February 2008 Rev 11 1/20
20
KFxxB
Very low drop voltage regulators with inhibit
Features
■Very low dropout voltage (0.4 V)
■Very low quiescent current (typ. 50 µA in OFF
mode, 500 µA in ON mode)
■Output current up to 500 mA
■Logic-controlled electronic shutdown
■Output voltages of 1.5; 2.5; 3.3; 4; 5; 8 V
■Internal current and thermal limit
■Only 2.2 µF for stability
■Available in ± 2 % accuracy at 25 °C
■Supply voltage rejection: 70 db (typ.)
■Temperature range: -40 to 125 °C
Description
The KFxx series are very low drop regulators
available in SO-8 package and in a wide range of
output voltages.
The very low drop voltage (0.4 V) and the very low
quiescent current make them particularly
suitable for low noise, low power applications and
specially in battery powered systems.
A shutdown logic control function is available (pin
5, TTL compatible). This means that when the
device is used as a local regulator, it is possible to
put a part of the board in standby, decreasing the
total power consumption. It requires only a 2.2 µF
capacitor for stability allowing space and cost
saving.
DPAK
SO-8
Table 1. Device summary
Part numbers
KF15B KF40B
KF25B KF50B
KF33B KF80B
www.st.com
Contents KFxxB
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Contents
1 Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
2 Pin configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
3 Maximum ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4 Electrical characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
5 Typical performance characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . 12
6 Package mechanical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
7 Order codes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
8 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
KFxxB Diagram
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1 Diagram
Figure 1. Schematic diagram
Pin configuration KFxxB
4/20
2 Pin configuration
Figure 2. Pin connections (top view)
DPAK
SO-8
KFxxB Maximum ratings
5/20
3 Maximum ratings
Note: Absolute maximum ratings are those values beyond which damage to the device may occur.
Functional operation under these condition is not implied.
Table 2. Absolute maximum ratings
Symbol Parameter Value Unit
VIDC input voltage -0.5 to 20 V
IOOutput current Internally Limited
PTOT Power dissipation Internally Limited
TSTG Storage temperature range -40 to 150 °C
TOP Operating junction temperature range -40 to 125 °C
Table 3. Thermal data
Symbol Parameter DPAK SO-8 Unit
RthJC Thermal resistance junction-case 8 20 °C/W
Figure 3. Test circuit
Electrical characteristics KFxxB
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4 Electrical characteristics
Table 4. Electrical characteristics for KF15 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 3.5 V 1.47 1.5 1.53 V
IO = 50 mA, VI = 3.5 V, Ta = -25 to 85°C 1.44 1.56
VIOperating input voltage IO = 500 mA 2.5 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 2.5 to 20 V, IO = 5 mA 2 12 mV
ΔVOLoad regulation VI = 2.8 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 2.5 to 20V, IO = 0mA ON MODE 0.5 1 mA
VI = 2.8 to 20V, IO=500mA 12
VI = 6 V OFF MODE 50 100 µA
SVR Supply voltage rejection IO = 5 mA, VI = 3.5 ± 1 V
f = 120 Hz 82
dBf = 1 kHz 77
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 kHz 50 µV
VdDropout voltage IO = 200 mA 1 V
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
KFxxB Electrical characteristics
7/20
Table 5. Electrical characteristics for KF25 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 4.5 V 2.45 2.5 2.55 V
IO = 50 mA, VI = 4.5 V, Ta = -25 to 85°C 2.4 2.6
VIOperating input voltage IO = 500 mA 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 3.5 to 20 V, IO = 5 mA 2 12 mV
ΔVOLoad regulation VI = 3.8 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 3.5 to 20V, IO = 0mA ON MODE 0.5 1 mA
VI = 3.8 to 20V, IO=500mA 12
VI = 6 V OFF MODE 50 100 µA
SVR Supply voltage rejection IO = 5 mA, VI = 4.5 ± 1 V
f = 120 Hz 82
dBf = 1 kHz 77
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 KHz 50 µV
VdDropout voltage IO = 200 mA 0.2 0.35 V
IO = 500 mA 0.4 0.7
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
Electrical characteristics KFxxB
