SRK1000 / SRK1000A /
SRK1000B
Datasheet production data
Features
Applications
Description
SOT23-6L
Table 1. Device summary
Part number Package Packing
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Contents SRK1000 / SRK1000A / SRK1000B
Contents
1 Block diagram and pin connections . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
3 Typical application schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5 Operation description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11
6 Layout guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
7 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
SRK1000 / SRK1000A / SRK1000B Block diagram and pin connections
1 Block diagram and pin connections
Figure 1. Internal block diagram
Figure 2. Pin connections (top view)
Table 2. Pin functions
No. Name Function
Block diagram and pin connections SRK1000 / SRK1000A / SRK1000B
Table 2. Pin functions
No. Name Function
SRK1000 / SRK1000A / SRK1000B Maximum ratings
2 Maximum ratings
Table 3
Table 3. Absolute maximum ratings
Symbol Pin Parameter Value Unit
Table 4. Thermal data
Symbol Parameter Value Unit
Typical application schematics SRK1000 / SRK1000A / SRK1000B
3 Typical application schematics
Figure 3. Typical application schematic: QR flyback charger with CV-CC regulation
Figure 4. Typical application schematic: QR flyback adapter (CV regulation)
SRK1000 / SRK1000A / SRK1000B Typical application schematics
Figure 5. Typical application schematic: fixed frequency CCM flyback adapter (CV
regulation)
Electrical characteristics SRK1000 / SRK1000A / SRK1000B
4 Electrical characteristics
Table 5. Electrical characteristics
Symbol Parameter Test condition Min. Typ. Max. Unit
Supply section
Drain-source sensing inputs and synch functions
Blanking time after turn-on and after turn-off
SRK1000 / SRK1000A / SRK1000B Electrical characteristics
Low consumption mode
Gate drivers
Figure 6
Figure 6
Figure 6
Table 5. Electrical characteristics (continued)
Symbol Parameter Test condition Min. Typ. Max. Unit
Electrical characteristics SRK1000 / SRK1000A / SRK1000B
Figure 6. Rise and fall time definition
SRK1000 / SRK1000A / SRK1000B Operation description
5 Operation description
Figure 1
Table 5: Electrical
characteristics
Figure 7
Operation description SRK1000 / SRK1000A / SRK1000B
Figure 7. Comparison between adaptive turn-off and comparator based turn-off
5.1 Drain voltage sensing
5.2 Turn-on
5.3 Minimum TON programming
SRK1000 / SRK1000A / SRK1000B Operation description
Equation 1
Section 5.7: Low consumption mode operation: sleep mode
and burst mode
5.4 Adaptive turn-off and TIMER
Figure 8
Figure 8. ZCD_OFF threshold adapting for body diode target conduction
TON_MIN = 12 10 12– RTON
Operation description SRK1000 / SRK1000A / SRK1000B
Fixed frequency mixed DCM/CCM operation
Figure 9
Figure 9. Timer anticipation for fixed frequency CCM operation (100 pF mounted on
TON pin)
QR operation (with valley skipping)
SRK1000 / SRK1000A / SRK1000B Operation description
Figure 10
Figure 10
Figure 10. Timer anticipation for QR operating circuit (no capacitor mounted on TON
pin)
Fixed frequency DCM operation
5.5 Minimum TOFF
Operation description SRK1000 / SRK1000A / SRK1000B
Figure 11
Figure 11. Blanking time after turn-off
Figure 12
Section 5.8: VAUX pin
operation in CC regulation
SRK1000 / SRK1000A / SRK1000B Operation description
Figure 12. Comparator for blanking time termination
5.6 Start-up phase
Section 5.7: Low consumption mode operation: sleep mode and burst mode
5.7 Low consumption mode operation: sleep mode and burst
mode
Equation 2
TON_sleep_in = TON_MIN + 300 ns
Operation description SRK1000 / SRK1000A / SRK1000B
Equation 3
5.8 VAUX pin operation in CC regulation
Figure 13
TON_sleep_out = 1.2 TON_MIN + 300 ns
SRK1000 / SRK1000A / SRK1000B Operation description
Figure 13. VAUX supply for CC regulation operation (from rectified SR MOSFET drain)
Figure 13
Figure 14
Figure 14. VAUX supply for CC regulation operation from auxiliary winding
Figure 13
Operation description SRK1000 / SRK1000A / SRK1000B
Figure 15
SRK1000 / SRK1000A / SRK1000B Operation description
Figure 15. VAUX pin operation
5.9 Operation in CC regulation and short-circuit
5.10 Adaptive gate drive
Operation description SRK1000 / SRK1000A / SRK1000B
Equation 4
TD = 300 ns + TON_min (n + 6)/6
SRK1000 / SRK1000A / SRK1000B Layout guidelines
6 Layout guidelines
Package mechanical data SRK1000 / SRK1000A / SRK1000B
7 Package mechanical data
Table 6. SOT23-6L mechanical data
Dimensions
Ref
mm inch
Min. Typ. Max. Min. Typ. Max.
θ
SRK1000 / SRK1000A / SRK1000B Package mechanical data
Figure 16. SOT23-6L package outline
RECOMMENDED FOOTPRINT
SRK1000 / SRK1000A / SRK1000B
IMPORTANT NOTICE – PLEASE READ CAREFULLY
