/DC
Converter
PWRGD-C
6.81K
PWRGD-B
PS11
PWRGD-A
OV
VEE
9.76K
Opto-coupler
+3.3V
/EN
COM
TB
RTB
TC
RTC
TD
V-
Ramp
10nF
RTD
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Other power good outputs will have the same
configuration as PWGRGD-A for Active Low Enabled
Converters.
Increasing the Under and Over Voltage Hysteresis
If the internal UV hysteresis is insufficient for a particular system application, then it may be increased by using separate resistor dividers for UV and OV and providing a resistor feedback from UV pin to the PWRGD pin.
GND
487k
499k
VIN
PWRGD-D
UV
V+
DC/DC
Converter
PWRGD-C
+3.3V
PWRGD-B
PS10
Ruvhys
PWRGD-A
EN
OV
VEE
16.5k
COM
TB
TC
TD
V-
Ramp
9.76k
RTB
RTC
RTD
10nF
-48V
Note:
1. Other power good outputs will have the same configuration as
PWGRGD-A for Active High Enabled Converters.
2. Over voltage shut down set to 63.6V
Ruvhys can be calculated based on higher UV On voltage (say
42V):
Ruvhys = (Vuvon - Vdiode - Vpwrgdlow)/((Vin-Vuvon)/487k Vuvon/16.5k)
= (1.22-0.65-0.4)/((42-1.22)/487k - 1.22/16.5k)
= 17.35k
10
A051204
PS10/PS11
Increasing the Under and Over Voltage Hysteresis, continued
GND
499k
487k
VIN
V+
PWRGD-D
DC/DC
Converter
PWRGD-C
UV
+3.3V
PWRGD-B
PS11
/EN
PWRGD-A
OV
COM
Ruvhys
16.5k
VEE
TB
TD
TC
V-
Ramp
10k
9.76k
RTB
RTC
10nF
RTD
-48V
Note:
1. Other power good outputs will have the same configuration as
PWGRGD-A for Active Low Enabled Converters.
2. Over voltage shut down set to 63.6V
Ruvhys can be calculated based on higher UV On voltage (say
42V):
Ruvhys = (Vuvon - Vdiode - Vce/((Vin-Vuvon)/487k Vuvon/16.5k)
= (1.22-0.65-0.1)/((42-1.22)/487k - 1.22/16.5k)
= 47.97k
Power Down Sequencing
In some applications, a power down sequence may be required. To accomplish this, a capacitor is connected to the power
good pins that need to be sequenced down. The power good turn off delays can be approximated by
TPWRGD-B(off) = C1 x VENOFF / IPULLUP ,
TPWRGD-C(off) = C2 x VENOFF / IPULLUP ,
TPWRGD-D(off) = C3 x VENOFF / IPULLUP ,
where:
TPWRGD-B(off)
-Time delay from PWRGD-A going High to PWRGD-B going high.
TPWRGD-c(off)
-Time delay from PWRGD-A going High to PWRGD-C going high.
TPWRGD-D(off)
-Time delay from PWRGD-A going High to PWRGD-D going high.
VENOFF
- DC/DC minimum off voltage (2.7V typ)
IPULLUP
- DC/DC /EN pin pull-up current (1mA typ)
Note: Adding C1, C2, C3 will have a negligible affect on the power good fall time.
GND
487K
V
IN
V+
/EN4
DC/DC
Converter
PWRGD-D
UV
/EN3
PWRGD-C
6.81K
/EN2
PWRGD-B
PS11
+3.3V
/EN
PWRGD-A
OV
COM
9.76K
VEE
TB
RTB
TD
TC
RTC
RTD
V-
Ramp
10nF
C3
C2
C1
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Only PWRGD-A to DC/DC converter connection is shown
for simplicity.
11
A051204
PS10/PS11
PS10 Power Good Clamp
If the active high enabled dc/dc converter used does not have an internal clamp, an external zener diode may be used to protect the module.
GND
487K
VIN
V+
PWRGD-D
UV
PWRGD-C
6.81K
DC/DC
Converter
49.9k
PWRGD-B
PS10
+3.3V
EN
PWRGD-A
OV
9.76K
COM
VEE
TB
RTB
TC
RTC
TD
V-
Ramp
10nF
RTD
-48V
Notes:
1. Under Voltage Shutdown (UV) set to 37V.
2. Over Voltage Shutdown (OV) to 57.8V.
3. Other power good outputs will have the same
configuration as PWGRGD-A for Active High Enabled
Converters.
