4
LTC1929/LTC1929-PG
SYMBOL PARAMETER CONDITIONS MIN TYP MAX UNITS
I
B
Input Bias Current Op Amp Mode (LTC1929 Only) 30 200 nA
A
OL
Open Loop DC Gain Op Amp Mode; 0.7V ≤ V
DIFFOUT
< 10V 5000 V/mV
(LTC1929 Only)
V
CM
Common Mode Input Voltage Range Op Amp Mode (LTC1929 Only) 0 3 V
CMRR
OA
Common Mode Rejection Ratio Op Amp Mode; 0V < V
CM
< 3V (LTC1929 Only) 70 90 dB
PSRR
OA
Power Supply Rejection Ratio Op Amp Mode; 6V < V
IN
< 30V (LTC1929 Only) 70 90 dB
I
CL
Maximum Output Current Op Amp Mode; V
DIFFOUT
= 0V (LTC1929 Only) 10 35 mA
V
O(MAX)
Maximum Output Voltage Op Amp Mode; I
DIFFOUT
= 1mA (LTC1929 Only) 10 11 V
GBW Gain-Bandwidth Product Op Amp Mode; I
DIFFOUT
= 1mA (LTC1929 Only) 2 MHz
SR Slew Rate Op Amp Mode; R
L
= 2k (LTC1929 Only) 5 V/µs
ELECTRICAL CHARACTERISTICS
temperature range, otherwise specifications are at T
A
= 25°C. V
IN
= 15V, V
RUN/SS
= 5V unless otherwise noted.
Note 5: When the AMPMD pin is high (default for the LTC1929-PG), the
LTC1929 IC pins are connected directly to the internal op amp inputs.
When the AMPMD pin is low, internal MOSFET switches connect four
40k resistors around the op amp to create a standard unity-gain
differential amp.
Note 6: Minimum on-time condition corresponds to the on inductor
peak-to-peak ripple current ≥40% of I
MAX
(see minimum on-time
considerations in the Applications Information section).
Note 1: Absolute Maximum Ratings are those values beyond which the
life of a device may be impaired.
Note 2: T
J
is calculated from the ambient temperature T
A
and power
dissipation P
D
according to the following formulas:
LTC1929CG: T
J
= T
A
+ (P
D
• 95°C/W)
Note 3: The LTC1929 is tested in a feedback loop that servos V
ITH
to a
specified voltage and measures the resultant V
EAIN
.
Note 4: Dynamic supply current is higher due to the gate charge being
delivered at the switching frequency. See Applications Information.
TYPICAL PERFOR A CE CHARACTERISTICS
UW
Efficiency vs Output Current
(Figure 13)
OUTPUT CURRENT (A)
0.1
EFFICIENCY (%)
100
80
60
40
20
0
1929 G01
1 10 100
V
OUT
= 2V
V
EXTVCC
= 0V
FREQ = 200kHz
V
IN
= 5V
V
IN
= 8V
V
IN
= 12V
V
IN
= 20V
OUTPUT CURRENT (A)
0.1
EFFICIENCY (%)
40
60
1929 G02
20
0
101 100
100
80
V
IN
= 12V
V
OUT
= 2V
FREQ = 200kHz
V
EXTVCC
= 5V
V
EXTVCC
= 0V
V
IN
(V)
5
EFFICIENCY (%)
100
90
80
70
60
50
1929 G03
10 15 20
V
EXTVCC
= 5V
I
OUT
= 20A
V
OUT
= 2V
V
OUT
= 1.6V
Efficiency vs Output Current
(Figure 13)
Efficiency vs V
IN
(Figure 13)
The ● denotes the specifications which apply over the full operating
