ADVANCED INFORMATION
ADVANCED
INFORMATION
FEATURES
TK654xx
STEP-DOWN CONVERTER WITH BATTERY MONITOR
APPLICATIONS
s
Battery Powered Systems
s
Cellular Telephones
s
s
s
s
Pagers
Personal Communications Equipment
Radio Controlled Systems
Toys
s
Minimum External Component Count (1 coil, 1 cap)
s
Miniature 6 Pin SOT23L-6 Surface Mount Package
s
Up To 95% Efficient
s
Extremely Low Operating Current (24
µ
A)
s
Low Quiescent Current (18
µ
A)
s
Low Ripple
s
Fast Transient Response
s
Linear Dropout Characteristics
s
Short Circuit Protection
s
Regulates Down to 1.8 V
s
Synchronous Rectification
s
Internal Battery Monitor
Driving the SB pin low will disable the TK654xx and drop
the quiescent current on the input supply to approximately
18
µA.
Pulse Current Amplitude control is used to regulate the
voltage at the V
OUT
pin of the IC. When the output voltage
of the TK654xx drops below the regulation threshold, a
current pulse is transferred from the input supply to the
output. The TK654xx utilizes a proprietary control scheme,
where the average amplitude of the current pulse is varied
depending upon the current loads. The proprietary
architecture allows fast transient response and minimal
ripple while maintaining ease-of-use and low component
count.
The TK654xx is available in a miniature 6-pin SOT23L-6
surface mount package.
TK654xxM
DESCRIPTION
The TK654xx low power step-down converter is designed
for portable battery systems, capable of operating from a
single Li-ion battery cell or multiple alkaline or rechargeable
(NiCd or NiMH) battery cells (up to 6 V). The TK654xx
provides the power switch, synchronous rectifier, and the
control circuit for a buck step-down converter. Only two
external components are required to complete the step-
down conversion.
The TK654xx provides laser-trimmed output voltages
ranging from 1.8 V to 3.3 V. The low resistance MOSFET
switch and synchronous rectifier allow average currents
up to 200 mA, while maintaining peak efficiencies up to
95%. A low-battery threshold and turn-off threshold can
be individually programmed by the user, utilizing a single
resistor divider connected to the Low Battery Input (LBI)
pin. When the resistively-divided supply voltage on the
LBI pin drops below approximately 1.22 V, the Low Battery
Output (LBO) pin will become asserted. The dual-function
LBI pin can alternatively be used as a Standby (SB) pin.
LBO
LBI/SB
VOUT
SW
GND
VIN
BLOCK DIAGRAM
VIN
ORDERING INFORMATION
TK654xxM
Tape/Reel Code
Voltage Code
VOUT
CONTROL
CIRCUIT
SW
GND
REF
OFF
BATTERY
MONITOR
LBO
LBI/SB
LBO
VOLTAGE CODE
18 = 1.8 V
21 = 2.1 V
24 = 2.4 V
25 = 2.5 V
27 = 2.7 V
30 = 3.0 V
33 = 3.3 V
TAPE/REEL CODE
TL: Tape Left
September 1999 TOKO, Inc.
Page 1
TK654xx
ADVANCED INFORMATION
ABSOLUTE MAXIMUM RATINGS
All Pins Except GND ............................................... 6.5 V
Power Dissipation (Note 1) ................................ 400 mW
Storage Temperature Range ................... -55 to +150
°C
Operating Temperature Range ...................-20 to +80
°C
Junction Temperature ........................................... 150
°C
Lead Soldering Temperature (10 s.) ..................... 235
°C
TK654xx ELECTRICAL CHARACTERISTICS
Test conditions: V
IN
= 5 V, I
OUT
= 1 mA, T
A
= T
J
= Full Operating Temperature Range, unless otherwise specified.
SYMBOL
V
IN
V
OUT(REG)
∆V
OUT(LOAD)
∆V
OUT(LINE)
I
Q(VOUT)
I
Q(VIN)
V
TH(LBI)
V
TH(SB)
I
B(SB)
I
OUT(MAX)
I
OUT(SC)
I
Q(CONV)
I
STBY
PARAMETER
Input Voltage
Output Voltage
Load Regulation
Line Regulation
Quiescent Current into V
OUT
Pin
Quiescent Current into V
IN
Pin
LBI Input Threshold
Standby Threshold
SB Input Bias Current
Note 4 at (V
TH(SB)
- 100 mV)
Maximum Output Current
Short Circuit Current
Converter Quiescent Current
Converter Standby Current
(Note 3)
(Note 3)
(Note 3) I
OUT
= 0 mA
SB pin = 0 V, Pin 1 open
I
OUT
= 50 mA, (Note 3)
T
A
= T
J
= 25° C (TK65418)
I
OUT
= 50 mA, (Note 3)
T
A
= T
J
= 25° C (TK65433)
I
OUT
= 50 mA, (Note 5)
T
A
= T
J
= 25 ° C (TK65418)
I
OUT
= 50 mA, (Note 6)
T
A
= T
J
= 25 ° C (TK65433)
86
90
24
18
91
95
100
75
195
145
400
720
100
250
90
65
1000
nA
mA
mA
µA
µA
%
%
mV
mV
T
A
= T
J
= 25 ° C (Note 2)
TEST CONDITIONS
MIN
2
-3%
-5%
I
LOAD
= 0 to 100 mA, (Note 3)
V
IN
= 4 to 6 V, (Note 3)
V
OUT
= V
OUT(REG)
+ 50 mV
(Note 3)
V
OUT
= V
OUT(REG)
+ 50 mV
T
A
= T
J
= 25 ° C
T
A
= T
J
= 25 ° C
Note 3
1.157
1.157
P
TYP
MAX
6
UNITS
V
V
V
mV
mV
µA
µA
V
V
nA
V
REG
3%
+5%
45
6
10
15
1.22
1.22
0
120
20
50
65
1.282
1.282
EFF
Converter Efficiency
V
DROP
Dropout Voltage
Note 1: Power dissipation is 400 mW when mounted as recommended. Derate at 3.2 mW/°C for operation above 25
°C.
Power dissipation is 200
mW in Free Air. Derate at 1.6 mW/°C for operation above 25
°C
Note 2: V
REG
= 3.3, 3.0, 2.7, 2.5, 2.4, 2.1, 1.8 V.
Note 3: When using test circuit.
Note 4: When using test circuit and ramping V
IN
down.
Note 5: When using test circuit with SB pin resistors removed and tied to V
IN
. (V
IN
= 1.8 V)
Note 6: When using test circuit with SB pin resistors removed and tied to V
IN
. (V
IN
= 3.3 V)
Page 2
September 1999 TOKO, Inc.
Test/Measurement
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