Datasheet

LPC178X_7X All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2014. All rights reserved.
Product data sheet Rev. 5 — 9 September 2014 87 of 122
NXP Semiconductors
LPC178x/7x
32-bit ARM Cortex-M3 microcontroller
11.3 External clock
11.4 Internal oscillators
[1] Parameters are valid over operating temperature range unless otherwise specified.
[2] Typical ratings are not guaranteed. The values listed are at room temperature (25 C), nominal supply
voltages.
11.5 I/O pins
[1] Applies to standard port pins.
Table 21. Dynamic characteristic: external clock (see Figure 36)
T
amb
=  40  C to +85  C; V
DD(3V3)
over specified ranges.
Symbol Parameter Min Typ Max Unit
f
osc
oscillator frequency 1 12 25 MHz
T
cy(clk)
clock cycle time 40 83.3 1000 ns
t
CHCX
clock HIGH time T
cy(clk)
 0.4 - - ns
t
CLCX
clock LOW time T
cy(clk)
 0.4 - - ns
t
CLCH
clock rise time - - 5 ns
t
CHCL
clock fall time - - 5 ns
Fig 20. External clock timing (with an amplitude of at least V
i(RMS)
= 200 mV)
t
CHCL
t
CLCX
t
CHCX
T
cy(clk)
t
CLCH
002aaa907
Table 22. Dynamic characteristic: internal oscillators
T
amb
=  40  C to +85  C; 2.7 V  V
DD(REG)(3V3)
 3.6 V.
[1]
Symbol Parameter Min Typ
[2]
Max Unit
f
osc(RC)
internal RC oscillator frequency 11.88 12 12.12 MHz
f
i(RTC)
RTC input frequency - 32.768 - kHz
Table 23. Dynamic characteristic: I/O pins
[1]
C
L
=10pF, T
amb
=  40  C to +85  C; V
DD(3V3)
= 3.0 V to 3.6 V.
Symbol Parameter Conditions Min Typ Max Unit
t
r
rise time pin configured as
output
3.0 - 5.0 ns
t
f
fall time pin configured as
output
2.5 - 5.0 ns