8/20
Table 6. Electrical characteristics for KF33 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 5.3 V 3.234 3.3 3.366 V
IO = 50 mA, VI = 5.3 V, Ta = -25 to 85°C 3.168 3.432
VIOperating input voltage IO = 500 mA 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 4.3 to 20 V, IO = 5 mA 2 12 mV
ΔVOLoad regulation VI = 4.6 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 4.3 to 20V, IO = 0mA ON MODE 0.5 1 mA
VI = 4.6 to 20V, IO=500mA 12
VI = 6 V OFF MODE 50 100 µA
SVR Supply voltage rejection IO = 5 mA, VI = 5.3 ± 1 V
f = 120 Hz 80
dBf = 1 kHz 75
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 KHz 50 µV
VdDropout voltage IO = 200 mA 0.2 0.35 V
IO = 500 mA 0.4 0.7
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
KFxxB Electrical characteristics
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Table 7. Electrical characteristics for KF40 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 6 V 3.9244.08V
IO = 50 mA, VI = 6 V, Ta = -25 to 85°C 3.84 4.16
VIOperating input voltage IO = 500 mA 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 5 to 20 V, IO = 5 mA 3 18 mV
ΔVOLoad regulation VI = 5.3 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 5 to 20V, IO = 0mA ON MODE 0.5 1 mA
VI = 5.3 to 20V, IO=500mA 12
VI = 6 V OFF MODE 50 100 µA
SVR Supply voltage rejection IO = 5 mA, VI = 6 ± 1 V
f = 120 Hz 78
dBf = 1 kHz 73
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 KHz 50 µV
VdDropout voltage IO = 200 mA 0.2 0.35 V
IO = 500 mA 0.4 0.7
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
Electrical characteristics KFxxB
10/20
Table 8. Electrical characteristics for KF50 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 7 V 4.9 5 5.1 V
IO = 50 mA, VI = 7 V, Ta = -25 to 85°C 4.8 5.2
VIOperating input voltage IO = 500 mA 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 6 to 20 V, IO = 5 mA 3 18 mV
ΔVOLoad regulation VI = 6.3 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 6 to 20V, IO = 0mA ON MODE 0.5 1 mA
VI = 6.3 to 20V, IO=500mA 12
VI = 6 V OFF MODE 50 100 µA
SVR Supply voltage rejection IO = 5 mA, VI = 7 ± 1 V
f = 120 Hz 76
dBf = 1 kHz 71
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 KHz 50 µV
VdDropout voltage IO = 200 mA 0.2 0.35 V
IO = 500 mA 0.4 0.7
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
KFxxB Electrical characteristics
11/20
Table 9. Electrical characteristics for KF80 (refer to the test circuits, TJ = 25 °C, CI = 0.1 µF,
CO = 2.2 µF unless otherwise specified.)
Symbol Parameter Test conditions Min. Typ. Max. Unit
VOOutput voltage IO = 50 mA, VI = 10 V 7.84 8 8.16 V
IO = 50 mA, VI = 10 V, Ta = -25 to 85°C 7.68 8.32
VIOperating input voltage IO = 500 mA 20 V
IOOutput current limit 1 A
ΔVOLine regulation VI = 9 to 20 V, IO = 5 mA 4 24 mV
ΔVOLoad regulation VI = 9.3 V, IO = 5 to 500 mA 2 50 mV
IdQuiescent current
VI = 9 to 20V, IO = 0mA ON MODE 0.7 1.5 mA
VI = 9.3 to 20V, IO=500mA 12
VI = 9 V OFF MODE 70 140 µA
SVR Supply voltage rejection IO = 5 mA, VI = 10 ± 1 V
f = 120 Hz 72
dBf = 1 kHz 67
f = 10 kHz 60
eN Output noise voltage B = 10 Hz to 100 KHz 50 µV
VdDropout voltage IO = 200 mA 0.2 0.35 V
IO = 500 mA 0.4 0.7
VIL Control input logic low Ta = -40 to 125°C 0.8 V
VIH Control input logic high Ta = -40 to 125°C 2 V
IIControl input current VI = 6 V, VC = 6 V 10 µA
CO
Output bypass
capacitance ESR = 0.1 to 10 Ω, IO = 0 to 500 mA 2 10 µF
Typical performance characteristics KFxxB
12/20
5 Typical performance characteristics
(unless otherwise specified VO(NOM) = 3.3 V)
Figure 4. Dropout voltage vs output current Figure 5. Dropout voltage vs temperature
Figure 6. Supply current vs input voltage Figure 7. Supply current vs input voltage
Figure 8. Short circuit current vs input
voltage
Figure 9. Supply current vs temperature
KFxxB Package mechanical data
13/20
6 Package mechanical data
In order to meet environmental requirements, ST offers these devices in ECOPACK®
packages. These packages have a lead-free second level interconnect. The category of
second Level Interconnect is marked on the package and on the inner box label, in
compliance with JEDEC Standard JESD97. The maximum ratings related to soldering
conditions are also marked on the inner box label. ECOPACK is an ST trademark.
