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FEATURES
§ Provides power switching of up to 1.5 amps at
voltages between 3.0 and 5.0 volts
§ Five separate power switches
§ Selectable battery switches for use with
§ battery-backed systems
§ Very low on impedance of 0.7O
§ Battery backup current of 4 mA
§ Diode-isolated battery path
§ Available in 16-pin DIP or 16-pin SOIC
surface
§ mount package
§ Low voltage drop battery path
§ Connects directly to a variety of Dallas
Semiconductor devices, adding increased
switching capability for large battery backup
current applications
PIN ASSIGNMENT
PIN DESCRIPTION
VCC/IN1 - +5V Input and Input 1
IN2 - IN5 - Inputs 2 - 5
OUT1 - 5 - Outputs 1 - 5
VBATIN - External Battery Input
VBAT01 - Diode Protected Battery Output
VBAT02 - Low Voltage Drop Battery
Output
PF,
PF
- Power-fail Inputs
GND - Ground
DESCRIPTION
The DS1336 Afterburner Chip is designed to provide power switching between a primary power supply
(VCC) and a backup battery power supply (VBAT). Five VCC and two battery paths are provided which can
be used individually or in parallel to supply uninterrupted power in applications such as SRAM networks.
When used with one of the Dallas power monitoring devices listed in Table 1, the DS1336 allows a load
to be switched from its main power supply VCC to a battery backup supply when VCC falls out of
tolerance. A user may selectively tie together any combination of the output pins to provide the desired
high current supply, providing up to 300 mA per OUT pin or a maximum of 1.5A. Depending upon the
user’s backup supply load requirements, either of the VBAT outputs may be tied to the OUT pins to supply
DS1336
Afterburner Chip
www.dalsemi.com
16-Pin DIP (300-mil)
See Mach. Drawings
Section
16-Pin DIP SOIC (300-mil)
See Mach. Drawings
Section
OUT5
PF
VBATIN
VBAT02
OUT4
1
16
15
14
13
12
11
10
9
2
3
4
5
6
7
8
V
CC
/IN1
PF
GND
OUT1
OUT2
OUT3
VBAT01
OUT5
PF
VBATIN
VBAT02
OUT4
1
16
15
14
13
12
11
10
9
2
3
4
5
6
7
8
V
CC
/IN1
PF
GND
OUT1
OUT2
OUT3
VBAT01
DS1336
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current when VCC is out of tolerance. The DS1336 switches back to the higher current VCC from battery
current when PF and
PF
become inactive.
OPERATION
The required PF or
PF
input which controls the switching between the main VCC and backup battery can
be supplied by any of the devices listed in Table 1. All of the devices provide the DS1336 with a PF or
PF
signal, switching between a main supply VCC and backup supply VBAT when VCC falls out of
tolerance. For applications requiring switching from the VCC supply inputs to VBAT, the required PF or
PF
input to the DS1336 can be provided by the DS1236, DS1239, DS5001, or DS5340. For applications
requiring switching from the VCC inputs to the VBAT input when VCC begins falling out of tolerance, any
of the Dallas Semiconductor devices listed in Table 1 can provide the DS1336 with the required
switching input. A typical application is shown in Figure 1. For applications where switching between
VCC and VBAT must occur at a voltage level such that VCC is still greater than VBAT, the OUT5 pin is
recommended as it provides a diode path which will provide for a gradual transition between VCC and
VBAT. OUT5 can be tied to the other OUTPUT pins to provide a gradual transition for all five current
paths. In applications where tri-state switching is desired, OUT5 should be omitted. Only the PF/
PF
pin
is required for switching. In cases where the PF input will not be used, it should be connected to GND.
When either PF or
PF
is active, either of the VBAT0X outputs is available, although they should not be tied
together (Figure 2, “DS1336 Block Diagram”). VBAT01 is recommended for sensitive applications such as
providing backup current to timekeepers, because its diode isolated path provides for increased
protection. VBAT02 is not recommended for applications where it would be tied to an OUTPUT pin
supplying a voltage greater than that of the backup battery because VBAT02 is not a diode isolated current
path.
TYPICAL APPLICATION Figure 1
DS1336
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DS1336 BLOCK DIAGRAM Figure 2
DS1336
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DALLAS SEMICONDUCTOR DEVICES WHICH PROVIDE PF OR
PF
INPUT
TO NIL Table 1
DEVICE SWITCH >
VBAT
SWITCH AT
VBAT DEVICE SWITCH >
VBAT
SWITCH AT
VBAT
DS1211 X DS1238 X X
DS1212 X DS1239 X X
DS1231 X DS1259 X
DS1232 X DS1260 X
DS1233 X DS1610 X
DS1233A X DS1632 X
DS1233D X DS1833 X
DS1234 X DS5001 X X
DS1236 X X DS5340 X X
DS1237 X
DS1336
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ABSOLUTE MAXIMUM RATINGS*
Voltage on Any Pin Relative to Ground -0.3V to +7.0V
Operating Temperature 0°C to 70°C
Storage Temperature -55°C to +125°C
Soldering Temperature 260°C for 10 seconds
∗ This is a stress rating only and functional operation of the device at these or any other conditions
above those indicated in the operation sections of this specification is not implied. Exposure to
absolute maximum rating conditions for extended periods of time may affect reliability.
DC OPERATING CONDITIONS (tA = 0°C to 70°C; VCC = 5V ± 10%)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Supply Voltage VCC1 3.0 5.0 5.5 V 1
Supply Current ICC1 0.25 1.0 mA
Supply Current ICC2 50 100 nA 3
Input Low Voltage VIL 0.8 V 1
Input High Voltage VIH 2.0 VCC V 1
Current Output
VCC=VCC1, PF=0,
PF
=1 ICCO 300 mA 2
Current Output
VCC=0, PF=1,
PF
=0 IBAT01-2 4.0 mA 4
Current, Forward Bias of
VCC5 Diode IFB 20 mA
Off Impedance ROFF1 5.0 MΩ5
Off Impedance ROFF2 10 MΩ6
On Impedance RON1 0.7 Ω7
On Impedance RON2 50 Ω8
AC CHARACTERISTICS (tA = 0°C to 70°C; VCC = 5V ± 10%)
PARAMETER SYMBOL MIN TYP MAX UNITS NOTES
Propagation Delay tPD 10 ns 9
Switch Delay Power-fail tPF 100 ns
Switch Delay Power-on tPON 100 ns
Capacitance PF,
PF
CI7 pF
NOTES:
1. All voltages referenced to ground.
2. ICCO with a voltage drop of 0.2 volts from any VCCO output.
3. VCC=0, VBATIN=3.0 volts.
4. VBAT01 with a voltage drop of 1.0 volts.
5. ROFF1 applies to VCCO1, 2, 3, 4.
6. ROFF2 applies to VBATO1, 2.
DS1336
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7. Applies to VCCO1-5, 300 mA.
8. Applies to VBATO1-2, 4 mA.
9. VCCI3 to VCCO3 delay when used as chip enable control for write protection of a memory device. In
this application a current 8 mA source current on VCCI3 with 50 pF load on VCCO3 can be
accommodated.