ST1S10
3 A, 900 kHz, monolithic synchronous step-down regulator IC
Datasheet
-
production data
Description
The ST1S10 is a high efficiency step-down PWM
current mode switching regulator capable of
providing up to 3 A of output current. The device
operates with an input supply range from 2.5 V to
18 V and provides an adjustable output voltage
from 0.8 V (V
FB
) to 0.85 * V
IN_SW
[V
OUT
= V
FB
*
(1 + R1/R2)]. It operates either at a 900 kHz fixed
frequency or can be synchronized to an external
clock (from 400 kHz to 1.2 MHz). The high
switching frequency allows the use of tiny SMD
external components, while the integrated
synchronous rectifier eliminates the need for a
Schottky diode. The ST1S10 provides excellent
transient response, and is fully protected against
thermal overheating, switching overcurrent and
output short-circuit.
The ST1S10 is the ideal choice for point of load
regulators or LDO pre-regulation.
Table 1. Device summary
Order codes
Part number
DFN8 (4 x 4 mm)
ST1S10
ST1S10PUR
PowerSO-8
ST1S10PHR
DFN8 (4 x 4 mm)
PowerSO-8
Features
Step-down current mode PWM regulator
Output voltage adjustable from 0.8 V
Input voltage from 2.5 V up to 18 V
2% DC output voltage tolerance
Synchronous rectification
Inhibit function
Synchronizable switching frequency from 400
kHz up to 1.2 MHz
Internal soft start
Dynamic short-circuit protection
Typical efficiency: 90%
3 A output current capability
Standby supply current: max. 6 µA over
temperature range
Operative junction temp.: from -40 °C to 125 °C
Applications
Consumer
– STB, DVD, DVD recorders, TV, VCR, car
audio, LCD monitors
Networking
– XDSL, modems, DC-DC modules
Computer
– Optical storage, HD drivers, printers,
audio/graphic cards
Industrial and security
– Battery chargers, DC-DC converters, PLD,
PLA, FPGA, LED drivers
March 2015
This is information on a product in full production.
DocID13844 Rev 6
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Contents
ST1S10
Contents
1
2
3
4
5
Application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Application information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.1
5.2
5.3
5.4
5.5
5.6
5.7
5.8
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
External components selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Input capacitor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
Output capacitor (V
OUT
> 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11
Output capacitor (0.8 V < V
OUT
< 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . 12
Output voltage selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
Inductor (V
OUT
> 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Inductor (0.8 V < V
OUT
< 2.5 V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Function operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
5.8.1
5.8.2
5.8.3
5.8.4
5.8.5
Sync operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
Inhibit function . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
OCP (overcurrent protection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SCP (short-circuit protection) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
SCP and OCP operation with high capacitive load . . . . . . . . . . . . . . . . 14
6
Layout considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Thermal considerations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
7
8
Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
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Package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
9.1
9.2
Power SO-8 package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
DFN8 (4 x 4) package information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
10
Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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List of tables
ST1S10
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.
Device summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Pin description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Absolute maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Thermal data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
ESD protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
Power SO-8 (exposed pad) package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Power SO-8 (exposed pad) tape and reel mechanical data . . . . . . . . . . . . . . . . . . . . . . . . 26
DFN8 (4 x 4) package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
DFN8 (4 x 4) tape and reel mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Document revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
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List of figures
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.
Typical application circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Pin connections (top view for PowerSO-8, bottom view for DFN8) . . . . . . . . . . . . . . . . . . . 7
Application schematic for heavy capacitive load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Application schematic for low output voltage (V
OUT
< 2.5 V) and 2.5 V < V
IN
< 8 V . . . . . 16
Application schematic for low output voltage (V
OUT
< 2.5 V) and 8 V < V
IN
< 16 V . . . . . . 16
PCB layout suggestion - top . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
PCB layout suggestion - bottom . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
Voltage feedback vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Oscillator frequency vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Max. duty cycle vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Inhibit threshold vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
Reference line regulation vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Reference load regulation vs. temperature. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
ON mode quiescent current vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Shutdown mode quiescent current vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
PMOS ON resistance vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
NMOS ON resistance vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Efficiency vs. temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Efficiency vs. output current at V
out
= 5 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Efficiency vs. output current at V
out
= 3.3 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Efficiency vs. output current at V
out
= 12 V . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
Power SO-8 (exposed pad) package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Power SO-8 (exposed pad) recommended footprint . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Power SO-8 (exposed pad) tape and reel dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
DFN8 (4 x 4) package outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
DFN8 (4 x 4) tape and reel dimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
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