ECOPACK specifications are available at: www.st.com.
Package mechanical data KFxxB
14/20
Dim. mm. inch.
Min. Typ. Max. Min. Typ. Max.
A1.35 1.75 0.0530.069
A1 0.10 0.25 0.04 0.010
A2 1.10 1.65 0.0430.065
B0.33 0.51 0.0130.020
C0.190.25 0.007 0.010
D4.80 5.00 0.189 0.197
E3.80 4.00 0.150 0.157
e 1.27 0.050
H5.80 6.20 0.2280.244
h 0.25 0.50 0.010 0.020
L 0.40 1.27 0.016 0.050
k8° (max.)
ddd 0.1 0.04
SO-8 mechanical data
0016023/C
KFxxB Package mechanical data
15/20
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A 2.2 2.4 0.086 0.094
A1 0.91.1 0.035 0.043
A2 0.030.230.001 0.009
B 0.64 0.90.025 0.035
b4 5.2 5.4 0.204 0.212
C 0.45 0.6 0.017 0.023
C2 0.480.6 0.0190.023
D 6 6.2 0.236 0.244
D1 5.1 0.200
E 6.4 6.6 0.252 0.260
E1 4.7 0.185
e2.280.090
e1 4.4 4.6 0.1730.181
H9.35 10.1 0.3680.397
L 1 0.039
(L1) 2.80.110
L2 0.80.031
L4 0.6 1 0.0230.039
R 0.2 0.008
V2 0° 8°0° 8°
DPAK mechanical data
0068772-F
Package mechanical data KFxxB
16/20
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A330 12.992
C 12.813.2 0.504 0.519
D 20.2 0.795
N60 2.362
T 22.4 0.882
Ao 8.1 8.5 0.3190.335
Bo 5.5 5.90.216 0.232
Ko 2.1 2.30.082 0.090
Po 3.94.1 0.1530.161
P7.98.1 0.311 0.319
Tape & reel SO-8 mechanical data
KFxxB Package mechanical data
17/20
Dim.
mm. inch.
Min. Typ. Max. Min. Typ. Max.
A330 12.992
C12.813.0 13.2 0.504 0.512 0.519
D 20.2 0.795
N60 2.362
T22.40.882
Ao 6.806.90 7.00 0.2680.272 0.2.76
Bo 10.40 10.50 10.60 0.4090.4130.417
Ko 2.55 2.65 2.75 0.100 0.104 0.105
Po 3.94.0 4.1 0.1530.157 0.161
P7.98.0 8.1 0.311 0.315 0.319
Tape & reel DPAK-PPAK mechanical data
Order codes KFxxB
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7 Order codes
Table 10. Order codes
Packages
Output voltage
SO-8 (tape and reel) DPAK (tape and reel)
KF15BDT-TR 1.5 V
KF25BD-TR KF25BDT-TR 2.5 V
KF33BD-TR KF33BDT-TR 3.3 V
KF40BDT-TR 4 V
KF50BD-TR KF50BDT-TR 5 V
KF80BDT-TR 8 V
KFxxB
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