Typical Application Circuit for a 12V Non-Isolated System
Most FPGAs, Processors, ASICs, and DSPs require sequencing and rail voltage limitation during start-up and power down
sequence of its rails. A typical requirement is: VDD_CORE must not exceed VDD_IO more than 0.6V and VDD_IO must not exceed VIN at any time. This can be accomplished by sequencing the dc/dc converters by the following manner:
Turn On: VDD_CORE first, VDD_IO second, and VIN last.
Tun-Off: VIN first, VDD_IO second, and VDD_CORE last.
The Schottky diodes will limit the voltage between the rails to around 0.3V @ 3A during the power-up and power-down
sequence.
Assuming that the /EN pins of the dc/dc converters have no pull-up and have a 1.0V turn-off threshold, the power-down
sequence time delays can be approximated by:
TPWRGD-C to TPWRGD-B = 1µF x 1V / 1mA = 1ms
TPWRGD-B to TPWRGD-A = (2µF-1µF) x 1V / 1mA = 1ms
+12V
R9 R8
14
R1
VIN
6
1
PWRGD-D
UV
PWRGD-C
R2
PWRGD-B
5
R3
7
VEE
/EN
2
Buck
Converter
3
+5V
TC
11
TD
12
13
/EN
+3.3V
RTC
RTD
VDD_IO
30BQ015
Ramp
/EN
10
Buck
Converter
RTB
LOAD
4
Buck
Converter
TB
VIN
30BQ015
PWRGD-A
PS11
OV
12k 12k
10nF
VDD_CORE
GND
+2.5V
C1 C2
2uF 1uF
GND
Supertex Inc. does not recommend the use of its products in life support applications and will not knowingly sell its products for use in such applications unless it receives an
adequate "products liability indemnification insurance agreement." Supertex does not assume responsibility for use of devices described and limits its liability to the replacement of
devices determined to be defective due to workmanship. No responsibility is assumed for possible omissions or inaccuracies. Circuitry and specifications are subject to change
without notice. For the latest product specifications, refer to the Supertex website: http://www.supertex.com. For complete liability information on all Supertex products, refer to the
most current databook or to the Legal/Disclaimer page on the Supertex website.
2004 Supertex Inc. All rights reserved. Unauthorized use or reproduction prohibited.
A051204
Doc. #: DSFP-PS10PS11
12
A051204
1235 Bordeaux Drive, Sunnyvale, CA 94089
TEL: (408) 222-8888 / FAX: (408) 222-4895
www.supertex.com
Package Outlines
14-LEAD SO PACKAGE (NG) (NARROW BODY)
0.340 ± 0.005
(8.636 ± 0.127)
D
0.017 ± 0.003
(0.4318 ± 0.0762)
B
E
H
0.156 ± 0.002
(3.9624 ± 0.0508)
0.500
T Y P.
(12.700)
0.2335 ± 0.0105
(5.9309 ± 0.2667)
0.193 ± 0.012
(4.9022 ± 0.3048)
0.350
T Y P.
(8.890)
D1
h
0.006 ± 0.002
(0.1524 ± 0.0508)
A
7° (4 P LC S )
45°
L1
A1
C
0° - 8 °
e
0.063 ± 0.005
(1.600 ± 0.127)
0.020 ± 0.009
(0.508 ± 0.2286)
0.050
T Y P.
(1.270)
Note: C ircle (e.g. B ) indicates J E DE C R eference.
Doc. #: DSPD14SONG
©2004 S upertex Inc. All rights res erved. Unauthorized us e or reproduction prohibited.
L
0.006 ± 0.004
(0.1524 ± 0.1016)
0.035 ± 0.015
(0.889 ± 0.381)
Meas urement Legend =
0.0275 ± 0.0025
(0.6985 ± 0.0635)
Dimens ions in Inches
(Dimens ions in Millimeters )
A050604
1235 B ordeaux Drive, S unnyvale, C A 94089
T E L: (408) 222-8888 / F AX : (408) 222-4895
www.s upertex.com